Indigenous Sheep Breeds Research Articles

Insight into the Possible Formation Mechanism of the Intersex Phenotype of Lanzhou Fat-Tailed Sheep Using Whole-Genome Resequencing.

Simple SummaryIndividuals with hermaphroditism are a serious hazard to animal husbandry and production due to their abnormal fertility. The molecular mechanism of sheep intersex formation was unclear. This study was the first to locate the homologous sequence of the goat polled intersex syndrome (PIS) region in sheep and found that the intersex traits of Lanzhou fat-tailed sheep were not caused by the lack of this region. By detecting the selective sweep regions, vital genes associated with androgen biosynthesis and the follicle stimulating hormone response entry were found, including steroid 5 alpha-reductase 2 (SRD5A2), and pro-apoptotic WT1 regulator (PAWR). Additionally, the copy number variations of the four regions on chr9, chr1, chr4, and chr16 may affect the expression of the gonadal development genes, zinc finger protein, FOG family member 2 (ZFPM2), LIM homeobox 8 (LHX8), inner mitochondrial membrane peptidase subunit 2 (IMMP2L) and slit guidance ligand 3 (SLIT3), respectively, and further affect the formation of intersex traits.Intersex, also known as hermaphroditism, is a serious hazard to animal husbandry and production. The mechanism of ovine intersex formation is not clear. Therefore, genome-wide resequencing on the only two intersex and two normal Lanzhou fat-tailed (LFT) sheep, an excellent but endangered Chinese indigenous sheep breed, was performed. Herein, the deletion of homologous sequences of the goat polled intersex syndrome (PIS) region (8787 bp, 247747059–247755846) on chromosome 1 of the LFT sheep was not the cause of the ovine intersex trait. By detecting the selective sweep regions, we found that the genes related to androgen biosynthesis and follicle stimulating hormone response items, such as steroid 5 alpha-reductase 2 (SRD5A2), steroid 5 alpha-reductase 3 (SRD5A3), and pro-apoptotic WT1 regulator (PAWR), may be involved in the formation of intersex traits. Furthermore, the copy number variations of the four regions, chr9: 71660801–71662800, chr1: 50776001–50778000, chr4: 58119201–58121600, and chr16: 778801–780800, may affect the expression of the zinc finger protein, FOG family member 2 (ZFPM2), LIM homeobox 8 (LHX8), inner mitochondrial membrane peptidase subunit 2 (IMMP2L) and slit guidance ligand 3 (SLIT3) genes, respectively, which contribute to the appearance of intersex traits. These results may supply a theoretical basis for the timely detection and elimination of intersex individuals in sheep, which could accelerate the healthy development of animal husbandry.

Effect of feeding regime on skin/leather characteristics of f1 crossbreed sheep in the highlands of Ethiopia

This study was conducted to determine the effects of different levels of concentrate supplementation on the skin quality attributes of Awassi X Bonga (AB), Awassi X Washera (AW) Dorper X Menz (DM) crossbreed sheep. Forty-four lambs were assigned in to three-breed three-concentrate supplementation groups each based on body weight, randomly. Experimental animals were kept on natural pasture grazing dominated by Andropogon longipes grasses, the legume Trifolium species were supplemented 300, 600- and 900-gram concentrate. The concentrate feed had 21% crude protein 14 MJ/kg metabolizable energy on a dry matter basis with a composition of 49.5% wheat bran, 49.0% Noug cake (Guizotia abyssinica), 1% limestone and 0.5% salt. After completion of the 90 days of experimental period, animals were slaughtered fresh skins were taken to the Leather Industry Development Institute (LIDI) for skin quality-related tests. Higher level of concentrate supplementation (900g) significantly (p0.05) improved skin weight, size, thickness tear load. However, supplementation level did not show significant difference (p0.05) on moisture content at raw wet blue stage, fat content hide substance percentage. Except thickness, average tear load moisture content for raw skin, which was higher (p0.05) for DM than AB AW, all physico-chemical tests were not significantly (p0.05) different among the breeds. Nevertheless, for some of the values of quality parameters, skins from DM, 900g supplementation level are by far better. It can be concluded that skins from DM, AB AW, 300-900g concentrate supplementation levels in the diet improves production of leather that meet the acceptable range set by LIDI. Further studies on skin quality attributes including the high and lowland indigenous sheep breeds along with their different blood levels of cross breed is suggested.

Genomic Scan for Selection Signature Reveals Fat Deposition in Chinese Indigenous Sheep with Extreme Tail Types.

Simple SummaryAccording to the tail types, sheep can be briefly classified into three groups (fat-tailed, fat-rumped, and thin-tailed sheep). In this study, we used these three typical breeds from Chinese indigenous sheep breeds to perform a genome scan for selective sweeps using Ovine Infinium HD SNP BeadChip genotype data. Results showed that 25 genomic regions exhibited selection signals and harbored 73 positional candidate genes. These genes were documented not only to be associated with tail fat formation, but also be related to reproduction, body conformation, and appearance. Our findings contributed to understanding genetic basis of fat deposition in sheep tail and provide a reference for developing new sheep breeds with an ideal tail type.It is a unique feature that fat can be deposited in sheep tails and rumps. To elucidate the genetic mechanism underlying this trait, we collected 120 individuals from three Chinese indigenous sheep breeds with extreme tail types, namely large fat-tailed sheep (n = 40), Altay sheep (n = 40), and Tibetan sheep (n = 40), and genotyped them using the Ovine Infinium HD SNP BeadChip. Then genomic scan for selection signatures was performed using the hapFLK. In total, we identified 25 genomic regions exhibiting evidence of having been under selection. Bioinformatic analysis of the genomic regions showed that selection signatures related to multiple candidate genes had a demonstrated role in phenotypic variation. Nine genes have documented association with sheep tail types, including WDR92, TBX12, WARS2, BMP2, VEGFA, PDGFD, HOXA10, ALX4, and ETAA1. Moreover, a number of genes were of particular interest, including RXFP2 associated with the presence/absence and morphology of horns; MITF involved in coat color; LIN52 and SYNDIG1L related to the number of teats; MSRB3 gene associated with ear sizes; LTBP2 considered as a positional candidate genes for number of ribs; JAZF1 regulating lipid metabolism; PGRMC2, SPAG17, TSHR, GTF2A1, and LARP1B implicated with reproductive traits. Our findings provide insights into fat tail formation and a reference for carrying out molecular breeding and conservation in sheep.

Genetic improvement of indigenous Greek sheep and goat breeds

The objective of the study was twofold: (i) to review the genetics of production and resilience traits of indigenous Greek small ruminant breeds as well as the evolution of national breeding programs, and (ii) explore innovative and feasible approaches to overcome the challenges and constraints towards improving these breeds and enhancing the sustainability of the small ruminant sector. Previous studies on the genetic basis of production and resilience traits of indigenous breeds revealed high improvement potential. However, the lack of follow-up action has failed to produce applicable results. Thus, implementation of scientific findings in existing breeding programs for these breeds is extremely limited. The latter has contributed to the overall poor success of such programs. Furthermore, due to the fact that most farmers do not comprehend the strategic importance of genetic improvement and lack motivation for self-funding, breeding programs have mostly relied on European or government funding; the latter has resulted in intermittent implementation. Therefore, most programs failed to improve performance of indigenous Greek breeds, many of which were consequently replaced by foreign breeds of higher productivity and documented merit. In order to facilitate the design of breeding schemes and overcome the challenges towards improvement of indigenous breeds, an integrative approach is necessary. The latter should be based on identification of specific breeding objectives, reflecting the priorities and needs of the sector, as well as the capacity of the indigenous populations. Scientific advances exemplified by genomic selection and novel reproductive technologies will enable faster and more effective genetic improvement. The overall approach is expected to enhance the competitiveness of indigenous Greek small ruminant breeds and the sustainability of the sector.

Genetic structure of Iranian indigenous sheep breeds: insights for conservation.

Genetic structure and genetic diversity levels of indigenous Iranian sheep breeds are not clear, despite the interest this region has in itself as an important center for domestication of livestock. Early population genetic studies have reported high levels of diversity among Iranian sheep breeds until recently, when high admixture levels and genetic homogeneity have been detected. The rapid reduction of diversity observed in Iranian breeds might be due to an increasing trend of intensive crossbreeding practices or even total replacement of native breeds by highly specialized and productive ones. From a conservative perspective, this situation is highly concerning; thus, it might be wise to consider a conservation program in Iran to preserve the original genetic diversity in native sheep breeds. In this study, a total of 1065 animals with the purest morphological features representing 24 Iranian indigenous sheep breeds were sampled, corresponding to ancestral breed diversity. These samples were genotyped for 17 microsatellite loci in order to (1) determine the native ancestral diversity of Iranian breeds, (2) define the degree of genetic relationship among studied breeds, and (3) assess conservation priorities among defined groups. Our results showed no recent loss of diversity, but high genetic diversity levels for indigenous sheep breeds in Iran. Indeed, the analysis of conservation priorities pointed out the importance of 8 breeds for maintaining Iranian sheep breeds' maximum genetic diversity. Thus, under a genetic perspective, these 8 breeds should be the ones included into conservation programs for restocking endangered areas.

Conservation-based breeding program for indigenous sheep breeds in Ethiopia: the way forward.

Conservation-based breeding program for indigenous sheep breeds in Ethiopia: the way forward.

Evaluating fertility and growth rate potential of indigenous sheep breeds submitted to heat stress under different management systems.

Objective:Sheep farming is an important source of livelihood in the southern Khyber Pakhtun Khwa province of Pakistan where they are reared under extensive system (ES). This system has limitations of improper feeding, rearing, and management which negatively affect their productivity. The present study compares different rearing systems and their stresses on fertility, behavior, and growth rate potential of two sheep breeds of Pakistan.Materials and Methods:Eighty ewes were selected; forty each from Damani and Balkhi breeds reared in semi-intensive system (SIS) and ES at Paharpur district, Dera Ismail Khan. Blood samples were collected in triplicate on days 0, 14, and 28 of May, and the molecular and behavioral stress, growth, and fertility rates were recorded.Results:The highest growth and fertility rate were observed in both the breeds in SIS than in ES (p < 0.01). The values of stress indicators (cortisol, heat shock protein (HSP-70)) and behavioral stress parameters were found lower in Damani breed as compared to Balkhi breed in both rearing systems (p < 0.01). All the molecular stress and behavioral stress parameters were negatively associated with metabolic hormones (T3 and T4) (p < 0.01). A positive correlation was observed among all the molecular stress and behavioral stress parameters (p < 0.01). Similarly, T3 and T4 were positively interlinked to one another (p < 0.01).Conclusion:It was concluded that both Damani and Balkhi sheep showed lower stress levels and better fertility and growth parameter in SIS than ES system of rearing. Local Damani breed exhibited well tolerant ability and genetic adaptation to the local environment as compared to Balkhi breed.

Review on Production Systems, Farmers Trait Preferences and Breeding Practice of Indigenous Sheep Breeds in Ethiopia

In Ethiopia sheep serve as a source of income, meat, milk, skin, manure and employment for smallholder rural farmers. Sheep are the most preferred animals by rural poor communities as they require small investment, have shorter production cycles faster growth rates and greater environmental adaptability as compare to large ruminant. The objective of this senior seminar is reviewing on Production Systems, Selection criteria and Breeding practice of indigenous Sheep Breeds in Ethiopia. Rural households are practicing animal husbandry in diverse production systems and climatic zone which are classified as three major different production systems; highland sheep-barely, mixed crop-livestock and pastoral and agro-pastoral production systems. However, sheep production and productivity in the country is challenged by scarcity of feed, diseases outbreak, poor infrastructure, lack of market information, lack of knowledge, absence of planned breeding programs and policies. The existed sheep type in the country is really the output of human intervention and natural selection. Traits like coat color, tail type, horn and ear size of sheep can also have dynamic effect on the price of sheep marketing. For selecting breeding ram’s farmers consider different traits like body conformation, coat color, tail type/size, growth rate, sexual drives, dentation and the quality of being adapted and record of ancestors. Breeding ewes are selected by farmers as a replacement stock based on their Coat color, twining ability, lamb growth, lamb survival, age at first lambing and lambing intervals. In Ethiopia the main objective of sheep production is to provide income, meat, milk, skin, manure and employment for smallholder rural farmers. In Ethiopia both pure-breeding and crossbreeding are the most common sheep breeding practice. Farmers practice both selection and crossbreeding to improve their breeding stocks. Therefore, the economic value each trait should be assessed because it influenced the market value of sheep and the decision of farmers in selecting breeding stocks. The establishment of standard marketing systems and market information calls further investigation.

Productivity of Krivovir Strain and its Importance on Sheep Farming in Republic of Serbia

The area of central Serbia is very suitable for sheep production, because of it’s hilly and mountainous configuration. Such area is rich in pastures for ruminants. In the territory of central Serbia, representative of autochthonous (indigenous) sheep breeds is pramenka (zackel) with its differentiated strains: Sjenica strain, Svrljig strain, Krivovir strain, Karakachan strain, Pirot strain, Lipa strain and Bardoka (White Metohian strain). Aim of this study was to investigate Krivovir strain: number of controlled heads and their part in total sheep population, their productivity parameters and milk parameters. In this study, total of 789 adult animals were observed. Average observed body weight (BW) of lambs were: BW on birth 3.22 kg, BW after 30 days 10.55 kg and BW on weaning 24.99 kg, while BW of adult sheep was 50.52 kg. Fertility index was 1.17 and average wool production was 2.88 kg. Average lactation after weaning lasted for 100 days, with milk production 65.16 kg, 3.91% protein and 6.72% milk fat. Krivovir strain is participating with 0.4% of total number of controlled sheep in central Serbia. Although in small number, this strain is irreplaceable in sustainable systems because they are evolutionary adapted to the conditions in which they are reared and because of their contribution to gene pool and agro-biodiversity.

Characterization of the wool fiber physical properties of Ethiopian indigenous sheep breeds

The physical properties of wool fiber considered as vital attribute to grade, classify and select a raw wool fiber for different textile applications. Limited works have been done in Ethiopia to address this subject. In this research, the physical properties (mainly the fineness, crimp and strength) of wool fiber of Ethiopian indigenous sheep breeds have been investigated. Four Ethiopian indigenous sheep breeds such as Menz, Wollo (no wool from its belly), Farta and Tikur (no wool from its belly) were considered. Fibers sampled from four body parts at four defined ages of each sheep breeds. All samples have been conditioned for 24 h at 20 ± 1 °C temperature and 65 ± 2% relative humidity. The results revealed that the fineness, crimps and strength of the four indigenous sheep breeds are significantly different from each other. The wool fiber from Ethiopian sheep breeds is suitable for textile production. Hence, these wool fibers are classified based on their breeds to use for different textile applications.

Transcriptomic analyses revealed common tailed and perirenal adipose differentially expressed genes in four Chinese indigenous sheep breeds

ABSTRACT Fat deposition and distribution in different body sites are associated with livestock productivity. In some sheep breeds, fat is excessively accumulated around the tail region, which is regarded as the fat-tail phenotype. Though some plausible genes or genomic regions associated with the fat-tail phenotype were identified, further validation of them in different individuals and breeds is still required. In this study, we implemented differential expression analysis using RNA-seq data in longissimus dorsi muscle tissue (MUT), perirenal adipose tissue (PAT) and tail adipose tissue (TAT) of Hu sheep, which is a representative of short fat-tailed sheep. The result identified 1336, 427 and 665 differentially expressed genes (DEGs) in MUT, PAT and TAT of Hu sheep respectively. Of those, 600 DEGs and 336 DEGs showed unique expression in TAT and PAT, respectively. In addition, integrated analyses of our data with published data from small-tailed Han sheep, Guangling large-tailed sheep and Tan sheep found 9 DEGs in PAT and 13 DEGs in TAT of Hu sheep have similar expression patterns in the remaining three sheep breeds. Among 9 DEGs in PAT, WT1, TCF21, PPFIBP1 and WNT10B may have important roles in perirenal adipose formation. Among 13 DEGs in TAT, PKD2L1 and MST1 may play significant roles in the maintenance of unsaturated fatty acid content in TAT. Five genes that were previously reported to be correlated with tailed fat deposition were further validated in current study, including CITED1, HOTAIR_2, HOTAIR_3, HOXC12 and HOXC13. Furthermore, we also investigated the expression pattern of 42 candidate genes identified by selection signature analysis or genome wide association analysis from published studies. Two of them were found to be highly expressed in TAT, including PPP1CA and PEX6. Our findings identify candidate genes for tail fat deposition across different breeds and pave a solid foundation for studying the regulation of fat deposition in sheep in the future.

A Preliminary Study on Grazing Pattern of Sheep Transhumance in Turkey

Grazing activities of indigenous sheep breed of the Turkish breed Karakaş and Koçeri which were transhumance flocks were investigated in a typical unimproved mountainous pasture in the East of Turkey. Data were collected from two different flocks on main daily activities (grazing, resting, moving or standing) every fifteen minutes. The characteristics of the pastures around the routes were assessed according to CORINE Land Cover classification system. Standing was a residual activity in both study paths. The animals concentrated their activity mostly on grazing while resting and moving occurred in specific times during the whole grazing period. Once the animals were heading back to their main settlement areas to be milked, grazing activity have been increased. Further studies on grazing behavior and changes in land cover will help to adjust the management strategies to the available natural resources.

Molecular genetic diversity and relationship of indigenous sheep breeds of Pakistan based on nuclear microsatellite loci

&lt;p&gt;En Pakistán los recursos genéticos ovinos son abundantes, disponiéndose de varias diferentes castas extendidas en todo el país. No obstante, la diversidad molecular de las razas de ovejas es poco conocida en la región. Por ello, en el presente estudio se investigaron 16 marcadores microsatelitales de las razas indígenas Buchi y Hashtnagri, en las provincias de Pendjab y Balochistan respectivamente. Para indagar la diversidad genética se obtuvieron muestras de sangre de 25 animales de cada raza. El promedio del número de alelos en Buchi y Hashtnagri fue de 3,375±1,455 y 3,50±1,591 respectivamente. Los promedios de heterocigosis registradas fueron de 0,878±0,204 para la raza Buchi y 0,885±0,218 para Hashtnagri. Los índices de Shannon fueron 1,032±0,371 para Buchi y 1,070±0,412 para Hashtnagri, respectivamente. La estimación de los coeficientes de endogamia (FIS y FIT) mostró valores negativos, en tanto que el flujo genético (migración) fue de 10,09 y el promedio de la diferencia poblacional (FST) resultó de 2,4%. En ambas razas, el índice de información polimórfica fue 0,56, indicando el valor del marcador del tablero. Entre las ovejas Buchi y Hashtnagri, la distancia genética estándar de Nei (Ds) fue 0,0218. Según estos resultados, ambas razas mostraron considerable diversidad genética. Los datos obtenidos permiten vislumbrar una promisoria mejoría en el área de la conservación y en el diseño de las estrategias para la cría de ovejas en el futuro cercano.&lt;/p&gt;

Inferring the population structure of the Maghreb sheep breeds using a medium-density SNP chip.

North Africa has a great diversity of indigenous sheep breeds whose origin is linked to its environmental characteristics and to certain historical events that took place in the region. To date, few genome-wide studies have been conducted to investigate the population structure of North African indigenous sheep. The objective of the present study was to provide a detailed assessment of the genetic structure and admixture patterns of six Maghreb sheep populations using the Illumina 50K Ovine BeadChip and comparisons with 22 global populations of sheep and mouflon. Regardless of the method of analysis used, patterns of multiple hybridization events were observed within all North African populations, leading to a heterogeneous genetic architecture that varies according to the breed. The Barbarine population showed the lowest genetic heterogeneity and major southwest Asian ancestry, providing additional support to the Asian origin of the North African fat-tailed sheep. All other breeds presented substantial Merino introgression ranging from 15% for D'man to 31% for Black Thibar. We highlighted several signals of ancestral introgression between North African and southern European sheep. In addition, we identified two opposite gradients of ancestry, southwest Asian and central European, occurring between North Africa and central Europe. Our results provide further evidence of the weak global population structure of sheep resulting from high levels of gene flow among breeds occurring worldwide. At the regional level, signs of recent admixture among North African populations, resulting in a change of the original genomic architecture of minority breeds, were also detected.

Characterizing the Wool Fiber Fineness and Crimps of Menz, Dorper and Their Crossbreed Sheep

Ethiopia possesses about 30 million of sheep population which could be taken as a source of raw material for textile industries as a wise strategy to manage their natural fibers scarcity. This work explored the possible wool fiber potentials on selected sheep breeds. Three representative breeds as indigenous (Menz), exotic (Dorper) and crossbreed (50% Dorper/50% Menz) sheep breeds were considered to characterize the wool fiber properties. Samples have been taken from four main body parts for four age categories of each sheep breeds. All samples were allowed to standard laboratory conditioning before testing, and then, properties are measured based on ASTM. The results revealed that the fibers diameter and crimp frequencies of wool fiber of the three sheep breeds in Ethiopia are significantly different from each other. The crossbreeding of the Menz sheep with Dorper provides fine wool fiber. The wool fiber properties particularly the fineness and crimps of Menz, Dorper and 50% Dorper sheep of different parts and age categories are significantly different. Hence, these wool fibers shall be classified and graded based on their breeds to use for different applications, and also it could help to explore more on wool fiber production.

Detection of copy number variation and selection signatures on the X chromosome in Chinese indigenous sheep with different types of tail.

ObjectiveChinese indigenous sheep breeds can be classified into the following three categories by their tail morphology: fat-tailed, fat-rumped and thin-tailed sheep. The typical sheep breeds corresponding to fat-tailed, fat-rumped, and thin-tailed sheep are large-tailed Han, Altay, and Tibetan sheep, respectively. Detection of copy number variation (CNV) and selection signatures provides information on the genetic mechanisms underlying the phenotypic differences of the different sheep types.MethodsIn this study, PennCNV software and F-statistics (FST) were implemented to detect CNV and selection signatures, respectively, on the X chromosome in three Chinese indigenous sheep breeds using ovine high-density 600K single nucleotide polymorphism arrays.ResultsIn large-tailed Han, Altay, and Tibetan sheep, respectively, a total of six, four and 22 CNV regions (CNVRs) with lengths of 1.23, 0.93, and 7.02 Mb were identified on the X chromosome. In addition, 49, 34, and 55 candidate selection regions with respective lengths of 27.49, 16.47, and 25.42 Mb were identified in large-tailed Han, Altay, and Tibetan sheep, respectively. The bioinformatics analysis results indicated several genes in these regions were associated with fat, including dehydrogenase/reductase X-linked, calcium voltage-gated channel subunit alpha1 F, and patatin like phospholipase domain containing 4. In addition, three other genes were identified from this analysis: the family with sequence similarity 58 member A gene was associated with energy metabolism, the serine/arginine-rich protein specific kinase 3 gene was associated with skeletal muscle development, and the interleukin 2 receptor subunit gamma gene was associated with the immune system.ConclusionThe results of this study indicated CNVRs and selection regions on the X chromosome of Chinese indigenous sheep contained several genes associated with various heritable traits.

Insights into Sheep Genetic Improvement Practices Through Crossbreeding in Ethiopia: Achievements, Challenges and Future Prospects

Crossbreeding is one of the genetic improvement methods that enables to utilize between breed genetic variations. It is one of the main sheep genetic improvement strategies practiced for decades in Ethiopia. This review assessed achievements, challenges and future prospects of sheep genetic improvement through crossbreeding in Ethiopia. The crossbreeding scheme involves crossing of exotic breeds with indigenous as well as between indigenous sheep breeds. To improve growth performance of indigenous sheep, a number of exotic sheep breeds were imported from abroad although literature sources about the performance of crossbreeds is available only for Awassi and Dorper sheep crosses. Promising results have been reported in few areas where crossbreeding has been performed effectively. An evidence for this is the realization of up to 10kg yearling live weight superiority of crossbreeds with 50% and above Awassi and Dorper sheep blood levels over the indigenous sheep. As a national genetic improvement strategy, however, crossbreeding achievement in terms of improving productivity of indigenous sheep is generally minimal. Notably, Absence of well-deigned crossbreeding program, miss-match between genotypes and the environment, and resource limitation to maintain and multiply adequate number of exotic sheep and crossbreeds are the major challenges hindering the success of indigenous sheep genetic improvement through crossbreeding. In the future, the use of crossbreeding as a potential strategy for indigenous sheep genetic improvement relies on bringing long lasting solutions to the current problems. In general, implementing well-designed crossbreeding program, particularly between improved exotic sheep and indigenous sheep, should be the primary focus to improve productivity of indigenous sheep. In this way, the contribution of indigenous sheep resources for the smallholder farmers in particular and the country’s economic growth in general can be maximized. At the same time, protecting the valuable genetic resources of indigenous sheep should be an integral part of the crossbreeding program. Keywords: genetic improvement, indigenous sheep of Ethiopia, sheep crossbreeding DOI : 10.7176/ALST/75-01 Publication date :June 30 th 2019

Genetic homogenization of indigenous sheep breeds in Northwest Africa

Northwest-African sheep represent an ideal case-study for assessing the potential impact of genetic homogenization as a threat to the future of traditional breeds that are adapted to local conditions. We studied ten Algerian and Moroccan breeds of sheep, including three transboundary breeds, distributed over a large part of the Maghreb region, which represents a geographically and historically coherent unit. Our analysis of the dataset that involved carrying out Genome-wide SNP genotyping, revealed a high level of homogenization (ADMIXTURE, NetView, fineSTRUCTURE and IBD segments analyses), in such a way that some breeds from different origins appeared genetically undistinguished: by grouping the eight most admixed populations, we obtained a mean global FST value of 0.0024. The sPCA analysis revealed that the major part of Morocco and the Northern part of Algeria were affected by the phenomenon, including most of the breeds considered. Unsupervised cross-breeding with the popular Ouled-Djellal breed was identified as a proximate cause of this homogenization. The issue of transboundary breeds was investigated, and the Hamra breed in particular was examined via ROH fragments analysis. Genetic diversity was considered in the light of historical archives and anthropological works. All of these elements taken together suggest that homogenization as a factor affecting the Maghrebin sheep stock, has been particularly significant over the last few decades, although this process probably started much earlier. In particular, we have identified the policies set by the French administration during the colonial period of the region’s history as a causal factor that probably contributed significantly to this process. The genetic homogenization that we have observed calls into question the integrity of the farm animal genomic resources represented by these local breeds, whose conservation is of critical importance to the future of the livestock sector.

Genetic polymorphism in IGF-1 gene in four sheep and goat breeds and its association with biometrical traits in migratory Gaddi goat breed of western Himalayan state of Himachal Pradesh, India

Sheep and goat production is a predominant livestock activity in harsh climatic regions of the country particularly in hilly areas. The goat and sheep population in Himachal Pradesh is 1.12 and 0.81 million respectively. Gaddi and Rampur-Bushair are the two indigenous sheep breeds of the state well adapted to the prevalent migratory production system. The somatotrophic axis (GH/IGF-I axis) is considered as the key in postnatal growth and metabolism in different mammals including farm animals. The technique of PCR-RFLP was used to analyze polymorphism of IGF-1 gene in sheep and goat breeds of Himachal Pradesh and to study association with body measurements in Gaddi goats. For polymorphism studies, genomic DNA was isolated from 63, 68, 197 and 73 animals belonging to Gaddi sheep, Rampur- Bushair sheep, Gaddi goat and Chegu goats, respectively.. PCR amplification of IGF-1 yielded 363 bp amplicon. The PCR-RFLP digestion of amplified products with HaeIII revealed three fragments of 363 bp, 264 bp and 99 bp after digestion. Allele frequencies for A allele were 0.66 0.59, 0.65 and 0.70 and for B allele were 0.34, 0.41, 0.35 and 0.20 in Gaddi sheep, Rampur-Bushair sheep, Gaddi goat and Chegu goat, respectively. The frequency of AA, AB and BB genotypes ranged from 0.38 to 0.55, 0.30 to 0.42 and 0.14 to 0.19 in different breeds studied .The Ne, Hobs and Hexp ranged from 1.80 to 1.99, 0.30 to 0.43, 0.42 to 0.48, and 0.33 to 0.37, respectively in different populations. The PIC revealed median level of polymorphism in studied breeds. Alignment of sequences also confirmed presence of C/G substitution at 264 bp. Nucleotide variability was found at 17 places between different breeds. Genetic variability was detected among all four breeds studied, however no significant association could be detected in Gaddi goats.

Dorper sheep cross breeding with Indigenous sheep breed in Ethiopia

The objective of this review paper was to review dorper sheep cross breeding with indigenous sheep breed in Ethiopia. The paper reviewed and discussed the history of dorper breed introduction, research and development efforts in crossbreeding and their performance under on-station and on-farm management. Formal survey on farmers perception on Dorper cross sheep indicated that the crossbred dorper sheep have non selective feed behavior and excellent in meat production under farmer`s management. On other study showed that dorper sheep was not meet farmer interest in breeding sheep aspect because of black coat color. The performance of indigenous sheep and their crosses with Dorper varied as per the location, management, farming conditions and percentage of exotic blood level inheritance. Different research output by team of researchers on farm and on station performance evaluation of dorper indicated that crossbreds often outperformed their local contemporaries. Under on farm condition, body weight at different ages was significantly higher in 50% Dorper crosses as compared to their 25% and75% counter parts.On station birth weight of Dorper (3.39 3.8 kg) better than crossbreed (3.0 3.24 ± 0.04 kg) and local sheep (2.36 2.77 kg), respectively.While the mean weaning weight (14 16 kg) and yearling weight (26.95 32.43 ± 0.46 kg) of 50% Dorper crossbreed was better than indigenous sheep breeds. However, crossbred ewes and local sheep breeds did not differ in litter size. Dorper crosses with Afar under on station is not economically important due to lower weight in all aspects. Crossbreeding programs of dorper with indigenous sheep require strong research and development support from public service and non-governmental institutions for sustainable design, optimization, and implementation in clearly defined production environments.