GADI Research Report

RESEARCH REPORT

of the

GROOTFONTEIN AGRICULTURAL

DEVELOPMENT INSTITUTE

2007

Published by

Department of Agriculture

Design and layout by:

Directorate: Grootfontein Agricultural Development Institute

Private Bag X529, Middelburg, 5900

ISBN 978-1-86871-253-3

[Return]

PREFACE

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 to a large extent 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 organizations, 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 70% of the operational cost of the GADI R&D program. Financial support during the reporting period was obtained from Cape Wools SA, Mohair South Africa, the Red Meat Research and Development Trust and the Grootfontein Research Trust. Financial support from different stakeholders to the GADI R&D program is mediated through the Grootfontein Research Trust, which is registered with the Receiver of Revenue 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 Eastern Cape Department of Agriculture (Cradock and Jansenville Experimental Stations), Northern Cape Department of Agriculture and Land Reform (Carnarvon and Koopmansfontein Experimental Stations), North West Department of Agriculture, Conservation, Environment and Tourism (Potchefstroom Livestock Centre), twenty communities in the Transkei and Ciskei areas of the Eastern Cape, forty farmers and their farm workers in seven provinces, the Agricultural Research Council and the University of Pretoria.

INVESTIGATION INTO PRODUCTION AND REPRODUCTION SELECTION CRITERIA IN AFRINO SHEEP

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

· 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 and the project on maternal values.

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. Lambs of the flock are also part of the projects on parasite resistance and ultrasound scanning of M. Longissimus dorsi area. Ewes of the flock are part of the project on maternal values in sheep.

Selection in the flock is aimed at increasing reproductive performance, increasing body weight, decreasing fibre diameter, keeping wool weight constant and improving wool quality traits. The average productive performance of the ram and ewe lambs over the past 18 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 18 years of ram and ewe lambs in the Carnarvon Afrino flock

Table 2. Production of Afrino ewes over the past 18 years in the Carnarvon flock

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

Too much emphasis on reducing fibre diameter, without considering wool weight, led to a slight reduction in clean fleece weight up to 2001. Furthermore, a reduction in the density of the fleece also occurred. The emphasis on crimp quality, together with the emphasis on fibre diameter, also led to a correlated increase in the appearance of creeping belly. It was therefore decided in 2001 that less emphasis would in future be put on fibre diameter, especially with the selection of young ewes, and more emphasis on wool weight. As far as the other fleece traits are concerned, positive genetic trends were observed for staple length, evenness of fleece and staple strength.

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.

· Results of the project on maternal values could probably be implemented in the selection program in five or six years’ time.

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

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.

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

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

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 costs 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. This current report contains information and results that were collected since August 2006.

All adult animals were shorn during the last week of July 2006. These 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 September 2006, the ewes mated during April/May 2006 were brought in from the veld and placed in individual pens and provided with a pelleted roughage diet. 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 2006 progeny and the ewe flock was according to the project protocol. The 2006 lambs were weaned on 05 January 2007 and shorn on 18 January 2007.

The 2005 progeny was provisionally classed on 30 October 2006, shorn on 31 October 2006 and the 12-month wool production data collected. Final inspection of the Dohne ewes was performed on 16 March 2007.

During March 2007, the 28 Dohne stud ewes bought during the previous reporting period from breeders, together with 12 ewes from the Grootfontein flock were used in a multiple ovulation and embryo transfer program (MOET). This procedure was repeated in May 2007 with 26 of the Dohne ewes bought from stud breeders, together with 14 ewes from the Grootfontein flock. These donor ewes were laparoscopically inseminated with semen from ED020410, SD010570, JV010608, GF041070 and GF051148. The 778 embryos recovered from the 80 donor ewes were implanted into 462 recipients. The remaining 135 Dohne ewes were mated to own rams (GF041070, GF041077, GF051029, GF051049 and GF051148), while the 102 Letelle ewes were mated to three Letelle rams (042012, 052019 and 052097) from 29 March 2007.

The GLM procedure of SAS (1990) 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.

During the 2006 mating season, 287 embryos were recovered from the 30 Dohne ewes in the MOET. Of the 136 recipients to whom the embryos were transferred, 99 eventually lambed giving birth to 151 lambs in August/September 2006. The other 130 Dohne and 87 Letelle ewes gave birth to 186 and 77 lambs respectively.

Body weights recorded for the 2006 progeny are shown in Table 1, while the production data of the adult ewes in the two flocks are shown in Table 2.

Table 2. Production data (± s.e.) of adult ewes in the nucleus flocks (2006 ewe flock)

The EBV’s for BW, CFW and FD of the 2005 progeny born in the Dohne flock were 0.418 kg, 0.035 kg and –0.502 µm. Although the genetic trends indicate that progress with regard to the initial objectives of the project is made, too little data with insufficient genetic links to the industry might still limit interpretation of the genetic progress. Genetic progress will be re-evaluated after the data from the 2006 progeny are available. During 2006, Dohne stud ewes and rams from breeders were introduced into the Grootfontein flock, and rams from Grootfontein were also used in other studs that will improve the genetic links. 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.

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.

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

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.

· 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:

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

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

It was decided to include the natural challenge method 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 purpose of developing a protocol to evaluate breeding values for resistance of sires born in the extensive sheep grazing areas, the natural challenge procedure will definitely not be an option. This is largely due to the low and unpredictable rainfall, with the resultant variable parasite challenge, which makes this procedure unreliable for use at a specific time each year.

· Furthermore, using breeding values for parasite resistance based on the Famacha©-system, will also not be feasible for the evaluation of breeding sires in the extensive areas. The reason for this is that the recording period is too long before differences between animals are expressed. Furthermore, employing the Famacha©-system after natural challenge is unfeasible, as mentioned above. To employ the Famacha©-system after artificial challenge would be unpractical, as faecal egg counts can already be recorded on day 28 after infection, after which the test can be finished. The data collected during this study, however, confirm that the Famacha©-system is an excellent management tool to identify animals that need anthelmintic treatment.

· For the most important part of the study, where animals selected in a dry area (Carnarvon) are evaluated under a higher rainfall area (Potchefstroom), much more data still need to be recorded.

· Although HEMA has a high genetic correlation with FEC, it is more difficult and expensive to measure, while other factors could also influence the anaemic status of an animal. Therefore, HEMA as such, would not be a feasible selection criterion as indicator of resistance.

· For the purpose of developing a protocol to evaluate sires born in the extensive sheep grazing areas, FEC after an artificial challenge procedure seems the best option as selection criteria for resistance against internal parasites. The following should be taken into account:

- The availability of a viable, non-resistant strain of H. contortus is an important issue, which should be addressed as soon as possible.

- Animals should receive a pre-test dose of larvae to activate their immune response.

- The level of infection should be high enough to ensure that genetic differences can be expressed.

· The part of the project that involves the natural challenge procedures with the fine wool Merino stud at Cradock and the Mutton Merino flock at Potchefstroom will be terminated.

· That part which involves the evaluation of resistance in the two different environments (Carnarvon and Potchefstroom) will continue for at least another four years.

ACKNOWLEDGEMENTS

The project leader wants to convey her sincere appreciation to the following people for their valuable contribution in the execution of the project:

SNYMAN, M.A., VENTER, Y., VAN HEERDEN, M. & BUYS, T., 2006. Internal parasite resistance of sheep evaluated in two different environments. Proceedings 41st SASAS congress, Bloemfontein, 3 – 6 April 2006.

SNYMAN, M.A., 2007. Prospects for the utilization of variation in parasite resistance among individual sheep within a flock. Grootfontein Agric 7(1): 29-34.

INVESTIGATION INTO THE SELECTION CRITERIA OF MERINO SHEEP

The aim of this study is to evaluate the effect of two different breeding strategies on the wool production and wool characteristics of Merino sheep.

· To evaluate the effect of two different breeding strategies to decrease fibre diameter on the wool production and wool characteristics of Merino sheep

· To make rams available to the wool industry through the annual ram sale of Grootfontein

· To use the animals from this study for the training of the students at the Grootfontein Agricultural College.

The increase in the demand for fine and super fine wool, as well as the price premium paid for fine wool during the 1990’s, caused a shift towards the production of fine wool in an increased number of flocks in South Africa. Fibre diameter can be decreased either through within flock selection or through the use of genetic fine wool rams.

One of the perceptions with regard to fine wool production is that the use of genetic fine wool animals on strong wool animals will have a negative effect on the quality of the wool. It is assumed that the progeny of these animals will have under-crimped wool, as well as a large variation over the fleece.

It is therefore important for the Merino industry of South Africa to quantify what possible effects these two breeding strategies may have on wool production and characteristics of Merino sheep. Two selection lines, namely a fine wool and a control line, were therefore established within the Grootfontein Merino stud in 2001. The same selection objectives are used in both lines. The only difference between the two lines is that genetic fine wool rams from the Cradock fine wool Merino stud are mated to the fine wool line ewes, while the control ewes are mated to rams selected for fineness from within the control line.

The genetic trends for body weight, clean fleece weight, fibre diameter, staple length and profit per small stock unit are depicted in Figure 1. The progeny of the C-line were heavier (P<0.01) and produced more wool (P<0.01), while the F-line progeny produced finer (P<0.01) wool. There were no significant differences in staple length or relative economic value between the respective lines.

It is evident from the results of this study that the 2005 progeny of the F-line had a lower coefficient of variation compared to their contemporaries at 16 months of age. The F-line ram and ewe lambs had stronger staples than the ram and ewe lambs of the C-line. Furthermore, the results of this study support the negative relationship between coefficient of variation and staple strength.

The rams that were selected in 2006 for breeding purposes will have a positive effect on the breeding objectives of this stud with regard to body weight (C-line) and mean fibre diameter. These rams will also increase the profit per small stock unit of both lines.

It is evident from the results of this project that there were no differences between the body weights and clean fleece weights of the ewes in the two lines. The differences that existed between the reproduction performances of the two lines were largely the result of the problems that occurred during the 2006 mating season. Selection for decreased fibre diameter can be successfully achieved either by within flock selection or the use of external sires. However, it is important that the other economically important traits must be included in the selection objectives.

During the last two years there was a problem with obtaining sufficient numbers of replacement ewe lambs from both lines. This is partly due to the problems that existed with regard to the number of lambs that died from birth until selection age. This problem was accentuated due to the low number of ewes per line (± 130 ewes). The same problem with regard to the number of ewes existed in the Grootfontein fine wool Merino flock.

A meeting was therefore held in March 2007 with regard to the future of the Grootfontein Merino stud and the Grootfontein fine wool Merino flock. It was decided at this meeting to combine these two ewe flocks. Furthermore, it was decided to end this project and to include the Grootfontein Merino stud in the “Breeding sheep for increased profit per hectare” project. It was also decided to increase the size of the ewe flocks at Grootfontein and Cradock to ± 400 ewes each. The first mating of this combined ewe flock at Grootfontein was during April 2007.

EVALUATION OF SELECTION CRITERIA FOR BOER GOATS UNDER EXTENSIVE CONDITIONS

W.J. Olivier

The aim of this study is to evaluate selection criteria currently used in the Small Stock Improvement Scheme (SSIS) of the Agricultural Research Council: Livestock Business Division: Animal Production (ARC:LBD Animal Production) for Boer goats under extensive conditions.

· To determine whether selection based on the traits measured in the SSIS would result in increased lifetime production and reproduction efficiency in Boer goats

· To linearly assess subjective traits included in the breed standards and to estimate heritabilities and correlations of these traits with production and reproduction traits

· To linearly assess 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 construct a viable breeding plan for Boer goats based on the results of this project

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

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 utilize 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:LBD (Animal Production) 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 producer receives a growth and reproduction report from which he can make his selection on weaning weight, body weight and ewe productivity. 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 down 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 on the farms of six Boer goat breeders, Koopmansfontein Experimental Station and the Boer goat flock at Grootfontein Agricultural Development Institute.

Subjective teat scores of animals in the participating flocks are illustrated in Figure 1. It is evident from the figure that the largest proportion of the animals in these flocks had only one teat or one teat with a non-functional teat on either halves of the udder. Furthermore, it is visible in these figures that there is a relatively large variation with regard to teat score, especially in the Grootfontein and Koopmansfontein flocks.

Figure 1. Subjective teat scores of the animals in the Boer goat flocks at Grootfontein, Daniëlskuil, Griekwastad and Koopmansfontein

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. The progress report will be discussed with the participants at the annual the meeting of the Society that will be held in Kimberley in October 2007.

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

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

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.

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

· 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

Body weight has always been one of the important traits considered during selection of both replacement ewes and rams in many wool and mutton sheep breeding enterprises. Using body weight as the sole selection criterion for improved early growth rate in lambs, could have some detrimental effects. Firstly, overall efficiency of pre-weaning growth could be negatively influenced due to a possible negative genetic relationship between additive direct and additive maternal components of traits affected by both direct and maternal effects. Early growth traits in sheep all fall within the latter category. Secondly, as body weight at all ages is highly genetically correlated, increasing body weight at an early age will also increase mature body weight. This will have a negative effect on overall profitability of the enterprise, if the increase in body weight is not accompanied by an increase in lambing percentage or a net increase in income from wool production.

It is therefore important that selection emphasis should be shifted from body weight to include some measure of maternal performance as well, be it direct maternal breeding values for early body weight, such as weaning weight, or milk production potential of the ewe.

The project commenced in 2004. During the first year of the study 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 stud 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. During the 2006 lambing season, milk production of all ewes that lambed in the Carnarvon Afrino flock, Cradock fine wool Merino stud and the Elsenburg Merino flock was determined at three and twelve weeks of lactation.

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) over the recording period for ewes in the three flocks

Afrino ewes had the highest milk production per ewe, followed by the Cradock fine wool Merino ewes and the Elsenburg Merino ewes. These differences could be ascribed to breed and environmental influences. For the Afrino ewes, only the 4 and 6-year old ewes produced significantly less milk than the 5-year old ewes. No differences between age groups were observed for the fine wool Merino ewes. In the Elsenburg Merino flock, 2-year old ewes produced less milk than 4, 5 and 6-year old ewes, while 3-year old ewes produced less milk than the 4-year old ewes (P<0.01). The number of suckling lambs had a significant influence on milk production in all flocks.

The data collected on the ewes during the 2006 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.

For the Carnarvon Afrino flock, correlations of maternal EBV-42-day and maternal EBV-weaning weight of both the dam and maternal grandsire with the traits in question were of the same order. Low positive correlations were estimated between maternal EBV of the dam and total milk production (TMP) and total weight of lamb weaned (TWW), while high positive correlations were obtained with weaning weight 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 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 both the dam and maternal grandsire with the traits in question were of the same order. 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 maternal EBV-early body weight of lambs. In this flock, total milk production was negatively correlated with direct EBV-early body weight of the lambs, indicating a possible negative direct-maternal covariance.

Both dam and maternal grandsire maternal EBV were positively correlated with TMP, weaning weight and lamb EBV in the Elsenburg Merino flock. Total milk production of the ewe was positively correlated with individual weaning weight of lambs, direct and maternal EBV-weaning weight of the lambs.

At this early stage of the project, the following was evident from the data collected during the 2006 lambing season on the Carnarvon Afrino, Cradock fine wool Merino and Elsenburg Merino ewes:

· 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. In the Cradock fine wool Merino stud, TMP was negatively correlated with direct EBV-early body weight of the lambs.

· Correlations of maternal breeding values for 42-day and weaning weight of the dam has a positive correlation 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 and Elsenburg with the yearly recording of milk production of all ewes that lamb in each flock.

The author wishes to convey her sincere appreciation to all the involved 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.

BREEDING SHEEP FOR INCREASED PROFIT PER HECTARE

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

· 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 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).

The genetic trends for body weight, clean fleece weight, fibre diameter, staple length and profit per small stock unit (SSU) are depicted in Figure 1. It is evident from this figure that there was a positive trend in the profit per SSU. The trends of the Grootfontein fine wool Merino are not included in the graphs due to the lack of enough data.

The rams that were selected in 2006 for breeding purposes will have a positive effect on the breeding objective of both these flocks. The 2006 progeny will be performance tested at the end of 2007. The conception rate in the Cradock stud was higher than in the previous year. This, together with the increase in the number of ewes available for mating and the higher fecundity, lead to an increase in the number of animals that will be available for selection in 2008.

It is evident from the results of this study thus far that the selection objective was achieved, as there is an increase in the profit per SSU of both lines. Furthermore, the staple length of the Cradock fine wool Merino stud also improved.

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.

A meeting was held during March 2007 with regard to the future of the Grootfontein Merino flock and the Grootfontein Merino stud. It was decided at this meeting to combine these two ewe flocks and to include the Grootfontein Merino stud in this project. Furthermore, it was decided to increase the size of the ewe flocks at Grootfontein and Cradock to ± 400 ewes each. The first mating of this larger ewe flock at Grootfontein was during April 2007. The project is running according to the project proposal.

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

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

INVESTIGATION INTO THE EXTENT OF MICRON BLOWOUT IN SOUTH AFRICAN WOOL SHEEP

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

· To compare the fibre diameter profile of sheep with micron blowout to sheep with no micron blowout

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

Micron blowout, 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 believe 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 blowout.

A mayor 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 blowout 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).

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 and are not mated in order to keep their physiological status the same. 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 over coats (“Jassies”).

The ewes of the CAS, GMF and GDMS were shorn in August 2006, while the ewes of CMS and GMS were shorn in February and March 2007 for the first time. Body and fleece weights were recorded for the ewes of the CAS, CMS and GMS. 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, standard deviation (SD) and coefficient of variation (CV) at selection age (2005) and the first shearing (2006) for the respective flocks are presented in Table 1. It is evident from this table that the MFD of CMS, GMS-F and GMS-C animals increase significantly during the first year.

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

Values with the same superscript differed significantly (P<0.01), ^a = CMS, ^b = GMS-F, ^c = GMS-C

CLOSING REMARKS

· The ewes from the GMF, GDMS and CAS will be shorn at the end of July 2007, while the CMS and GMS ewes will be shorn during February and March 2008. The GMF and GDMS ewes will be shorn at the same time in 2008 as the GMS ewes.

[Contents]

THE EFFECT OF EARLY GROWTH ENVIRONMENT OF DORPER LAMBS ON M. LONGISSIMUS DORSI AREA AT 16 MONTHS OF AGE

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

· 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.

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 since birth. Producers have encountered the situation that they must choose between these two types of rams. 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 such 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 (if ever) it will take veld-reared lambs to catch up to lambs subjected to a higher plane of feeding during early growth.

Forty-eight weaned Dorper ewe lambs (± 4 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 is summarized in Table 1.

Groups A and B were subjected to a high plane of nutrition (high protein and high energy) for a 6 months period under kraal conditions. Groups C and D were kept under veld conditions for the same period. After 6 months (September 2007), Group C will change to the high diet level and Group B will be run under veld conditions for a further 6 months period, while lambs in Groups A and D will stay within 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.

The M. Longissimus dorsi measurements (area and fat) as well as the respective body weight per group are shown in Table 2. As expected, the size of the area of the eye muscle increased with an increase in age of the lambs. The muscle area in the kraal group increased from 9.6 to 26.0 cm², while that of the veld group increased from 9.7 to 15.8 cm². The fat depth of the kraal group increased from 3.0 to 7.0 mm and that of the veld group from 2.5 to 4.0 mm. The body weight of lambs in the kraal group increased from 23.4 to 46.8 kg since the start of the trial on 6 February 2007 up untill 3 July 2007. The veld group increased from 22.6 to 34.8 kg for the same period. At the first weighing there were no differences between the kraal and the veld groups in any of the traits measured. From six months of age, the area of the eye muscle and the body weight of the lambs differed significantly between the kraal and veld groups. From eight months of age, all three components evaluated, differed significantly between the two groups.

Table 2. Eye muscle area (cm² ± s.e.), fat depth (mm ± s.e.) of M. Longissimus dorsi and body weight (kg ± s.e.) of lambs in each group over the first six months of the trial period

The project is running according to the protocol. No conclusions are possible at this stage, as only the forst phase of the project has been completed.

INVESTIGATION INTO REPRODUCTION AND KID MORTALITY OF SOUTH AFRICAN ANGORA GOATS

The aim of this study is to identify the factors contributing to a low reproductive rate and high kid mortality in South African Angora goats.

· To collect data on all management aspects, such as management during mating and kidding, supplementary feeding practices, animal health practices and weather conditions

· To analyse data and identify important factors contributing to a low reproductive rate and high kid mortality in South African Angora goats.

Reproduction and kid survival rate are the most important traits influencing income in Angora goats. High reproductive and kid survival rates will ensure a large proportion of the more expensive kid and young goat mohair in the clip, and will also contribute to higher selection intensity. The poor reproductive performance and high kid mortality rate of Angora goats are well documented. Factors influencing the survival rate of kids include birth weight of the kid, genetic influences, mothering ability and milk production of the dam, adverse environmental or feeding conditions, diseases and predators. A study was done on 10 Angora goat studs and the two experimental flocks at the Jansenville Experimental Station to investigate the factors contributing to kid mortalities and reproductive performance. The project started with the September 2000 kidding season. The 2004 kidding season was the last one to be recorded. Management data, as well as data on post-weaning mortalities, growth performance and hair production of the 2004-born kids were recorded during the 2005/2006 report year. Most of the data collected during the survey period have already been analysed. A comprehensive final report will be submitted at the end of 2007.

Data on kid body weights and kid mortalities were already analysed and the following publications written on these aspects:

SNYMAN, M.A., 2005. Influence of ewe age structure on reproductive efficiency of Angora goats. The Angora Goat and Mohair Journal, March 2005, 47(1): 17-22

SNYMAN, M.A., 2007. Determining the most appropriate animal model for the genetic analysis of body weight and growth traits in South African Angora goats. Small Rumin. Res. (Submitted)

SNYMAN, M.A., 2007. Investigation into body weight and growth rate of South African Angora goat kids under various management systems. Grootfontein Agric 7(1): 14-22

SNYMAN, M.A., 2007. Investigation into body weight and growth rate of South African Angora goat kids under various pre- and post weaning management systems. S. Afr. J. Anim. Sci. 37 (2): 132-141

SNYMAN, M.A., 2007. Body weight and growth rate of Angora kids. The Angora Goat and Mohair Journal 49(1): 24-35

SNYMAN, M.A., 2007. Kid mortality in South African Angora goats. The Angora Goat and Mohair Journal 49(2): 24-28

SNYMAN, M.A., 2007. Influence of body weight, age and management system on reproduction of South African Angora goat ewes. S. Afr. J. Anim. Sci. (Submitted)

· It is clear that pre-weaning mortality rate in the Angora studs included in this study is not exceptionally high (average 11.9 %). In fact, it compares favourable with that recorded for most sheep breeds.

· The most important single cause of kid mortalities was predators (4.7 % kids lost), while a combination of small, unthrifty kids who needed help suckling, ewes having little or no milk, thick teats and udder problems and ewes discarding their kids (problems due to mothering ability), was responsible for 35.7% of the pre-weaning mortalities.

· Causes that could be addressed through the application of relevant management practices were responsible for 67.5% of the known deaths.

· Despite large differences in mortality rate recorded between sires within flocks (0 to 50%), a heritability of 0.04±0.01 was estimated for pre-weaning mortality rate. This could be explained by the fact that many of the causes of mortality have no genetic background.

· More than 45% of kid mortalities, where ewes lost three kids over the recording period, were due to small, unthrifty kids who needed help suckling, ewes having thick teats and udder problems, ewes having little or no milk or ewes discarding their kids. This indicates that these problems will occur repeatedly in the same ewes.

· Nearly 20% of the ewes did not reproduce. Of these, 9% had lost their fetuses between scanning and kidding. This aspect is usually not taken into account when the relatively poor weaning percentage of Angora goats is under discussion. High kid mortalities are usually blamed for the low weaning percentage.

· It is evident that pre-weaning growth rate of ram and ewe kids under the management systems followed in the participating studs is satisfactory. However, post-weaning growth rate of those kids (ram and ewe) that did not receive supplementary feeding after weaning was poor.

· The poor growth rate of especially ewe kids after weaning till 12 months of age is a serious problem that should be addressed, as it directly influences the reproductive ability of the young ewes. This was again evident from the poor reproductive performance of the young ewes in some of the studs.

· From the results of this survey it seems if viable mohair production under natural veld conditions is not possible without supplementation of kids pre- and post-weaning. The results obtained with this survey provide a good basis for scientific research into specific aspects, as it is evident that post-weaning growth and nutrition is a critical period in the productive cycle of the Angora goat.

From the results of this survey, the following recommendations could be made to decrease pre-weaning kid mortalities:

· Losses due to predators account for more than twice the number of losses due to the next important cause of kid mortalities. Predator control methods are a very controversial issue and will not be addressed here. However, it is important that a concerted effort be made to prevent these losses.

· The second most important aspect, namely the combination of udder problems, ewes with too little milk or ewes that discard their kids, should be addressed by culling those ewes with kalbas teats or udder problems and ewes with too little milk, if the latter is not a major problem in the specific flock. Suitable feeding practices during the last part of pregnancy and first part of lactation could address the problem of ewes with too little milk, if this is a general problem in the flock.

· Furthermore, illnesses could largely be circumvented by the application of a suitable inoculation and drenching program for the ewes and kids. Enzootic abortion could cause severe losses through abortions and the birth of small, weak and unthrifty kids. Inoculation of ewes against enzootic abortion should be done as a preventative measure.

· Small, unthrifty kids and deformed kids have a genetic basis and should be addressed by avoiding using sires that produced an above average number of such kids. Sons of such sires should also not be selected as breeding parents.

· If a large number of small, weak kids are born in the flock, a supplementary feeding program during the last part of pregnancy should be implemented as a standard practice. As too low birth weights are also linked to higher mortality rates, such feeding practices would also increase birth weights of kids and thereby survival rate.

The author wishes to convey her sincere appreciation to all the breeders who participated in the project, to everybody who assisted with data collection on the farms and to Mohair South Africa for funding of the project. Participating breeders were very positive about the project and gave excellent co-operation.

BREEDING PROGRAM FOR LIVESTOCK GUARDING DOGS

AIM AND OBJECTIVES

The aim of this project is to breed livestock guarding dogs (LGD’s) for evaluation under South African conditions.

Livestock losses as a result of predators, stray dogs and stock theft is a major problem facing small stock farmers throughout South Africa. Losses in the small stock industry in South Africa due to predators amounts to approximately 1 million sheep per year. For the past few decades, this problem has been a discussion point on every forum in the small stock industry. The National Problem Animal Policy Committee was established with the aim to guide the control of predators and to ensure that the control methods employed are correctly applied. Through the years, different methods of control have been used, such as poisoning, traps, hunting dogs and electric fences. From practice it is also evident that professional predator hunters and hunting clubs have limited success in the control of problem animals.

An additional method for predator control is the LGD’s. LGD’s are being used with great success against predators in the USA, Britain, Australia and Namibia, as well as the countries of origin of these dogs. There are eight different breeds of dogs that can be used as LGD’s. Of these breeds, the Anatolian Shepherd dog is widely considered to be the best, owing to its size, aggressiveness, loyalty, braveness and working ability. The dogs protect the herd by the following methods: patrolling, barking, urine marking, chasing and attacking the predator if it threatens the herd.

RESULTS

The breeding program started at Grootfontein Agricultural Development Institute (GADI) in 2002 with five dogs. Currently the project has eight animals in its breeding program, three males and five females. During the reporting period 17 puppies were born from three bitches. The number of puppies that were born, died and placed with farmers is summarized in Table 1. The four deaths that occurred were due to natural causes. Currently puppies are vaccinated at the ages of two, four and six weeks to combat the parvovirus infection, as this was a major cause of death during the previous reporting period. Thirteen puppies were placed with farmers after vaccination and deworming. Each farmer received guidelines for raising and training of the puppies.

Table1. Number of puppies born, died and placed with participants

The placement of the puppies is summarized in Table 2. Evaluation was done on all the dogs, six months and older, that were placed with farmers that participated in the project. The dogs are only evaluated up to 2 years of age. Seven of the puppies placed were sold to farmers outside the project, due to the lack of interest from participating farmers in the project. These dogs were not evaluated, as no records were available from these farmers. The list of farmers and districts of the participants with dogs older than six months is presented in Table 3.

The evaluation of the dogs was in the form of a questionnaire that the farmers completed for each dog. Most of the dogs worked well.

Due to the fact that not enough data are available, it is not possible to make any conclusive remarks from the evaluation of the puppies. It is evident from the results that participants should take care that the dogs be handled in accordance with the guidelines of the project. Furthermore, bloodlines that consistently breed dogs with a poor working ability or behavioral problems should be identified and eliminated.

The project is running to satisfaction and the results, positive or negative, is helping to establish a working knowledge of these dogs under South African conditions.

A SURVEY ON THE EFFECTIVENESS OF DIFFERENT PROBLEM ANIMAL CONTROL METHODS IN THE SMALL STOCK PRODUCING AREAS OF SOUTH AFRICA

The aim of this project is to investigate the extent of problem animals and the effectiveness of livestock guarding dogs, as a method of problem animal control.

BACKGROUND

Loss of livestock to predation remains one of the major problems experienced by sheep and goat farmers. Many ways of dealing with the problem are practiced by farmers and new techniques are introduced on a regular basis. The effect of these methods used by farmers differs from region to region and even from farm to farm. The farmers also use their own methods for which there are no records available. The use of livestock guarding dogs (LGD’s) is a proven technique in other parts of the world and is now also gaining popularity in South Africa. This project, to obtain reliable information on the extent of livestock losses from individual producers and for the evaluation of the impact of different problem animal control methods, started in 2003. In addition, Anatolian Shepherd dogs are also introduced into the project as they become available from the Grootfontein Research Trust breeding program. Farmers buy these dogs at a subsidised price and integrate them into their flocks as prescribed. The data on the effect of these dogs on stock losses are then integrated into the database. In this way it is possible to study the efficiency of these dogs. Thirty-seven Anatolian Shepherd dogs were already placed with participants during previous reporting periods.

EXPERIMENTAL PROCEDURES

The project consists of a survey among sheep and goat farmers throughout South Africa. During the reporting period, questionnaires were sent out to 103 farmers who registered during previous years for the project. The survey is conducted by means of an annual questionnaire in which particulars of his farming enterprise, neighboring farms as well as livestock numbers were requested. Losses of livestock and predators killed were reported by means of completing a monthly questionnaire. During the reporting period, 13 more puppies (8 weeks of age) were placed with participating farmers.

The number of participating farmers and those returning their questionnaires has dropped dramatically during 2006 as indicated in Table 1.

Table 1. The number of participating farmers and those returning their questionnaires

From Table 1 it is evident that a very poor response from farmers was achieved during the reporting period. It was also noticed that most farmers withdrew from the survey part of the project soon after they received livestock guarding dogs. Due to the incompleteness of the data for 2006, it will not serve any purpose to analyse it.

EVALUATION OF PROJECT STATUS

· From the lack of co-operation, it would appear that farmers do not perceive problem animals as a matter of concern. This is in accordance with results of previous years that indicate that only approximately 4% of unweaned lambs are caught by predators.

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

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

· To carry out trials to investigate and identify the predisposing factors as well as the causative agent(s) responsible 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 Ostertagia circumcincta infection has been listed as one of the predisposing factors for the disease, this 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. The possibility that there are different clinical forms of the disease should also be kept in mind, as reported cases differed considerably in the extent of oedema, as well as with regard to other associated parameters and the duration and outcome of the disease.

A questionnaire, investigating the epidemiology of swelling disease was drawn up, and sent out to 500 Angora goat producers on 7 March 2005. Of all the questionnaires sent out, 32.2 % were returned. Of these, 65% of the respondents have encountered swelling disease on their farms, while 35% have never seen the disease.

· Only three cases of swelling disease outbreaks were reported since October 2006: one during December 2006 in the Uniondale district, one during January 2007 in the Cradock district and the third during April 2007 also near Cradock.

· For retrospective pathology, it is essential that affected goats should not be transported for a long distance and that samples be taken within 15 minutes of death. An outbreak of swelling disease occurred on a farm just outside Middelburg during March 2006. Samples from these animals were obtained for retrospective pathological investigations at Onderstepoort. There were no microscopical lesions in most of the submitted organs and tissues (skeletal muscle from scapular region, sub-iliac lymph node, myocardium, lungs, brain, liver, spleen, pancreas, kidney, adrenal gland, ileo-caecal lymph node, rumen, abomasum, duodenum/jejunum, ileum and caecum).

· In most of the cases there was clear evidence of a stereotypic dermatitis, and in some cases also multifocal steatitis of the subcutaneous fat. Even though the transudate does not appear to contain much protein (i.e. does not stain with eosin), it is likely that the oedema is the result of injury to vascular endothelium by the inflammatory process, rather than the result of osmotic or pressure changes in the vasculature. The fact that in three cases parasites, presumably alive since they did not elicit any host response, were present in the subcutis suggests that they may play a role in the development of this inflammatory oedema. The parasites that were found on and in the skin are the nymphs of the red louse (Damalinia limbata).

· The fact that the finding of parasites did not seem to correlate with the severity of oedema may be the result of either insufficient sampling or it may represent different individual host responses in time. It is, however, imperative to examine the possibility that swelling disease may be caused by infestations by red lice.

· The latter aspect should be investigated further before any conclusive results can be obtained.

ACKNOWLEDGEMENTS

The project leader wants to convey her sincere appreciation to the following people for their valuable contribution in the execution of the project:

AN INVESTIGATION INTO THE EFFECT OF DIFFERENT WEANING PRACTICES ON THE POST-WEANING GROWTH OF ANGORA KIDS and reproduction of Angora ewes

AIM AND OBJECTIVES

The aim of the project is to find practical solutions for the problems generally associated with post-weaning stress in Angora goats.

The objective of the study is to determine the effect of different weaning methods on:

BACKGROUND

Weaning is normally a stressful period in the young kids’ life and is often characterised by a decrease in weight gain 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 minimize 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.

Weaning shock and its subsequent negative effects, is one of the biggest problems in the Angora goat industry. The weaned kid goes through a very critical growth stage from weaning (4-5 months of age) until it reaches the young goat stage (2-tooth). Farmers use different practical methods in an effort to limit the negative effect of weaning shock on the post-weaning growth of the kids.

The project was started on a farm in the Middelburg district during the 2003/2004 kidding season. It was repeated at the same locality during the 2004/2005, 2005/2006 and the 2006/2007 kidding seasons. In 2006, a second participant was identified in the Jansenville district. At both localities, the farmers’ own animals were used and the animals grazed on natural veld. At the Middelburg locality, the nucleus of ewes in each group consisted of ewes that were also used in the project during the previous kidding season. Since ewes are culled from the flock as a normal management practice, replacement ewes were added randomly to the nucleus. The replacement ewes, as well as the kids of all the ewes, were randomly tagged with three different colour ear tags and numbered individually at the onset of kidding in September 2006. At Jansenville, a flock of Angora ewes and their kids were also randomly tagged with three different colour ear tags and numbered individually at the onset of kidding in August 2006. At weaning (January 2007 at Jansenville; February 2007 at Middelburg) the three treatments commenced as follow: Treatment 1 (Weaned) – Kids and ewes separated, i.e. normal weaning; Treatment 2 (Swopped) – Kids separated from their mothers and placed with other mature ewes, i.e. normal weaning, but weaned kids stayed with other ewes; Treatment 3 (Not weaned) – Kids and ewes remained together, i.e. no weaning took place.

A lot of problems were, however, experienced at the Jansenville locality. Severe drought conditions occurred at this locality in the period November 2006 until the end of February 2007. Furthermore, more than 60 kids were lost in less than two months due to predators, mainly caracal, in the camps where the animals were kept for the trial. These problems necessitated the participant to move the animals to a camp closer to home in order to supply supplementary feeding and also to protect them from predators. Therefore, the trial was terminated at this locality for the 2006/2007 kidding season and this report deals only with the Middelburg locality.

Body weights of ewes at the Middelburg locality were recorded at weaning (28/02/2007) and at scanning (11/06/2007). The mating season started on 27/03/2007 and ended on 26/04/2007. Body weights of the kids of all three groups were recorded at weaning (28/02/2007), 8-month (03/05/2007), 9-month age (11/06/2007) and 10-month age (31/07/2007). The conception and scanning percentages of all the ewes of the three groups were determined on 11/06/2007 by means of ultrasound scanning. The animals stayed in their respective groups from weaning (28/02/2007) until the final body weights of kids were recorded in July 2007. All the animals were subjected to the same management practices throughout the experimental period.

RESULTS AND DISCUSSION

The combined data of the kids for the three-year period (2003/2004 - 2005/2006 kidding season) showed that the ADG of the kids of Treatment 1 (Weaned) did not differ (P>0.05) from Treatment 3 (Not weaned), but were higher (P<0.05) than the ADG of kids of Treatment 2 (Swopped). The combined data also indicated a decline in body weight of kids after eight months of age, coinciding with the start of the dry, winter period and subsequent deterioration in grazing conditions. In the 2006/2007 kidding season, the body weight of the kids of Treatment 3 (Not weaned) was higher (P<0.05) at 9 months of age than the kids of Treatment 1 (Weaned), but did not differ (P>0.05) from Treatment 2 (Swopped).

The combined data for the three-year period from 2003/2004 to 2005/2006 indicated that the body weight change of the ewes where kids were weaned (Treatment 1) was higher (P<0.05) than for the other two groups. In 2006/2007, the body weight of the ewes at scanning was higher (P<0.05) for the ewes of Treatment 1 (Weaned) compared to Treatment 2 (Swopped), but did not differ (P>0.05) from Treatment 3 (Not weaned). In 2006/2007, the body weight change of the ewes of Treatment 1 (Weaned) from weaning until scanning was also higher than the other two groups.

In 2003/2004 and especially in 2004/2005, the conception and scanning percentages were generally in favour of the ewes of Treatment 2 (Swopped) and Treatment 3 (Not weaned), compared to the ewes of Treatment 1 (Weaned). In 2005/2006, the differences in conception and scanning percentages were relatively small and did not follow the same trend observed in 2003/2004 and 2004/2005, with slightly higher values observed for Treatment 2 (Swopped). In 2006/2007, higher values in conception and scanning percentages were observed for the ewes of Treatment 1 (Weaned) and Treatment 3 (Not weaned). Despite the variation in conception and scanning percentages of ewes observed over the past four years, it is clear that the non-weaning of kids did not have any negative effect on the reproductive rate of the ewes.

In 2004/2005 the hair production of the kids of Treatment 3 (Not weaned) and Treatment 2 (Swopped) were higher (P<0.05) that that of Treatment 1 (Weaned), which concurred with the differences observed in their body weights. The fibre diameter of the kids of Treatment 3 (Not weaned) were also higher (P<0.05) than that of Treatment 1 (Weaned) and Treatment 2 (Swopped), possibly indicating better nutritional conditions. However, in 2005/2006 no differences in hair production of kids were observed among all three groups, but the production was in general considerably lower than in the previous season.

The project procedures were repeated for a fourth year at the locality in the Middelburg district. The ADG of the kids from weaning until approximately 10 months of age did not differ between the weaned and the unweaned kids for the three-year period from 2003/2004 to 2005/2006. With regard to the body weight of the ewes, it is clear that the weaning of kids had a positive effect on body weight change from weaning until mating/scanning in all four years. The average hair production and fibre diameter of kids at the second shearing in 2004/2005 was also influenced positively by the practice of non-weaning, but no difference in hair production of kids was observed in 2005/2006 among the three groups. The project will be completed at the Middelburg locality with the final data recording in August 2007. The most important result from this study is that the non-weaning of kids did not have any negative effect on the reproduction rate of the ewes in any of the years.

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

· Mohair SA for funding of the project

· The participating farmers, Mr Jannie Moolman (Rusoord, Middelburg) and Mr Fransie Fourie (Ferreiraslaagte, Jansenville)

INVESTIGATION INTO THE EFFECT OF PLANTS AS DEWORMING AGENTS IN THE VALLEY BUSHVELD IN BOER GOATS

The aim of this project is to investigate the use of bioactive forages in the Valley Bushveld to control internal parasitism in Boer goats.

The objective of this study is to gain knowledge for the incorporation of plant secondary metabolites rich forages into grazing systems for parasite control.

Since the 1960’s, when the first anthelmintic drugs for gastrointestinal parasite control became available, chemoprophylaxis has been the main method of control. However, the emergence of resistance to anthelmintic drugs, which is now a worldwide phenomenon, together with the increased awareness of consumers about drug residues that potentially enter the food chain, has stimulated investigation into alternative approaches to the control of gastrointestinal parasitism in ruminants. Alternative approaches to the use of anthelmintics that are currently under investigation include: biological control of nematodes by using nematophagous fungi, breeding livestock for nematode resistance, nutrient supplementation of parasitised herbivores, development of vaccines against helminths and the consumption of bioactive forages. The purpose of this study is to evaluate the effect of plants as deworming agents in the Valley Bushveld in Boer goats.

The trial started on the 28 November 2006 when 267 adult Boer goat ewes were divided into 3 groups with equal body weight. Body weights were recorded every month, except December 2006. Faecal samples of all the goats were also collected monthly for determination of faecal egg counts (FEC). The animals were managed as one flock for the duration of the trial.

Body weight and monthly faecal egg counts recorded on the three ewe groups over the trial period are presented in Tables 2 and 3 respectively.

There were no differences in body weight among groups. It is noteworthy that the FEC of all the goats were very low during the entire recording period (Table 3). During the March weighing of Group C (27/03/2007), all these ewes were dosed with 8000 infective third stage Haemonchus contortus larvae. Despite this, the FEC of the goats in Group C during the following month were not higher than those of the other two groups.

Table 3. Roundworm faecal egg counts of Boer goats in the respective groups (eggs/g ± s.e.)

Natural as well as artificial infections with Haemonchus contortus were very low during the trial period. This could have been due to rather dry environmental conditions experienced. The project will continue in the next summer season.

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INVESTIGATION INTO THE EFFECT OF VITAMIN B₁₂ SUPPLEMENTATION ON THE GROWTH OF DORPER LAMBS AT KOOPMANSFONTEIN EXPERIMENTAL STATION

The aim of this project was to investigate the effect of vitamin B₁₂ supplementation on the growth of Dorper lambs.

· To identify the effect of vitamin B₁₂ supplementation via intramuscular injections on the growth performance of lambs

· To obtain information to enable better advice to sheep farmers in the Koopmansfontein area.

With regard to animal requirements, cobalt deficiency is recognised throughout the world particularly in grazing animals, meaning that almost all natural ruminant diets must be supplemented with cobalt. Cobalt is essential for ruminants, because it is required for the synthesis of vitamin B₁₂ and the only source of this vitamin in the animal body is from microorganisms in the rumen. Cobalt deficiency in ewes may influence the growth of their lambs through two mechanisms. Firstly, cobalt deficiency reduces the feed intake of ewes, thereby reducing milk production. Secondly, cobalt deficiency limits the supply of vitamin B₁₂ to the lamb during both pre-natal and post-natal development. A characteristic of cobalt deficiency is progressive weight loss in the absence of any apparent disease. Cobalt deficiency is a chronic disease with no specific signs that distinguish it from other conditions. Weight loss, poor performance and emaciation are seen. Sheep are more sensitive to the effects of a cobalt deficiency than cattle.

Koopmansfontein Experimental Station is situated in an area where the lime content of the soil is very high and has a high content of manganese, which may reduce the amount of cobalt available to plants. From previous data collected at Koopmansfontein it was evident that the reproduction and growth rates of Dorper lambs were far below average. A possible reason for the low reproduction rate could be the low growth rate of ewe lambs up to 18 months of age, which was the normal mating age. The purpose of this study was to evaluate the effect of vitamin B₁₂ injections administered intramuscularly on an interval basis to Dorper lambs at Koopmansfontein Experimental Station on their growth performance.

At the start of the project, 250 Dorper lambs with an average age of 42 days were divided into 5 groups with equal sexes in each group. Table 1 illustrates the experimental procedures that were conducted. All the treatment groups were intramuscularly injected with a commercial vitamin B₁₂ product (Vitamin B₁₂ Forté: Bayer).

The average body weights and average daily gain over the trial period for the different groups are given in Table 2. These results indicated that there were no significant differences among the groups. The final weight confirmed the results of a previous study that Dorper lambs obtained a relatively low body weight at eight months of age. The low body weight at eight months could result in a low mating weight at first mating, which in turn might be responsible for the low reproductive rate of young ewes.

Table 2. Monthly body weights (kg ± s.e.) of the different experimental groups over the trial period

From this trial it is evident that the application of a commercial vitamin B₁₂ supplement via intramuscular injections did not improve the growth rate of Dorper lambs over a period of six months at Koopmansfontein Experimental Station.

[Contents]

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.

· To supply rams bred in these community ram breeding flocks to neighboring 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. This project started in August 2002 with the identification of 16 communities by the committee members of regions 20 to 24 of the NWGA, which represent the former Transkei and Ciskei areas. The layout of the woolled sheep development program consists of:

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

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

This specific report deals with the latter of the abovementioned aspects. The nine participating communities, as well as their geographical location, are given in Table 1 and Figure 1.

Table 1. Participating communities and district municipalities in the Eastern Cape

One new community, Xume, was added as a participating community. This community is situated about 18 kilometers from Tsomo. The quality of the farmers’ sheep is below average, but the farmers are positive and also have sheep camps. Selection was done in May 2007 and 250 ewes were mated. This community was visited regularly to assist the farmers with sheep management. A farmers’ day is planned for early August 2007.

· Good progress was made at the other eight communities and these communities were better assisted than in the previous years.

· The biggest problem with selection of rams is that the farmers do not have a market place or place to keep these rams. These problems will be addressed in the next reporting year.

· Sheep scab is still one of the biggest problems experienced, especially in the surrounding communities. This problem impacts negatively on wool production and quality of affected sheep.

· Agricultural Research Council: Livestock Business Division - Animal Production.

EVALUATION OF THE GENETIC POTENTIAL FOR GROWTH AND WOOL PRODUCTION OF TYPICAL TRANSKEI EWES AND RAMS

The aim of this project was to determine the impact of the NWGA livestock improvement project in the communal areas of the Eastern Cape.

· To evaluate the commercial rams bred for the NWGA project vs. the communal rams in the communal areas of the Eastern Cape through progeny tests

· To evaluate the communal rams vs. the commercial rams in the commercial areas of the Eastern Cape through progeny tests.

This project forms part of a larger livestock improvement project for woolled sheep development in the communal areas of the Eastern Cape. The larger project of the NWGA includes a program whereby 3000 commercially bred rams are annually supplied to the communal farmers in the Eastern Cape. The aim of this project is to evaluate the impact of these rams supplied by the NWGA ram breeding project to increase the production potential of the wool sheep in the communal areas. This project was done in two phases, namely, 1) evaluating the progeny from communal and commercial bred rams under commercial conditions and 2) to evaluate the progeny of these rams under communal conditions.

The project started in March 2004 at four localities in the Tarkastad and Cathcart districts. These farmers represent the commercial farming group in the project. To establish the Transkei part of the project, four communal areas were selected on a basis that they must represent the average farming conditions of the Transkei region. In this report only the results of the wool traits will be discussed.

The average wool production and wool traits of the various progeny groups are summarised in Table 1. At the commercial farms, the average fleece weight at 6 months of age differed significantly between the commercial progeny group (2.8 kg) and that of the Transkei progeny group (2.4 kg). The average wool traits (fibre diameter, coefficient of variation, standard deviation, comfort factor and clean yield) of the commercial progeny group were better than that of the Transkei progeny group. The average wool income of the commercial progeny group was R32.58 per sheep higher than that of the Transkei progeny group.

At 3 months of age all the lambs in the communal trial were shorn due to sheep scab. At 12 months of wool growth all the lambs were again shorn for comparisons between progeny groups. The average fleece weight of 2.0 kg of the commercial progeny group was significantly higher than the 1.7 kg of the Transkei progeny group. With the exception of the percentage clean yield, the other wool traits did not differ significantly between the commercial and Transkei progeny groups. The average wool income from the commercial progeny group in the communal area was R 17.34 per sheep higher than that of the Transkei progeny group.

^{a, b} values in the same row with different superscript differ significantly (P<0.05)

These results demonstrated that by introducing commercial rams to communities in the Transkei, an improvement in the wool income is possible.

[Contents]

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

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

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.

The project commenced on the 23 February 2007 with 30 adult Merino ewes that were randomly divided into three groups, a control (10 sheep) and two treatment groups (10 sheep/group). The groups received a maintenance diet 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 is divided into two phases of 3 months each. Phase 1 was a pre-treatment phase, during which none of the groups 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. Since then, animals in treatment Group 1 received 1.5 g methionine per day orally, while the animals in treatment Group 2 received 2.5 g per day orally. The animals in the third group received an oral placebo treatment of water at the same time when the other animals received their methionine.

The body weight and staple length are collected monthly. The body weights and staple lengths of the three groups are summarized in Table 1. There are no significant differences among the staple lengths of the three groups at this stage.

ESTABLISHMENT OF A BIOLOGICAL BANK FOR THE ANGORA GOAT POPULATION IN SOUTH AFRICA

The aim of the project is to establish a biological (DNA) bank for Angora goats in South Africa. A DNA bank is essential for the application of more recent techniques for studying genetic variation, identification of genetic disorders and the search for quantitative trait loci.

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.

The first step was to establish a biological bank for the South African Angora goat population. There are various contributors to a biological bank. The first is a suitable population of live animals, the second is a source of DNA of the animals, the third is a data basis of phenotypic data of all animals in the biological bank, and the fourth is skilled manpower to operate and maintain the bank.

The mohair industry has identified the establishment of a biological bank as a priority and indicated that genetic research should in future be concentrated on molecular genetics (genomics). At the annual meeting of the Angora Goat Research Advisory Committee in August 2006, it was decided that a long-term plan for DNA research work in Angora goats should be drawn up. An important aspect is the safe storage and preservation of the blood and DNA samples in a biological bank. Consequently, a workshop was held on 17 and 18 October 2006 in Port Elizabeth to discuss the practical implementation, implications and requirements of such a biological bank. All technical people involved with Angora goat research, especially genomic research, attended the workshop. Researchers from the Department of Biochemistry at the University of Stellenbosch, the Department of Animal Science and Wildlife at the University of Pretoria, the Livestock Business Division: Animal Production of the ARC and Grootfontein Agricultural Development Institute (GADI), attended the workshop, which was funded by Mohair South Africa.

Steps are already underway to establish a DNA laboratory and central storage facility for a biological bank for South African small stock breeds at GADI. Suitable storage facilities, including –80°C freezers, are planned. A scientist, trained in biotechnology, has already been appointed to run the laboratory. Once established, the biological bank will be part of the national scientific research capacity of South Africa. It will serve as a depot of resource material for genomic research projects.

Angora goat breeders are concerned about the apparent slow rate of genetic progress within the industry. Despite the availability of scientific selection aids, such as performance testing and breeding values, very few of the breeders make use of these aids. Subsequently, the Department of Agriculture was requested to coordinate a project that will enable breeders to identify superior breeding material at an early age, and to implement this process in the industry. As much of the data that will be needed for such an investigation are already being collected through the current DNA-bank project, it was decided to extent the DNA-project to incorporate the additional traits.

The aim of this extended part of the current DNA-project is to increase profitability and competitiveness of the Angora goat industry through breeding of animals that are able to maintain a high level of mohair production (fleece weight as well as fleece quality) and reproduction throughout their herd life. The construction of a single database incorporating all available performance records of Angora goats, together with the above-mentioned data, should be a priority. This database should include data from the participants of the DNA-project, but also from other breeders that participate in the performance testing scheme. This database will be available for the identification of superior sires and dams for the entire industry.

During January 2007, blood samples were collected into 10 ml EDTA vacutainer blood collection tubes from all 2006-born kids on the farms of the participants. A total of 1306 blood samples were collected. After collection, the blood samples were divided into four to five aliquots of 1.5 – 2.0 ml blood each into Eppendorf micro tubes. These samples were frozen for future use.

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

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DETERMINING THE OPTIMUM GRAZING CAPACITY IN THE EASTERN MIXED KAROO

The aim of this project is to determine the optimum stocking rate for the Eastern Mixed Karoo veld.

During the 1970’s to mid 1980’s it became evident that much uncertainty existed amongst pasture researchers and the farming community about the stocking rates that can be applied in different veld types. The grazing capacity strategy was launched by the then Minister of Agriculture, Mr Sarel Hayward, but the Department was severely criticised by the farming community when the first grazing capacity map for South Africa was released during early 1981. This necessitated drastic measures to be undertaken and the so-called stocking rate trials came into being all over South Africa in all the provinces. One trial was initiated at Grootfontein, known as the Hereford/Afrikaner stocking rate trial. Merino and Dorper sheep were stocked at three stocking rates. The middle stocking rate was at the recommended grazing capacity, one stocking rate was slightly higher and one was slightly lower. The animals grazed in a two-paddock system with a period of grazing of four months, one of the systems that farmers were advised to follow. However, the middle stocking rate of the Merino sheep, which were stocked at the grazing capacity norm, was duplicated. In this system the paddock for the four months were sub-divided into four even sized paddocks and the sheep are moved between paddocks on a two-weekly basis.

This experiment is being carried out on two blocks of veld at Grootfontein known as Afrikaner camp and Hereford camp. The grazing period of four months results in the staggering of the grazing period, so that no paddock is grazed at the same time for two years running.

The weight gained by animals in 2005/2006 for 335 days are presented in Table 1.

Table 1. The weight gained by the Merino and Dorper sheep in the different treatments

As can be expected, the low stocking rate sheep produced well, the medium stocking rate grazing the paddock continuously for four months and continuously for two weeks faired less well and the high stocking rate did not produce well. However, production of animals in this trial was still poorer than that of the sheep in the sheep : cattle ratio trial.

From this trial it can be concluded that both the low and the high stocking rates cannot be recommended because the low stocking rate is uneconomical and the high stocking rate sheep did not produce well.

FIXED SEASON GRAZING OF THE MOUNTAIN PADDOCK IN THE FALSE UPPER KAROO

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

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

This trial was laid out by Dr C.E.M. Tidmarsh on the hilly areas of Grootfontein in 1943 for the same reasons used for initiating the Camp 6 grazing experiment. The experiment consists of six different paddocks, each being grazed differently (Table 1).

The current grazing capacity of the different paddocks is also presented in Table 1.

Table 1. Experimental layout and current grazing capacity of the different paddocks

Trait	Rams	Ewes
Birth weight (kg)	4.8±0.02	4.6±0.02
42-day body weight (kg)	16.7±0.2	15.5±0.2
120-day weaning weight (kg)	31.6±0.6	29.0±0.6
5-month body weight (kg)	32.4±0.6	29.4±0.6
6-month body weight (kg)	36.7±0.6	33.2±0.6
7-month body weight (kg)	39.4±0.7	36.2±0.7
8-month body weight (kg)	44.0±0.6	39.9±0.6
9-month body weight (kg)	47.9±0.6	42.9±0.6
10-month body weight (kg)	50.9±0.6	45.0±0.6
11-month body weight (kg)	54.4±0.6	46.5±0.6
12-month body weight (kg)	60.3±0.8	51.5±0.8
16-month body weight (kg)	63.6±0.5	51.7±0.5
Greasy fleece weight (kg)	3.45±0.06	3.14±0.06
Clean fleece weight (kg)	2.02±0.04	1.96±0.04
Fibre diameter (µm)	20.1±0.1	20.4±0.1
Clean yield (%)	58.9±0.7	61.6±0.7
Staple length (mm)	83.0±1.4	86.7±1.4
CV (%)	17.1±0.3	17.0±0.3
Staple strength (N/Ktex)	33.1±1.3	34.2±1.2

Trait	Average ± s.e.
Body weight (kg)	65.8±6.0
Clean fleece weight (kg)	1.69±0.40
Fibre diameter (µm)	20.9±1.0
Clean yield (%)	65.6±6.0
Staple length (mm)	73.9±10.1
Number of lambing opportunities	3.30
Total weight of lamb weaned (kg)	129.0±41.5
Number of lambs born	4.65±1.30
Number of lambs weaned	4.21±1.38

Trait	Genetic trend	R²
Birth weight (kg)	y = 0.0150x-0.0460	0.9335
42-day body weight (kg)	y = 0.0422x-0.0744	0.9516
120-day weaning weight (kg)	y = 0.0987x+0.0004	0.9505
9-month body weight (kg)	y = 0.3053x+0.0946	0.9851
16-month body weight (kg)	y = 0.2219x+0.1702	0.9399
Clean fleece weight (kg)	y = 0.0026x-0.1008	0.0617
Fibre diameter (µm)	y = -0.0827x-0.0362	0.9210
Crimp quality	y = 2.1695Ln(x)-0.7407	0.8992
Evenness of fleece	y = 0.0820x+0.0955	0.4624
Density of fleece	y = -0.0329x-0.1330	0.5376
Creeping belly	y = -0.0596x-1.3866	0.0937
Staple length (mm)	y = 0.0924x-2.1248	0.0960
Staple strength (N/Ktex)	y = 0.0986x-0.3933	0.6083
Total weight of lamb weaned (kg)	y = 0.0577x+0.8501	0.1256
Number of lambs born	y = 0.0024x+0.0305	0.1277
Number of lambs weaned	y = 0.0021x+0.0309	0.1118

Body weight at:	Ram Lambs		Ewe Lambs
Body weight at:	Dohne (kg)	Letelle (kg)	Dohne (kg)	Letelle (kg)
Birth	5.2 ± 0.1	5.1 ± 0.1	4.8 ± 0.1	4.5 ± 0.1
42 Days	16.1 ± 0.4	19.1 ± 0.6	15.1 ± 0.4	17.9 ± 0.6
Weaning	24.7 ± 0.8	25.1 ± 1.0	24.0 ± 0.8	23.0 ± 1.0
6 Months	36.6 ± 0.8	33.2 ± 1.2	33.3 ± 0.9	28.6 ± 1.2
8 Months	47.4 ± 0.9	43.6 ± 1.2	42.6 ± 0.9	37.6 ± 1.3

Trait	Dohne	Letelle
Body weight at mating (kg)	61.1 ± 0.6	51.4 ± 0.7
Greasy wool (kg)	3.56 ± 0.05	2.66 ± 0.07
Clean yield (%)	70.8 ± 0.4	66.9 ± 0.5
Clean wool (kg)	2.52 ± 0.04	1.79 ± 0.05
Fibre diameter (µm)	19.4 ± 0.1	17.9 ± 0.1
Staple length (mm)	77.7 ± 1.0	72.5 ± 1.3
CV (%)	19.2 ± 0.2	20.0 ± 0.2
Comfort factor (%)	99.3 ± 0.1	99.8 ± 0.1
Crimps per 25 mm	12.6 ± 0.2	15.0 ± 0.2
Duerden	96.1 ± 0.8	95.2 ± 1.0

Trait	Afrino ewes (liter)	Fine wool Merino ewes (liter)	Elsenburg Merino ewes (liter)
TMP (CV%)	162.12 (31.09)	151.46 (31.98)	77.41 (32.00)
Week 3 (CV%)	32.44 (38.51)	29.03 (38.51)	14.62 (35.79)
Week 12 (CV%)	13.87 (38.79)	14.28 (47.05)	7.49 (46.40)

Trait	Year	Flock (No. of ewes)
Trait	Year	CMS (20)	GMS-F (10)	GMS-C (10)	GMF (10)	CAS (10)	GDMS (10)
MFD (µm)	2005	17.19^a ± 0.30	16.16^b± 0.42	16.62^c± 0.44	14.4 ± 0.44	20.42 ± 0.54	15.38 ± 0.42
MFD (µm)	2006	18.68^a± 0.30	18.58^b± 0.42	19.25^c± 0.47		20.88 ± 0.38
SD (µm)	2005	3.08 ± 0.12	2.98 ± 0.17	3.26^c± 0.18	2.89 ± 0.18	4.33 ± 0.22	3.32 ± 0.17
SD (µm)	2006	3.24 ± 0.12	3.6 ± 0.17	4.01^c± 0.19		4.03 ± 0.18
CV (%)	2005	17.92 ± 0.53	18.45 ± 0.75	19.64 ± 0.79	20.08 ± 0.79	21.2 ± 0.97	21.62 ± 0.75
CV (%)	2006	17.38 ± 0.54	19.37 ± 0.75	20.73 ± 0.84		19.19 ± 0.69

Feeding period	Kraal		Veld
4–10 months of age (6 months trial period)	Group A	Group B	Group C	Group D
11-16 months of age (6 months trial period)	Group A	Group C	Group B	Group D

Trial	Groups	n	Trait	Age
Trial	Groups	n	Trait	5 months	6 months	7 months	8 months	9 months	10 months
Kraal	A	12	Area (cm² )	9.6±1.1	16.0±2.2	14.6±2.6	19.0±2.7	21.0±2.8	22.7±3.2
			Fat (mm)	3.0±0.4	3.3±0.4	3.4±0.6	5.1±0.7	5.2±0.8	5.9±0.9
			Weight (kg)	23.4±0.8	26.5±3.7	30.3±4.2	37.5±5.2	39.5±5.5	40.4±5.7
	B	12	Area (cm² )	9.6±0.9	16.9±0.5	17.5±0.5	20.3±1.9	24.5±0.6	26.0±0.6
			Fat (mm)	3.0±0.3	4.2±0.1	4.0±0.1	4.2±0.4	5.4±0.3	7.0±0.4
			Weight (kg)	24.5±0.5	31.5±0.6	34.3±1.0	41.0±1.1	45.2±1.3	46.8±1.0
Veld	C	12	Area (cm² )	11.1±0.6	12.9±1.3	11.3±1.5	10.3±2.2	12.8±1.7	15.8±1.5
			Fat (mm)	3.2±0.1	3.8±0.4	2.8±0.4	2.7±0.6	3.5±0.5	4.0±0.4
			Weight (kg)	23.4±0.7	24.4±0.6	28.6±0.6	31.5±0.5	34.9±0.6	34.8±0.6
	D	12	Area (cm² )	9.7±1.2	11.0±1.5	10.0±1.3	11.8±1.6	11.9±1.6	13.3±1.9
			Fat (mm)	2.5±0.4	3.5±0.5	3.2±0.5	3.5±0.5	3.2±0.5	3.7±0.5
			Weight (kg)	22.6±0.7	22.5±2.1	25.7±2.4	29.4±2.7	32.8±3.1	31.6±2.9

Litter number	Born alive	Died at birth	Died due to illness	Placed with participants
1	9	2	0	7
2	4	1	0	3
3	4	1	0	3
Total	17	4	0	13

Farmer	District
First litter February 2007
J. Bowker	Middelburg
J. van Onselen	Middelburg
T. van der Walt	Noupoort
T. Phillips	Grahamstown
B. Davenport	Steynsburg
K. Niemand	Modderrivier
W.P. Burger	Brandvlei
Second litter February 2007
A.G. Diedericks	Hofmeyr
A.J.L. Fourie	Hofmeyr
P.D.D. van der Vyver	Middelburg
Third litter March 2007
Cheetah Outreach Foundation	Stellenbosch
J.L. Moolman	Cradock
G. Kingwill	Graaff-Reinet

Participant Number	Farmer	District
GRT02/020	L. Botes	Prince Albert
GRT03/011	J. Niemann	Modderrivier
GRT01/020	T. van der Walt	Noupoort
GRT03/028	G. Buchanan-Clark	Middelburg
GRT01/005	T. Phillips	Grahamstown
GRT03/007	W.P. Burger	Brandvlei

	Number
Number of farmers to whom questionnaires were sent	103
Number of farmers who returned all 12 monthly questionnaires	0
Number of farmers returning 9 or more of the 12 monthly questionnaires	2
Number of farmers who returned none of the monthly questionnaires	83
Number of monthly questionnaires sent out to farmers	1236
Number of monthly questionnaires filled in and returned	106
Percentage monthly questionnaires returned	8.6%

Name	Contribution
Dr A.E. Snyman Middelburg Provincial Veterinary Laboratory	Performing of post mortem examinations
Prof M. Williams Onderstepoort Faculty of Veterinary Sciences	Retrospective pathology
Mohair South Africa	Funding of project
Participating producers	Supplying of animals Completion of questionnaires

		Dosing of animals according to management program
		No	Yes
Dosing of animals with parasites	No	No/No (Group A)	No/Yes (Group B)
Dosing of animals with parasites	Yes	Yes/No (Group C)

Groups	n	Nov 2006	Jan 2007	Feb 2007	March 2007	April 2007
A	97	53.4±0.9	53.0±0.8	54.4±0.9	56.2±0.9	57.0±0.9
B	89	53.1±0.9	55.0±0.9	55.1±0.9	55.9±0.9	56.6±1.0
C	81	50.3±0.8	54.4±1.01	54.4±1.0	54.2±0.8	54.0±0.9

Groups	n	Nov 2006	Jan 2007	Feb 2007	March 2007	April 2007
A	97	0	0	100±3.4	0	0
B	89	0	0	100±3.9	0	0
C	81	0	0	100±1.2	700±2.1	100±4.1

Groups	Interval of injections	Injection volume (ml)
A	Control - none	0
B	Every month	0.50
C	Every second month	0.50
D	Every month	1.0
E	Every second month	1.0

Group	Body weight (kg) at:								ADG (g/day)
Group	42 days	2 months	3 months	4 months	5 months	6 months	7 months	8 months	ADG (g/day)
A	24.9±0.8	25.9±0.8	26.9±0.8	27.7±0.8	27.9±0.9	28.3±1.3	26.0±0.8	29.3±1.0	24.3±3.6
B	24.3±0.6	25.3±0.7	26.2±0.6	26.7±0.7	27.7±0.7	27.7±0.7	26.6±0.7	28.7±0.7	24.5±2.1
C	25.4±0.7	26.4±0.7	27.8±0.6	28.1±0.6	28.8±0.6	28.6±0.7	26.3±0.7	30.0±0.7	29.2±2.3
D	24.1±0.7	25.1±0.7	26.3±0.6	26.6±0.6	27.6±0.5	27.9±0.5	25.9±0.5	28.8±0.5	25.0±2.1
E	24.7±0.8	25.7±0.8	26.4±0.8	27.0±0.8	26.8±0.8	27.5±0.9	25.5±0.8	28.3±0.9	22.4±1.9

Community	Region	District municipality
Dudumasha	20	Amathole
Lushington	21	Amathole
Xume	20	Chris Hani
Allan Waters	21	Chris Hani
Beckles Farm	21	Chris Hani
Qoqodala	23	Chris Hani
Rockcliff	23	Ukhahlamba
Luzi	24	Ukhahlamba
Lephakoeng	24	Ukhahlamba

	Control	Treatment 1 (1.5g/day)	Treatment 2 (2.5g/day)
Body weight (kg)
Month 1	42.65±1.13	42.50±1.13	42.90±1.13
Month 2	41.28±0.47	41.30±047	40.62±0.47
Month 3	41.08±0.62	41.38±0.62	41.09±0.62
Month 4	41.97±078	41.52±0.78	41.16±0.78
Month 5	41.73±063	42.51±0.63	41.31±0.63
Staple length (mm)
Month 2	12.29±0.37	12.24±0.37	12.80±0.37
Month 3	20.70±0.49	20.95±0.49	21.47±0.49
Month 4	30.45±0.73	31.10±0.73	31.03±0.73
Month 5	46.11±0.81	45.96±0.81	45.93±0.81

Stocking rate	Gain/animal (kg)	ADG (kg/day)
Merino sheep
Light	18.54	0.055
Medium (4 months)	14.34	0.043
Heavy	11.78	0.035
Medium (2 weeks)	14.71	0.044
Dorper sheep
Light	29.88	0.089
Medium	24.84	0.074
Heavy	17.91	0.054

Paddocks	Grazing capacity (ha/LSU)
Continuously rested	9.28
Continuously grazed	37.79

[Return]

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

AIM AND OBJECTIVES

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

BACKGROUND

ACKNOWLEDGEMENTS

Contribution

INVESTIGATION INTO THE SELECTION CRITERIA OF MERINO SHEEP

EVALUATION OF SELECTION CRITERIA FOR BOER GOATS UNDER EXTENSIVE CONDITIONS

W.J. Olivier

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

BACKGROUND

BREEDING SHEEP FOR INCREASED PROFIT PER HECTARE

INVESTIGATION INTO THE EXTENT OF MICRON BLOWOUT IN SOUTH AFRICAN WOOL SHEEP

CLOSING REMARKS

[Contents]

THE EFFECT OF EARLY GROWTH ENVIRONMENT OF DORPER LAMBS ON M. LONGISSIMUS DORSI AREA AT 16 MONTHS OF AGE

INVESTIGATION INTO REPRODUCTION AND KID MORTALITY OF SOUTH AFRICAN ANGORA GOATS

BREEDING PROGRAM FOR LIVESTOCK GUARDING DOGS

AIM AND OBJECTIVES

RESULTS

Table1. Number of puppies born, died and placed with participants

Litter number

First litter February 2007

Third litter March 2007

BACKGROUND

EXPERIMENTAL PROCEDURES

Number

EVALUATION OF PROJECT STATUS

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

BACKGROUND

ACKNOWLEDGEMENTS

AN INVESTIGATION INTO THE EFFECT OF DIFFERENT WEANING PRACTICES ON THE POST-WEANING GROWTH OF ANGORA KIDS and reproduction of Angora ewes

AIM AND OBJECTIVES

BACKGROUND

RESULTS AND DISCUSSION

· Mohair SA for funding of the project

· The participating farmers, Mr Jannie Moolman (Rusoord, Middelburg) and Mr Fransie Fourie (Ferreiraslaagte, Jansenville)

INVESTIGATION INTO THE EFFECT OF PLANTS AS DEWORMING AGENTS IN THE VALLEY BUSHVELD IN BOER GOATS

[Contents]

INVESTIGATION INTO THE EFFECT OF VITAMIN B12 SUPPLEMENTATION ON THE GROWTH OF DORPER LAMBS AT KOOPMANSFONTEIN EXPERIMENTAL STATION

[Contents]

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

B.R. King

AIM AND OBJECTIVES

INTRODUCTION

EVALUATION OF THE GENETIC POTENTIAL FOR GROWTH AND WOOL PRODUCTION OF TYPICAL TRANSKEI EWES AND RAMS

[Contents]

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

ESTABLISHMENT OF A BIOLOGICAL BANK FOR THE ANGORA GOAT POPULATION IN SOUTH AFRICA

[Contents]

DETERMINING THE OPTIMUM GRAZING CAPACITY IN THE EASTERN MIXED KAROO

FIXED SEASON GRAZING OF THE MOUNTAIN PADDOCK IN THE FALSE UPPER KAROO

INVESTIGATION INTO THE EFFECT OF VITAMIN B₁₂ SUPPLEMENTATION ON THE GROWTH OF DORPER LAMBS AT KOOPMANSFONTEIN EXPERIMENTAL STATION