藏青牛遗传资源现状及种质特性鉴定研究OA

[Objective]To evaluate the resource status,germplasm characteristics and development potential of Tibetan gray cattle,and thereby clarify their status as an independent genetic resource.[Method]This study focused on Shannan City as the research scope,and conducted investigations and analysis of the cattle.In September-October of 2023,the team completed field surveys,data collection,body measurement,production performance investigation,and combined with molecular genetic analysis by integrating genomic data of 98 Tibetan cattle.[Result]The results showed that the core distribution area of Tibetan gray cattle is located in Langkazi and Luozha counties of Shannan City,as well as Bailang,Dingjie and Kangma counties of Shigatse City,Tibet Autonomous Region,with an average altitude exceeding 4000 meter above sea level.The population size was approximately 3100 head at the end of 2021.Tibetan gray cattle are characterized by a distinctive iron-gray or bluish-gray coat color.Phenotypically,they exhibit predominantly white facial markings,white horns with black tips and a robust body conformation.Moreover,they possess strong adaptability to cold climates,efficient utilization of coarse forage resources and remarkable tolerance to high-altitude environments.Morphometric analyses revealed significant differences(P<0.05)in body height,body length,bust and shank circumference among different age groups.Production performance evaluation indicated that the average daily milk yield of Tibetan gray cattle was 3.60 kilogram,ranging from 1.50 to 9.00 kilogram per day.Population genetic analyses based on 104339970 high-quality single nucleotide polymorphisms demonstrated that Tibetan gray cattle formed a stable monophyletic lineage with a relatively homogeneous and stable genetic composition.Furthermore,the population exhibited high genetic consistency within the breed and clear genetic differentiation from other Tibetan cattle populations,supporting its status as a genetically distinct population with an independent genetic structure.These findings demonstrate that Tibetan gray cattle possess a unique genetic background and an independent population genetic structure,supporting their recognition as a distinct indigenous cattle genetic resource on the Qinghai-Tibet Plateau.[Conclusion]The research has clarified the distribution area,population size,phenotypic characteristics and independent genetic traits of the Tibetan gray cattle.It revealed that they face high risks of inbreeding depression,imperfect conservation system and an unoptimized breeding structure.