Sheep Breeds Research Articles

Distribution of genotypes by the growth diferential factor 9 (GDF-9) gene locus in the romanov breed sheep population

The FecG gene, also known as GDF-9 (growth factor differentiation factor 9), plays an important role in regulating reproductive function in mammals. This paper presents the results of a study of a point mutation in the differential growth factor gene in Romanov breed sheep. Mutations in exon 1 of the GDF-9 gene can lead to disturbances in ovarian development and ovulation, resulting in infertility or reduced reproductive capacity in animals. The object of the study was Romanov breed sheep in a sample of 30 individuals. For DNA extraction, venous blood samples were taken from the jugular vein. In Romanov breed sheep for the GDF-9 gene, it was found that at the G1 locus of this gene there are two alleles – G and A. Three genotypes were also identified: GG (254 bp/117 bp), AG (410bp/254/117 bp) and AA (410 bp/410 bp). The observed χ2 criterion was less than expected, therefore, the empirical and theoretical frequencies do not differ significantly, and deviations from the distribution according to the Hardy-Weinberg law are not observed. The observed heterozygosity index (Ho) was 0.27. Allele frequencies were 0,8 for G and 0,2 for A. For genotypes the following were obtained: GG – 0,66, GA – 0,27 and AA – 0,07.It can be noted that the data on the frequencies of alleles and genotypes in the population of Romanov breed sheep differ from the results for the Kulunda fine-wool, Dagestan mountain, Salsk, Lacaune and Merino breeds. The research results can be used to monitor changes in allele frequencies and genotypes in sheep during the selection process.

Integration analysis of transcriptome and metabolome revealed the potential mechanism of spermatogenesis in Tibetan sheep (Ovis aries) at extreme high altitude

Testis has an indispensable function in male reproduction of domestic animals. Numerous genes and metabolites were related to testicular development and spermatogenesis. However, little is known about the biological regulation pathways associated with fecundity in male Tibetan sheep. In this study, Testes were collected from Huoba Tibetan sheep (HB, 4614 m) and Gangba Tibetan sheep (GB, 4401 m) at extreme high altitude, and Alpine Merino sheep (AM, 2500 m, control group) at medium-high altitude, investigating the genes and metabolites levels of them. The histological analysis of testicular tissue using hematoxylin-eosin (HE) staining was performed for Tibetan sheep and Alpine Merino sheep, and the testes of them were analyzed by transcriptomics and metabolomics to explore the potential mechanism of testicular development and spermatogenesis. The statistical results showed that the cross-sectional area of testicular seminiferous tubules, diameter of seminiferous tubules, and spermatogenic epithelium thickness were significantly smaller in HB and GB than in AM (P < 0.05). Overall, 5648 differentially expressed genes (DEGs) and 336 differential metabolites (DMs) were identified in three sheep breeds, which were significantly enriched in spermatogenesis and other related pathways. According to integrated metabolomic and transcriptomic analysis, glycolysis/gluconeogenesis, AMPK signaling pathway, and TCA cycle, were predicted to have dramatic effects on the spermatogenesis of Tibetan sheep. Several genes (including Wnt2, Rab3a, Sox9, Hspa8, and Slc38a2) and metabolites (including L-histidinol, Glucose, Fumaric acid, Malic acid, and Galactose) were significantly enriched in pathways related to testicular development and spermatogenesis, and might affect the reproduction of Tibetan sheep by regulating the acrosome reaction, meiotic gene expression, and the production of sex hormones. Our results provide further understanding of the key genes and metabolites involved in testicular development and spermatogenesis in Tibetan sheep.

Genome-Wide Scan for Copy Number Variations in Chinese Merino Sheep Based on Ovine High-Density 600K SNP Arrays

Sheep are a vital species in the global agricultural economy, providing essential resources such as meat, milk, and wool. Merino sheep (Junken type) are a key breed of fine wool sheep in China. However, research on fine wool traits has largely overlooked the role of SNPs and their association with phenotypes. Copy number variations (CNVs) have emerged as one of the most important sources of genetic variation, influencing phenotypic traits by altering gene expression and dosage. To generate a comprehensive CNVR map of the ovine genome, we conducted genome-wide CNV detection using genotyping data from 285 fine wool sheep. This analysis revealed 656 CNVRs, including 628 on autosomes and 28 on the X chromosome, covering a total of 43.9 Mbs of the sheep genome. The proportion of CNVRs varied across chromosomes, from 0.45% on chromosome 26 to 3.72% on chromosome 10. Functional annotation through Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses highlighted significantly enriched GO terms, including odorant binding, ATP binding, and sulfuric ester hydrolase activity. The KEGG analysis identified involvement in pathways such as neuroactive ligand–receptor interaction, axon guidance, ECM–receptor interaction, the one-carbon pool by folate, and focal adhesion (p &lt; 0.05). To validate these CNVRs, we performed quantitative real-time PCR experiments to verify copy number predictions made by PennCNV software (v1.0.5). Out of 11 selected CNVRs with predicted gain, loss, or gain–loss statuses, 8 (IDs 68, 156, 201, 284, 307, 352, 411, 601) were successfully confirmed. This study marks a significant step forward in mapping CNVs in the ovine genome and offers a valuable resource for future research on genetic variation in sheep.

Comparative Phenotypic Traits and Performances of Native Sheep in Naikhongchhari Hilly Area of Bangladesh

Background: Many studies have been conducted to investigate the performance of native sheep in plains and coastal regions, but no studies have been conducted in hilly regions of Bangladesh. Considering this fact, Coastal, Barind and Jamuna River Basin sheep were evaluated for their phenotypic traits, productive and reproductive abilities to gain insights into their performance in the hilly region. Methods: The Coastal, Barind and Jamuna River Basin sheep were collected from Bangladesh Livestock Research Institute (BLRI), Savar, Dhaka for the first time to Regional Station, Naikhongchhari, BLRI and separated based on their phenotypic characteristics. A breeding program was established to ensure purity, using independent culling levels and selection indexes. Ewes were allowed to lamb throughout the year, mated with rams in a 15-20 to 1 ratio. The sheep were kept in a semi-intensive system. Result: The highest lamb birth weight was observed in coastal Region sheep, both male (1.43 kg) and female (1.22 kg), followed by Barind males (1.36 kg) and females (1.15 kg), respectively. The highest average daily gain was found in coastal region sheep (41.87 g/d), which was significantly higher compared to others. The lowest age at first heat, gestation length, age at first lambing, post-partum heat period, days open, lambing interval was observed in Barind sheep. Finally, the study offers valuable insights into the potentialities of native sheep in hilly regions, guiding future research and extension efforts for sheep farming in these areas.

The Population History of Domestic Sheep Revealed by Paleogenomes.

Sheep was one of the first domesticated animals in Neolithic West Eurasia. The zooarchaeological record suggests that domestication first took place in Southwest Asia, although much remains unresolved about the precise location(s) and timing(s) of earliest domestication, or the post-domestication history of sheep. Here, we present 24 new partial sheep paleogenomes, including a 13,000-year-old Epipaleolithic Central Anatolian wild sheep, as well as 14 domestic sheep from Neolithic Anatolia, two from Neolithic Iran, two from Neolithic Iberia, three from Neolithic France, and one each from Late Neolithic/Bronze Age Baltic and South Russia, in addition to five present-day Central Anatolian Mouflons and two present-day Cyprian Mouflons. We find that Neolithic European, as well as domestic sheep breeds, are genetically closer to the Anatolian Epipaleolithic sheep and the present-day Anatolian and Cyprian Mouflon than to the Iranian Mouflon. This supports a Central Anatolian source for domestication, presenting strong evidence for a domestication event in SW Asia outside the Fertile Crescent, although we cannot rule out multiple domestication events also within the Neolithic Fertile Crescent. We further find evidence for multiple admixture and replacement events, including one that parallels the Pontic Steppe-related ancestry expansion in Europe, as well as a post-Bronze Age event that appears to have further spread Asia-related alleles across global sheep breeds. Our findings mark the dynamism of past domestic sheep populations in their potential for dispersal and admixture, sometimes being paralleled by their shepherds and in other cases not.

Added Value of Products from Endangered Local Sheep Breeds in Mountain Areas.

Local sheep breeds in the Italian eastern Alps passed from ex situ to in situ conservation. These breeds are mainly reared by smallholders in low-input farming systems. To allow the sustainable use of genetic resources, the economic sustainability of farmers must be supported through production guidelines. Analyzing meat and milk composition and fatty acid profile, we aimed to characterize their products based on breed and diet to identify tailormade sales strategies. Results showed that both meat and milk have good nutritional values and can benefit from a pasture-based diet, irrespective of the breed. These results support the redaction of production guidelines based on the peculiar characteristics of these breeds: being multi-purpose breeds adapted to mountain areas and to grazing, thus contributing to the conservation of cultural and landscape heritage.

Characterisation of Three Ovine KRTAP13 Family Genes and Their Association with Wool Traits in Chinese Tan Sheep.

Understanding the genetic basis of wool traits is crucial for improving wool production. In this study, we investigated the ovine KAP13 gene family, which in humans contains multiple members, while only one member has been identified to date in sheep. Three ovine KRTAP13 genes, likely representing KRTAP13-1, KRTAP13-2, and KRTAP13-4, were identified through sequence analysis and phylogenetic comparisons. These genes are positioned on chromosome 1, between KRTAP15-1 and KRTAP27-1, in a pattern that is like the arrangement in humans but not identical. Analyses revealed multiple sequence variants of each gene in 356 sheep from a variety of wool, meat, and dual-purpose breeds. The effect of these genes on four fibre traits: mean fibre curvature (MFC), mean fibre diameter (MFD), coefficient of variation of fibre diameter (CVFD), and fibre diameter standard deviation (FDSD), was assessed in 240 lambs of the Chinese Tan sheep breed. An allele of KRTAP13-2 was revealed to be associated with a decrease in FDSD and CVFD in heterotypic fibres. No associations were found between KRTAP13-4 variation and wool traits, and an association analysis for KRTAP13-1 was not conducted because no variation was found in this gene in the Chinese Tan sheep studied. These findings suggest a potential role for KRTAP13-2 in regulating wool traits, particularly fibre diameter uniformity in larger heterotypic hair fibres, and suggest its potential use as a marker for improving wool traits.

Effect of Bone Morphogenetic Protein Receptor-1B (BMPR-1B) Gene Variant on Litter Size in Akkaraman Sheep Breed

The BMPR-1B gene, a significant fertility gene, has been examined for its relationship with fertility characteristics in various sheep populations globally. This investigation explored the impact of the BMPR-1B gene on litter size within the Akkaraman sheep population residing in the Elâzığ Region. To locate the FecB gene in Akkaraman sheep, 104 milk samples were collected, and genetic material was isolated using the salting out technique. During the 2021–2022 period, no significant correlations were observed between the genetic make-up of Akkaraman sheep and factors including age, mastitis and disease history, milk yield, birthing type, and the number of births (p &gt; 0.05). However, there was a noteworthy relationship identified between the distribution of genetic make-up and live weight, indicating a potential influence of genetics on the live weight of Akkaraman sheep (p &lt; 0.05). In this study, the BMPR-1B gene determined multiple births and it was determined that Akkaraman sheep were monomorphic in terms of this gene. In light of this information, it was concluded that more comprehensive studies should be carried out regarding this gene determining multiple births in the Akkaraman sheep breed.

Livestock guarding dogs shape activity patterns of sympatric mesocarnivores in sheep ranches of the Patagonia region

Predation of livestock by wild carnivores is a source of human-wildlife conflict. Livestock Guarding Dogs (LGDs) are one of the most effective non-lethal methods used. LGDs could impact wildlife due to their possible top predator role; their effect on mesocarnivores has been studied mainly in terms of space use, however, temporal effects may also exist. Our study sought to determine the possible effects of LGD presence on the activity patterns of the native foxes Lycalopex griseus and L. culpaeus in southern Chile. Activity patterns were estimated from fox detections with camera traps set on ranches with and without LGDs in Isla Riesco, Magallanes region, Chile, between 2016 and 2018. We quantified the activity patterns of each fox species in presence/absence of LGDs, and under different conditions including breeding vs non-breeding season, moon phase and vegetation cover. Both species modified their daily activity pattern, avoiding times of day of high LGD activity; nevertheless, these modifications did not change the temporal interaction between the native foxes. Activity patterns of foxes without LGDs did not differ from those in natural areas. The effect of LGDs on fox activity patterns was stronger than other ecological variables (breeding season, moon phase or vegetation cover). Since LGDs change the activity patterns of foxes, they cannot be seen as a totally innocuous predation control tool; however, carnivores’ temporal avoidance of areas with a fear-evoking agent like LGDs would result in fewer livestock-predators encounters, thus reducing sheep predation risk. LGDs appear to exert non-lethal effects upon carnivores that would contribute to reduced predation rates and may help decrease producers’ economic losses, as well as the retaliatory hunting of wild carnivores. Thus, our results support that LGDs could be contributing to the co-existence with native predators in areas destined for livestock production.

Environmental and additive genetic factors that affect artificial insemination success in Latxa dairy sheep breed

In the Latxa breed, flocks within the breeding program make use of high genetic value rams to inseminate their ewes once per year. Despite the relevance of the insemination results in the genetic progress and on farms’ productivity, external and genetic factors that affect artificial insemination (AI) success have not been up to now explored in this sheep population. For that, 135,351 edited AI records from 63,480 inseminated Latxa Cara Negra from Euskadi ewes, using 853 service rams, collected between 2000 and 2021, were used. The outcome of an AI event was treated as a binary response of either success or failure in becoming pregnant. To identify the environmental factors influencing the AI result, a multiple logistic regression was first calculated on a selection of variables related to the ewes, to the ram, and to other non-sex-specific aspects. With relevant variables detected, a threshold model, including the pedigree information of the inseminated ewes and the service rams, was used to estimate the genetic components of the trait in both sexes. Findings show that the AI success is higher in ewes who had the previous parturition from an AI event, in those with a lambing-AI interval longer than 210d, with 3 years and 2 lambings, with high prolificacy and in those having their first parturition at 1 year of age rather than at 2 or 3 years of age. In counterpart, the higher the milk produced in the nearest record before AI date, the poorer the AI results. Furthermore, relevant variability was linked to the year of insemination, the herd and the technician in charge of the insemination procedure. Regarding genetic parameters, heritability values, on the observable scale, and repeatability were 0.057 ± 0.004 and 0.204±0.007 in females and 0.009 ± 0.037 and 0.032 ± 0.002 in males, respectively. These results evidence that the AI success is under moderately low additive genetic control, with the surrounding environmental variables being the strongest controlling factor. An effort to enhance some farm management practices should be encouraged to efficiently improve reproductive results. Although genetic selection on AI success is viable, the genetic progress may be scarce. An option to improve reproduction by means of selective breeding might be the development of a multi-trait index.

Predicting Livestock Farmers’ Attitudes towards Improved Sheep Breeds in Ahar City through Data Mining Methods

Sheep breeding is one of the most important economic activities in Ahar City, Iran. However, due to traditional production techniques, livestock farmers face the problem of low productivity. To address this issue, traditional breeds can be replaced with improved and high-yielding ones; in the first stage, this requires the acceptance of these new sheep breeds by the region’s ranchers. This research aimed to evaluate the attitudes of the livestock breeders of Ahar City towards the improved breeds of sheep and the influential factors. We collected data through in-person interviews using a simple random sampling method, surveying 100 sheep breeders in Ahar. The breeders were categorized into three groups based on their attitudes towards improved breeds: negative, indifferent, and positive. Next, we employed data mining-based methods, including multilayer perceptron neural networks, random forest, and random tree algorithms. These helped identify essential variables affecting ranchers’ attitudes. The results showed that several factors contribute to the ranchers’ philosophy, with the number of sheep sold in the past year and the total sheep ownership being the most significant ones. Comparing statistical evaluation criteria, we found that the random tree algorithm outperformed other methods in predicting and classifying livestock farmers, achieving a prediction accuracy rate of 86% for a sample of 100 farmers. Based on our findings, promoting training courses and raising awareness about the benefits of breeding new sheep breeds, along with providing facilities and credits based on economic conditions, can foster a positive attitude among herders. Increasing the number of sheep owned and improving marketing strategies can further enhance this positive outlook.

An environmental cost-benefit analysis of organic and non-organic sheep farming in Iceland

This paper presents an environmental cost-benefit analysis (CBA) comparing organic and non-organic sheep farming in Iceland over three decades. Environmental life cycle costing (ELCC) is the basis for the aggregate cost framework, encompassing costs for investment, operations, maintenance, and environmental externalities. Greenhouse gas emissions are included as an external cost as they relate to the monetization of damages to society. Net present value (NPV) and benefit-cost ratio (BCR) indicators reveal both systems as unprofitable over thirty years with and without subsidies. Depending on the discount rate, the organic farm's BCR ranges from 0.26 to 0.38, with a NPV between (-2.4) and (-1.1) million euros. The non-organic farm's BCR ranges from 0.12 to 0.19, with NPV between (-8.6) and (-3.7) million euros. Greenhouse gas emission costs constitute 28% and 33% of total life cycle costs for organic and non-organic farms. Across three discount rates, the LCC and ELCC per kilogram of organic lamb ranged between €13.78 – 25.27 and €18.23 – 37.07, respectively. The LCC and ELCC per kilogram of non-organic lamb ranged between €9.75 – 18.05 and €13.80 – 28.82, respectively. Due to a shortened value chain, organic sheep farming demonstrated revenue advantages as compared to non-organic. The external cost of greenhouse gas emissions from sheep farming forms a significant portion of lifetime costs suggesting that policymakers could incentivize organic practices aimed at reducing greenhouse gas emissions. Finally, this study provides a deeper understanding of the long-term economic prospectivity of sheep farming under different production approaches.

Morphological adaptation to environmental stress in small ruminants from the sahelian zones of Niger and potential associations with carcass yield

This study analyses, in the Sahelian zone of Niger, the morphological traits of sheep and goats' responses to environmental stress and the contribution of adaptive traits to herd productivity. The study utilized 2490 adult small ruminants, including 653 red and Sahelian goats and 1837 Peulh (with three varieties: Balami, Oudah and Bali-Bali) and Tuareg (Ara-ara) sheep from 13 sites with a marked aridity gradient within the country's northern latitude. Carcass yield was assessed on a second sample of 1617 adult animals, comprising 876 sheep and 741 goats. Variations in thorax auricular index (ratio of ear length to thorax depth), gracility index (which reflects the subtraction of the animal's body from the ground) and hot carcass yield, according to climate zones and breed, were subjected to an analysis of variance at the 5% risk threshold. Principal Component Analysis was used to analyze correlations between biometric and heat indices. For most breeds, the auricular thorax index and the gracility index were higher for animals in arid zones than those in humid zones. The increase in the average values of the body indices had as a result an increase in the animals' carcass yield and live weight. In all sheep and goat breeds, gracility increases with heat index. Gracility differed (p < 0.05) between breeds, with Bali-Bali and Oudah subgenetics of the Peulh sheep breed being more gracile than the Ara-ara sheep. Also, the auricular thorax index was higher (p < 0.05) in Sahelian goat than in red goat. The importance of biometric indices in terms of animals' adaptability to their environment means that we need to define important heat stress indicators specific to sheep and goats in Sahelian farming systems.

The acceptance of social media as a channel of communication and livestock information for sheep farmers

Abstract The development of technology and information in the Industry 4.0 era, especially the internet, is experiencing very rapid progress. Searching for information through new media will increase human resource capacity and work efficiency. Using technology acceptance model (TAM) theory, this study aims to identify social media usage as a communication and information medium and analyze the influence between constructs in social media acceptance. A cross-sectional survey was used in this study design. A structured questionnaire from previous related studies was used as the instrument. One hundred and eleven sheep farmers from several villages in Sukabumi, West Java groups, participated in this survey. Stratified sampling was adopted to select and interview the respondents. The findings show that social media usage as a channel for communication and livestock information is quite adequate. Many farmers already use WhatsApp and YouTube. However, only a few farmers use Facebook and Instagram. The results of the TAM analysis (limited to only the WhatsApp application) indicate that perceived ease of use positively influences perceived usefulness (PU). A positive relationship is also shown between PU and behavioral intention to use. The theoretical implication is that this study proves how social media adopts in disseminating messages and seeking information. Regarding managerial implications, the findings suggest that stakeholders in the agricultural industry across the value chain could enhance their services by fostering a broader ecosystem of social media applications.

Prevalence and genetic diversity of Giardia duodenalis in sheep from large-scale farms in Southern Xinjiang, China

Giardia duodenalis is a significant zoonotic parasite. In this study, 767 fresh fecal samples were collected randomly from six large-scale sheep farms in Southern Xinjiang, China. Initially, G. duodenalis was screened using PCR at the SSU rRNA gene. Positive samples then underwent PCR amplification at the bg, gdh, and tpi genes. The prevalence of G. duodenalis in sheep was 17.5% (134/767), with the highest prevalence observed in the 3-6 months age group at 26.8% (56/209) and the lowest in the over 12 months age group at 6.8% (14/205). Among the 134 positive samples, only Assemblage E was identified. A total of 106, 92, and 98 sequences of G. duodenalis were obtained at the gdh, tpi, and bg genes, respectively. Fourteen isolates of G. duodenalis were successfully amplified at all three genes, resulting in nine G. duodenalis multilocus genotypes (MLG) named MLG E1-MLG E14, indicating high genetic diversity. In conclusion, G. duodenalis infection in sheep from large-scale farms is common in Southern Xinjiang, China, showing geographical regional distributions and genetic diversity.

Technical efficiency analysis in Italian sheep and goat farms using FADN dataset

The sheep and goat farms are one of the main breeding in many Italian regions located in mountainous and disadvantaged rural areas. One of the main Italian Protected Designation Origin cheese as Pecorino Romano is made by sheep milk from many regions. The main purpose of this research was to asses by a quantitative approach the technical efficiency in sheep and goat farms part of the Farm Accountancy Data Network (FADN) in all Italian regions since 2008 to 2020. By the Multi-direction Efficiency Analysis (MEA) it has been possible to overcome one of the main bottlenecks of the technical efficiency estimation analysing which is the excess in each input able to impact to the technical efficiency. Main results have pointed out that the Italian sheep and goat farms have a higher technical efficiency compared to other studies carried out in other European countries. Land capital, labour and assets have been the main inputs able to impact to the technical efficiency. Furthermore, an important role of subsidies to the sheep and goat Italian farms exists.

RNA-Seq based selection signature analysis for identifying genomic footprints associated with the fat-tail phenotype in sheep.

Understanding the genetic background behind fat-tail development in sheep can be useful to develop breeding programs for genetic improvement, while the genetic basis of fat-tail formation is still not well understood. Here, to identify genomic regions influencing fat-tail size in sheep, a comprehensive selection signature identification analysis was performed through comparison of fat- and thin-tailed sheep breeds. Furthermore, to gain the first insights into the potential use of RNA-Seq for selection signature identification analysis, SNP calling was performed using RNA-Seq datasets. In total, 45 RNA-Seq samples from seven cohort studies were analyzed, and the FST method was used to detect selection signatures. Our findings indicated that RNA-Seq could be of potential utility for selection signature identification analysis. In total, 877 SNPs related to 103 genes were found to be under selection in 92 genomic regions. Functional annotation analysis reinforced the hypothesis that genes involved in fatty acid oxidation May modulate fat accumulation in the tail of sheep and highlighted the potential regulatory role of angiogenesis process in the fat deposition. In agreement with most previous studies, our results re-emphasize that the BMP2 gene is targeted by selection during sheep evolution. Further gene annotation analysis of the regions targeted by the sheep evolution process revealed that a large number of genes included in these regions are directly associated with fat metabolism, including those previously reported as candidates involved in sheep fat-tail morphology, such as NID2, IKBKG, RGMA, IGFBP7, UBR5, VEGFD and WLS. Moreover, a number of genes, including BDH2, ECHS1, AUH, ERBIN and CYP4V2 were of particular interest because they are well-known fat metabolism-associated genes and are considered novel candidates involved in fat-tail size. Consistent with the selection signature identification analysis, principal component analysis clustered the samples into two completely separate groups according to fat- and thin-tailed breeds. Our results provide novel insights into the genomic basis of phenotypic diversity related to the fat-tail of sheep breeds and can be used to determine directions for improving breeding strategies in the future.

Resequencing reveals population structure and genetic diversity in Tibetan sheep

BackgroundThe Tibetan sheep is one of the three major primitive sheep breeds in China, representing a unique and high-quality genetic resource in the Qinghai-Tibet Plateau and neighboring high-altitude regions, exhibiting exceptional adaptability to high-altitude climatic environments. However, research on the genetic relationships among different populations of Tibetan sheep at the whole-genome level remains insufficient. This study aims to explore the population structure and historical dynamics among 11 Tibetan sheep populations, accurately assess the genetic diversity within the populations, and providing a theoretical basis for the development of targeted genetic breeding strategies for Tibetan sheep.ResultsIn this study, a total of 10,884,454 high-quality SNPs were obtained. All Tibetan sheep populations exhibited varying degrees of linkage disequilibrium, with similar decay rates; among them, the WT population showed the fastest decay, while the TS population exhibited the slowest decay rate. Analyses using Tajima’s D and π indicated that the genetic diversity levels of the Tibetan sheep populations are generally low. Fst results revealed that most populations exhibited moderate to low levels of genetic differentiation. The effective population size among Tibetan sheep populations showed an increasing trend over time. The evolutionary relationships among Tibetan sheep populations reflect the correlation between their geographical locations and genomic genetic distances, while also indirectly confirming the impact of historical activities such as early human migration, admixture, fusion, and expansion on the population sizes and distributions of Tibetan sheep.ConclusionsThe results indicate that the genetic diversity levels and genetic differentiation among Tibetan sheep populations are relatively low. In this study, we identified the genetic characteristics of Tibetan sheep populations, which exhibit low levels of diversity, genetic differentiation, and a strong population structure. A deeper genomic exploration of the population structure and diversity status of Tibetan sheep populations will provide theoretical support for subsequent genetic breeding and diversity conservation efforts.

Merinos in Poland – an analysis of breeding condition, selected performance traits and perspectives for the protection of genetic resources in relation to the country’s total sheep population

The purpose of the study was to analyse the breeding condition and performance traits of merino sheep belonging to three breeds in 2008-2022. The experimental material consisted of data derived from annual reports published by the Polish Sheep Breeding Association on breeding of three merino breeds: Polish Merino, Coloured Merino, old-type Polish Merino and data on the number and distribution of flocks, as well as data on the implementation of the sheep genetic resources protection programme from the database of the National Research Institute of Animal Production covering the period of the last 15 years. Analysing the population size over the last 15 years, significant changes were observed in the breed structure of the Merino sheep population. The implementation of conservation programmes and the opportunity to obtain subsidies for conservation breeds have had an impact on the breeding of these breeds in our country. Currently, the largest share of the merino sheep population is represented by the old-type Polish merino. Merino breeding has a regional and large-scale profile, concentrated in the historical areas of their maintenance, in Wielkopolska and Kujawy, usually in flocks of about 100 dams. Reproduction rates expressed by maternal prolificacy were found to be in line with the breed pattern. The Polish merino and the old-type Polish merino were distinguished by similar parameters of reproductive traits and higher fertility as well as rearing indices than those of the coloured merino. The coloured merino is the breed with the highest fertility and breeding performance. Body weight of lambs was higher for the white varieties. However, reproductive and meat performance indices show the potential of merino sheep in the context of lamb production, which is currently the main focus of sheep production in Poland.

SNP Markers: Analysis of Genetic Diversity and Identification of Genomic Regions in Pantaneiro Sheep and Texel Sheep Under Natural Selection.

Sheep farming is growing substantially in Brazil, driven by the increasing demand for sheep meat. This rising demand has heightened the focus on sheep, making them the subject of numerous studies, including those centered on genetic analysis. A notable research area involves Pantaneiro sheep, which are indigenous to the Pantanal region of Mato Grosso do Sul and other locations. These sheep are of particular interest due to their adaptation to the unique environmental conditions of the Pantanal, a floodplain characterized by its distinctive climatic and ecological features. This study primarily aimed to conduct a comprehensive genomic analysis of Pantanal sheep subjected to natural selection within the Pantanal region and compare different sample herds using methodological approaches. Genomic analysis was performed to examine genetic diversity and structure via GGP50K single nucleotide polymorphism (SNP) analysis. A sample of 192 adult sheep over 4 years old was categorized into seven populations based on location: Six populations comprised Pantaneiro sheep with one Texel sheep population. Outlier SNPs were assessed to pinpoint regions under natural selection, with comparisons between the Pantaneiro and the commercial Texel breeds. All data analyses were conducted using the R programming language, employing specialized genetic analysis packages. These outlier SNPs were detected using three methodologies, PCAdapt, OutFLANK, and FDIST2/fsthet, with false discovery rate (FDR) corrections applied to ensure result accuracy. Each method was evaluated, and the genes associated with the identified SNPs were cross-referenced with the most recent sheep genome database, focusing specifically on genes with known phenotypic traits. Analysis of a sample comprising 192 adult individuals revealed greater genetic variability within the Pantaneiro breed than the Texel breed, highlighting the adaptation of the Pantaneiro breed to the unique Pantanal environment. Conversely, the Texel breed exhibited significantly higher levels of inbreeding, attributed to its controlled breeding practices. Outlier SNPs were detected with notable variation across different methodologies, underscoring the importance of FDR correction in ensuring the reliability and concentration of identified outliers. These outlier SNPs facilitated the identification of genes associated with key phenotypic traits, including hair growth, tissue regeneration, pigmentation regulation, and muscle capacity. The integrated analysis of methodologies demonstrated significant efficiency in elucidating the genomic landscape of Pantanal sheep, highlighting the genetic richness inherent in sheep from the Pantanal region of Mato Grosso do Sul. The techniques employed effectively identified outlier SNPs associated with phenotypically relevant genes. These findings, which reveal greater genetic variability and adaptability, underscore the potential of these animals for future research and their significance within Brazilian sheep farming. The Texel breed served as a valuable comparative group, illustrating the limited genetic variability in highly controlled breeding environments.