The Damara in the context of Southern Africa fat-tailed sheep breeds

Sheep production is one of the most important activities in animal production in tropical regions. Southern Africa (SA) fat-tailed sheep such as the Afrikaner, Namaqua Afrikaner, Nguni, Persian Black Head, Tswana, Pedi, Sabi, and particularly the Damara are important animal genetic resources very well adapted to their harsh home environments. In this review, autochthonous sheep genetic resources of SA are reviewed regarding history and productive performance. A special focus is made to the most internationalized of such breeds: the Damara. The following aspects are reviewed: history, standards, productive performance in SA, and importation to Australia. Finally, a reference is made to the influence of fat-tailed sheep formation of composite breeds such as the Dorper or the Meatmaster.     

Multivariate characterisation of the phenotypic traits of Djallonke and Sahel sheep in Northern Ghana

The characterisation of the small ruminant populations in developing countries will play a major role in the maintenance of the genetic resources as the basis for future improvement in livestock production. The present study aimed at morphological characterisation of the two main breeds of sheep in Ghana by assessing variation within and between breed populations using principal component and discriminant analyses. The two breeds were the Sahel and the Djallonke sheep of both sexes and of two groups namely, young (1 year old, consisting of 74 animals) and mature sheep (≥2 years old, comprising 219 animals). The analysis of variance revealed significant (P?<?0.05) differences in the morphological traits of the Sahel and the Djallonke sheep breeds with higher values recorded for the former. Sexual dimorphism was in favour of male animals in all the morphological traits examined. Mature animals also had comparative advantage over the young. Two principal components were extracted to discern the structure of the two genetic groups. The most discriminating traits between the two sheep breeds were rump height, height at withers, neck girth and pin-bone width. Mahalanobis distance between the two genetic groups was 5.723 (P?<?0.0001). The developed discriminant functions clearly discriminated and classified the Sahel and the Djallonke sheep into their breeds of origin, thus yielding 100, 93.4 and 90.4 % accurate classification for the rams, ewes and the overall sheep population, respectively. The present approach would greatly help in establishing management and conservation policies for the sustainable production of the two Ghanaian sheep breeds.     

Genetic diversity of Afrikaner cattle in southern Africa

The Afrikaner is an indigenous South African breed of “Sanga” type beef cattle along with breeds such as the Drakensberger and Nguni. Six composite breeds have been developed from crosses with the Afrikaner. Additionally, Afrikaner has been the base from which exotic breeds were established in South Africa through backcrossing. The study examined genetic diversity of Afrikaner cattle by genotyping 1257 animals from 27 herds in different geographic areas of South Africa and Namibia using 11 microsatellite markers. Multiple-locus assignment, performed using the Bayesian clustering algorithm of STRUCTURE, revealed three underlying genotypic groups. These groups were not geographically localized. Across herds and markers, the proportion of unbiased heterozygosity ranged from 0.49 to 0.72 averaging 0.57; mean number of alleles per locus ranged from 3.18 to 7.09, averaging 4.81; and allelic richness ranged from 2.35 to 3.38, averaging 2.67. It is concluded that a low inbreeding level of 2.7% and a moderate to high degree of variation still persists within the Afrikaner cattle breed, despite the recent decline in numbers of animals.     

Genetic and demographic bottleneck analysis of Indian camel breeds by microsatellite markers

The genetic and demographic bottleneck analysis of Indian camel breeds was carried out utilizing 40 microsatellite markers. Allelic polymorphism was observed at 20 loci in the Indian dromedary breeds. A total of 66 alleles were scored. The average number of alleles, expected heterozygosity and polymorphic information content were, respectively, 3.25?±?0.27, 0.56?±?0.04 and 0.49?±?0.04 in Bikaneri; 3.25?±?0.25, 0.53?±?0.03 and 0.46?±?0.03 in Jaisalmeri; 3.0?±?0.21, 0.53?±?0.04 and 0.45?±?0.03 in Kachchhi and 3.1?±?0.19, 0.51?±?0.03 and 0.44?±?0.03 in Mewari breed. Higher genetic variation was observed in most numerous Bikaneri breed. Genetic distances were least between the breed pair Bikaneri and Jaisalmeri which was closely placed with the Kachchhi breed. The Mewari camels had relatively higher genetic distance from the other three Indian dromedary breeds. The bottleneck analysis revealed the presence of genetic bottleneck in all four breeds of Indian dromedary. However, the qualitative graphical method resulted in normal L-shaped distribution of allele frequencies in Jaisalmeri breeds and shifted mode in Bikaneri, Kachchhi and Mewari breeds. The demographic bottleneck analysis revealed minimum reduction (?9.65 %) in the population of camels in Jaisalmeri breeding tract as compared to that of Bikaneri (?14.18 %), Kachchhi (?27.78 %) and Mewari (?32 %) breeding tracts. Conclusively, the genetic bottleneck analysis could explain the demographic bottleneck in the Indian dromedary populations. Therefore, appropriate conservation and improvement efforts are needed in all four dromedary breeds with immediate attention on Mewari and Kachchhi breeds. The present study is the first report in demonstrating the genetic basis of demographic bottleneck in the Indian dromedary populations.     

Genetic diversity of Swiss sheep breeds in the focus of conservation research

There is constant pressure to improve evaluation of animal genetic resources in order to prevent their erosion. Maintaining the integrity of livestock species as well as their genetic diversity is of paramount interest for long-term agricultural policies. One major use of DNA techniques in conservation is to reveal genetic diversity within and between populations. Forty-one microsatellites were analysed to assess genetic diversity in nine Swiss sheep breeds and to measure the loss of the overall diversity when one breed would become extinct. The expected heterozygosities varied from 0.65 to 0.74 and 10.8% of the total genetic diversity can be explained by the variation among breeds. Based on the proportion of shared alleles, each of the nine breeds were clearly defined in their own cluster in the neighbour-joining tree describing the relationships among the breeds. Bayesian clustering methods assign individuals to groups based on their genetic similarity and infer the number of populations. In STRUCTURE, this approach pooled the Valais Blacknose and the Valais Red. With BAPS method the two Valais sheep breeds could be separated. Caballero & Toro approach (2002) was used to calculate the loss or gain of genetic diversity when each of the breeds would be removed from the set. The changes in diversity based on between-breed variation ranged from −12.2% (Valais Blacknose) to 0% (Swiss Black Brown Mountain and Mirror Sheep); based on within-breed diversity the removal of a breed could also produce an increase in diversity (−0.6% to + 0.6%). Allelic richness ranged from 4.9 (Valais Red) to 6.7 (Brown Headed Meat sheep and Red Engadine Sheep). Breed conservation decisions cannot be limited to genetic diversity alone. In Switzerland, conservation goals are embedded in the desire to carry the cultural legacy over to future generations.     

Temporal and spatial patterns of abundance and breeding activity of Namaqua sandgrouse in South Africa

We examined various measures of temporal and spatial patterns of abundance and breeding activity of Namaqua sandgrouse Pterocles namaqua (presumably mostly for P. n. furvus) in South Africa. Bird-atlas maps indicating reporting-rates and extensive-counts showed that the majority of Namaqua sandgrouse concentrate in Bushmanland, in the north-western Cape Province, from December to March. From April to July the sandgrouse move north and east of Bushmanland and apparently return to Bushmanland from August to November. This west-east movement occurs at a relatively constant rate of 30-50 km per month. Only 15% of the sandgrouse ringed at an estate within the eastern part of this species range returned the following winter. Follicle diameter and brood-patch measurements increased significantly from July to August, at the time when the majority of birds leave the estate. Belly-soaking was more prevalent in early summer in Bushmanland than in any season in the east. South African populations of Namaqua sandgrouse are partial migrants which breed primarily in early summer (October - November) in Bushmanland.     

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.     

Diversity analysis of sheep breeds from Southern peninsular and Eastern regions of India

Information is presented on the genetic diversity and relationship among six Indian sheep breeds/populations belonging to the Southern peninsular and Eastern agroecological zones, based on microsatellite markers. Parameters of genetic variation, viz., allele diversity, observed heterozygosity, gene diversity and population inbreeding estimates, were calculated for the six breeds. The allele diversity ranged from 6.40 to 7.92, whereas the gene diversity varied from 0.617 to 0.727. The highest allele and gene diversity was observed for Nellore sheep, while the lowest was exhibited by Garole breed. Within population inbreeding estimate (F _IS) revealed a significant deficit of heterozygotes in Deccani, Madgyal, Nellore and Garole, whereas Ganjam and Chhotanagpuri sheep showed an excess of heterozygotes. The contribution of each breed to the total diversity of the breeds was quantified by the Weitzman approach. The marginal loss of diversity incurred with removal of Nellore and Garole breeds was higher (>27%), whereas removal of Deccani breed resulted in lowest loss of diversity (3.84%) from the set. Estimation of the genetic differentiation (F _ST) and genetic distance (D _A) between the pairs of breeds revealed a close relationship between Deccani and Madgyal sheep (F _ST = 0.017; D _A = 0.080) and greatest demarcation between Madgyal and Garole breeds (F _ST = 0.110; D _A = 0.622). The information generated would help in shaping genetic management and conservation programs for the sheep breeds under consideration.     

Opportunities for conservation and utilisation of local pig breeds in low-input production systems in Zimbabwe and South Africa

Purpose and methods

In situ conservation of pig genetic resources requires understanding of the farming systems under which the pigs are kept. The objective of the study was to characterise smallholder pig production systems where indigenous pigs are kept in order to assess opportunities for in situ conservation of these pigs. Factors influencing pig herd sizes, ranking of pigs in smallholder production systems, breeds and breed preferences, pig ownership patterns, traits preferred by farmers and constraints to production were investigated in a survey involving 199 farmers from Chirimhanzu District of Zimbabwe, Vhembe, Alfred Nzo and O. R. Tambo Districts of South Africa.

Results

Income was the major factor influencing most pig production related parameters. Most pigs (69.67 %) were owned by women, with most of the women falling into the very low income group. Farmers kept pigs for several reasons that were common across geographical zones and income groups. The odds of a farmer ranking pigs first in the production system depended on the absence of other livestock (P?<?0.05). Farmers in the higher income group tended to mention poor feed resources and access to information as constraints (P?<?0.05) compared to the very low income group. There was preference heterogeneity in the breeds kept and the reasons for breed choice across the income groups and geographical zones. Fewer farmers in the very low income group (42.62 %) recognised the need to conserve local pigs compared to the low income group (80.49 %), the medium income group (50.00 %) and the high income group (100.00 %; χ ²?=?19.14; P?<?0.001).

Conclusions

It was concluded that farmers see value in local pigs and are willing to conserve them. In situ conservation programmes are possible and these should recognise the role of poor women in conserving and enhancing indigenous pig genetic resources.     

Genetic analysis of post-weaning growth traits of Thalli sheep under tropical conditions

Present investigation was carried out to study the influence of genetic and non-genetic factors affecting post-weaning performance traits in Thalli sheep. Data on post-weaning growth of Thalli sheep maintained at Livestock Experiment Station, Rakh Ghulaman, District Bhakkar-Punjab, Pakistan during 1977–2003 were subjected to genetic analysis. The average values for weight at 180 and 270 days of age, yearling weight and post-weaning average daily gain were 22.37?±?4.21, 25.96?±?4.90 and 28.93?±?5.20 kg and 28?±?0.01 g/day, respectively. Weight at 180, 270 and 365 days of age and post-weaning average daily gain were significantly affected by year of birth, sex, type of birth and weaning weight (covariable) whereas season of birth was a significant source of variation for 180 and 270 days of age. The heritability estimates for 180 and 270 days, yearling weight and post-weaning average daily gain were 0.07?±?0.02, 0.08?±?0.02, 0.07?±?0.02 and 0.07?±?0.02, respectively.     

Clinicopathological investigation on caseous lymphadenitis in local breed sheep in Algeria

This study was carried out of 4,419 animals raised in an extensive system on local breed sheep of the Tiaret region during 2 years (2010–2011) to determine some clinical and pathological aspects associated to caseous lymphadenitis (CL). Clinical examination revealed a prevalence rate of 5.7 %. CL prevalence rate was significantly higher in females (6 %) than in males (4.8 %). The most affected superficial lymph nodes were mandibular lymph nodes (46.1 %). Gross examination of 1,679 carcasses of sheep at the abattoir revealed the presence of abscesses on 250 carcasses (14.9 %). Out of 105 cases showing lesions of CL, Corynebacterium pseudotuberculosis (53.6 %) was isolated as mixed infection with Staphylococcus aureus (43 %) and Escherechia coli (17.9 %). CL prevalence was significantly higher in adult than in young sheep and in female than in male ones. Visceral form of CL was associated to “thin ewe syndrome” responsible for significant economic losses in Algeria.     

Prevalence, molecular diagnosis and treatment of Mycoplasma conjunctivae isolated from infectious keratoconjunctivitis affected Lohi sheep maintained at Livestock Experiment Station, Bahadurnagar, Okara, Pakistan

Mycoplasma conjunctivae are etiological agents of infectious keratoconjunctivitis (IKC), commonly known as pink-eye in domestic sheep, goats and other wild animals in many parts of the world. A few young Lohi lambs maintained at Livestock Experiment Station (LES), Bahadurnagar, Okara, Pakistan showed clinical signs and symptoms of conjunctivitis, keratitis, severe lacrimation and varying degree of blindness. During January to March, 2011, a total of 36 ocular swabs were collected from IKC affected animals and were processed for isolation, identification, and characterization of M. conjunctivae. Sixteen (44.44 %) out of 36 samples showed turbidity in PPLO broth. Twelve (75 %) out of 16 broth samples showed colony growth on PPLO agar. All 16 (44.44 %) out of 36 turbid broth samples, 12 (75 %) out of 16 cultured on agar plate samples, and 21 (59 %) out of 36 sheep ocular direct swab samples were found positive for M. conjunctivae through polymerase chain reaction test by using M. conjunctivae-specific primer pair McoF1 and McoR1 and detecting a 750 base pair fragment on agarose gel. Topical application of 0.5 % sterile solution of gentamycin (100 mg/ml) (Gentafar 10 %, FARVET, Netherlands) proved suitable for the treatment of IKC in Lohi lambs as all clinical signs of IKC disappeared after 5 days of treatment with this antibiotic. This is the first report about the prevalence, molecular diagnosis, and treatment of M. conjunctivae in Lohi sheep affected with infectious keratoconjunctivitis at LES, Bahadurnagar, Okara, Pakistan.     

Genetic diversity and conservation of South African indigenous chicken populations

In this study, we compare the level and distribution of genetic variation between South African conserved and village chicken populations using microsatellite markers. In addition, diversity in South African chickens was compared to that of a reference data set consisting of other African and purebred commercial lines. Three chicken populations Venda, Ovambo and Eastern Cape and four conserved flocks of the Venda, Ovambo, Naked Neck and Potchefstroom Koekoek from the Poultry Breeding Resource Unit of the Agricultural Research Council were genotyped at 29 autosomal microsatellite loci. All markers were polymorphic. Village chicken populations were more diverse than conservation flocks. structure software was used to cluster individuals to a predefined number of 2 ≤ K ≤ 6 clusters. The most probable clustering was found at K = 5 (95% identical runs). At this level of differentiation, the four conservation flocks separated as four independent clusters, while the three village chicken populations together formed another cluster. Thus, cluster analysis indicated a clear subdivision of each of the conservation flocks that were different from the three village chicken populations. The contribution of each South African chicken populations to the total diversity of the chickens studied was determined by calculating the optimal core set contributions based on Marker estimated kinship. Safe set analysis was carried out using bootstrapped kinship values calculated to relate the added genetic diversity of seven South African chicken populations to a set of reference populations consisting of other African and purebred commercial broiler and layer chickens. In both core set and the safe set analyses, village chicken populations scored slightly higher to the reference set compared to conservation flocks. Overall, the present study demonstrated that the conservation flocks of South African chickens displayed considerable genetic variability that is different from that of the assumed founder populations (village chickens).     

Indigenous sheep breeds of North Ethiopia: characterization of their phenotype and major production system

A study was conducted in Tigrai, Northern Ethiopia to describe the sheep breeds and their production system. The survey was done in selected districts known for their high sheep population density. The phenotype characterization identified distinct features for each breed. The breeds are Aberegelle, Ille, Begait, and the common Tigrai highland sheep. The strong discriminating phenotypes are face profile, tail type, and compactness; accounting for 83.48, 17.95, and 2.93 % respectively of the total variability among breeds. The flock structure are affected by the market demand; requirements of breeding females and feed availability. Farmers tend to keep more female sheep for longer (culling age of 5.9?±?0.4 and 1.9?±?0.5 for females and males, respectively) for the reasons of feed shortage and need to maximize number of breeding female. The ratio of male to overall female is large (1:6) and thus a single ram gets maximum contact time with ewes and ewe lambs. The overall average age at puberty for females is 9–14 months. However, the presence of very young lamb rams and uncontrolled mating system lead to early breeding of females which results in low conception rate, low birth weight, poor survival rates, and in extreme cases causing inbreeding. It was also possible to identify the critical control points such as breed, age of animals, nutrition, and feeding systems affecting the provision of live animals for good meat quality.     

Population genetic structure of Santa Inês sheep in Brazil

This study aimed to describe the population genetic structure and evaluate the state of conservation of the genetic variability of Santa Inês sheep in Brazil. We used pedigree data of the Santa Inês breed available in electronic processing of the Brazilian Association of Sheep Breeders. A file with 20,206 records, which enabled the calculation of the genetic conservation index (GCI), individual inbreeding coefficient (F), change in inbreeding (ΔF), effective population size (Ne), effective number of founders (?_e), effective number of ancestors (?_ɑ), generation interval (L), average relatedness coefficient of each individual (AR), and Wright’s F-statistics (F _IT, F _IS, and F _ST). For pedigree analysis and calculation of population parameters, the program ENDOG was used. The average inbreeding coefficient (\( \overline{F} \)) was 0.97% and the mean average relatedness (\( \overline{\mathrm{AR}} \)) 0.49%. The effective numbers of founders and ancestors were, respectively, 199 and 161. The average values of F and AR increased significantly over the years. The effective population size fluctuated over the years concurrently to oscillations in inbreeding rates, wherein N _e reached just 68 in the year 2012. The mean average generation interval was 5.3 years. The Santa Inês breed in Brazil is under genetic drift process, with loss of genetic variation. It requires the implementation of a genetic management plan in the herd, for conservation and improvement of the breed.     

Research opportunities in the field of animal genetic resources

Animal genetic resources are those animal species that are used, or may be used, for the production of food and agriculture, and the populations within each of them. The working unit of a database for farm animal genetic resources is the breed, a term taken in its widest possible sense to mean a population within the species, possessing a number of particular traits that permit the grouping of these animals under a common label and are associated to geographical areas and human groups. Research opportunities cover a wide range of thematic areas. The biggest gap in knowledge is animal breeding for local populations in harsh environments. There is also a lack of research in functional genetics and genomics of adaptation and disease resistance traits. By comparison, breed characterization, in particular molecular characterization, has been a more popular research subject. The same can be said for conservation, although some fundamental questions on genetic diversity and risk of its loss are still unanswered. Research is required to understand the socio-economic, infrastructural, technical and formal constraints that limit the operation of sustainable conservation programs in less developed countries. Information systems on animal genetic resources need input from research and data capture networks, in order to achieve a reasonable degree of completeness. Economic analysis and issues related to gene flow and access and benefit sharing should also profit from more research.     

采用微卫星DNA标记分析巢湖鸭异地小群保种效果

本研究利用筛选后的12对荧光标记微卫星引物分析巢湖鸭原产地(庐江)与国家水禽种质资源基因库(泰州)2个群体的保种效果。检测判定了160个个体的基因型,通过计算2个群体的优势等位基因频率(P)i、期望杂合度(He)、多态信息含量(PIC)、群体内近交系数(Fi)s分析了巢湖鸭群体内和群体间的遗传变异,采用配对试验均数差异t检验比较了基因库保种群体与原产地群体的遗传差异。结果表明:基因库保种群体与原产地群体间的Pi无显著性差异(Pi=0.480>0.05);He和PIC均略高于原产地群体,但差异均不显著(PHe=0.209、PPIC=0.118);Fis显著高于原产地群体(PFis=0.022<0.05)。结果说明,基因库较好地保存了该品种并在一定程度上丰富了品种的遗传多样性,初步表明对巢湖鸭采取异地小群保种的方法是可行的。     

Genetic structure and diversity among sheep breeds in the United States: identification of the major gene pools

Understanding existing levels of genetic diversity of sheep breeds facilitates in situ and ex situ conservation activities. A comprehensive evaluation of US sheep breeds has not been previously performed; therefore, we evaluated the genetic diversity among and within 28 US sheep breeds. Both major and minor breeds were included in the analysis and consisted of 666 animals from 222 producers located in 38 states. The level of within-breed genetic diversity was variable and not dependent upon status of a breed as a major or minor breed. Bayesian cluster analysis indicated the breeds were grouped more by physiological differences (meat vs. wool production) rather than geographic origin. Results suggest several actionable items to improve in situ and ex situ conservation. The results clearly identify breeds in need of increased in situ and ex situ management (e.g., Hog Island and Karakul) and allow several suggestions for in situ management of flocks. Conversely, several of the breeds appear genetically similar and therefore require less emphasis on collecting germplasm samples for the gene bank. Commercially important breeds (e.g., Rambouillet and Suffolk) were found to have substantial variation, which should enable breeders to proceed, unencumbered by genetic diversity concerns, with selection strategies that maximize profit.     

我国6个绵(山)羊群体遗传分化的微卫星分析

为进一步了解我国绵(山)羊群体的品种特性及其遗传分化,本文利用微卫星标记对我国6个绵(山)羊群体遗传分化进行了分析。采用中心产区典型群随机抽样方法用聚丙烯酰胺凝胶电泳检测乌珠穆沁羊7个微卫星位点,并引用同实验室小尾寒羊、滩羊、湖羊、同羊、长江三角洲白山羊(参照群体)的相关资料进行群体遗传分化水平分析。研究表明:7个微卫星位点在乌珠穆沁羊、小尾寒羊、滩羊、湖羊、同羊、山羊这6个品种中均存在遗传多态性,各座位等位基因均较丰富。根据标准遗传距离、DA遗传距离以及模糊相容关系进行聚类分析,湖羊与同羊首先聚为一类,乌珠穆沁羊和小尾寒羊聚为一类,然后与滩羊聚为一类,5个绵羊品种最后与山羊相聚。