The Grootfontein Agricultural Development Institute (GADI) is situated near the town of Middelburg in the Eastern Cape and the institution serves the small stock sector of the country. It hosts the Grootfontein College of Agriculture and has expertise to provide the highly sought-after education of its small stock focused curriculum. The College is fully accredited as an institution of higher learning as well as a further education institution. In addition, the institute is nationally a key role-player in sheep and goat production research and has built a knowledge base that supports the profitability and sustainability of the small stock sector and enhances natural resources management in small stock producing areas. The research program is strongly client-driven and is financially supported by the industry.

The strategic goal of the institute is to promote accelerated and shared growth in the sheep and goat industries of the RSA and the key result areas are (i) to promote knowledge and skills in small stock farming amongst existing farmers, emerging farmers and the youth, through higher and further education; (ii) to develop, evaluate and provide new technology for profitable and sustainable small stock production; (iii) to enhance sustainable and increased natural resources management and use in the small stock producing areas and (iv) to provide advisory services to small stock farmers to enhance profitable and sustainable small stock farming. This research report gives an account of the activities and outputs with regard to the second and third key result areas. For monitoring and evaluation of progress with the R&D program, researchers are annually requested to submit comprehensive progress reports on each individual R&D project by the end of July. For this, data collected to date in each project are analysed and reported. For obvious reasons, the preliminary results reported in some progress reports cannot be released, as it might be misleading or may be misinterpreted. Therefore, this research report only contains abstracts from the comprehensive progress reports.

The primary beneficiaries of the GADI R&D program are land users in the extensive sheep and goat producing regions of South Africa. The interests of most land users are represented by the Departments of Agriculture (National and Provincial), commodity organisations, agribusiness, breeders’ associations and organised agriculture. As GADI’s R&D program is largely driven by client needs, different stakeholders financially support many of the research projects. The stakeholders provided approximately 50% of the operational cost of the GADI R&D program. Financial support during the reporting period was obtained from Cape Wools SA and Mohair South Africa. Financial support from different stakeholders to the GADI R&D program is mediated through the Grootfontein Research Trust, which is registered with SARS as a private, non-profitable trust fund. The trust has its own administrative officer who is responsible to procure research consumables, required for the different research projects.

Other stakeholders and research partners who contributed towards the GADI R&D program in the form of physical execution (manpower) of research projects are the Eastern Cape Department of Agriculture (Cradock and Jansenville Experimental Stations), Northern Cape Department of Agriculture and Land Reform (Carnarvon, Karakul and Koopmansfontein Experimental Stations), North West Department of Agriculture, Conservation, Environment and Tourism (Potchefstroom Livestock Centre), nine communities in the Transkei and Ciskei areas of the Eastern Cape and six farmers and their farm workers in three provinces.

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INVESTIGATION INTO PRODUCTION AND REPRODUCTION SELECTION CRITERIA IN AFRINO SHEEP

M.A. Snyman

AIM AND OBJECTIVES

The aim of this study is to identify effective selection methods and criteria to increase efficiency of mutton and wool production under extensive grazing conditions.

The objectives of this study are:

· To evaluate selection criteria to improve reproductive efficiency of dual purpose sheep breeds under extensive grazing conditions

· To evaluate selection criteria to improve mutton and wool production efficiency of dual purpose sheep breeds

· To maintain a comprehensive database for evaluation of selection criteria for mutton and woolled sheep in South Africa

· To provide research animals for other projects, such as the parasite project, the project on maternal values and the DNA bank project.

BACKGROUND

This is a co-operative project between the Northern Cape Department of Agriculture and Land Reform and Grootfontein Agricultural Development Institute (GADI). The project is continuing as in the past. Researchers and technicians from GADI are still responsible for data collection and capturing, linear scoring of subjective traits and selection of breeding sires and dams. This is done in collaboration with the farm personnel at Carnarvon Experimental Station.

RESULTS AND DISCUSSION

Selection in the flock is aimed at increasing reproductive performance, increasing body weight, maintaining wool weight and fibre diameter and improving wool quality traits. The average productive performance of the ram and ewe lambs over the past 15 years are summarised in Table 1. Productive performance of the ewe flock is presented in Table 2.

Table 1. Average productive performance (± s.e.) over the past 15 years of ram and ewe lambs in the Carnarvon Afrino flock

Trait	Rams	Ewes
Birth weight (kg)	4.6±0.1	4.4±0.1
42-day body weight (kg)	17.0±0.2	15.9±0.2
120-day weaning weight (kg)	31.5±0.4	29.0±0.4
5-month body weight (kg)	32.3±0.6	29.5±0.6
6-month body weight (kg)	36.2±0.7	32.8±0.7
7-month body weight (kg)	39.1±0.7	36.0±0.7
8-month body weight (kg)	43.7±0.7	39.8±0.7
9-month body weight (kg)	47.2±0.7	42.5±0.7
10-month body weight (kg)	50.9±0.7	45.1±0.8
11-month body weight (kg)	55.1±0.8	47.5±0.8
12-month body weight (kg)	60.0±0.8	51.4±0.8
16-month body weight (kg)	63.6±0.6	51.6±0.6
Clean fleece weight (kg)	2.00±0.05	1.94±0.05
Fibre diameter (µm)	20.0±0.2	20.3±0.2
Clean yield (%)	58.8±0.9	61.4±0.9
Staple length (mm)	82.7±1.6	86.3±1.6
Number of crimps/25 mm	20.7±2.4	19.2±2.4
Coefficient of variation (%)	16.9±0.3	16.6±0.3
Standard deviation (µm)	3.3±0.1	3.3±0.1
Comfort factor (%)	99.5±0.1	99.4±0.1
Staple strength (N/Ktex)	32.5±1.3	34.1±1.3

Table 2. Production of Afrino ewes over the past 26 years in the Carnarvon flock

Trait	Average ± s.e.
Body weight (kg)	63.9±0.7
Greasy fleece weight (kg)	2.77±0.20
Clean fleece weight (kg)	1.75±0.20
Fibre diameter (µm)	21.3±0.4
Clean yield (%)	63.0±0.3
Staple length (mm)	75.1±0.2
Number of crimps/25 mm	13.9±0.2
Coefficient of variation (%) (2000-2007)	17.9±0.04
Standard deviation (µm) (2000-2007)	3.57±0.04
Comfort factor (%) (2000-2007)	99.2±0.03
Creeping belly score (2004-2007)	35.0±0.5
Number of lambing opportunities	3.52
Total weight of lamb weaned / year (kg)	39.07±0.06
Number of lambs born / year	1.43±0.11
Number of lambs weaned / year	1.26±0.06

Genetic trends in the most important production and reproduction traits are presented in Table 3. From these it is evident that the selection objectives with regard to reproductive performance, body weight and fibre diameter have been obtained. A positive direct genetic trend was observed for birth weight, while a slightly negative maternal genetic trend was evident for birth weight, indicating a negative direct maternal genetic correlation. However, positive direct as well as maternal genetic trends were observed for 42-day body weight and weaning weight. Positive trends were also observed for body weights at a later stage in life.

Table 3. Genetic trends in production and reproduction traits in the Carnarvon Afrino flock over the past 18 years

Trait	Genetic trend	R²
Birth weight (kg)	y = 0.0156x-0.0491	0.9355
42-day body weight (kg)	y = 0.0331x-0.0523	0.9597
120-day weaning weight (kg)	y = 0.0826x+0.0069	0.9617
9-month body weight (kg)	y = 0.3024x+0.1118	0.9823
16-month body weight (kg)	y = 0.4160x+0.1184	0.9804
Clean fleece weight (kg)	y = 0.0084x-0.1048	0.3529
Fibre diameter (µm)	y = -0.0953x-0.0459	0.9407
Crimp quality	y = 2.5330Ln(x)-1.1673	0.9334
Evenness of fleece	y = 0.0625x+0.0490	0.3710
Density of fleece	y = -0.0336x-0.1498	0.5143
Creeping belly	y = -0.6059Ln(x)-0.7273	0.2317
Staple length (mm)	y = 0.1839x-2.2778	0.0477
Staple strength (N/Ktex)	y = 0.1704x-0.6929	0.6977
Total weight of lamb weaned (kg)	y = -0.019x+0.8584	0.0520
Number of lambs born	y = -0.0003x+0.0254	0.0169
Number of lambs weaned	y = 0.0002x+0.0180	0.0047

CONCLUDING REMARKS

· The project is running according to the project protocol and progress has been satisfactory. As this is a long-term project, which involves the evaluation of selection criteria, it will continue in its current form.

· The data set collected on this research flock, is one of the most comprehensive data sets on productive and reproductive traits of woolled mutton sheep available worldwide.

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ESTABLISHMENT OF A GENETIC POOL OF DUAL PURPOSE SHEEP WITH PREMIUM QUALITY MEAT AND SUPER FINE WOOL UNDER EXTENSIVE CONDITIONS

M.J. Herselman

AIM AND OBJECTIVES

The aim of the study is to establish a genetic pool of dual purpose sheep with premium quality meat and super fine wool under extensive conditions for future evaluation and distribution to the industry.

The objectives of the study are:

· To establish a genetic pool of dual purpose sheep (150 breeding ewes) which is superior with regard to wool quality (fibre diameter)

· To increase the numbers of the pool to 400 breeding ewes

· To improve the wool and meat quality while maintaining other production traits such as reproduction and growth.

INTRODUCTION

The project originated from a request by the wool industry for the establishment of a genetic pool of dual purpose sheep with super fine wool. The wool industry supplied the funds for the initial purchasing of the ewes, as well as the running cost for the first two years. A memorandum of agreement between the Department of Agriculture: Grootfontein Agricultural Development Institute (GADI), the Agricultural Research Council and the Grootfontein Research Trust formalised co-operation between the parties involved in the project. The project started in January 2001 with the screening, identification and buying of ewes for the nucleus flocks at Grootfontein. During 2001 and 2002 a total of 217 ewes were bought from 25 Dohne Merino breeders, while 145 ewes were bought from 15 Letelle breeders. The first mating took place during May 2001.

The current report contains information and results that were collected since August 2007. In some cases the results of previous reporting periods are given together with the results obtained during this year for better interpretation.

MATERIAL AND METHODS

All adult animals were shorn on 20 July 2007. This data were not reported earlier as the analysis of wool samples was not completed in the previous reporting period. One week before the onset of lambing in August 2007, the ewes implanted with embryos during March 2007 and those naturally mated were brought in from the veld and placed in individual pens and provided with a pelleted roughage diet. The ewes implanted with embryos during May 2007 were brought in to lamb in October. This was done to accommodate accurate parent-offspring identification. Ewes and their lambs were taken back to the veld within two weeks after lambing, except for triplets, which remained in the pens for approximately one month. Data collection on the 2007 progeny and the ewe flock was according to the project protocol. The 2007 lambs were weaned in two groups namely the first half on 10 December 2007 and the other half on 05 February 2008. All lambs were shorn together on 06 February 2008.

The 2006 progeny was provisionally classed on 5 November 2007, shorn on 6 November 2007 and the 12-month wool production data collected. Final inspection of the Dohne ewes was performed on 14 February 2008.

During April 2008, 40 Dohne stud ewes were used in a multiple ovulation and embryo transfer (MOET) program. These donor ewes were laparoscopically inseminated with semen of own-bred rams. The 348 embryos recovered from the 40 donor ewes were implanted into 215 recipients. The remaining 163 Dohne ewes were inseminated with semen of own rams (GF061061, GF061109, GF061166, GF061179 and GF051049), while 100 Letelle ewes were inseminated with semen of three Letelle rams (GF052097, GF062004 and GF062025). The same rams were used as follow-up rams.

The general linear model procedure was used for statistical analysis. For birth weight, the age of dam, birth status, sex and breed were used as fixed effects, while birth date was included as a covariable for the analysis of body weight at 42 days of age. For other body weights and wool production traits, the age of dam, rearing status, sex and breed were used as fixed effects, while date of birth was included as a covariable.

RESULTS

In total, 778 embryos were recovered from the 80 Dohne ewes in the MOET program during April 2007. Of the 462 recipients to whom the embryos were transferred, 307 eventually lambed giving birth to 427 lambs. The other 135 Dohne and 102 Letelle ewes gave birth to 175 and 137 lambs respectively. The production data of the adult ewes in the two flocks are shown in Table 1, while the genetic trends in body weight (EBV-BW), clean fleece weight (EBV-CFW) and fibre diameter (EBV-FD) are illustrated in Figure 1.

Table 1. Production data (± s.e.) of adult ewes in the nucleus flocks (2007 ewe flock)

Trait	Dohne	Letelle
Body weight at mating (kg)	55.4±0.5	51.1±0.7
Greasy wool (kg)	3.9±0.1	2.9±0.1
Clean yield (%)	66.8±0.4	63.1±0.5
Clean wool (kg)	2.61±0.04	1.86±0.04
Fibre diameter (µm)	19.4±0.1	18.6±0.1
Staple length (mm)	80.9±1.2	76.6±1.3
CV (%)	18.5±0.2	18.3±0.2
Comfort factor (%)	99.6±0.04	99.8±0.04
Crimps per 25 mm	13.9±0.2	15.2±0.2
Duerden	100.0±0.6	95.2±0.7
Staple strength (N/Ktex)	34.0±0.9	29.4±1.0

Figure 1. Genetic trends in body weight (EBV-BW), clean fleece weight (EBV-CFW) and fibre diameter (EBV-FD) of the National versus Grootfontein Dohne flock

The large change in genetic trends observed in the Dohne flock for 2006 is a reflection of the impact of the embryo transfer program with ewes selected for high body weight and fleece weight and low fibre diameter. The estimated breeding values for the Dohne flock for the 2006 progeny versus the National herd were 1.737 versus 1.005 kg for body weight, 0.122 versus 0.000 kg for clean fleece weight and -1.004 versus -0.292 µm for fibre diameter. With regard to the Letelle flock, too little data are available for reliable estimation of breeding values, as linkages with industry data are not possible.

CONCLUDING REMARKS

In general, good progress has been achieved with the project. A comprehensive re-evaluation of the continuation of the two separate lines (Dohne and Letelle) will be done during 2009. Indications are that both lines possess characteristics that are in line with the project objectives. The Dohne line has a relative high wool production and growth rate of lambs, whereas the Letelle line produces relative fine wool with a high lamb weight relative to adult ewe weight.

ACKNOWLEDGEMENTS

Cape Wools SA is acknowledged for their financial support of the project.

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DEVELOPMENT OF A METHOD FOR THE ESTIMATION OF BREEDING VALUES FOR RESISTANCE OF SHEEP TO INTERNAL PARASITES, WHICH WILL BE APPLICABLE UNDER ANY ENVIRONMENTAL CONDITIONS

M.A. Snyman

AIM AND OBJECTIVES

The aim of this study is to develop a protocol for the evaluation of internal parasite resistance of breeding sires, bred in the extensive sheep grazing areas of South Africa where the natural infection of Haemonchus contortus is limited.

The objectives of this study are as follow:

· To identify effective selection methods for internal parasite resistance in small stock and to apply these methods in practice

· To compare the natural and artificial challenge methods under intensive as well as extensive conditions in order to evaluate the latter in practice

· To estimate genetic parameters for indicators of parasite resistance, and correlations of these indicators with production and reproduction traits under South African conditions.

BACKGROUND

Internal parasite infection plays an important role in the ability of animals to produce and reproduce to their full capability. Despite various control measures, internal parasites remain one of the largest animal health problems in the small stock industry. To make matters worse, resistance of parasites to available anthelmintics increased drastically during the past decades. The possibility of selection for animals resistant to internal parasites has been investigated and selection programs based on faecal egg counts (FEC) have been implemented in Australia and New Zealand. However, not all questions concerning the practical use of FEC in breeding programs have been answered. For example, repeatability of FEC under various conditions has been shown to be highly variable. Furthermore, many of the ram breeders in South Africa are located in the drier, western parts of the country, with a lower natural parasite infection. As no breeding program will have parasite resistance as its sole objective, the genetic relationship of resistance with other production and reproduction traits should also be considered.

The project started during March 1998. Since then, each year, lambs in each of the following research flocks were infected with third stage Haemonchus contortus larvae at 6-8 months of age for the artificial challenge procedure:

· Afrino flock at the Carnarvon Experimental Station (1997 to 2007)

· Dorper flock at the Carnarvon Experimental Station (1998 to 2002)

· Fine wool Merino stud at the Cradock Experimental Station (1997, 1998, 1999, 2001)

· Merino stud at GADI (1997, 1998, 1999, 2001)

· SA Mutton Merino flock at the Potchefstroom Livestock Centre (2002)

Faecal egg counts (FEC), haematocrit (HEMA) and Famacha©-scores (FAM) were done 28 days after infection.

The natural challenge method was included in the project from October 2000, in order to be able to compare results obtained with artificial challenge with those obtained with natural parasite infections. This part is done on lambs from the fine wool Merino stud at Cradock Experimental Station, and since 2002 on the Potchefstroom Mutton Merino flock.

For the part of the study where the correlation of resistance measured under extensive conditions with resistance measured in higher rainfall areas is evaluated, 40 Afrino ram lambs from the Carnarvon Afrino flock, progeny of sires with high and low breeding values for resistance (estimated from artificial challenge), were annually transferred to Potchefstroom at 12 months of age from September 2003 to September 2007. At Potchefstroom, these lambs were kept on pastures for eight months. During this period, resistance of the animals was evaluated through several natural challenge tests.

RESULTS AND DISCUSSION

The description of the data set for artificial challenge FEC and HEMA over the experimental period for the Afrino flock is presented in Table 1. It is obvious that there were large differences in FEC between years/tests. Heritability estimates of and genetic and phenotypic correlations among FEC, FAM and HEMA are presented in Table 2. These heritabilities fall within the range reported in the literature. Phenotypic correlations between different FEC’s of Afrino ram lambs, the progeny of sires with high and low breeding values for FEC, are summarised in Table 3.

Table 1. Description of the data set for artificial challenge FEC and HEMA over the experimental period for the Afrino flock

Year of birth	FEC ± s.e.	HEMA ± s.e.	FEC range *	n
1997	1494±643	33.2±0.6	0 (2) – 14800	216
1998	221±647	35.5±0.6	0 (41) – 2400	236
1999	15553±660	27.6±0.6	0 (5) – 87800	201
2000	2845±646	25.4±0.6	0 (8) – 12100	225
2001	10493±644	27.7±0.6	0 (22) – 76000	264
2002	2161±646	30.6±0.6	0 (4) – 12400	251
2003	1949±630	29.6±0.5	0 (18) – 19200	303
2004	1243±639	35.9±0.6	0 (3) – 6700	291
2005	3117±655	32.7±0.6	0 (5) – 7900	218
2006	2681±621	32.6±0.5	0 (3) – 12100	300

* Range of FEC within years (value in brackets is number of animals with 0 eggs per gram); n = number of animals in group

Table 2. Heritabilities of FEC, FAM and HEMA, and genetic and phenotypic correlations among these traits, estimated under artificial challenge procedures

Trait	FEC	FAM	HEMA
FEC	0.20±0.03	0.29±0.12	-0.66±0.13
FAM	0.29	0.17±0.03	-0.48±0.15
HEMA	-0.41	-0.49	0.20±0.03

Heritabilities (± s.e.) on diagonal, genetic correlations (±s.e.) above diagonal and phenotypic correlations below diagonal

Table 3. Phenotypic correlations between different FEC’s of Afrino ram lambs, the progeny of sires with high and low breeding values for FEC

	FEC(art) of lambs (Carnarvon)	FEC(nat) of lambs (Potchefstroom)
FEC(art) of sires (Carnarvon)	-0.19±0.01	-0.04±0.56
FEC(art) of lambs (Carnarvon)		-0.04±0.56

CONCLUDING REMARKS

Prospects for developing a protocol to evaluate sires born in the extensive sheep grazing areas in terms of host resistance against internal parasites do not look promising if the results of this study are considered. More work in this regard should be done.

The following possibilities should be investigated:

· Establishment of a flock in which selection for host resistance could be practiced

· Evaluation of sires bred in this flock at other locations

· Refinement of artificial challenge procedure

· Investigation of other possible phenotypic or genetic markers for host-resistance.

ACKNOWLEDGEMENTS

The project leader wants to convey her sincere appreciation to the personnel at the various experimental stations and the Middelburg Provincial Veterinary Laboratory for their valuable contribution to the execution of the project.

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INVESTIGATION INTO THE EFFECT OF DIFFERENT TYPES OF TEATS ON THE PRODUCTION AND REPRODUCTION OF BOER GOATS

W.J. Olivier

AIM AND OBJECTIVES

The aim of this study is to investigate the effect that the different types of teats (according to the breed standards) have on the production and reproduction of Boer goats.

The objectives of this study are:

· To quantify whether the different types of teats have an effect on the production and reproduction of Boer goats

· To do a linear assessment of the number of teats and to estimate heritability and correlations of this trait with production and reproduction traits, in order to investigate the possible inclusion of number of teats as a selection criterion for ram selection

· To establish a database for the estimation of accurate genetic parameters for Boer goats

· To determine whether selection based on the traits measured in the National Small Stock Improvement Scheme (SSIS) would result in increased lifetime production and reproduction efficiency in Boer goats.

INTRODUCTION

Red meat is one of the most important sources of protein for the population of the RSA. Due to the limited natural resources in many of the small stock producing areas of the RSA, efficiency of meat production should be increased to utilise the existing resource optimally and also to simultaneously conserve it for future generations. In order to achieve this goal, selection should be aimed at increasing the efficiency of meat production and more specific goat meat production. The ARC: Livestock Business Division established the SSIS: Boer goat performance testing plan to provide farmers with a selection tool with which the efficiency of goat meat production can be improved. The purpose of the SSIS is to improve the overall productivity of the breed through the identification of high producing animals and to select these animals as the parents of the next generation. The SSIS incorporates 100-day weaning weight, 270-day body weight and reproduction traits. The producers receive a growth and reproduction report from which selection on weaning weight, body weight and ewe productivity can be done. One of the objectives of this study is to investigate and evaluate selection criteria currently used in the SSIS for Boer goats under extensive conditions.

The importance of number of teats and teat conformation in breeding sires and dams has been discussed on several occasions. The breed standards of the Boer Goat Breeders’ Society specify the different types of teat arrangements that are acceptable and those that are not acceptable for both rams and ewes. It is therefore important to determine the heritability of the number of teats, as well as the correlation of this trait with production and reproduction traits, in order to decide whether it should be included in the performance testing scheme.

Stud breeders are responsible for the genetic progress made in any breed, as superior genetic material is distributed to the commercial and small-scale farmers. The full spectrum of Boer goat farmers will therefore benefit from the results of this study.

This project commenced in 2004 at the Koopmansfontein Experimental Station in the Northern Cape Province.

RESULTS AND DISCUSSION

The frequency of the different teat scores at Koopmansfontein Experimental Station is depicted in Figure 1. These are the scores of all the adult does that were mated from 2005 to 2008 in the flock. The different types of teats are depicted in Figure 2. It is evident from Figure 1 that there is some variation in the different types of teats within the Koopmansfontein flock. However, most of the does have only one functional teat (type 15) or one functional teat with one non-functional teat (type 14) on each side of the udder. There are currently about 200 does in the Koopmansfontein flock that are mated during autumn and spring each year.

Figure 1. The frequency of the subjective teat scores of the adult doe flock at Koopmansfontein Experimental Station

Figure 2. Score card for the different types of teats

CLOSING REMARKS

The results obtained from this study will assist the Boer Goat Breeders’ Society in decision making with regard to the culling of animals on certain teat types in both the rams and ewes. Furthermore, the correlations between the production, reproduction and type traits will also be of aid in constructing a breeding plan to improve the profit of Boer goat producers.

ACKNOWLEDGEMENTS

The author wants to express his gratitude to the Department of Agriculture and Land Reform of the Northern Cape Province.

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INVESTIGATION INTO THE RELATIONSHIP BETWEEN MILK PRODUCTION OF GRAZING EWES AND MATERNAL BREEDING VALUES FOR EARLY GROWTH TRAITS IN SOUTH AFRICAN SHEEP FLOCKS

M.A. Snyman

AIM AND OBJECTIVES

The aim of this study is to evaluate the use of maternal breeding values for early growth traits as alternative or additional selection criterion for improved growth efficiency in slaughter lamb production enterprises.

The objectives of this study are:

· To determine milk production potential of woolled sheep ewes under different grazing conditions

· To estimate genetic parameters for milk production of these ewes

· To determine the relationship between milk production of ewes and direct and maternal breeding values, as well as actual weaning weight of their lambs in three sheep flocks, under different grazing conditions

· To determine the relationship between maternal breeding values for early growth traits of sires and milk production of their daughters, as well as growth performance of the daughters’ lambs.

BACKGROUND

The project commenced in 2004. During the first year of the project at each location, repeated milk recordings on a selected sample of the ewe flock were done, in order to obtain the average shape of the lactation curves for the ewes in each of the experimental flocks. During 2004, ewes in the Carnarvon Afrino flock were milked. Ewes in the Cradock fine wool Merino flock and the Merino ewes in the high and low reproduction lines at Elsenburg were milked during 2005 to obtain the average shape of the lactation curves of these two flocks. Since the 2006 lambing season, milk production of all ewes that lambed in the Carnarvon Afrino, Cradock fine wool Merino and the Elsenburg Merino flocks was determined at three and twelve weeks of lactation. The Grootfontein Merino flock was included in the project in 2007.

RESULTS AND DISCUSSION

Total milk production over the lactation period from three to twelve weeks was calculated for each ewe in each of the flocks from the recorded three and twelve week milk productions by employing regression procedures. The total milk production over the recording period (TMP) is given in Table 1.

Table 1. Total milk production (TMP ± s.e.) over the recording period for ewes in the three flocks

Effect	Afrino ewes (litre)	Fine wool Merino ewes (litre)	Grootfontein Merino ewes (litre)	Elsenburg Merino ewes (litre)
Age of dam
2	131.80±6.27	173.60±9.31	130.60±15.07	71.32±4.16
3	134.06±6.56	168.20±10.05	135.68±14.88	80.39±4.26
4	136.78±6.72	155.83±10.76	139.07±14.40	92.83±4.00
5	139.16±5.85	149.40±10.87	151.26±16.38	109.03±6.67
6	123.97±7.19	163.06±13.18	151.73±17.18	95.97±5.30
7	137.71±9.05	167.57±14.65		115.96±10.17
8				65.94±9.54
Number of lambs weaned
1	100.48±2.91 ^a	136.04±5.80 ^{a, b}	122.79±5.28	82.62±2.87 ^a
2	117.91±3.39 ^a	170.26±5.64 ^a	134.70±5.78	97.79±4.18 ^a
3	183.35±13.85 ^a	182.86±19.32 ^b	167.52±39.75
Average (CV%)
TMP	109.19 (24.56)	154.86 (37.18)	124.89 (31.12)	81.51 (30.46)

^a,b Values with the same superscripts differed significantly (P<0.05) within flocks and effects

Cradock fine wool Merino ewes had the highest milk production per ewe, followed by the Grootfontein Merino ewes, the Afrino ewes and then the Elsenburg Merino ewes. These differences could be ascribed to breed and environmental influences. No differences between age groups were observed for the Afrino ewes or the Grootfontein Merino ewes. The 2-year old Cradock fine wool Merino ewes produced significantly more milk than the 5-year old ewes. In the Elsenburg Merino flock, 2-, 3- and 8-year old ewes produced less milk than the ewes in the other age groups (P<0.01). The number of suckling lambs had a significant influence on milk production in all flocks, with the exception of the Grootfontein Merino flock.

Correlations between maternal breeding values and milk production

The data collected on the ewes during the 2007 lambing seasons were used to estimate correlations between milk production and early body weights of lambs on the one hand, and maternal breeding values for 42-day and weaning weight of the dam and maternal grandsire on the other hand.

Correlations of maternal EBV-42-day and maternal EBV-weaning weight of the dam with the traits in question were higher than those of the maternal grandsire in the Afrino flock. Low to medium positive correlations were estimated between maternal EBV of the dam and total milk production (TMP), total weight of lamb weaned (TWW), weaning weight of the lamb and the various breeding values for early growth traits of the lamb. Maternal EBV of the maternal grandsire had close to zero correlations with TMP and TWW, and was positively correlated with the other traits of the lambs. Total milk production of the ewe was also positively correlated with total weight of lamb weaned, individual weight of lambs, direct and maternal EBV-early body weight of lambs.

In the Cradock fine wool Merino stud, correlations of maternal EBV-42-day and maternal EBV-weaning weight of the dam with the traits in question were higher than those of the maternal grandsire. In this flock, maternal EBV of the dam was also positively correlated with TMP, medium positively correlated with weaning weight and direct EBV and high positively correlated with the maternal EBV of the lamb. Maternal EBV of the maternal grandsire was low positively correlated with TMP and low negatively correlated with TWW. Higher correlations were estimated with maternal EBV of the lamb traits than with the direct EBV of the respective traits. Total milk production of the ewe was positively correlated with total weight of lamb weaned, individual weight of lambs and EBV-early body weight of lambs.

Total milk production of the ewe was positively correlated with individual weaning weight of lambs, TWW and direct EBV-weaning weight of the lambs in the Grootfontein Merino flock. A low negative correlation was estimated between TMP and maternal EBV-weaning weight of the lambs.

CONCLUDING REMARKS

At this stage of the project, the following is evident from the data collected during the 2007 lambing season on the Carnarvon Afrino, Cradock fine wool Merino and Grootfontein Merino flocks:

· Total milk production of the ewe was positively correlated with total weight of lamb weaned, individual weaning weight of lambs and maternal EBV-early body weight of the lambs in all three flocks

· Correlations of maternal breeding values for 42-day and weaning weight of the dam were positive with total milk production and individual weaning weight of her lambs, as well as with direct and maternal EBV-early body weight of her lambs

· Correlations of maternal breeding values for 42-day and weaning weight of the maternal grandsire with the recorded traits were variable. Most of these correlations have large standard errors, indicating that more data are needed to estimate accurate and reliable correlations. However, the majority of the estimated correlations are favourable.

As this project has just started, no reliable conclusions with regard to the other project objectives could be made at this stage. The project will continue at Carnarvon, Cradock, Grootfontein and Elsenburg with the yearly recording of milk production of all ewes that lambed in each flock.

ACKNOWLEDGEMENTS

The author wishes to convey her sincere appreciation to the personnel at GADI, Carnarvon Experimental Station, Cradock Experimental Station and Elsenburg Institute for Animal Production for their valuable assistance in the execution of the project.

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BREEDING SHEEP FOR INCREASED PROFIT PER HECTARE

W.J. Olivier

AIM AND OBJECTIVES

The aim of this study is to evaluate profit per hectare (ha) as a selection criterion in woolled sheep.

The objectives of this study are:

· To evaluate profit per hectare as a selection criterion for woolled sheep

· To breed sheep for increased income per hectare

To supply the Eastern Cape Department of Agriculture Livestock Improvement Program with genetic material to improve the profit per hectare in the communal areas
To make animals available for student and farmer training
To create a comprehensive phenotypic database that can be combined with the DNA samples of the biological bank for Merino sheep for genomic research.

INTRODUCTION

To ensure continued success of both commercial and communal wool farmers, it is important that the animals with the highest profit per hectare can be identified, rather than the animals with the highest gross income per head. This will result in the selection of animals that will increase the profit per hectare of a wool farming enterprise. Furthermore, it will also ensure that the wool industry of South Africa produce wool and mutton at optimal levels without increasing the pressure on the natural resources. Two flocks are used for this experiment. One is kept under intensive conditions on irrigated pastures at Cradock Experimental Station (Cradock), while the second is kept under extensive conditions on natural pastures at Grootfontein Agricultural Development Institute (Grootfontein). Both these flocks are selected for increased profit per hectare, according to Herselman (2004).

RESULTS AND DISCUSSION

The average selection differentials based on BLUP of breeding values of the National analyses for the production traits of the 2005-born rams and ewes selected for breeding purposes in 2007 are summarised in Table 1. The genetic trends for body weight, clean fleece weight, fibre diameter, staple length and profit per hectare (ha) are depicted in Figure 1. It is evident from this figure that there was a positive trend in the profit per ha.

Table 1. The average selection differentials based on BLUP of breeding values of the National analyses for the production traits of the 2005-born rams and ewes selected for breeding purposes in 2007

	BW (kg)	CFW (kg)	MFD (µm)	STPL (mm)	TWW (kg)	Profit / ha (R)	Profit / ha (R) (Reproduction)
Cradock sires
Group (n=164)	0.56	-0.20	-1.47	0.04	2.46	11.02	18.93
Selected (n=9)	2.64	-0.27	-2.00	2.87	3.06	23.55	30.32
Selection differential	+2.08	-0.07	-0.53	+2.84	+0.59	+12.53	+11.39
Cradock replacement ewes
Group (n=178)	0.30	-0.19	-1.52	-0.47	2.38	10.65	18.65
Selected (n=89)	0.77	-0.20	-1.52	-0.36	2.49	11.24	19.04
Selection differential	+0.47	-0.01	0.00	+0.11	+0.11	+0.59	+0.40
Grootfontein sires
Group (n=145)	1.51	-0.03	-0.84	-0.28	2.27	10.70	16.74
Selected (n=9)	3.91	0.11	-0.94	0.70	2.35	18.09	21.15
Selection differential	+2.41	+0.14	-0.10	+0.97	+0.08	+7.38	+4.40
Grootfontein replacement ewes
Group (n=167)	1.37	-0.02	-0.84	-0.39	2.22	10.40	16.44
Selected (n=89)	1.75	0.03	-0.70	0.29	2.24	11.16	16.71
Selection differential	+0.38	+0.05	+0.14	+0.69	+0.02	+0.75	+0.17

Figure 1. Genetic trends in the Cradock fine wool Merino stud for body weight, clean fleece weight, fibre diameter, staple length and profit per hectare

CONCLUSION

The rams that were selected in 2007 for breeding purposes will have a positive effect on the breeding objectives of both these flocks.

During the reporting period, 60 rams of the Cradock fine wool Merino stud were supplied to the Livestock Improvement Program of the Eastern Cape Department of Agriculture. Thirteen communities in the Eastern Cape benefited from these rams.

ACKNOWLEDGEMENTS

The author wishes to express his gratitude to Cape Wools SA for funding of the project, Dr J.J. Olivier, the Department of Agriculture of the Eastern Cape and officials from BKB and CMW for assisting in the execution of the project.

[Contents]

INVESTIGATION INTO THE EXTENT OF MICRON BLOW-OUT IN SOUTH AFRICAN WOOL SHEEP

W.J. Olivier

AIM AND OBJECTIVES

The aim of this study is to investigate the extent of micron blow-out in South African wool sheep.

The objectives of this study are:

· To compare the fibre diameter profile of sheep with micron blow-out to sheep with no micron blow-out

· To determine the differences between breeds and genotypes with regard to the rate at which fibre diameter increases

· To define micron blow-out more specifically.

INTRODUCTION

Micron blow-out, by definition, is when the fibre diameter of an animal increases with age at a more rapid rate than the average rate of the group with which it is compared. To the breeder or producer it means that the fibre diameter at test age is not a good indicator of that animal’s fibre diameter at a later stage in life. It is a common belief within the wool industry of South Africa and in other wool producing countries that some animals have the ability to maintain their mean fibre diameter throughout their lifetime. Thus, these animals will have no micron blow-out.

A major concern of the South African wool producers is that the fibre diameter of some rams that are bought at ram sales has the tendency to blow out later in life. This is a big problem in a market where the need for genetic fine wool animals is increasing, and the demand is met with animals that are not always genetically fine. The aim of this study is therefore to investigate the extent of micron blow-out in South African wool sheep.

This project is conducted at the Cradock Experimental Station (CRA), Grootfontein Agricultural Development Institute (GADI) and Carnarvon Experimental Station (CAR). The following flocks are used in this experiment: Cradock fine wool Merino stud (CMS), fine wool and control lines of the Grootfontein Merino stud (GMS), the Grootfontein Merino flock (GMF), the Grootfontein Dohne Merino stud (GDMS) and the Carnarvon Afrino stud (CAS).

RESULTS AND DISCUSSIONPRIVATE

Selection of the ewes from each flock for this project took place during November and December 2005. The ewes were born in August and September 2004 and were the same age as the replacement ewes for the 2006 mating season. These ewes are run together with the adult ewes of each flock for the duration of the experiment but are not mated in order to eliminate the effect of reproductive status on fibre diameter. Selection was done on mean fibre diameter (MFD). Ewes with below or above average MFD were selected from each flock. A patch of wool was kept intact on the midrib area of these ewes; this patch will be used at the end of the project to determine the change in MFD over the length of the fibre. The wool patches are protected from environmental effects with overcoats (“Jassies”).

The ewes of the CAS were shorn for the second time in August 2007, while the ewes of CMS, GMS, GMF and GDMS were shorn in February and March 2008. A midrib fleece sample was also taken for each ewe for complete wool analysis.

The number of ewes in each flock, as well as the MFD and coefficient of variation (CV) at selection age (2005), the first shearing (2006) and second shearing (2007) for the respective flocks are presented in Table 1. It is evident from this table that the MFD of the ewes from all the flocks increased from selection age to the second shearing.

Table 1. Mean fibre diameter and coefficient of variation (± s.e.) of the respective flocks

Trait

Year

Flock (No. of ewes)

CMS

(20)

GMS-F

(10)

GMS-C

(10)

GMF

(10)

CAS

(10)

GDMS

(10)

MFD (µm)

2005

17.19^b,c

± 0.30

16.16^b,c

± 0.42

16.62^b,c

± 0.44

14.40^b,c

± 0.44

20.42^c

± 0.54

15.38^b,c

± 0.42

2006

18.68^a

± 0.30

18.58^a,c

± 0.42

19.25^a

± 0.47

18.10^a,c

± 0.60

20.88

± 0.38

18.90^a,c

± 0.47

2007

18.94^a

± 0.33

20.03^a,b

± 0.44

19.88^a

± 0.49

19.36^a,b

± 0.53

21.40^a

± 0.44

20.29^a,b

± 0.50

CV (%)

2005

17.92

± 0.53

18.45^b,c

± 0.75

19.64

± 0.79

20.08^b,c

± 0.79

21.20

± 0.97

21.62^c

± 0.75

2006

17.38

± 0.54

19.37^a,c

± 0.75

20.73^c

± 0.84

18.46^a,c

± 0.69

19.19

± 0.69

19.93

± 0.64

2007

17.64

± 0.55

15.31^a,b

±0.70

17.23^b

± 0.78

15.86^a,b

± 0.84

20.04

± 0.80

17.48^a

± 0.78

Values with different superscripts within each flock differed significantly (P<0.01), a = 2005, b = 2006, c = 2007

CLOSING REMARKS

· The project is running according to the project proposal.

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THE EFFECT OF EARLY GROWTH ENVIRONMENT OF DORPER LAMBS ON

M. LONGISSIMUS DORSI AREA AT 16 MONTHS OF AGE

P. G. Marais

AIM AND OBJECTIVES

The aim of this project was to determine the effect of the early growth environment of Dorper lambs on their M. longissimus dorsi area at 16 months of age.

The objectives of this project were:

· To determine if early growth environment has a carry-over effect on tissue measurements (muscle and fat) at a later stage in life

· To determine if lambs kept under veld conditions for a period of time during early growth, can compensate in terms of muscle and fat deposition when subjected to a higher plane of feeding for a subsequent period.

INTRODUCTION

In practice, many Dorper stud rams are still subjected to relatively high and intensive feeding conditions early in life. In contrast to these rams, others are reared under natural veld conditions from birth. Rams that were part of a veld ram test, for instance, are usually “finished off” for a period of a month or two before the ram sale. When these rams are put on sale together with rams that have been subjected to a high plane of nutrition throughout their lifetime, it is difficult to decide which ram is the better ram, on the basis of phenotype alone. Despite having growth performance data available, the “veld rams” could still be at a disadvantage. It was claimed that the veld rams should have “caught up” to their intensively reared counterparts after two to three months in terms of M. longissimus dorsi area. It is, however, not clear how long it will take veld-reared lambs to catch up with lambs subjected to a higher plane of feeding during early growth.

EXPERIMENTAL PROCEDURES

Forty-eight weaned Dorper ewe lambs (± 5 months of age; 25-28 kg) were used for the trial. These lambs were divided into four groups on a stratified weight basis. The experimental layout was as follow: Group A and B were subjected to a high diet level (high protein and high energy) for an 8-month period under kraal conditions. Group C and D were kept under veld conditions for the same period. After 8 months (November 2007), Group C was changed to the high diet level and Group B was ran under veld conditions for a further 4-month period, while lambs in groups A and D stayed in their original groups. Group feeding was executed on an ad libitum basis for the kraal fed lambs. The normal health and management program was followed.

RESULTS AND DISCUSSION

This trial started on 06/02/2007 and at that time Grootfontein had exceptionally good rains resulting in above average veld conditions. The body weight of lambs in the kraal group increased from 23.5 to 59.4 kg since the start of the trial at 5 months of age up to 12 months of age. The veld group increased from 23.2 to 42.0 kg for the same period. From the second weighing (6 months of age) (Fig. 1) body weight of the kraal and veld groups differed significantly and these differences continue to the end of the trial. After 12 months of age the body weight of the kraal/veld group decreased from 61.1 to 56.9 kg, while that of the veld/kraal group increased from 43.7 to 53.7 kg. These responses could be attributed to the respective feeding levels.

As expected (Fig. 2) the muscle area of the lambs in the kraal/kraal group increased from 10.0 to 28.9 cm², while that of the veld/veld group increased from 11.1 to 21.5 cm² from 5 to 12 months of age. After 12 months of age the muscle area of lambs in veld/kraal group increased from 19.7 to 28.3 cm². The fat thickness of the kraal/kraal group increased from 2.8 to 9.3 mm and that of the veld/veld group from 3.3 to 5.4 mm (Fig. 3). After the change over in feeding level at 12 months of age, the fat thickness of the veld/kraal group increased from 4.6 to 6.8 over the second phase, but two months after the chance in feeding, fat thickness of the kraal/veld group started to decrease. From these results it is evident that feeding level had a direct influence on fat thickness.

Figure1. Body weight at different ages

Figure 2. Eye muscle area (cm²) at different ages

Figure 3. Fat thickness (mm) over the eye muscle at different ages

CONCLUSION

It is evident from the results that compensatory growth ocurred in lambs when they are switched from a low to a higher feeding level. Irrespective of feeding level, the differences in M. longissimus dorsi area between groups decreased towards the end of the experimental period. However, lambs reared on the higher feeding early in life, retained their advantage over those lambs reared on a lower feeding level. The effect of feeding regime on fat depth was more pronounced than the effect on M. longissimus dorsi area.

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THE EFFECT OF SUPPLEMENTATION OF REPLACEMENT EWES AFTER WEANING ON THEIR LIFETIME REPRODUCTION POTENTIAL UNDER NATURAL VELD CONDITIONS

J.H. Hoon

AIM AND OBJECTIVES

The aim of the project is to determine the effect of high levels of supplementation of replacement ewe lambs from weaning until first mating on their lifetime reproduction potential under natural veld conditions.

The objectives of the project are:

To determine the effect of supplementation after weaning on the reproduction of the ewe over her lifetime
To determine the effect of supplementation on mating weight of the ewe over her lifetime
To determine the effect of supplementation after weaning on wool production and wool characteristics of the ewe over her lifetime.

BACKGROUND

Weaner ewe lambs are one of the most important assets of the small stock producer. There is therefore no better investment than to allow replacement ewes to grow out and develop optimally, as this will determine the animal’s lifetime production and reproduction potential. The growth and development of weaner ewe lambs and young ewes on dry veld are often impaired. Intakes of supplementary feeding by lambs that are just weaned are often low, which further aggravates the stress associated with weaning. These stress factors suppress the immune system, lower resistance and make the animals more susceptible to diseases.

To ensure a high lifetime reproduction rate, ewe lambs have to maintain a high growth rate until weaning and at least a moderate growth rate from weaning until 12 months of age. When weaner ewe lambs are only grazing on dry veld, it often happens that they lose weight during the dry season. This is probably one of the main reasons for low lambing percentages in many sheep flocks.

The aim of this project is therefore to determine the effect of high levels of supplementation of replacement ewe lambs from weaning until first mating on their lifetime reproduction potential under natural veld conditions.

EXPERIMENTAL PROCEDURES

The project started in October 2007 on a wool sheep farm in a predominantly grass veld area (Trompsburg), using the participant’s own animals. The April/May 2007-born ewe lambs, weaned in September/October 2007, are used in the study. The animals are kept on natural veld throughout the year and the existing management practices with regard to animal health, supplementary feeding, etc., are maintained. All the management procedures are the same for both the control and treatment groups.

The ewe lambs were divided into two equal groups of 150 each after weaning, namely a control and a treatment group. The animals of the two groups grazed separate camps, comparable in size and veld quantity and quality. Animals were rotated between the two camps on a regular basis in order to minimise possible camp effects. The treatment group received supplementation in the form of a pelleted diet (Voermol Maxiwol production pellets). The supply of additional feeding continued from weaning until approximately 12 months of age.

At the start of the first mating, the animals of the control and treatment groups were joined into one flock in order to minimise possible camp and ram effects. The animals will stay in one group until shortly before the start of the lambing season when they will be separated into their respective groups. The lambs of the two groups will be tagged shortly after birth with the same colour ear tags as the ewes. Data of all the progeny of both groups will be collected up until weaning age. These procedures will be repeated on a yearly basis on the progeny of the ewes from the original control and treatment groups until most of these ewes are culled from the flock.

The ewe lambs of both the control and treatment groups were mated for the first time at 12 to 14 months of age during May/June 2008 and the conception and scanning percentages of the animals will be determined by means of ultrasound scanning during August 2008.

The body weights of the ewe lambs of both groups were recorded at the start of the project (after weaning) and at monthly intervals thereafter until first mating (12 to 14 months of age). The greasy fleece weight of each animal from both groups will be recorded at shearing (August 2008) and a midrib sample will be taken for the determination of mean fibre diameter, clean yield, staple length, coefficient of variation (CV), standard deviation (SD), comfort factor, number of crimps per 25 mm, Duerden and staple strength.

Body weight at mating, as well as conception and scanning percentage (ultrasound scanning), will be recorded each year on all the ewes (control and treatment group) over their lifetime. The lambing percentage (number of lambs born/ewes mated) and weaning percentage (number of lambs weaned/ewes mated) will also be recorded. The body weight of the progeny of the ewes used in the trial will also be recorded each year at weaning. The amount of supplementary feeding supplied to the animals of both groups will also be monitored on a continuous basis.

RESULTS AND DISCUSSION

The body weights, body weight change (BWC) and average daily gain (ADG) of the ewe lambs until ±12 months of age are presented in Table 1.

Table 1. Body weights, body weight change and average daily gain (± s.e.) of the ewe lambs

Age	Control (kg)	Treatment (kg)
Weaning	23.91±0.23^a	26.03±0.24^b
7 months	28.00±0.11	27.87±0.11
9 months	33.76±0.17	34.06±0.17
10 months	36.43±0.19^a	37.04±0.19^b
11 months	39.84±0.21	40.35±0.21
12 months	40.85±0.28^a	44.05±0.28^b
Body weight change	15.79±0.28^a	18.99±0.28^b
Average daily gain	0.085±0.002^a	0.106±0.02^b

^ab Values with different superscripts in rows, differ significantly (P<0.05)

The BWC and ADG of the ewe lambs of the treatment group from weaning until ±12 months of age were higher (P<0.05) than the ewe lambs of the control group.

Due to the high rainfall and favourable grazing condition, the animals of the control group did not receive any supplementary feeding during the feeding period. An average supplementary feed intake of approximately 200 g/animal/day was recorded for the treatment group over the feeding period, which was lower than the proposed intake of 300-500 g/animal/day.

CONCLUDING REMARKS

The provision of supplementary feeding increased the growth rate of the ewe lambs of the treatment group, compared to the animals of the control group.

The same feeding procedures will be repeated at the Trompsburg locality with another group of ewe lambs that will be born in September/October 2008 and weaned in January/February 2009. This will be done to compare the effect of supplementary feeding of ewe lambs during different times of the year, e.g. green vs. dry season. The project will continue over the full reproductive life of the ewe groups (April/May 2007-born and September/October 2008-born ewe lambs) and data of all the progeny of the control and treatment groups will be collected up until weaning age. The project will also start during September/October 2008 at the Graaff-Reinet locality with the April/May 2008-born ewe lambs.

ACKNOWLEDGEMENTS

The following persons are thanked for their contribution to the project:

The participating farmer, W.J. Botha (Trompsburg)
G. Calldo (CMW, Trompsburg) for technical inputs.

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INVESTIGATION INTO THE CAUSE, PREDISPOSING FACTORS AND EFFECTIVE TREATMENT OF SWELLING DISEASE IN SOUTH AFRICAN ANGORA GOATS

J.A. van Rooyen

AIM AND OBJECTIVES

The aim of this study is to identify the causative agent(s) responsible for swelling disease in South African Angora goats.

The objectives of this study are:

· To carry out trials to investigate and identify the predisposing factors as well as the causative agent(s) responsible for swelling disease

· To identify the most effective treatment for swelling disease.

BACKGROUND

During the early 1970’s Angora goat farmers reported a condition in their goats, characterised by the sudden onset of severe subcutaneous oedema of the lower body parts. Some goats died of the condition, while others seemed to recuperate spontaneously. According to various internal reports of the Regional Veterinary Laboratory at Middelburg (EC), numerous trials were conducted to investigate the cause of this disease. However, no conclusive evidence was found as far as the cause of the disease is concerned. Therefore, results of these trials were not published.

Outbreaks of swelling disease still occur periodically and some losses are still experienced by Angora goat producers. No definite cure is known; various farmers practice different treatments, not all of which are always successful. As a result, delegates at the 60^th Annual General Congress of the Mohair Growers’ Association of South Africa unanimously accepted a resolution that purposeful research should be carried out on the cause, treatment and prevention of swelling disease in various areas among all age groups of Angora goats in South Africa.

From all the information available on swelling disease in Angora goats, it is obvious that it is a complex condition, of which little is known regarding the mechanisms involved in the initiation and course of the disease. Results obtained thus far with the present study indicated that, although Teladorsagia circumcincta infection has been listed as one of the predisposing factors for the disease, T. circumcincta infection alone does not cause swelling disease. The results of this study further indicated that higher dietary protein levels could possibly aid in the prevention of swelling disease. In a questionnaire, investigating the epidemiology of swelling disease, 65 % of the respondents have encountered swelling disease on their farms, while 35 % have never seen the disease.

Dr. J.A. van Rooyen was appointed as Veterinarian at Grootfontein Agricultural Development Institute in December 2007 and has taken over the responsibility for this project. No cases of swelling disease were reported in this period. An attempt was made to formulate a possible hypothesis on the cause of the disease.

ACTIVITIES DURING THE REPORT YEAR

Copies of laboratory reports from the Provincial Veterinary Laboratory (PVL) at Middelburg were obtained and a list of abnormal findings was made. These reports dated from 1980 to 2006 and were performed by a number of successive veterinarians. The selection of tests that were performed on cases varied greatly and statistical analyses were not possible. Abnormal findings in the reports are summarised in Table 1. Three sets of findings were commonly found:

· Decreased red blood cell count coupled with increased white blood cell count

· Decreased lymphocytes coupled with increased neutrophiles

· Decreased albumin coupled with increased globulin.

A review of the findings to date as well as the provisional literature study of similar medical conditions in other species or breeds indicates that a number of predisposing causes and pathways can lead to swelling disease. Swelling disease occurs when one or more of the pathways are active. These can possibly be grouped into four main pathways that lead to a common end result:

· Insufficient protein inputs

· Loss or consumption of protein

· Abnormal metabolic pathways

· Increased capillary permeability.

Table 1. Abnormal findings in cases of swelling disease at the PVL-Middelburg

No	Abnormality
1	Decreased blood glucose
2	Decreased hemoglobin
3	Decreased plasma albumin
4	Decreased total plasma protein (TPP) (some cases were normal)
5	Increased Globulin : Albumin ratio
6	Decreased copper levels
7	Decreased serum calcium
8	Increased SGOT enzyme
9	Decreased lymphocytes, increased neutrophiles
10	Decreased red blood cell count
11	Increased haematocrit/packed cell volume (PCV)
12	Increased white blood cell count
13	Monocytosis
14	Clostridium perfringens A (red gut)
15	Clostridium perfringens D (enterotoxaemia)
16	Mannheimia spp. (Pasteurella)
17	Increased chromaffin cells in adrenal gland (Chronic case)
18	Increased white pulp in spleen (Chronic case)
19	Nephrosis and hemoglobin casts in renal tubules
20	Zenker’s hyalin degeneration of myocardium (Chronic case)
21	Presence of coccidia
22	Presence of Haemonchus contortus
23	Presence of Nematodirus spathiger (long-necked bankrupt worm)
24	Presence of Teladorsagia circumcincta (brown stomach worm) in abomasum
25	Presence of Trichostrongylus in small intestine
26	Decreased appetite
27	Hematurea (blood in urine)

CONCLUSIONS

· Further studies into the hypothesis of Wiese (1990) should be designed once the genetic aspects and the precise metabolic pathway of the adreno-cortical abnormalities have been clarified

· A standardised battery of tests should be applied to all cases in future to enable statistical analysis. This battery should include tests that can clarify the role of mediators and complement. The search for inclusion bodies and the appearance of rosetting should continue

· Electron microscopic and anatomical studies should be done on the capillary vessels and the adrenal blood supply of Angora goats

· A number of flocks with a known presence of swelling disease should be included in the proposed GADI program for sustainable integrated parasite control (IMPaCT) to possibly provide a basis for a controlled trial

· The project will continue.

ACKNOWLEDGEMENTS

The project leader wants to convey his sincere appreciation to the following persons / institution for their valuable contribution in the execution of the project:

· Mohair South Africa for funding of project

· Participating producers for supplying of animals.

[Contents]

AN INVESTIGATION INTO THE EFFECT OF DIFFERENT WEANING PRACTICES ON THE POST-WEANING GROWTH OF ANGORA KIDS AND REPRODUCTION OF ANGORA EWES

J.H. Hoon

AIM AND OBJECTIVES

The aim of the project was to find practical solutions for the problems generally experienced by Angora goats during the post-weaning period.

The objective was to determine the effect of different weaning practices on:

· The post-weaning growth of Angora kids

· The body weight change of ewes from weaning until mating/scanning

· The milk production of the ewes

· The conception rate of the ewes in the next breeding season.

INTRODUCTION

Weaning is normally a stressful period in the young kid’s life and is often characterised by a decrease in weight gain, total cease in growth and in some cases even weight loss. This response is referred to as weaning shock. The level or degree of shock depends on age and weight of the kids, as well as the feeding program before weaning. From studies with both goats and sheep, it appears that body weight at weaning is normally more important than age when attempting to minimise weaning shock. Other factors influencing the effect of weaning shock on the growth of Angora kids are, amongst others, the general health of the kids, sex and other stress factors. The weaned kid goes through a very critical growth stage from weaning (4 to 5 months of age) until it reaches the young goat stage (2-tooth). Some farmers use different practical methods in an effort to limit the large negative effect of weaning shock on the post-weaning growth of the kids.

The aim of this project was to determine the effect of different weaning practices on the growth of kids, body weights of ewes and the conception rate of ewes in the next breeding season.

MATERIAL AND METHODS

The project started on a farm in the Middelburg, Eastern Cape district during the 2003/2004 kidding season and was repeated at the same locality during the 2004/2005, 2005/2006 and the 2006/2007 kidding seasons. The farmer’s own animals were used and the animals grazed on natural veld. At the start of the project, a flock of Angora ewes were randomly tagged with three different colour ear tags. In the following years, the nucleus of ewes in each group consisted of ewes that were also used in the project during the previous kidding season. Since ewes were culled from the flock as a normal management practice, replacement ewes were added randomly to the nucleus. At the onset of kidding each year, all the kids in each group were tagged with the same colour ear tags as their mothers. At the time of weaning each year (February), the three treatments commenced:

Weaned – kids and ewes were separated, i.e. normal weaning took place
Swopped – kids were separated from their mothers, but were put with other mature ewes, i.e. normal weaning, but weaned kids stayed with other ewes
Not weaned – kids and ewes remained together, i.e. no weaning took place.

In the 2003/2004 kidding season, the milk production of 10 ewes per group with single kids was recorded on a weekly basis for the 5-week period from the commencement of the treatments until the start of the mating period. In the 2004/2005 kidding season, ten ewes from each group that kidded in the same week and had single kids, were identified and marked. Milk production of these 30 ewes was recorded on a weekly basis from three weeks until six weeks after kidding and on a two-weekly basis thereafter until the start of the next mating period. The oxytocin method was used to determine the 4-hour milk production of the ewes. Body weights of all the ewes were recorded at weaning and at mating/scanning. Body weights of the kids of all three groups were recorded at weaning and on a monthly basis up until the age of 10 months. The conception and scanning percentages of all the ewes of the three groups were determined by means of ultrasound scanning. The hair production of the individual kids was recorded at second shearing (± 12-month age) in 2005, 2006 and 2007. All the animals stayed in their respective groups until the final body weights of kids were recorded at 10-month age. The animals were subjected to the same management practices throughout the experimental period.

RESULTS AND DISCUSSION

The average milk production of the 10 ewes per group from the commencement of the treatments until the start of the mating period in the 2003/2004 kidding season indicated that the milk production of the ewes of the Not weaned group, where kids stayed with their mothers, was higher (P<0.05) than the other two groups. The ewes of all three groups still produced some milk five weeks after the commencement of the treatments, although in small amounts especially in the case of the Weaned and Swopped groups. The average milk production of the 30 ewes determined over their lactation period until weaning in the 2004/2005 kidding season, showed that the ewes reached their peak milk production at 4-6 weeks after lambing.

The combined data of the body weights of the kids from weaning until ± 10 months of age for the 4-year period showed that the body weight change (BWC) and average daily gain (ADG) of the kids of the Weaned group did not differ (P>0.05) from the Not weaned group, but both were higher (P<0.05) than the kids of the Swopped group. The combined data also indicated a decline in growth rate of kids after eight months of age, coinciding with the start of the dry, winter period and subsequent deterioration in grazing conditions. The BWC of the castrated male and ewe kids of the Weaned and Not weaned groups were higher (P<0.05) than the respective Swopped groups. The ADG of the castrated male kids of the Weaned group were higher (P<0.05) than the other two groups, while the ADG of the ewe kids of the Weaned and Not weaned groups were higher (P<0.05) than the Swopped group. However, the overall ADG of the castrated male and ewe kids did not differ (P>0.05).

The combined data of the body weights of the ewes from weaning until mating for the 4-year period indicated that the BWC of the ewes where kids were weaned (Weaned), was higher (P<0.05) than for the other two groups (Not weaned, Swopped).

The average conception and scanning percentages of the ewes for the 4-year period were in favour of the ewes of the Swopped (92.2 %; 112.0 %) and Not weaned groups (92.9 %; 112.3 %), compared to the ewes of the Weaned group (87.2 %; 104.4 %). Despite the variation in conception and scanning percentages of ewes observed over the 4-year period, it is clear that the non-weaning of kids did not have any negative effect on the reproductive rate of the ewes.

The differences in average hair production of kids at second shearing for the 3-year period were relatively small, with a higher value (P<0.05) for the Swopped group compared to the Weaned group. No differences (P>0.05) in hair production were, however, observed between the Weaned and Not weaned groups, as well as between the Swopped and Not weaned groups.

CONCLUSION

The body weight change (BWC) and average daily gain (ADG) of the kids from weaning until approximately 10 months of age did not differ between the weaned and the unweaned kids for the 4-year period from 2003/2004 to 2006/2007. Also, no differences in BWC and ADG between the castrated male and ewe kids were observed over the 4-year period. With regard to the body weight of the ewes, it is evident that the weaning of kids had a positive effect on body weight change from weaning until mating/scanning in all four years. Only small differences in the average hair production of kids at second shearing for the 3-year period from 2005 to 2007 were observed among the three groups. The most important result from this study is, however, that the non-weaning of kids did not have any negative effect on the reproduction rate of the ewes in any of the years.

It is always important to consider the effect of environmental conditions when interpreting results from studies of this nature. During the 4-year period of this trial, average to above-average rainfall conditions with subsequent good grazing conditions were experienced, which probably allowed the ewes to maintain their body weights sufficiently for successful conception in the next mating season, despite the presence of kids. However, in years with lower rainfall the results might differ from that obtained in this study, especially with regard to the reproduction of the ewes.

ACKNOWLEDGEMENTS

The following institution /person are thanked for their contribution to the project:

· Mohair SA for funding of the project

· The participating farmer, J.H. Moolman (Rusoord, Middelburg, Eastern Cape).

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EFFECT OF DIETARY CHROMIUM LEVELS ON FAT DEPOSITION, CARCASS AND MEAT CHARACTERISTICS OF DORPER LAMBS

B.R. King

AIM AND OBJECTIVES

The aim of the project is to investigate the effect of the inclusion level of chromium in two different diets on the rate of fat deposition and carcass and meat characteristics of Dorper lambs.

The objectives of the project are:

· To determine the effect of two levels of chromium on the rate of fat deposition in Dorper lambs

· To determine the effect of two levels of chromium on feed conversion ratio, growth and carcass and meat characteristics.

BACKGROUND

The need for a sheep breed suitable for the production of slaughter lambs under the adverse conditions of South Africa resulted in the establishment of the Dorper breed in the early 1940s. The early fat deposition that occurs in Dorper lambs in South Africa is a major constraint with regard to income of this mutton-producing enterprise due to downgrading of carcasses, resulting in a loss of income. In practice, too much fat deposition in Dorper lambs at a relatively early age force producers to market the lambs at a relative low body weight, especially during good seasons. This also applies to Dorper lambs in feedlots. On the other hand, the ability of Dorper ewes to store fat is essential in their ability to adapt to dry and harsh climates.

There are three possible ways to address this problem, namely to select against animals with an early fat deposition, to do crossbreeding or to change the diet of the animals. Different breeds of sheep excel in certain economic traits, so it should be advantageous to combine these various traits to produce superior offspring. From published literature, chromium added to pig, cattle and sheep diets to reduce fat, had varying results. The aim of this project is to investigate the effect of different inclusion levels of chromium in two different diets on the rate of fat deposition and carcass and meat characteristics of Dorper lambs.

MATERIAL AND METHODS

Seventy-two Dorper weaner lambs (between 25 and 28 kg) were used in this study. The animals were divided on a stratified body weight basis into six groups of 12 animals each. The experimental layout describing the different groups, composition of the diets fed to the groups and number of animals slaughtered are summarised Table 1. The animals were fed pelleted diets in individual pens on an ad libitum basis. The estimated nutritional values of the diets are summarised in Table 2.

Table 1. Experimental layout

Group	Number of animals	Quality of diet	Level of chromium	Number of animals slaughtered at 38 kg	Number of animals slaughtered at 44 kg
1	12	high	high	6	6
2	12	high	low	6	6
3	12	high	zero	6	6
4	12	low	high	6	6
5	12	low	low	6	6
6	12	low	zero	6	6

Table 2. Estimated nutritional values of the diets

Nutrient	Low feeding level (%)	High feeding level (%)
Protein	12.8	14.5
Energy (TDN)	56.0	65.2
Calcium	0.88	1.01
Phosphorus	0.20	0.22

RESULTS AND DISCUSSION

The average daily gain (ADG) of the lambs that received the high feeding levels was higher (P<0.05) than the lambs that received the low feeding levels between the two slaughter weights and between the rams and ewes. The lambs receiving the different chromium levels only differed significantly between the low and zero chromium with regard to number of days to reach slaughter weight (NDSW). The rams reached the slaughter weight about 20 days faster (P<0.05) than the ewes.

The dressing percentage at the two feeding levels differed significantly. There was also a difference (P<0.05) between the lambs that received the higher chromium level compared to the low and zero levels. The rams also had a higher dressing percentage (P<0.05) than the ewes. The different fat measurements of the carcasses at the different feeding and chromium levels did not differ (P>0.05). The ewes had higher fat measurements (P<0.05) than the rams.

The omentum fat of the ewe lambs weighed 400 grams more (P<0.05) than that of the ram lambs. There was also a significant difference between the lambs slaughtered at 38 and 44 kg with regard to omentum fat. The lambs that received the high feeding level had more kidney fat (P<0.05) than the low feeding level. There was also a difference (P<0.05) in the kidney fat between the ewes and rams.

The ribs percentage of the carcasses of the lambs slaughtered at 44 kg was higher (P<0.05) than that of lambs slaughtered at 38 kg. Most of the retail cuts of the carcasses differed (P<0.05) between the ewes and rams. The lambs that received the high feeding level had a higher fat percentage in the meat:bone:fat ratio (P<0.05) than the lambs that received the low feeding level. The rams also had more fat and meat (P<0.05) in the meat:bone:fat ratio than the ewes. The ewes had a higher cooking loss percentage (P<0.05) than the rams.

The lambs that received the high feeding level with low and zero chromium had a significantly higher ADG than the lambs receiving the low feeding level with high chromium. The lambs that received the high feeding level with high chromium and low chromium had a better FCR (P<0.05) than the lambs receiving the low feeding level with high and low chromium. The dressing percentage of the lambs slaughtered at 38 kg which received the high feeding level with the high and low chromium, had a lower dressing percentage (P<0.05) than the lambs receiving the low feeding level with low and zero chromium. The lambs slaughtered at 38 kg receiving the high feeding level with high chromium had more omentum fat (P<0.05) than lambs receiving the low feeding level with high and low chromium.

The ADG of the lambs that received the high feeding level with low chromium was higher (P<0.05) than the lambs receiving the low feeding level with the high chromium. The FCR of lambs that received the high feeding level with high chromium and low chromium was significantly higher than those lambs receiving the low feeding level with high and low chromium.

The dressing percentage of the lambs slaughtered at 44 kg that received the high feeding level with high and low chromium had a lower dressing percentage (P<0.05) than the lambs that received the low feeding level with low chromium and zero chromium. The lambs that received the high feeding level with high chromium had more omentum fat (P<0.05) than the lambs that received the low feeding level with high and low chromium. Lambs that received the low level feed with high chromium had a higher V3 fat measurement (P<0.05) than the lambs that received the same feeding level with no chromium.

It is evident that most of the lambs slaughtered at 38 kg were graded into the A2 and A3 grades. More carcasses of the lambs slaughtered at the heavier slaughter weight of 44 kg, were graded into the fatter classes (A4 to A6).

CONCLUDING REMARKS

Not all the data from this study have been analysed to date. The final report will be completed in July 2009. Differences in the growth traits, carcass traits, commercial retail cuts and meat quality parameters were mainly observed between the high and low feeding levels, between the 38 kg and 44 kg slaughter weights and between the ewe and ram lambs.

From the available data, the general observation is that the addition of chromium to the different diets did not reduce fat deposition on the carcasses of Dorper lambs.

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THE EFFECT OF THE INCLUSION OF AN IONOPHORE AS A SILAGE ADDITIVE ON SILAGE CHARACTERISTICS

J.H. Hoon

AIM AND OBJECTIVES

The aim of the project is to determine the effect of the inclusion of an ionophore as a silage additive during the silage-making process on certain silage characteristics for possible future inclusion in silage diets to improve animal performance.

The objectives of the project are:

To determine the effect of the inclusion of an ionophore on silage characteristics such as pH, lactic acid, volatile fatty acids, ammonia nitrogen, water-soluble carbohydrates, neutral detergent fibre, crude protein, organic matter and in vitro organic matter digestibility (IVOMD)
To use the results of this study to determine if it is a viable option to include ionophores in silage diets in subsequent growth trials to improve animal performance.

BACKGROUND

Silage is the acid-fermented product of anaerobic fodder fermentation of greater than 50% moisture content, with the aim of preserving summer crops for winter-feeding. Silage additives have been developed over years to improve the nutritive value of silages and to reduce some of the risks during the ensiling process. A silage additive should be safe to handle, reduce dry matter (DM) losses, improve the hygienic quality of the silage, limit secondary fermentation, improve aerobic stability, increase the nutritive value of the silage and give the farmer a return greater than the cost of the additive.

Ionophores such as monensin (Romensin®) and lasalocid (Taurotec®) are commonly used as additives in ruminant diets. The most consistent response to the feeding of ionophores is the increased molar proportion of propionic acid with a concomitant decline in the molar proportion of acetic and butyric acids during volatile fatty acid (VFA) production in the rumen. A decrease in methane production is often associated with this change in VFA production. Ionophores are also known to influence nitrogen metabolism, both in the rumen and the animal.

The aim of this project is therefore to determine the effect of the inclusion of an ionophore as a silage additive on specific silage characteristics for possible future inclusion in silage diets to improve animal performance.

EXPERIMENTAL PROCEDURES

Plant material from maize, harvested with a commercial silage chopper at the Marlow Agricultural School in the Cradock district, was collected and transported to Grootfontein Agricultural Development Institute (GADI). The maize was harvested at the three-quarter milk line stage (hard dough stage). Approximately 50 kg of chopped material were collected, put into plastic bags, sealed to prevent the material from drying out and transported to GADI. The plant material of the control group was ensiled on its own, while an ionophore (Taurotec®), was added to the plant material of the treatment group at an inclusion level of 0.2 g per kg plant material and mixed well.

The chopped plant material was ensiled in 1.5 L glass bottles (mini silos). The same amount of plant material was weighed in a bucket for each bottle (797.5 ± 1.5 g). Twenty-one bottles were filled for the control and treatment groups respectively (42 bottles in total) to follow the fermentation dynamics during the ensiling period. Three bottles per treatment were filled for opening on day 1, 2, 4, 8, 16, 32 and 90 after ensiling (21 bottles per treatment). Representative samples of both the control and treatments groups were taken before ensiling. One sample was placed in an oven at 60 °C for 72 h to determine the dry matter content, put into paper bags and kept for analysis, while the other sample was put into a plastic bag in a freezer at –20 °C for analysis.

On each of the designated days three bottles per treatment were opened. One sample from each bottle was used for dry matter determination and kept for chemical analysis. The dried samples will be analysed for neutral detergent fibre (NDF), crude protein (CP), organic matter (OM) and in vitro organic matter digestibility (IVOMD). A wet sample from each bottle, stored at minus 20°C, will be used to determine water-soluble carbohydrates (WSC), pH, lactic acid (LA), volatile fatty acid (VFA) content and ammonia nitrogen (NH₃-N). LA, pH and WSC will be determined on samples taken at each sampling interval, while OM, NDF, CP, VFA, IVOMD and NH₃-N will only be determined on the samples collected at the start and the end of the ensiling period. The samples will be analysed at GADI and ARC: Irene (Pretoria).

RESULTS AND DISCUSSION

The dry matter content of the plant material decreased with an increase in the period of ensiling. There were, however, no differences (P>0.05) in dry matter content between the control and treatment groups. The gas and dry matter loss increased as the period of ensiling increased. However, no differences (P>0.05) in gas and dry matter loss occurred between the control and treatment groups.

CONCLUDING REMARKS

The preliminary results indicate a decrease in the dry matter content and increase in gas and dry matter loss with an increase in the period of ensiling. There were, however, no differences between the control and treatment groups.

The dry and wet samples that were taken and stored for each of the ensiling periods will be analysed to determine the effect of the inclusion of an ionophore on different silage characteristics. The results obtained from this study will be used to decide whether further trials should be done to determine the effect of the inclusion of an ionophore as a silage additive on animal performance.

ACKNOWLEDGEMENTS

Dr Robin Meeske, Outeniqua Experimental Station, George (Western Cape Department of Agriculture), is thanked for his contribution to the project.

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ESTABLISHMENT OF RAM BREEDING FLOCKS FOR DIFFERENT COMMUNAL FARMING AREAS OF THE EASTERN CAPE

B.R. King

AIM AND OBJECTIVES

The aim of this project is to establish ram breeding flocks for different communal farming areas.

The objectives are:

Improvement of woolled sheep flocks of rural communal farmers
Establishment of a group breeding nucleus in each community

· Community group breeding flocks supply rams to neighbouring communities in the long term.

INTRODUCTION

This project forms part of the larger program for woolled sheep development in the communal areas of the Eastern Cape. The project started in August 2002 with the identification of 16 communities by the committee members of regions 20 to 24 of the NWGA, which represents the former Transkei and Ciskei areas. The layout of the wool sheep development program consists of:

· The annual supply of 3000 rams to communal farmers – managed by the NWGA

· The evaluation of the impact of the rams that were introduced through the execution of progeny tests – performed by GADI

· The establishment of nine ram breeding groups in the communal areas, which will eventually supply rams to neighbouring communities - managed by GADI.

RESULTS & DISCUSSION

Rams

In association with the NWGA and the commercial breeders, 60 superior rams from the breeders in the group breeding scheme were selected. These are the breeders that also supply rams to the bigger project. These rams were then transported to and kept at a central farm (Dave Curry, Cathcart). The rams were kept under optimum conditions for at least four months, depending on when they had to be placed in different communities. These factors made the transporting and distribution of the rams to the nine communities much easier. All nine communities received rams during the period from October 2007 to May 2008 and mating took place at each of these places.

Dudumasha

Mating took place with 240 ewes selected from the community at the end of May 2008. These ewes will only lamb in October 2008. No scheduled farmers’ day was held, but a farmers’ tour was arranged to the Dohne Agricultural Development Institute in the Eastern Cape. This group visited the animal production and other departments.

Xume

In May 2008, 240 ewes were selected from the Xume farmers’ herds and will lamb in October 2008. No ram lambs from this progeny will be evaluated in 2009. This community has to be monitored closely because problems like scab occur regularly in this area. A farmers’ day is planned for November 2008 after the lambs have been born.

Allan Waters

Mating took place in May and June 2008 and lambing will take place in October and November 2008. In February 2008, all the young rams born during the 2007 season were weighed and classed. During September 2007, a rural show was organised and a number of farmers took part. The aim of show was to display their animals and also to give information. A number of short lectures were also given on how good producing ewes should look like. The next show will be held in September 2008. Due to the positive approach of this community, the lambing percentage and management of sheep are better than most of the other communities.

Beckles Farm

No mating could take place at this community, due to the fact that the area was hit by drought. It was decided that the project rams will be given to the community and no formal selection will take place. A number of previously selected ewes had given birth late in May 2008. A smaller group of rams will be selected according to the protocol later this year. A farmers’ day is planned for November 2008.

Lushington

Due to the fact that this is a large community, the breeding ewes have been divided into two groups. A group of about 180 ewes were selected and mated to six Merino rams in October and November 2007. The second group was mated in May 2008. The lambs of the first group have already been born. A farmers’ day will be held in November 2008 in the community on veld burning management.

Rockcliff

In May 2008, 240 ewes were selected from the Rockcliff farmers’ herds and will lamb in October 2008. The ram lambs from this progeny will be evaluated early in 2009. A farmers’ day will be held in September 2008 in the community on sheep management.

Qoqodala

Selection of ewes took place in May 2008. They were mated to six Merino rams and will lamb in October 2008. All ram lambs from the project will be castrated.

Luzi

In May 2008, 240 ewes were selected from the Luzi farmers’ herds and will lamb in October 2008. The ram lambs will be evaluated in 2009.

Lephakoeng

Two hundred and fourty ewes were selected in May 2008 and mated to six Merino rams. Ewes are expected to lamb in October 2008. A farmers’ day is planned for October 2008.

CLOSING REMARKS

Progress was made in a number of communities and the project is continuing. The first own-bred rams will be evaluated during the next reporting period in the following communities: Allan Waters, Dudumasha, Rockcliff, Luzi, Lushington, Lephakoeng and Beckles Farm.

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THE EFFECT OF METHIONINE SUPPLEMENTATION ON STAPLE LENGTH AND FIBRE DIAMETER IN WOOL SHEEP

W.J. Olivier

AIM AND OBJECTIVES

The aim of this project was to investigate the effect of feeding protected methionine to wool sheep on wool growth, staple length and fibre diameter.

The objectives of this project were:

· To determine how different levels of methionine, protected from ruminal degradation, affect different wool traits

· To use the results of this study in the development of a supplement for wool sheep.

INTRODUCTION

Fibre diameter is the most important wool trait influencing the price of wool. This is due to consumer demand for clothing made from finer wool types. The second trait that influences the price of wool is staple length. Furthermore, these two traits have a large influence on the amount of wool produced. The level of nutrition influences fibre diameter and staple length and amino acids are very important in the production of natural fibres. Amino acids can be supplemented to sheep to improve wool production. However, for amino acids to be efficient as a supplement, they must be protected from ruminal degradation in order to be absorbed in the abomasum.

MATERIAL AND METHODS

The project commenced on 23 February 2007 with 30 adult Merino ewes. The groups received a maintenance diet consisting of of lucerne (60%), maize stover (21.5%), molasses (8%), dicalcium phosphate (0.5%) and maize meal (10%). The amount of feed for each animal was calculated according to the animal’s individual body weight and supplied at maintenance level. The experimental animals were placed in individual pens and given a two-week adaptation period after which they were shorn. The project was divided into two phases of 3 months each. Phase 1 was a pre-treatment phase, during which none of the animals received any methionine. The first phase of the project finished during June 2007. Before commencement of the second phase, the animals were randomly divided into three groups according to body weight. The animals in Treatment 1 then received 1.5 g methionine per day orally, while the animals in Treatment 2 received 2.5 g per day orally. The animals in the Control group received an oral placebo treatment of water at the same time when the other animals received their methionine.

RESULTS AND DISCUSSIONPRIVATE

The staple length was measured monthly and a midrib fleece sample was taken at the end of the experiment for each animal. The staple lengths of the three groups are depicted in Figure 1 and the wool characteristics are summarised in Table 1. It is evident from the results of this study that at the end of the experiment there were no significant differences in staple lengths or the other wool characteristics between the three groups.

Table 1. Fleece characteristics (± s.e.) of the three groups

Trait	Control	Treatment 1 (1.5g/day)	Treatment 2 (2.5g/day)
Staple length (mm)	90.21±1.60	91.97±1.60	89.90±1.62
Fibre diameter (µm)	18.56±0.40	18.05±0.40	18.27±0.40
Coefficient of variation (%)	18.71±0.73	17.77±0.73	18.93±0.73
Standard deviation (µm)	3.47±0.15	3.20±0.15	3.47±0.15
Comfort factor (%)	99.48±0.20	99.61±0.20	99.34±0.20
Clean yield (%)	75.66±1.33	76.56±1.33	73.32±1.33
Number of crimps per 25mm (n)	11.70±0.20	11.70±0.20	11.70±0.20
Standard deviation along the length of the staple (µm)	0.75±0.05	0.67±0.04	0.69±0.04

Figure 1. The staple length of the three groups

CONCLUDING REMARKS

It can be concluded from the results of this study that methionine supplementation did not have any effect on the staple length and other wool characteristics in this experiment.

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ESTABLISHMENT OF THE SOUTH AFRICAN BIOLOGICAL RESERVE FOR SMALL STOCK RESEARCH AND CONSERVATION

M.A. Snyman

AIM AND OBJECTIVES

The aim of the South African Biological Reserve for Small Stock is to promote the improvement and conservation of South African sheep and goat breeds.

The objectives of this program are:

To maintain resource herds of various small stock breeds as reference populations and source of phenotypic data and genetic material in collaboration with provincial departments of agriculture and breeders
To collect blood samples from animals in the reference herds, store blood samples, extract and store DNA in two separate suitable minus 80° C storage facilities
To collect embryos, semen and somatic cell tissue samples from animals in the reference herds and store it in liquid nitrogen storage facilities at two centres
To develop and maintain a database with all relevant genetic, production and reproduction data
To provide biological material and data to South African research institutions for the promotion of genomic research on the improvement of the sheep and goat population of the country
To conserve and preserve the genetic diversity of South African sheep and goat breeds.

BACKGROUND

A project aimed at the establishment of a DNA bank for Angora goats was initiated in January 2005 as a collaborative effort between Grootfontein Agricultural Development Institute (GADI), the University of Pretoria (UP), the Angora goat producers and the mohair industry. A workshop was held on 17 and 18 October 2006 in Port Elizabeth to discuss the practical implementation, implications and requirements of a biological bank. The recommendations of this workshop were:

To establish and maintain a central storage facility for a biological bank for South African Angora goats, which could be extrapolated to other small stock breeds, at GADI
To establish a DNA laboratory at GADI
To investigate the possibility of establishing a reference herd for South African Angora goats.

ACTIVITIES DURING REPORT YEAR

Since the workshop in 2006, it was decided to include other breeds in the blood and DNA bank as well. As an outcome of two workshops on conservation of indigenous livestock, namely a workshop hosted by the Northern Cape Department of Agriculture and Land Reform during May 2007 at the Vaalharts Experimental Station, focusing on the endangered Namaqua Afrikaner sheep breed and a second workshop, held as a result of the first, during November 2007 in Pretoria, the National Department of Agriculture is in the process of implementing the following program: “Establishment of the South African Biological Reserve for Small Stock research and conservation”. The layout of this program is summarised in Table 1.

Establishment of a DNA laboratory and central storage facility at GADI

The DNA laboratory and central storage facility for the biological reserve for South African small stock breeds has already been established at GADI. Three minus 80°C freezers were bought, while another three have been ordered. A scientist, trained in biotechnology, was appointed to run the laboratory and has already started isolating DNA. As soon as the ordered three freezers arrive, isolation of DNA from the blood samples already stored will continue.

Blood sample collection and storage and DNA extraction

The following research herds at various departmental experimental stations are part of the DNA and blood bank projects:

Afrino herd at the Carnarvon Experimental Station (200 ewes)
Fine wool Merino stud at the Cradock Experimental Station (320 ewes)
Merino stud at GADI (320 ewes)
Namaqua Afrikaner herd at the Carnarvon Experimental Station (140 ewes)
Jansenville Angora fine hair herd at the Jansenville Experimental Station (450 ewes)
Four Angora goat studs from Angora goat breeders in the Eastern and Western Cape provinces (1500 ewes).

Table 1. Layout of the program

PROGRAM AP10 Establishment of the South African Biological Reserve for Small Stock research and conservation
PROJECT AP10/1 Establishment and maintenance of live herds of the endangered sheep and goat breeds in South Africa	PROJECT AP10/2 Cryopreservation bank for conservation of biodiversity of sheep and goat breeds in South Africa	PROJECT AP10/3 Blood and DNA bank for genomic research in sheep and goat breeds in South Africa
SUB-PROJECTS	SUB-PROJECTS	SUB-PROJECTS
AP10/1/1: Establishment and maintenance of live herds of the endangered Namaqua Afrikaner sheep breed in South Africa	AP10/2/1: Establishment and maintenance of a cryopreservation bank for Namaqua Afrikaner sheep	AP10/3/1: Maintenance of a biological bank for Angora goats in South Africa
		AP10/3/2: Maintenance of a biological bank for Namaqua Afrikaner sheep in South Africa
		AP10/3/3: Maintenance of a biological bank for Merino sheep in South Africa
		AP10/3/4: Maintenance of a biological bank for Afrino sheep in South Africa

During November 2007, blood samples were taken from all available animals in the Merino, Afrino and Namaqua Afrikaner herds. Blood samples were collected into 10 ml EDTA vacutainer blood collection tubes. After collection, the blood samples were divided into four aliquots of 2 ml blood each into cryo-vials. These samples were frozen at minus 80 °C for future use. During January 2008, blood samples were also taken from all the 2007-born Angora kids on the farms of the participants. To date, blood samples from 7695 Angora goats, 1947 Merino, 690 Afrino and 270 Namaqua Afrikaner sheep have been collected and are stored in the blood and DNA bank.

Reference herd for Angora goat DNA bank project

For the purpose of establishing a reference herd for the Angora goat blood and DNA bank, the number of ewes in the fine hair herd will be increased through a multiple ovulation and embryo transfer program (MOET). Thirty 7-8 years old Angora stud ewes were obtained as donor ewes during January 2008 from two Angora goat stud breeders who participate in the DNA project. Embryo flushing and implantation was done on 20 and 21 April 2008. An average of 5.6 grade A and B embryos per donor ewe were implanted into 100 receiver ewes from the Jansenville crossbred and fine hair herds.

CONCLUDING REMARKS

The program is running according to schedule and project activities will continue as stipulated in the project proposals.

Summary of activities performed during the 2007/08-report year:

To date, blood samples from 10 602 Angora goats and sheep have been collected and stored in the blood bank
All phenotypic data recorded have been entered into the database
A DNA laboratory and central storage facility has already been established at GADI and is already operational
Data for the longevity part of the Angora project are being collected
The Angora MOET program was completed for the 2008 breeding season.

ACKNOWLEDGEMENTS

The following persons / institutions are acknowledged for their contribution to this project:

· Participating breeders for their inputs

· Mohair South Africa for partial funding of the Angora goat part of the project

· Cape Wools for partial funding of the Merino part of the project

· Eastern Cape Department of Agriculture (ECDA)

· Northern Cape Department of Agriculture and Land Reform (NCDALR)

· Personnel at NCDALR and ECDA Experimental Stations.

[Contents]

DETERMINING THE CATTLE AND SHEEP GRAZING IMPACT IN THE EASTERN MIXED KAROO

T.P. Nengwenani and M. Coetzee

AIM AND OBJECTIVES

The aim of this project is to determine the influence that cattle and sheep, grazing the veld at the same time, have on the optimal but sustainable use of the veld, while the animals still produce at a high level and the vegetation is still afforded time to regenerate and improve over time.

The objectives of the project are:

· To utilise veld with different combinations of sheep and cattle

· To measure the impact on the veld

· To measure the production of the livestock

· To determine the sustainability and profitability of different veld management systems.

BACKGROUND

Various authors have hinted at the possibility of improving the profitability of a stock-farming venture by running more than one species of animal on the veld, citing as evidence the fact that different species graze differently and that they do not utilise the same species. This was, however, refuted on more than one occasion. It is also claimed that sheep produce more profitably where they are allowed to follow cattle in a grazing system. This is true, however, very detrimental to the vegetation due to the selective grazing habit of sheep and their ability to select the most palatable parts of the different plants. This was refuted on the grounds that sheep, by grazing so selectively, will damage the plants after the cattle has removed the rough growth and this will in fact detrimentally affect the plants species. The stocking rate starts off at a realistic but below grazing capacity norm, and as the animals grow the applied stocking rate in fact tend to approach the 16 ha/LSU grazing capacity norm. The cattle to sheep ratio are one-to-one on a large stocking rate unit basis, grazing the veld as one herd. The experiment consists of eleven paddocks that have different grazing periods, paddock sizes and terrains (Table 1).

Table 1. Grazing period, camp size and terrain of different paddocks

Paddocks	Grazing period	Paddock size (ha)	Terrain
1A	2 weeks	14	Plain
1B	2 weeks	14	Plain
2A	2 weeks	14	Plain
2B	2 weeks	14	Plain
3A	2 weeks	14	Plain
3B	2 weeks	14	Plain
4A	2 weeks	14	Semi-Plain/Mountain
4B	2 weeks	14	Semi-Plain/Mountain
5	4 weeks	46	Mountain
6A	4 weeks	26	Mountain
6B	4 weeks	31	Mountain

RESULTS AND DISCUSSION

Species composition

A total of 90 species (including bare patches) were sampled, with 33 being within the Plain, 20 in the Semi-Plain/Mountain and 44 in the Mountain terrains.

Analysis of similarity (ANOSIM) was used to establish significant differences within and between treatment/groups, based on herbaceous species composition. The global test for two-way crossed ANOSIM for differences between year groups (averaged across all paddock size groups) were insignificant (r = 0.046, P > 0.05). The global test for two-way crossed ANOSIM for different size groups (averaged across all year groups) was significant (r = 0.433, P < 0.05). There was significant high differences between paddock size groups 14 and 46 ha (r = 0.701, P < 0.05) and intermediate differences between groups 14 and 26 ha (r = 0.616, P < 0.05). The global test for differences between year groups (averaged across all terrain groups) were insignificant (r = 0.048, P > 0.05) but the global test for terrain groups (averaged across all years) were showed intermediate differences (r = 0.595, P < 0.001). The global test for year groups (averaged across all grazing periods) was insignificant (r = 0.048, P > 0.05), but it was significant (r = 0.595, P < 0.05) for grazing periods (averaged across all years). The two-way crossed ANOSIM global test for paddock size (averaged across terrain groups) as well as the pair wise tests was insignificant (P > 0.05). Hence, the results indicated that the length of the grazing period had significant impacts on the species-environment relation, but that the climatic variability between different years did not result in significant patterns. According to the ANOSIM, terrain type also did not result in significant differences with regard to species compositional patterns. However, although there were no statistical differences with regard to terrain type, this can possibly be due to inadequate replicates/representation within terrain groups, resulting in relatively low permutations. Hence, although the global test had an r-value of 0.722 for differences between terrain groups, while differences can also be observed visually (also refer to Figure 1 to indicate the separate clusters), the test was statistically insignificant (P = 0.067), being slightly higher than the P < 0.05 acceptance value. However, the lack of differences indicated by the statistical analyses could rather be attributed to the experimental layout (lack of adequate replicates within different terrain forms) not allowing to test statistically for differences.

Ordinary techniques are commonly used to reduce community composition variation in an ordination diagram (Ter Braak & Smilauer 1998). A CCA incorporating environmental and passive variables, revealed significant patterns related to these variables for both the first (F-ratio = 4.818, P < 0.05) and all canonical axes (F-ratio = 2.231, P < 0.05). The first two axes representing 78.8% of the species-environmental relation for the environmental data, 27.1% of species data and 53.1% of the species-passive data. The fourth axis described 34.4% of the cumulative variance of the species data, 100% of the species-environment relation for the environmental variables and 54.4% of the species-passive variable relation. The first axis was strongly associated with mountain treatment (r = 0.9399, first quadrant) and paddock size (Fig. 1). The passive variable, VCS, was best associated with first axis (r = 0.4426, second quadrant), the Plains terrain and the two weeks rotational grazing. The grazing capacity required (ha/LSU) was (fourth quadrant) associated with the Mountain terrain and the four weeks rotational grazing (Fig. 1). The Mountain and Plains terrain formed two distinct clusters, each being associated with its own species. The Plains and two weeks rotational treatment was consistently characterised by 4 climax species, while the Mountain and four weeks treatment was characterised by 37 species, mostly annual and weak perennial and unfavourable perennial species, typical of rangeland degradation (Fig. 1). Bare patches fell intermediate between the two clusters. Species having 10% and higher of their ranges being accounted for by the CCA ordination’s first two axes for were determined as a more effective management and monitoring “tool” towards identifying species that best represent each axis. Hence, it is suggested that these species could consistently act as indicators of each terrain form.

Simper analyses were done in support of the ordination results. The 2 weeks grazing treatment had an average similarity of 54.61 % and the 4 weeks grazing treatment 62.41%, hence showing the largest similarity within each paddock pertaining to herbaceous species composition. The 2 weeks treatment was dominated by Digitaria eriantha (av.abund = 23.00%, contribution = 30.96%). Bare patches had the second highest contribution (av. abund = 20.52%, contribution = 27.53%). The 4 weeks treatment was dominated by bare patches (av. abund = 24.25%, contribution = 31.96%) and Eragrostis curvula var conferta had the second highest contribution (av.abund = 12.78%, contribution = 16.80%). Digitaria eriantha, a palatable climax species, contributed to most of the dissimilarities between the 2 weeks and 4 weeks grazing treatments with average abundance = 23.00% within the 2 weeks grazing treatment and average abund = 11.08% within the 4 weeks grazing treatment. Eragrostis curvula var conferta was the second highest contributor to the dissimilarities between grazing period treatments, with an average abundance of only 1.55% within the two weeks treatment.

The veld condition score (VCS) and hectares per large stock unit (ha/LSU) with their averages for 2007 and 2008 are shown in Table 2. The results in Table 2 show that the highest average VCS (68.08%) for 2007/2008 years was recorded within paddock 1B, relating to a grazing capacity of 6.82 ha/LSU. Lowest average VCS for 2007/2008 years (42.70%) was recorded within paddock 5 with 10.96 ha/LSU. The best VCS associated with 2 weeks grazing treatment, whereas the lowest score associated with 4 weeks grazing treatment. Rangeland condition scores in general were higher within the 2 weeks rotational grazing paddocks, being lower in the Mountain paddocks and in paddocks 4A and 4B, which falls within the transitional zone between the Mountain and Plains terrain. The better rangeland condition within the 2 weeks rotational grazing can possibly be ascribed to an interrelationship between various factors: short grazing periods and long rest, opposed to the longer grazing periods within the Mountain paddocks. However, ANOSIM tests indicated no differences between paddock size camps, indicating that this did not primarily result in the observed species-environment relations. This can be ascribed to the fact that although grazing periods were longer within the Mountain paddocks, the paddocks were larger to accommodate for the longer grazing periods. Although terrain form did not statistically result in significant differences, due to a lack of sufficient replicates within and between terrain groups, it possibly did contribute to the observed species-environment relations between the different grazing periods.

There were significant differences between grazing periods on the herbaceous composition, with two distinct clusters being observable, each with its associated species. This also corresponded with the terrain form. The species composition patterns were primarily the result of different grazing periods. However, although the Plains and Mountain terrain groups did not show statistical significant differences while differences can be observed, it is suggested that this can primarily be attributed to a lack of sufficient replicates within and between terrain groups. It is thus suggested that terrain form in fact did contribute to the observed species-environment relations between the different grazing periods. A Key species approach was followed to identify species that were consistently associated with different grazing period and terrain groups. These species play an important role in correctly monitoring trends within and between factor groups over temporal scales. Rangeland condition scores were generally relatively high for the entire area, especially within the Plains and hence 2 weeks grazing paddocks, showing no detrimental but rather positive impacts from the combination cattle-sheep management practice, interrelated with the grazing management regimes. For the way forward, it should be critically evaluated whether the current demonstration trial, which does not include different treatments, should be adjusted to answer additional current needs within the farming community, thus reflecting on the animal type, animal production norms, reviewing survey procedures and experimental lay-out limitations. The current trial area is possibly not representative of the spatial variability of the larger area, cautioning against extrapolation across different spatial scales.

FIXED SEASON CONTINUOUS AND ROTATIONAL GRAZING OF THE PEDIMENTS AND PLAINS IN THE FALSE UPPER KAROO

The aim of this project is to demonstrate the disadvantages of fixed season grazing on mixed Karoo veld.

· To use the demonstration plot to train farmers in the concept of rotational grazing systems.

The late Dr C.E.M. Tidmarsh laid out this trial at Grootfontein in 1934, in order to demonstrate to the farming community the disadvantages, especially veld deterioration, of grazing the same paddock at the same time of year, year-after-year, due to the fact that certain paddocks on farms were reserved year-after-year for specific purposes at the same time of the year, such as mating, lambing and weaning.

A total of 81 species (including bare patches) were surveyed within the study area. Analysis of similarity (ANOSIM) was used to establish significant differences within and between treatments/groups, based on herbaceous species composition (relative abundances). The global one-way ANOSIM test for differences between treatments showed relatively low but significant differences (r = 0.265, P < 0.05), with pair wise tests showing intermediate differences between 1a and 3c (r = 0.303, P < 0.05), 1a and 6 (r = 0.481, P < 0.05) and 3a and 6 (r = 0.5, P < 0.05). Differences were insignificant between other treatments (P > 0.05), but it should be emphasised that although differences might be observed, the lack of replicates within treatments resulted in relatively few permutations, thus resulting in statistical insignificant pair wise tests, although the r-values might be informative. The global one-way ANOSIM test for differences between year groups showed relatively low but significant differences (r = 0.227, P < 0.05), with pair wise tests showing relatively low differences between 2006-2007 (r = 0.277, P < 0.05), intermediate differences between 2007-2008 (r = 0.407, P < 0.001), with no significant differences between 2006-2008 (P > 0.05). This indicates that the rainfall season of 2007 differed the most from the other two years with regard to its interrelationship and impact (non-equilibrium events) on the species compositional patterns, as was also supported by the SIMPER explanatory analysis. The global one-way ANOSIM test showed insignificant differences between terrain groups, but with pair wise tests showing highly significant differences between the Pediment-Plains groups (r = 0.788, P < 0.05) and the PedPlains-Plains groups (r = 0.957, P < 0.05), but being insignificant between the Pediment-Plains groups (P > 0.05). The global test from the two-way crossed ANOSIM indicated relatively small differences between treatment types (when averaged across all terrain groups) (r = 0.234), with terrain groups (when averaged across all treatments) showing no significant differences (P > 0.05). When compared to the one-way ANOSIMS for treatment differences, it is evident that the r-value was lower for the two-way crossed ANOSIM, implying that terrain/environmental differences did not primarily result in the treatment differences. The insignificance (P > 0.05) between for the global two-way crossed ANOSIM for differences in treatment groups (when averaged across all terrain groups), corresponds with the one-way ANOSIM, further suggesting that the interrelationship between treatment and terrain form, was not the primary causative factor for the species compositional patterns. The global one-way ANOSIM test was significant between all paddock size groups (r = 0.321, P < 0.05), with the pair wise tests showing relatively low but significant differences between paddock size groups 7.71 and 5.14 ha (r = 0.193, P < 0.05); intermediate between the 7.71 and 3.43 ha groups (r = 0.504, P < 0.05) and the 5.14 and 3.43 ha groups (r = 0.509, P < 0.05); and highly significant and different between the 7.71 and 6.85 ha groups (r = 0.854, P < 0.05), the 12.85 and 10.23 ha groups (r = 0.84, P < 0.05), the 12.85 and 6.85 ha groups (r = 0.957, P < 0.05), the 12.85 and 3.43 ha groups (r = 0.861, P < 0.05) and the 5.14 and 6.85 ha groups (r = 0.87, P < 0.05).

Ordination techniques are commonly used to reduce community composition variation in an ordination diagram. A CCA incorporating environmental and supplementary variables, revealed significant patterns related to these variables for both the first (F-ratio = 5.203, P < 0.005) and all canonical axes (F-ratio = 3.085, P < 0.005). The first two axes represented 50.5% of the species-environment relation for the environmental data, 32.6% of the species data and 57.9% of the species-supplementary data. The fourth axis described 48.1% of the cumulative variance of the species data, 74.4% of the species-environment relation for the environmental variables and 89.2% of the species-supplementary variables relation. The first axis was most strongly associated with the Plains terrain form (r = 0.939, quadrant 1), followed by Continuous August-August (ConAu-Au) grazing (5 U and 5 L, r = 0.6024, first quadrant. April-August grazing (paddock 3c) showed the strongest association with the second axis (r = 0.8633, second quadrant). The passive variable, VCS, was best associated with the second axis (r = 0.6204, first quadrant) followed by ha/LSU required (r = -0.4289, third quadrant) (Fig. 1).

Three distinct clusters can be observed (Fig. 1) Treatments 5 U and 5 L clustered separately (ConAuAu), being associated with several Key species such as the palatable Digitaria eriantha and with the VCS (%) within the first quadrant. The 3c treatment (Apr-Aug) formed a separate cluster within the second quadrant, being associated with only a few Key species such as the palatable Themeda triandra, also being associated with the VCS vector (close proximity between treatment variable and VCS vector) (Ter Braak and Smilauer, 1998). The remainder of the treatments formed a third cluster primarily within the third and fourth quadrants, near the centre of the axes (Fig. 1). The latter cluster was characterised by relative few Key species, primarily being annual species such as Aristida congesta, and species having intermediate grazing index values. The third cluster was also associated with increased ha/LSU required due to lower VCS (Fig. 1). Average daily gain per animal (quadrant 1) was positively correlated with the VCS vector, and with the Continuous August-August grazing (ConAuAu) treatments, notably treatment 5 L (Fig. 1, Table 2). Species having 10% and higher of their ranges being accounted for by the CCA ordination’s first two axes for were determined as a more effective management and monitoring “tool” towards identifying species that best represent each axis. Hence, it is suggested that these species could consistently act as indicators of each treatment. The 5 U and 5 L treatments were consistently associated by 17 species and another one marginal species (associated with third cluster); cluster 2 (April-August treatment - 3 c) by 4 species and the third cluster by 4 species (Fig. 1).

It was found that VCS was generally lowest within treatments being grazed during the summer months (1 a, 1b, 3b), while the Continuous grazing treatments (5L and 5 U) did not result in the lowest rangeland condition scores. The relationship between VCS and ha/LSU is best explained by a power fit (y = ax^b, with a = 464.39677, b = -1.0001534) (r = 0.99, S = 0.004). This implies that ha/LSU does not necessarily decrease inversely (linear function) with higher VCS, holding important implications for management, monitoring and training manual purposes (Fig. 3).

SIMPER analyses were done in support of the ordination results, also indicating species that contributed most to the similarity within each treatment or factor group. The similarities within treatments between 2006-2008 are as follows: 1a = 38.64%, 1b = 54.67%, 2a = 73%, 2b = 78.67%, 3a = 59.92%, 3b = 56.5%, 3c = 52%, 4a = 30.5%, 4b = 59.33%, 5U = 55%, 5L = 25.32% and 6 = 56.58%. The Pediment terrain group had an average similarity of 53.46%, the Pediment Plains group 77.97% and the Plains group 49.25%. Species contributing to 90% and higher of the similarity within each treatment/factor group were done, in support of the CCA Key species approach (Fig. 1), indicating the average abundances and contributions of species contributing consistently to the cumulative similarity of a treatment/factor group. This serves as a tool in monitoring trends within different treatments and factor groups, hence informing management decisions. It should be emphasised that although each cluster can be recognised by its own key species, SIMPER analysis indicated that bare patches had relatively high abundances within each treatment, ranging from 22.75% within 5L, up to 37% within 3b, indicative of the relative poor to intermediate rangeland condition of the entire trial area. This can primarily be ascribed to historical management impacts, as well as the interrelationship with inherent environmental differences and non-equilibrium events impacting different on the treatments (e.g. seasonal rainfall resulting in different phonological responses within treatments, depending on the grazing period, i.e. summer vs. winter vs. continuous, etc.).

A global one-way ANOSIM test based on Shannon’s diversity, Margalef’s species richness and Pielou’s evenness diversity indices, showed relatively low but significant differences between treatments (r = 0.18, P < 0.05). Pair wise test showed highly significant differences between treatments 1a and 2a (r = 0.938, P < 0.05), with no significant differences for the other pair wise tests, which can partially be accounted for by the relatively few permutations, resulting in informative r-values but being statistically insignificant. There were no significant differences between years (P > 0.05), with pair wise tests showing significant but relatively low differences between the Pediment-Pediment Plain terrain groups (r = 0.206, P < 0.05), and large differences between the Plains-Pediment Plains terrain groups (r = 0.84, P < 0.05). Pair wise tests for differences in paddock size groups showed relatively low differences between paddock sizes 15 and 6 (r = 0.206, P < 0.05), 6 and 6 (r = 0.248, P < 0.05), with intermediate differences between paddock size groups 15 and 12 (r = 0.605, P < 0.05), and large differences between paddock groups 15 and 8 (r = 0.84, P < 0.05) and 15 and 4 (r = 0.895, P < 0.05). Hence, some treatments, terrain groups and different paddock size groups resulted in different diversity and species richness patterns.

Paddock	Treatment	Paddock size (ha)	Terrain
1a	15 August – 15 February: 8 sheep	7.71	Pediment
1b	15 February – 15 August: 8 sheep	7.71	Pediment
2a	Continuously grazed – 1 sheep above norm: 9 sheep	12.85	Pediment-Plains
2b	Continuously grazed – 1 sheep below norm: 7 sheep	12.85	Pediment-Plains
3a	15 August – 15 December: 8 sheep	5.14	Pediment
3b	15 December – 15 April: 8 sheep	5.14	Pediment
3c	15 April – 15 August: 8 sheep	5.14	Pediment
4a	Cont. 15 August – 15 August/Rest year – reverse of 4b: 8 sheep	7.71	Pediment
4b	Cont. 15 August – 15 August/Rest year – reverse of 4a: 8 sheep	7.71	Pediment
5 lower (L)	Continuous 15 August – 15 August/Rest year: 4 sheep	10.23	Plains
5 upper (U)	Continuous 15 August – 15 August/Rest year: 5 sheep	6.85	Pediment
6	Continuous rest	3.43	Pediment

PREFACE

INVESTIGATION INTO PRODUCTION AND REPRODUCTION SELECTION CRITERIA IN AFRINO SHEEP

BACKGROUND

Trait

Trait

Average ± s.e.

Trait

CONCLUDING REMARKS

ESTABLISHMENT OF A GENETIC POOL OF DUAL PURPOSE SHEEP WITH PREMIUM QUALITY MEAT AND SUPER FINE WOOL UNDER EXTENSIVE CONDITIONS

Trait

DEVELOPMENT OF A METHOD FOR THE ESTIMATION OF BREEDING VALUES FOR RESISTANCE OF SHEEP TO INTERNAL PARASITES, WHICH WILL BE APPLICABLE UNDER ANY ENVIRONMENTAL CONDITIONS

BACKGROUND

FEC

ACKNOWLEDGEMENTS

INVESTIGATION INTO THE EFFECT OF DIFFERENT TYPES OF TEATS ON THE PRODUCTION AND REPRODUCTION OF BOER GOATS

W.J. Olivier

INVESTIGATION INTO THE RELATIONSHIP BETWEEN MILK PRODUCTION OF GRAZING EWES AND MATERNAL BREEDING VALUES FOR EARLY GROWTH TRAITS IN SOUTH AFRICAN SHEEP FLOCKS

BREEDING SHEEP FOR INCREASED PROFIT PER HECTARE

INVESTIGATION INTO THE EXTENT OF MICRON BLOW-OUT IN SOUTH AFRICAN WOOL SHEEP

CLOSING REMARKS

THE EFFECT OF EARLY GROWTH ENVIRONMENT OF DORPER LAMBS ON

M. LONGISSIMUS DORSI AREA AT 16 MONTHS OF AGE

THE EFFECT OF SUPPLEMENTATION OF REPLACEMENT EWES AFTER WEANING ON THEIR LIFETIME REPRODUCTION POTENTIAL UNDER NATURAL VELD CONDITIONS

INVESTIGATION INTO THE CAUSE, PREDISPOSING FACTORS AND EFFECTIVE TREATMENT OF SWELLING DISEASE IN SOUTH AFRICAN ANGORA GOATS

AN INVESTIGATION INTO THE EFFECT OF DIFFERENT WEANING PRACTICES ON THE POST-WEANING GROWTH OF ANGORA KIDS AND REPRODUCTION OF ANGORA EWES

RESULTS AND DISCUSSION

EFFECT OF DIETARY CHROMIUM LEVELS ON FAT DEPOSITION, CARCASS AND MEAT CHARACTERISTICS OF DORPER LAMBS

THE EFFECT OF THE INCLUSION OF AN IONOPHORE AS A SILAGE ADDITIVE ON SILAGE CHARACTERISTICS

ESTABLISHMENT OF RAM BREEDING FLOCKS FOR DIFFERENT COMMUNAL FARMING AREAS OF THE EASTERN CAPE

B.R. King

RESULTS & DISCUSSION

Rams

Dudumasha

Xume

Allan Waters

Beckles Farm

Lushington

Rockcliff

Qoqodala

Luzi

Lephakoeng

THE EFFECT OF METHIONINE SUPPLEMENTATION ON STAPLE LENGTH AND FIBRE DIAMETER IN WOOL SHEEP

ESTABLISHMENT OF THE SOUTH AFRICAN BIOLOGICAL RESERVE FOR SMALL STOCK RESEARCH AND CONSERVATION

DETERMINING THE CATTLE AND SHEEP GRAZING IMPACT IN THE EASTERN MIXED KAROO

FIXED SEASON CONTINUOUS AND ROTATIONAL GRAZING OF THE PEDIMENTS AND PLAINS IN THE FALSE UPPER KAROO

DETERMINING THE OPTI