Study on the Morphological Characteristics of Skin and Hair Coat of Yak and the Adaptability to the Cold Living Environment

Selecting 6 heads of new yak strains(the offspring of reciprocal cross of F1 produced by wild yak male mated with domestic yak female)and 6 domestic yaks at 3 and 12 age in months respectively at Datong Yak Farm of Qinghai Province. This paper was studied for the morphological characteristics of the skin and hair coat of yak and their adaptability to the cold living environment in Qinghai-Tibetan plateau. The results indicated that it should be of vital importance marker for the morphological characteristics of the skin and hair coat with two type of yaks at 3 and 12 age in months and their regulations of growth and development to adapt to the cold living environment in Qinghai-Tibetan plateau,The main morphological indexes of the skin and hair coat of the rearing new yak strain were higher than those of the domestic yaks at the same age in months, or speak precisely, the new yak strain was more powerful adaptable to the alpine cold living environment than that of the domestic yaks. The resvlts above provided scientific basis for the native strain breeding of yak and the new yak strain rearing.     

甘南牦牛不同杂交组合生产性能分析

为提高牦牛生产的社会、经济和生态效益,满足人们对无污染的牦牛奶、肉等绿色食品日益增长的需要,本研究利用娟姗牛、安格斯牛和野牦牛的冻精杂交改良甘南牦牛,筛选最佳杂交组合。结果发现,与当地牦牛相比,娟姗牛、安格斯牛和野牦牛与本地牦牛杂交的F1代公母犊牛的初生重、3月龄体重和6月龄体重均显著高于本地牦牛犊(P<0.05),其中娟姗牛、安格斯、野牦牛的杂交F1代的公犊牛初生重分别提高了30.12%、18.21%和13.21%;3月龄体重分别提高了7.89%、3.70%和1.94%;6月龄体重分别达到了81.26±1.23kg、79.26±1.04kg和78.42±1.13kg,而母犊牛6月龄体重分别为77.78±2.26kg、78.07±1.97kg和75.85±1.32kg。因此,利用娟姗牛、安格斯牛与牦牛种间杂交育种可显著改善犏牛生产性能,这将为提高甘南牦牛生产性能、生产优质牛肉提供依据。     

Study on some functional and compositional properties of yak butter lipid

The present experiment was performed to determine some functional properties of yak butter lipids such as lipid class composition; conjugated linoleic acid (CLA) composition, differential scanning calorimetric (DSC) analysis, tyrosinase inhibition activity and antioxidant property. Yak butter lipids composition contained 98% triacylglycerols, 0.9% free fatty acids, 0.32% free sterols and 0.27% phospholipids. The CLA content in yak butter was 2.5% and the major portion was of cis‐9 and trans‐11 (90%). The DSC analysis of yak butter lipids showed a similar path for transition temperature as cow butter lipids, although the enthalpy of yak lipid was higher (40.0 mJ/mg) compared to cow butter lipids (32.0 mJ/mg). Melting point of yak butter was observed at 41°C. Yak butter with lactic acid, NaCl, citric acid and ascorbic acid showed pronounced tyrosinase inhibition activity. Vegetable oils blended with yak butter have extended the oxidation induction time.     

Postpartum oestrous cycling resumption of yak cows following different calf weaning strategies under range conditions

Early weaning can improve body condition and reproductive performance of cows. The objectives of this study were to examine and compare oestrous cycling resumption, behaviour and blood parameters of yak cows following four different strategies of calf weaning. Twenty‐six yak cows (4–8 years) and their calves (94.3 ± 2.4 days) were studied in which calves were: weaned naturally with free access to their mothers (NW; n = 13); weaned abruptly and separated permanently from their mothers (PW; n = 5); separated temporarily from their mothers for 15 days (TW; n = 5); and fitted with nose plates for 15 days, but allowed free access to their mothers (NP; n = 3). Yak cows with sucking calves (NW) spent more time grazing in the cold season (from d 39 to 84). Based on serum progesterone concentrations, none of nine NW yak cows resumed oestrous cycling during the study, while seven of nine yak cows with weaned calves resumed cycling (3/3 for PW; 2/3 for TW; and 2/3 for NP yaks). We concluded that early weaning improved postpartum reproductive performance of yak cows on the Qinghai‐Tibetan plateau and that abrupt and permanent weaning was an appropriate strategy.     

西藏查吾拉地区不同性别牦牛产肉性能和肉营养成分的比较

为了研究性别对查吾拉地区牦牛的产肉性能及肉营养成分的影响,随机选取8岁健康的查吾拉牦牛10头,公母各半,对不同组别间牦牛进行屠宰试验比较肉营养品质的差异。结果表明,母牦牛屠宰率、净肉率、胴体率、骨肉比均高于公牦牛,但无统计学差异。肉营养成分分析结果显示,母牦牛肉中维生素A、E、B₁₂、半胱氨酸、组氨酸、精氨酸、钙、硒、脂肪酸含量高于公牦牛(P<0.05)。研究结果表明,查吾拉牦牛富含较高的营养成分,可为人类提供优质健康的动物蛋白,具备作为优质牦牛肉源生产的潜力。相比较,母牦牛肉优于公牦牛。     

Differential DNA methylation of the meiosis‐specific gene FKBP6 in testes of yak and cattle–yak hybrids

FK506‐binding protein 6 (FKBP6) is essential for meiosis during mammalian spermatogenesis. However, the molecular regulation of FKBP6 during spermatogenesis remains unclear. In the present study, we performed molecular characterization of the meiosis‐specific gene FKBP6 in yak testes. Yak FKBP6 encodes a polypeptide of 295 amino acid residues with an FK506‐binding domain (FKBP_C) and three tetratricopeptide repeat domains. The methylation level of the FKBP6 promoter in testes was significantly higher in cattle–yak with male sterility than in yak, and the FKBP6 promoter was methylated in liver tissues in which FKBP6 is not expressed. FKBP6 promoter activity was significantly decreased after treatment with the M.SssI methyltransferase in vitro. Furthermore, the FKBP6 gene was remarkably activated in bovine mammary epithelial cells treated with the DNA methyltransferase inhibitor 5‐aza‐2‐deoxycytidine. Taken together, our results demonstrate for the first time that the FKBP6 promoter is differentially methylated in testes; together with the functional promoter analysis, this suggests that methylation of this promoter may contribute to cattle–yak male infertility.     

半舍饲条件下淘汰母牦牛育肥及犊牦牛培育技术研究

旨在研发半舍饲条件下淘汰母牦牛育肥及犊牦牛培育技术。选取带犊母牦牛和公犊牛各66头,分别随机分为试验组和对照组。在犊牛培育期间（2017年12月4日—2018年3月5日）,对试验组母牦牛进行补饲,试验组犊牦牛断乳前（3月5日断乳）随母牦牛哺乳,并进行补饲;对照组母牦牛不进行补饲,按常规放牧方式饲养,对照组犊牦牛进行断乳并补饲。育肥期间（2018年3月5日至出栏）对试验组母牦牛进行补饲,于6月错峰出栏;对照组母牦牛不进行补饲,于集中出栏时间出售（9月或10月）。在犊牦牛培育期间,观察试验组母牦牛的体重变化情况;每月4日测定2组犊牦牛的体重和体尺指标,并进行统计学分析。计算试验组母牦牛错峰出栏收益。结果表明,在犊牦牛培育阶段,由于试验组犊牦牛随母牦牛哺乳,试验组母牦牛体重平均下降1.17 kg/头;2018年1月4日,试验组犊牦牛的体重极显著（P<0.01）高于对照组,体斜长和胸围显著（P<0.05）高于对照组;2018年2月4日和3月4日,试验组犊牦牛的体重、体高、体斜长、胸围均极显著（P<0.01）高于对照组。试验组母牦牛错峰出栏的效益为1 063.05元。研究结果为提高半舍饲条件下淘汰母牦牛养殖效益以及提升犊牛培育质量提供了技术支撑。     

不同犊牛培育方法对育成母牦牛生长发育的影响

采用不同犊牛培育方法,分别考察对传统饲养条件和高效繁育技术条件下对后代公犊牛及育成母牛生长发育的影响。研究结果表明:与传统对照组相比,犊牛培育组犊牛成活率达到97.23%,犊牛培育组的成活率、初选合格率、复选合格率和定选合格率分别为91.67%、80.56%和77.78%,分别比传统对照组提高12.90%、13.79%、11.54%和27.26%,差异显著(P<0.05)。犊牛体高、体斜长、胸围、管围及体重显著提高,差异显著(P<0.05)。采用犊牛培育技术,后代犊牛及育成牛生长发育各项指标较对照组明显增加,有效提高牦牛种母牛培育合格率,从而为建立优良种母牛核心群提供一条切实有效的生产途径。     

Adding heat‐treated rapeseed to the diet of yak improves growth performance and tenderness and nutritional quality of the meat

Heat‐treated rapeseed was supplemented to indoor fed yaks in winter to test the effect on dry matter intake (DMI), body mass change, and meat quality. Sixteen 3‐year‐old yak steers (124 ± 15.3 kg) were divided randomly into two groups and were offered either heat‐treated rapeseed (HTR) or rapeseed meal (CONT). The yaks were allowed 14 days for adjustment and measurements were made over 120 d. There was no difference in DMI between groups (p = 0.67), but average daily gain tended to be higher (p < 0.056) and feed to gain ratio tended to be lower (p = 0.050) in HTR than in CONT yaks. Meat from HTR yaks was more tender (p = 0.006), had higher intramuscular fat (p = 0.013), and had lower cholesterol content (p = 0.009) than from CONT yaks. In addition, the atherogenic index was lower (0.37 vs. 0.43; p = 0.049), the PUFA:SFA ratio was higher (0.55 vs. 0.37; p = 0.049), and the n‐6:n‐3 (n‐6 PUFA to n‐3 PUFA) ratio was lower (2.76 vs. 4.78; p = 0.003) in HTR than in CONT yaks, which all favoured the HTR yaks. Meat from HTR yaks met human health standards of a PUFA:SFA ratio of above 0.4 and n‐6:n‐3 ratio of less than 4, whereas meat from CONT yaks just missed these standards.     

Whole‐genome analysis identifying candidate genes of altitude adaptive ecological thresholds in yak populations

The domestic yak (Bos grunniens) is an iconic symbol of animal husbandry on the Qinghai–Tibet Plateau. Long‐term domestication and natural selection have led to a wide distribution of yak, forming many ecological populations to adapt to the local ecological environment. High altitude is closely related to oxygen density, and it is an important environmental ecological factor for biological survival and livestock production. The aim of the present study was to perform a preliminary analysis to identify the candidate genes of altitude distribution adapted ecological thresholds in yak using next‐generation sequence technology. A total of 15,762,829 SNPs were obtained from 29 yaks with high‐ and low‐altitude distribution by genome‐wide sequencing. According to the results of the selective sweep analysis with FST and ZHp, 21 candidate genes were identified. 14 genes (serine/threonine protein kinase TNNI3K, TEN1, DYM, ITPR1, ZC4H2, KNTC1, ADGRB3, CLYBL, TANGO6, ASCC3, KLHL3, PDE4D, DEPDC1B and AGBL4) were grouped into 32 Gene Ontology terms, and four genes (RPS6KA6, ITPR1, GNAO1 and PDE4D) annotated in 35 pathways, including seven environmental information processing and one environmental adaptation. Therefore, the novel candidate genes found in the current study do not only support new theories about high‐altitude adaptation, but also further explain the molecular mechanisms of altitude adaptation threshold in yaks.     

唐古拉山地区牦牛养殖情况调查

2005年～2006年对唐古拉山地区饲养的青海高原牦牛养殖情况进行了调查.据统计,唐古拉山地区现有牦牛12 400头,其中,适繁母牛4442头,母畜比例为35.82%.牦牛产肉、泌乳性能、产毛、役用及繁殖性能测定结果表明,唐古拉山地区牦牛对高寒的气候环境及粗放的饲养管理具有良好的适应性.     

牦牛病毒性腹泻病研究进展

牦牛感染牛病毒性腹泻病毒(Bovine viral diarrhea virus,BVDV)后常发生胃肠炎等消化系统疾患和呼吸系统疾患、繁殖障碍,造成机体损伤,给牦牛产业发展造成一定影响。基于5"-UTR的差异将BVDV分为BVDV-I和BVDV-II两种基因型,牦牛源BVDV的主要基因型为BVDV-1型;根据BVDV对宿主细胞的致病性,分为致细胞病变型(Cy-topathogenic,CP)和非致细胞病变型(Non-cytopathogenic,NCP)两个生物型,牦牛源BVDV既有CP型又有NCP型,且这两种生物型能相互转化。牦牛生活的高原地区风、鸟类的迁徙等因素可能都会导致牦牛BVD传播范围广泛,牛群中大量的BVDV携带者和牦牛特殊而又复杂的生态系统导致了BVDV种间传播的巨大潜力,影响着牦牛产业的健康发展和养殖经济收益。针对本病在牦牛群中的感染流行等情况未发现相关详细的研究报道,笔者就牦牛BVD病原学、流行病学调查、实验室诊断、综合防治等方面研究进展情况进行整理,供同仁在研究和防控中参考借鉴。     

Development of a New Yak Breed Through Utilization of Wild Yak Genetic Rsource-seral Technologies for the Development of the Datong Yak Breed

On the Datong Yak Breeding Farm of Qinghai Province(Datong farm), the scientists of the Lanzhou Institute of Animal Science and Veterinary Pharmaceutics of Chinese Academy of Agricultural Sciences, in collaboration with others,explored the possibility to cross wild yak bulls with domestic yak cows in the past 20years and a new yak breed, the Datong yak, has been developed.     

Serological evidence of bovine herpesvirus-1 (BoHV-1) infection in yaks (<Emphasis Type="Italic">Peophagus grunniens</Emphasis>) from the National Research Centre on Yak,India

Bovine herpesvirus-1 (BoHV-1) causes a variety of disease syndromes including, respiratory, nervous and reproductive disorders both in domestic as well as wild bovines and the disease is prevalent throughout the world including India. In this study, serum samples of yaks were screened for serological evidence of BoHV-1 in a yak farm with history of abortion and kerato-conjuctivitis by competition-ELISA. The result of seroprevalence of BoHV-1 infections in yaks (Poephagus grunniens) revealed that the overall seroprevalence was 60.1%. The sero-prevalence of BoHV-1 infections was highest in male calf (67.7%) followed by yak cows (62.6%), yak bulls (56.8%), and yak heifers (50.0%).     

安格斯肉牛与牦牛杂交及其效果研究

［目的］为了进一步优化牦牛肉品质,有效缩短牦牛养殖周期,提高其受胎率和犊牛成活率。［方法］本研究进行了安格斯肉牛与牦牛杂交试验,,利用安格斯肉牛冷冻精液,对251头经产母牦牛进行了人工授精。［结果］人工授精后,分别于2013年产犊42头,成活率66.67%;2014年产犊51头,成活率95.7%;2015年产犊67头,成活率91.04%。［结论］牦牛膘情较好时期,受胎率可达83.33%,接近于奶牛人工授精的受胎率,达到了青海省牦牛人工授精的较高水平。     

野血牦牛和本地牦牛舍饲育肥试验

家牦牛是半野生畜种,终年放牧,为验证野牦牛家养和育肥的可行性,本研究以野血牦牛为试验组,家牦牛为对照组,做了舍饲育肥试验,结果表明:2.5岁1/2野血牦牛、1/4野血牦牛比家牦牛多增重8.82 kg和6.21 kg,差异显著(P＜0.05);1.5岁1/2野血牦牛、1/4野血牦牛比家牦牛多增重9.71 kg和5.13 kg,差异显著(P＜0.05),结果表明野牦牛可以进行舍饲育肥.     

娟姗公牛引入牧区生理机能变化与种用效果分析

为全面掌握娟姗种公牛在高寒牧区的适应性和生理机能变化情况,将6月龄娟姗种公牛引入牧区后观测生理机能变化情况,待体成熟后与牦牛开展自然交配。对牦牛自然交配和人工授精方式下的繁殖性能进行对比分析,结果表明：自然交配方式下母牦牛受胎率、产犊成活率、繁殖率比采用人工授精技术的母牦牛相应指标分别高19.26%、25.71%和23.12%,流产率和初生犊牛死亡率则比采用人工授精技术的母牦牛分别低8.54和5.64个百分点。同时对两种杂交技术下牦牛所产的后代娟犏雌牛进行犊牛生产性能对比分析,结果表明：自然交配母牦牛所产的后代娟犏雌牛犊比人工授精的母牦牛所产娟犏雌牛犊的初生重、12月龄体重、初胎初乳量、初胎年均泌乳量分别高4.92 kg、21.86 kg、0.36 kg、197.89 kg,两组数据经差异显著性检验,自然交配组的娟犏雌牛犊初生重、12月龄体重、初胎年均泌乳量均极显著的高于人工授精组的相应指标（P＜0.01),初胎初乳量差异显著（P＜0.05)。     

Population genome of the newly discovered Jinchuan yak to understand its adaptive evolution in extreme environments and generation mechanism of the multirib trait

The adaptation and diversity of animals to the extreme environments of the Qinghai–Tibet Plateau (QTP) are typical materials to study adaptive evolution. The recently discovered Jinchuan yak population has many individuals with multiple ribs. However, little is known about this yak's origin, evolution, and the genetic mechanisms that formed its unique multirib trait. Here, we report a valuable population genome resource of the Jinchuan yak by resequencing the whole genome of 150 individuals. Population genetic polymorphism and structure analysis reveal that Jinchuan yak can be differentiated as a unique and original yak population among the domestic yak. Combined with geological change, the Jinchuan yak's evolutionary origin is speculated to be about 6290 years ago, which may be related to the unique geographical environment of the eastern edge of the QTP during this period. Compared with other domestic yaks, this new population has 280 positively selected genes. The genes related to skeletal function hold a considerable and remarkable proportion, suggesting that the specific skeletal characteristics have been enhanced in the adaptive evolution of Jinchuan yak in the extreme plateau environment. The genome-wide association study has revealed that TUBA8 and TUBA4A, the genes that regulate the cytoskeleton, are potential genes associated with the multirib trait. Our findings provide a basis to further understand the generation mechanism of the adaptive evolution of this new population in high-altitude extreme environments and the multivertebrate trait of domestic animals.     

唐古拉山牦牛群体的母系遗传多样性及遗传结构分析

[目的]从分子水平上探究青海省唐古拉山牦牛群体的母系遗传多样性、群体遗传结构及其遗传背景。[方法] 对52头唐古拉山牦牛个体mtDNA D-loop区序列进行测定后,使用生物信息学软件分析确定其核苷酸变异位点和单倍型数目,计算单倍型多样度和核苷酸多样度大小,并进行系统发育分析。[结果] 在619 bp唐古拉山牦牛D-loop区序列分析中,排除2处插入（缺失）后共检测到31处多态位点,包括单一多态位点5处和简约信息位点26处。根据序列间核苷酸变异共确定了13种单倍型,单倍型多样度和核苷酸多样度分别为0.821±0.043和0.007±0.004。与我国其他18个家牦牛品种和野牦牛相比,唐古拉山牦牛群体单倍型多样度和核苷酸多样度值均较低,表明该群体遗传变异较为贫乏,母系遗传多样性水平较低。以美洲野牛为外群,邻接法（即NJ法）构建的系统发育树结果显示：唐古拉山牦牛群体13种单倍型分布在A、B、C、D和E五种单倍型组中,且聚为2个大的母系分支（即I和II）,支系Ⅰ占比为77%,提示唐古拉山牦牛由2个母系支系组成,拥有2个母系起源且以支系Ⅰ为主。 [结论] 唐古拉山牦牛母系遗传多样性水平较低,由2个母系支系组成,以支系Ⅰ为主,推测其有2个母系起源。     

西藏嘉黎成年母牦牛体重与体尺指标的相关与回归分析

[目的]分析嘉黎成年母牦牛体尺指标与体重的相关性,并进一步进行了估测体重的回归分析,以指导该品种的生产实际及选育工作。[方法]以西藏嘉黎县测量的64头嘉黎成年母牦牛的体尺数据为基础,分析了嘉黎成年母牦牛体重与体高、体长、胸围、管围的相关系数,同时,进一步分析了估测成年母牦牛体重的回归模型。[结果]嘉黎成年母牦牛体重与体高、体长、胸围、管围的相关系数分别为0.887、0.828、0.807、0.712,经检验,体高、体长、胸围、管围与体重的相关系数达到了极显著水平(P<0.01);得到了3个估测体重的回归模型,估测值与实测值之间的相关程度分别为0.854、0.787和0.843。[结论]嘉黎成年母牦牛体重与体高、体长、胸围、管围存在明显的线性相关。