Zulu Sheep Research Articles

An Update on South African Indigenous Sheep Breeds’ Extinction Status and Difficulties during Conservation Attempts: A Review

South African indigenous breeds’ population is decreasing at a time when their genetic material is mandatory due to the rising climate change and global warming. South African indigenous sheep breeds include Namaqua Afrikaner, Zulu, BaPedi, and Damara sheep. These breeds are the most preferred breeds by rural farmers in South Africa due to their adaptability, low feed, and veterinary requirements. However, since they are characterized by small body sizes, farmers tend to crossbreed them with exotic breeds. An early survey conducted in Kwa-Zulu Natal revealed a 7.5% decline in Zulu sheep between 2008–2011. It has recently been observed that the population left is genotypically mixed with exotic genetic material due to uncontrolled breeding techniques that rural farmers apply. Therefore, the aim of this review is to address the present status, difficulties, and conservation approaches applied to save these breeds. However, this review will be limited to the current extinction status as it appears in the Food and Agriculture Organization (FAO) system, data from recent studies, difficulties limiting the conservation success of these breeds, and the current conservation approaches in use to conserve these breeds.

Influence of season and rangeland-type on serum biochemistry of indigenous Zulu sheep

Abstract There is a paucity of information on the serum biochemistry of indigenous Zulu sheep in different seasons and rangeland type. Twenty clinically healthy Zulu rams aged at least 12 months were selected in different rangeland type, namely, Moist Coast Forest and Thornveld (MCT), Dry Highland Sourveld (DHS), Moist Zululand Thornveld (MZT), Natal Sour Sandveld (NSS), and Lowveld (LV) in KwaZulu-Natal from November 2014 to June 2015. Sheep with highest body weights were observed in LV and NSS (P < 0.05). Sheep with highest body condition score were found in MCT, LV, and DHS (P < 0.05). The concentration of albumin was high (P < 0.05) in MZT and DHS and low (P < 0.05) in NSS. Globulin and total protein concentrations were high (P < 0.05) in NSS. Albumin, total protein, and creatinine levels were higher in dry season (P < 0.05). Glucose and blood urea nitrogen were higher in rainy season (P < 0.05). In LV, albumin concentration was high in rainy season than in dry season (P < 0.05). In NSS, albumin concentration was high in dry season than in rainy season (P < 0.05). Globulin concentration was higher during dry season in MCT (P < 0.05). In MCT, there was a higher total protein concentration in dry season than in rainy season (P < 0.05). In NSS, the concentration of β-hydroxyl-butyrate was significantly higher in rainy season compared to dry season. Creatinine concentration was significantly high during dry season in LV, NSS, and MCT. There was a positive correlation on body weight against globulin, total protein, creatinine, and β-hydroxyl-butyrate (P < 0.05). Serum biochemistry of Zulu sheep varied with rangeland type, season, and their interactive effect.

The Genetic Assessment of South African Nguni Sheep Breeds Using the Ovine 50K Chip

The indigenous sheep breeds of South Africa, such as the Nguni, are well adapted to different ecological regions throughout the country. This has resulted into different ecotypes. However, it is not clear if the differences among Nguni sheep are genetically distinct. The present study aimed to use the latest technology to assess the genetic relationship between Nguni sheep ecotypes and the relationship to other selected South African breeds using SNP markers. In the current study, 144 South African sheep samples (75 Nguni sheep and 69 mixed-breed sheep as a reference) were genotyped using the OvineSNP50 Bead Chip assay from Illumina. The Nguni consisted of 25 Pedi, 25 Swazi, and 25 Zulu sheep, with the reference group comprising 25 Namaqua, 23 Dorper, and 21 Damara sheep. After quality control of 54,241 SNPs, 48,429 SNPs remained for analysis (MAF > 0.05). There were genetic differences in the Nguni sheep population; notably, the Zulu and Swazi populations clustered together, but with a clear distinction from the Pedi ecotype. Genetic admixtures were detected in the Damara and Dorper sheep. This is most likely a consequence of recent intermixing between indigenous and commercial breeds. The levels of genetic diversity within individual types were generally lower compared to commercial breeds. This study revealed an understanding regarding genetic variation within and among indigenous sheep breeds, which can be used as baseline information for establishing conservation and breeding programmes.

A Comparative Study on the Reproductive Performance of South African Indigenous Sheep Breeds Following Oestrus Synchronization

The aim of the study was to compare the effect of age and live body weight on the oestrus response, duration, pregnancy rate and lambing rate among South African indigenous sheep breeds (Zulu sheep = 36, Bapedi sheep = 26, Damara sheep = 10 and Namaqua Afrikaner sheep = 9). Control Intravaginal Drug Release Dispensers (CIDR’s) were inserted into the vagina for 10 days. The twitching of tail and standing to be mounted in the presence of the teaser ram were most targeted signs of oestrus. Data were subjected to an appropriate analysis of variance (ANOVA). The scores were subjected to 1:1 Frequency table and a Chi-Square (χ²) test for the equal proportions test. One Bapedi ewe loss CIDR before removal date hence was removed from the experimental animals. All Namaqua Afrikaner (100%) ewes responded to the synchronization protocol with the longest oestrus duration (70.7±7.2 h). However, Namaqua Afrikaner sheep scored the lowest rate for conception (44%) and lambing (44%). No significant different (P>0.05) observed for the onset of oestrus among the breeds. Four years old ewes responded better to oestrus synchronization than ≤3, 5 and ≥6 years. Nevertheless, ewes that were ≥6 years old had higher conception rate (94%) and lambing rate (84%). Zulu sheep had higher (89%) lambing rate than Damara (60%) sheep and Namaqua Afrikaner (44%) sheep. Lighter ewes had higher conception (83%) and lambing rate (90%) than heavier (77 and 64%) and moderate (68 and 78%) weights, respectively. In conclusion, Zulu sheep were more fertile than other South African indigenous breeds following oestrus synchronization. On the other hand, young ewes (≤3 years) produced heavier lambs and weaning weight but had higher mortality rate due to inexperience.

Spatio-seasonal variations in the faecal bacterial community of Zulu sheep grazing in communally managed rangeland

The adaptation of Zulu (Nguni) sheep (Ovis aries) to environmental stress and survival under extensive conditions makes them uniquely important to rural Nguni farmers of South Africa. Here, the faecal bacterial community of five Zulu sheep populations managed under extensive conditions across summer and winter seasons was investigated in order to understand the influence of prevailing seasonal factors. Bacterial operational taxonomic units (OTUs)/species (at 97% 16S rRNA gene similarity) in Zulu sheep faeces were more diverse in winter than in summer at most (80%) sites and varied between seasons at specific sites. Firmicutes was the most abundant phyla in both summer and winter seasons, while the relative abundance of Actinobacteria reduced in 80% of sites from summer to winter. The genera (or family) such as Akkermansia, Eubacterium coprostanoligenes group, Intestinibacter, R-7 group (family Christensenellaceae), Ruminococcus, Ruminoclostridium, Treponema and UCG-005 (family Ruminococcaceae) were relatively more abundant and belonged to a ‘core microbiome’ of Zulu sheep faeces. Between seasons, Acinetobacter, Jeotgalicoccus, Methanobrevibacter, Phascolarctobacterium and Planomicrobium were differentially abundant. Overall, results suggest increased richness and diversity of bacteria from summer to winter which may be related to spatio-seasonal variations in grazing management, forage types and availability. This observation serves as baseline evidence, justifying further controlled studies investigating, amongst other factors, effects of forage type and availability across seasons on ruminal microbiota of Zulu sheep grazing in communally managed rangelands.
 Significance:
 
 Spatio-seasonal dynamics in the bacterial community of Zulu sheep faeces suggest differences in forage type and availability across sites potentially influence faecal bacteria of Zulu sheep.
 The study provides a basis for further controlled studies investigating the influence of environmental factors on rumen and faecal microbiomes of Zulu sheep.
 
 Open data set: 
 https://www.ncbi.nlm.nih.gov/sra/?term=PRJNA356736

The Current Status of Indigenous Ovine Genetic Resources in Southern Africa and Future Sustainable Utilisation to Improve Livelihoods

Indigenous sheep play an important role in the livelihoods of communal farmers in the Southern Africa Development Community (SADC), and this underlines the need to curb the genetic erosion of these valuable resources. This contribution reports that the phenotypic performance and genetics gains of institutional and commercial sheep in Southern Africa are well recorded. In contrast, there is a dearth of knowledge as far as the performance and genetic gains of indigenous ovine genetic resources utilized by smallholder farmers are concerned. High levels of genetic diversity have been observed in exotic breeds, whereas low levels of genetic diversity were found in the Zulu and Namaqua Afrikaner breeds. Phenotypic measurements for indigenous resources include linear measurements indicative of size and reproduction for Zulu sheep. Lamb survival, reproduction and resistance to ticks of the indigenous, fat-tailed Namaqua Afrikaner sheep, as well as growth and reproduction have also been recorded for Sabi and Landim sheep. This review discusses ways to sustainably utilize ovine genetic resources, which includes the suggested implementation of structured breeding and conservation programs, marketing, improving feed resources, health and diseases, as well as gender and age issues. Clearly, there is ample room for further research and development as far as the performance and improvement of African indigenous sheep are concerned.

Genetic structure of South African Nguni (Zulu) sheep populations reveals admixture with exotic breeds.

The population of Zulu sheep is reported to have declined by 7.4% between 2007 and 2011 due to crossbreeding. There is insufficient information on the genetic diversity of the Zulu sheep populations in the different area of KwaZulu Natal where they are reared. The study investigated genetic variation and genetic structure within and among eight Zulu sheep populations using 26 microsatellite markers. In addition, Damara, Dorper and South African Merino breeds were included to assess the genetic relationship between these breeds and the Zulu sheep. The results showed that there is considerable genetic diversity among the Zulu sheep populations (expected heterozygosity ranging from 0.57 to 0.69) and the level of inbreeding was not remarkable. The structure analysis results revealed that Makhathini Research Station and UNIZULU research station share common genetic structure, while three populations (Nongoma, Ulundi and Nquthu) had some admixture with the exotic Dorper breed. Thus, there is a need for sustainable breeding and conservation programmes to control the gene flow, in order to stop possible genetic dilution of the Zulu sheep.

17 Relationship Between Semen Parameters and Morphometric Characteristics of Zulu Rams

Zulu sheep is an adapted breed of South Africa with desirable traits such as their ability to thrive in a harsh environment and tolerant to various diseases. However, they are endangered, with their population size not exceeding 1000, and hence are associated with high inbreeding rates. Therefore, to limit biodiversity loss, there is a need to characterise and conserve its genetic materials. The aim of the study was to evaluate the relationship between morphometric characteristics and semen parameters of Zulu rams and conserve these genetics. The study was conducted at the Agricultural Research Council. Rams (n = 6, age = 3 years and average weight = 42 kg) were fed a standard diet and water was provided ad libitum. Semen was collected twice a week, using an artificial vagina, over 4 consecutive weeks. Semen volume, spermatozoa concentration, motility parameters, and viability were evaluated immediately after arrival in the laboratory. The experiment was carried out during breeding season (March to May 2017). Body measurements (rump height, body length, scrotum circumference, body weight, scrotal width, and scrotum length) were measured in the morning following the fasting period (night) using flexible measuring tape. Pearson correlation coefficient in Minitab 17 (Minitab Inc., State College, PA, USA) was used to determine the relationship among variables. A moderate significant correlation (P < 0.001) between body weight and %live spermatozoa (r = 0.46) was observed. Of note, a very weak (r = 0.28) significant correlation (P < 0.05) between scrotum circumference and live spermatozoa was observed. A very weak (r = 0.06) nonsignificant correlation (P > 0.05) was found between scrotum circumference and semen volume. These results indicate that body weight and scrotum circumference provide reliable spermatozoa viability estimates. Positive correlation between scrotum circumference and semen volume shows that scrotum circumference can be used to predict semen volume.

A comparative study on the quality of semen from Zulu rams at various ages and during different seasons in KwaZulu-Natal, South Africa

Zulu sheep is a Nguni breed indigenous to the KwaZulu-Natal (KZN) province of South Africa, and is reported to be under threat of extinction. Knowledge of factors that may cause the declining numbers is required for the planning of conservation programmes. We designed a study to evaluate the effect of ram age, season and geographic location on the quality of semen. The aim was to determine which rams are best for breeding and at which time of the year. A total of 192 rams were sampled for semen and blood in 8 different locations, three times each season. Semen was collected via electro-ejaculation into semen collection tubes while venous blood was collected from the jugular vein for testosterone and white blood cell (WBC) assay. Parameters used to assess semen quality were volume, pH, sperm concentration, progressive and mass motility, percentages of live and abnormal spermatozoa. The average semen volume and spermatozoa concentration per ejaculate were similar for autumn, winter and spring while being significantly different during summer (P<0.05). Average testosterone and WBC count were significantly higher in winter (P<0.05; P<0.005). The effects of age on all seminal parameters, except for pH, were significant (P<0.05). Semen volume, sperm concentration, motility and live sperm increased linearly up to 3 years of age while scrotal circumference and live spermatozoa were greater (P<0.05) for rams at 3 than 4 years. Rams at 3 years also showed average testosterone and WBC counts that were significantly higher (P<0.05; P<0.005). A positive correlation between age and semen volume, spermatozoa concentration and semen colour was observed. The geographical location of rams did not have a significant effect on most of the semen parameters. For conservation purposes it would be most efficient to select breeding sires from among the 3-year-old rams for the winter and spring breeding programme.

Morphological differentiation amongst Zulu sheep populations in KwaZulu-Natal, South Africa, as revealed by multivariate analysis

Understanding morphological structure and variation of Zulu sheep is crucial for its identification and preservation. We measured 14 linear body measurements and scored 5 qualitative traits to evaluate the morphological variation and relationships among eight Zulu sheep populations in KwaZulu-Natal. Sheep were sampled from Empangeni, Escourt, Eshowe, Jozini, Msinga, Mtubatuba, Nongoma, and Nquthu rural communities. Dark brown coat colour, either in solid form or white patched, was most frequent amongst studied sheep. There were significant variations in body measurements amongst sheep populations from different areas. Sheep from Nqutu measured highest in most morphometric variables while sheep from Empangeni measured lowest. Discriminant analysis identified rump-width, head-width, heart-girth, thorax-depth and tail-length as the most distinguishing variables amongst sheep populations. Hierarchical cluster analysis revealed two major groups, one formed by Empangeni, Mtubatuba and Nongoma, the other by Jozini, Msinga and Eshowe populations. Estcourt and Nqutu distanced themselves from these groups as individual entities. About 62% of individual sheep could be correctly identified with the populations from which they were sampled. Nqutu had the highest percentage (88.9%) of correct assignment whilst Mtubatuba had the lowest (46.7%). High assignment errors were ascribed to a certain gene flow between sheep populations. The overall significant morphostructural variation amongst Zulu sheep populations, infers considerable genetic variability within the breed and its populations. Maintaining this genetic variation is very crucial for the continuity of the breed, as it provides animals with options to respond to change in climate, disease or consumer preference.

Genetic and phenotypic variation among four Nguni sheep breeds using random amplified polymorphic DNA (RAPD) and morphological features.

This study was conducted to investigate phenotypic and genetic differentiation among the four Nguni sheep breeds. Sheep with two permanent incisors and above were sampled from areas, namely KwaZulu-Natal (Zulu sheep), Limpopo (Pedi sheep), Mozambique (Landim sheep) and Swaziland (Swazi sheep). The Dorper was used as an out-group. Eight morphometric variables were measured from each animal, and blood samples were collected (n = 50 per population) for genetic characterization. The mean body weights for sheep were 30.41 ± 0.41, 35.34 ± 0.43, 35.23 ± 0.43, 37.63 ± 0.42 and 52.84 ± 0.30 for Swazi, Zulu, Landim, Pedi and Dorper, respectively. Morphometric cluster analysis showed the Landim, Swazi and Zulu breeds in one cluster. The Pedi sheep were closer to the Dorper than to the other Nguni sheep. Random amplified polymorphic DNA (RAPD) technique was used to assess genetic variation. Eight primers were selected for analysis based on band pattern quality, reproducibility and the presence of distinctive bands. The Swazi sheep formed a cluster with Zulu sheep, and the Pedi formed a cluster with the Dorper. These results confirm indications by other researchers that Pedi sheep are genetically distant from Zulu and Swazi sheep breeds. This could indicate the possibility of cross breeding Zulu and Swazi sheep as a possible conservation strategy to control inbreeding. The mtDNA should be analyzed to trace the relationships between Pedi and the three Nguni sheep breeds through maternal lines.

Genetic Diversity in Four Populations of Nguni (Zulu) Sheep Assessed by Microsatellite Analysis

Zulu sheep are found mainly in the rural KwaZulu-Natal province and the numbers are declining due to indiscriminate inbreeding. There is thus a need for phenotypic and genetic characterisation as a first phase for planning conservation strategies. Zulu sheep populations sampled were from Makhathini research station (MS) (n=33), University of Zululand (UZ) (n=21), a community at KwaMthethwa (KM) (n=32) and from Msinga (EM) (n=33). One European breed Appenninica (AP) was used as out group. Microsatellite analysis using 29 microsatellite loci was used in this study. Among the Zulu sheep, the mean number of alleles per locus was the lowest (3.86) in UZ and the highest (6.24) was realised in EM. The mean values of observed and expected heterozygosity were 0.57 and 0.61, respectively. Neighbour-joining tree showed two main Zulu sheep clusters: the UZ, KM and MS sheep populations clustered together and the second cluster included only representatives from the EM population. The STRUCTURE analysis showed that KM, AP and EM were founded in separate clusters, whereas UZ and MS clustered together. The study demonstrated that there was a common origin of the population from the research stations (MS and UZ populations). It also demonstrated that the EM had a different history for the other three populations. This work suggests that exchange of rams could be useful in reducing inbreeding when considering conservation breeding programmes.

Characterization of Zulu sheep production system: Implications for conservation and improvement

Understanding the production environment under which Zulu sheep are raised is essential in strategizing the breed’s conservation and improvement programme. Ninety-six farmers across 11 rural areas of KwaZulu-Natal, South Africa, were interviewed using structured questionnaires to describe traditional Zulu sheep production system, evaluate its sustainability and identify some constraints limiting production. Sheep were the least owned livestock species amongst interviewed farmers after cattle and goats. Farmers began sheep production with sample stock of fewer than four animals, either bought from other farmers or inherited through patrilineality. Sheep flock sizes were 39.8±7.5 (±SD) on average, with each flock constituting of 3.12±0.31 rams, 21.81±5.61 ewes, 4.98±0.87 yearlings and 9.92±2.05 lambs. About 43.7% of the flocks interacted with 2 or fewer neighbouring flocks during grazing time. Rate of flock size decrease was estimated at 7.4% in the past 5 years. Drought and diseases were identified as leading causes of sheep loss. Methods to controlling external and gastro-intestinal parasites were only practised when sheep showed a need. Zulu sheep were used mainly as a source of meat, income and manure and were preferred over their exotic counterparts because they were regarded tolerant to diseases and drought and for their tasty meat. The information obtained in this study is crucial in planning suitable conservation, improvement and extension programs for the breed. Key words: Production environment, animal genetic resources, socio-economic, production systems.

Morphological structure of Zulu sheep based on principal component analysis of body measurements

Information regarding morphology of indigenous sheep in South Africa is scant, and even where data exist it is rarely presented using standardised methodologies. Principal component analysis (PCA) was applied to 13 body measurements in order to provide an objective description of the body shape and size of 1665 Zulu sheep, obtained from rural communities of KwaZulu Natal. Data was analysed separate for young (no permanent incisors) and adult sheep (≥2 pairs of permanent incisors). On average mature males measured higher than mature ewes in most morphometric traits. The correlation coefficients between different body measurements in young sheep were all significant except for correlation between ear length and tail length whilst in adult sheep 79 out of 96 combinations showed significant correlation. Body weight and heart girth had the highest correlations in both age groups. Ear length and tail length related combinations had lower correlation coefficients in both age groups. The PCA of morphometric traits extracted two components with a total variance of 66.85% in young sheep and four components in adult sheep which explained a total variance of 62.13%. The first factor (PC1) in each case had high loadings for variables relating to body size, whilst PC2 had high association with traits reflecting body shape. The PC3 had high factor loadings for head length and head width, and thus defined head size. Tail length, ear length and whither height on the other hand contributed least towards total variation. The use of principal components was more appropriate than the use of original correlated variables in predicting body weight of Zulu sheep. PCA was able to identify traits with greater variability, these can be improved with greater success in breeding programmes and also the number of variables was reduced to give a concise picture of morphological structure (body size and shape) of a Zulu sheep. These components can as well be used in predicting body weight of Zulu sheep.

A review of some characteristics, socio-economic aspects and utilization of Zulu sheep: implications for conservation

Zulu sheep are Nguni sheep of Zululand and are adapted to the harsh conditions of KwaZulu-Natal. They are used by rural farmers for economic purposes. Their numbers are declining, indicating a potential extinction threat. Knowledge of their phenotypic and genotypic characteristics is essential for conservation planning. In this review, there is a focus on the utilization, socio-economic aspects, phenotypic and genotypic characteristics as well as a proposed breeding programme. A survey has shown that rural farmers in the areas of northern KwaZulu-Natal prefer to keep this breed for its adaptability, resistance to diseases and meat quality. Zulu sheep are small-framed multi-coloured animals. Mature males weigh up to 38 kg and females up to 32 kg. Based on four morphological traits and live weight, phenotypic diversity between three populations was estimated at 48%. A genetic diversity between these three populations was estimated at 22%. Live weight of Zulu sheep can be estimated using the heart girth and wither height measurements. Scrotum circumference of young rams (up to 22 months old) is reliable for estimating the live weight. Animals that were characterized in the studies were grazed extensively and no supplements were provided. There is therefore a potential of weight increase if these animals are reared in a semi-extensive environment. An open nucleus breeding scheme is thus recommended for a sustainable use and conservation of this breed. For more conclusive results, larger numbers of phenotypic and genetic characteristics, in larger numbers of Zulu sheep populations, should be investigated.

131 EFFECT OF BREED AND FROZEN - THAWED RAM SEMEN ON IN VITRO FERTILIZATION AND OVINE EMBRYONIC DEVELOPMENT

Ovine embryonic development was evaluated 8 days following in vitro fertilization, after using fresh or frozen–thawed Merino and indigenous (Pedi and Zulu) sheep semen. Semen used was collected twice weekly over a 3-month period with the aid of an electro-ejaculator. Following collection, semen samples were evaluated and semen with acceptable sperm motility and a percentage live sperm of 60% diluted with an egg yolk-based extender (Egg-Yolk Citrate). Semen samples were cryopreserved in straws with a programmable freezer to –130°C and then plunged into liquid nitrogen (–196°C) until used for IVF. Fresh and frozen–thawed semen was used to fertilize the matured oocytes in vitro. A total of 791 oocytes were fertilized using fresh semen and 802 oocytes fertilized using frozen–thawed semen. No significant differences were recorded between the fresh and frozen–thawed semen regarding the embryonic developmental stages. The performance of fresh and frozen–thawed semen followed the same trend, with the cleavage rate gradually declining with the progression in time and the embryonic developmental stage. The lowest developmental rate recorded was the occurrence of blastocyst formation, ranging between 0.4 ± 0.4% and 2.6 ± 1.0%. Regarding breed, no significant difference was observed from cleavage to the 2- to 4-cell stages. The use of fresh and frozen–thawed Zulu semen resulted in a significantly (P &lt; 0.05) higher percentage of 8-cell development compared with the Pedi semen. However, the 8-cell embryonic stage recorded with the use of the Zulu ram semen (fresh and frozen–thawed), did not differ significantly from that of the Merino breed. No significant difference between the breeds regarding blastocyst formation was recorded. The overall cleavage rate, 2- to 4-cell, and blastocyst embryonic developmental stages following the use of fresh and frozen–thawed semen from the different rams were generally lower than those recorded by other researchers. The low blastocyst rates obtained warrant more research regarding the in vitro embryo production technique in order to improve the ovine blastocyst formation rate. The study was funded by the University of the Free State and conducted at the Germplasm Conservation and Reproduction Biotechnologies ARC.

Genetic and phenotypic diversity in Zulu sheep populations: Implications for exploitation and conservation

Zulu sheep are indigenous to KwaZulu-Natal, South Africa and provide food security for traditional farmers. Through traditional selection they adapted to the climatic conditions of KwaZulu-Natal. The goal of this study was to use genetic diversity and existing phenotypic data for the breed to argue exploitation opportunities and conservation needs. Three populations (52 Zulu sheep) were included and random amplified polymorphic DNA profiles were used to provide genetic diversity data. A similarity matrix consisting of 2744 RAPD bands (∼46.0% polymorphic) was constructed. Complete linkage analysis indicated lowest genetic similarity (88.96%) within the Makhathini population, greatest (94.83%) in the UNIZULU population and intermediate (91.38%) in the KwaMthethwa population. Similar phenotypic similarity was observed for UNIZULU and Makhathini populations (58.75% and 54.63%, respectively). Complete linkage dendrograms for genetic and linear body measurement data also show that UNIZULU and Makhathini populations are more closely related to each other than to the KwaMthethwa. This study demonstrated usefulness of RAPD profiling for genetic data for Zulu sheep. It also demonstrated that phenotypic and genetic data could be sensibly combined into a single database for this sheep breed. This is important since such information will be critical for decisions regarding Zulu sheep breed exploitation and conservation.

Determination of prediction equations for estimating body weight of Zulu (Nguni) sheep

Data on linear body measurements (LBM) of 403 sheep collected in three areas of KwaZulu-Natal were utilized to develop a prediction equation for live body weight of Zulu sheep. Data were collected on live weight (LW), heart girth (HG), wither height (WH) and scrotum circumference (SC) on sheep of all ages. The age of sheep was estimated by dentition. The analysis of variance showed that age and sex were important factors contributing to variation in LW of Zulu sheep. Phenotypic correlation coefficients and regression equations of LW on HG, WH and SC were computed within different age groups (milk set of teeth, one pair, two pairs and the three and four pairs of incisors). Low correlation coefficients ( r = 0.21–0.48) between LW, HG and WH were found among the pregnant ewes. The relationship between LBM and LW was stronger ( r = 0.66–0.86) for males than among females ( r = 0.42–0.75). The cubic polynomial of HG was the best fit ( R 2 = 0.76) for the live weight prediction of young sheep with milk set of teeth. The combination of HG and WH produced the best fit for the two tooth and above males and non-pregnant females. The LW prediction equations for pregnant females were not reliable ( R 2 = 0.05–0.26). The SC was more precise ( R 2 = 0.61–0.80) when estimating the live weight of young males (<15–22-month-old) than of the older rams ( R 2 = 0.23–0.56). It was concluded that LW of Zulu sheep can be reasonably estimated using the HG and WH. A table could be constructed for the farmers to estimate the LW of their animals.

Charaterisation of Zulu (Nguni) sheep using linear body measurements and some environmental factors affecting these measurements

Data on linear body measurements (LBM) of ca. 100 Zulu sheep raised under extensive management systems at four sites in northern KwaZulu-Natal were collected over a period of 2.5 years (October 2000 to May 2003). Data were used to quantify the live weight (LW), heart girth (HG), wither height (WH) and scrotum circumference (SC) of sheep in different age groups as well as the effects of some environmental factors on their LBM. Teeth numbers were used to estimate the age of sheep. The variation in LBM was influenced significantly by the location where an animal was raised and by its age. Mature rams that have three and four pairs of incisors had LWs of 37 and 38 kg, HG of 79 and 80 cm and WH of 65 and 64 cm, respectively. Mature ewes had LWs of 30 and 32 kg, HG of 76 cm and WH of 62 and 61 cm. Differences of 15 kg, 18 kg and 22 kg in LW among sheep with full sets of milk teeth and 28 kg, 35 kg and 40 kg among mature sheep were found between populations. The SC increased with age in mature rams (three and four pairs of incisors) and was 27 cm as compared to 18 cm for younger rams. Ear size ranged from ear buds to large ears of 9 - 14 cm. However, type of ear-length was found not to have any particular influence on the variation in LBM of Zulu sheep. It was concluded that an investigation of genetic variation between the populations would be necessary to develop effective conservation and utilization programmes and strategies for the breed. Keywords: Indigenous sheep, body measurements; scrotum circumference, extensive management South African Journal of Animal Science Vol. 37 (1) 2007: pp. 11-20

Four-horned Sheep

MR. RITCHIE'S note on four-horned sheep in NATURE of March 6 is interesting, but I am inclined to doubt whether there ever was, in Scotland or any other country, a breed in which four horns are normal. No doubt it is possible to fix this character in the male sex by careful selection, as has been done by some breeders of the spotted or Barbary sheep (sometimes called Spanish, Syrian, or Zulu sheep); but even these have not succeeded in fixing the character in the female sex. I have evidence, in the shape of specimens or photographs, of the existence of four-horned sheep in North and South Africa, Mongolia, China, the Himalayas, Baluchistan, and Chile. The Iceland breed was supposed to be four-horned, and no doubt four-horned examples were often found amongst them, a specimen I have being precisely similar in type to an abnormally four-horned Shetland.