Morphological Observation on the Test and Epididymis in Hybrid of Wild and Domestic Yaks During the Growth Periods

This paper was carried out on the morphological character of the test and epididymis of three types of yak bull age 6,12,18,24 months old (1/2 wild yak, cross 1/2 wild yak and domestic yak). The results showed that the weight and size of testes and epidiymis was increased with the age which was hardly affected by imbalance of food supply during the cold and warm seasons. The development were similar for three kinds of yak at the same age(P＞0.05).     

Growth and Development of Testes in Domesticated and Hybrid(wild × domesticated)Yak Bulls

Testicular tissue was studied in domesticated yak and in wild yak × domesticated yak(F1 and F2)bulls at 6,12,18 and 24 months of age by stereology for quautitative histology and by comparative studies on the lactate dehydrogenase(LDH)isoenzyme spectrum, LDH activity and the percentage content of LDH isoenzymes in testes. The results indicated that all three types of yak were similar in both the characteristics of ultrastructure of testicular tissue and the degree of germ cell development. The process of spermatogenesis was initiated and sperm were produced for the first time at the age of 12months in all three yak types. All yak types exhibited similar age-related, increases in weight of testes,volume density of both the seminiferous tubules and seminiferous epithelium and height of seminiferous epithelium but all these indexes were slightly affected by season. The number of LDH isoenzyme bands after electrophoresis varied with age as follows: four bands were present at 6 months of age, five bands at 12 and 18 months and six bands at 24 months of age. The sixth band was LDH -x ,which appeared between the LDH4 and LDH5 band. These results indicated that yak bulls reach sexual maturity at 24months of age and that puberty is not affected by infusion of wild strains.     

Analysis of High Reproductivity on Wild Yak Bull

Sperm concentration of wild yak bull is 2. 13 billion per milliliter. Survival time at 0-4 ℃ is 57hrs. After thawing survival time at 37 ℃ is 12 hrs. Resistance coefficient is 144,000. Abnormal sperm rate and acrosomal integrated rate of post-thawing is 9.17% and 87.53% respectively. Moving viscosity is 1. 169 cp. Total nitrogen is 1 437.7 mg/100 ml. Head of sperm is significantly shorter and end piece is significantly longer than that of domestic yak and yellow cattle. Activity of hyaluronidase is highly stronger than the domestic yak,and the activity of LDH is higher than the domestic yak by 48 %. Hence,the fertility of the wild yak bull is powerful and the artificial inseminated rate with domestic yak and yellow cattle is 88.9% and 71.58% respectively.     

牦牛和普通牛种间杂种公牛睾丸的组织学观测与研究

通过对牦牛和黄牛种间杂种公牛及未成年公牦掉睾丸的比较组织学观测，结果表明：杂种牛雄性不育的生殖隔离机制与生精小管及生精上皮细胞的发育状况、生精小管基膜的厚度、生精小管的间距、间质组织细胞的发育状况、间质组织与生精小管间形成大量组织液等因素有关。随种间杂交代数增加，睾丸组织的发育状况逐渐改善，精原细胞的死亡率相应降低，杂种3代（F3）已能完成减数分裂产生精子，并显示出精原细胞的死亡率的逐代减少与父本基因含量逐代增多有一定的相关性。     

犊牛睾丸组织培养及PGP 9.5基因的检测

收集新生牛睾丸,进行组织学观察与组织的体外培养,在10%血清培养液中培养1周和2周后进行组织学观察与RT-PCR分析。结果表明:新生牛睾丸组织经体外培养1周时,管腔直径增大,精原干细胞数明显增多;体外培养2周时,管腔直径继续扩增,精原干细胞数量减少;在新鲜睾丸组织、培养1周和2周的睾丸组织中PGP 9.5持续表达。     

青南地区牦牛生产性能的评估

通过1997－1999年对青海果洛家牦牛产乳性能、带犊、不带犊对母牛生长发育的影响、初生和1岁牦牛产肉性能及生长发育规律等生产性能综合研究，证实了导入野血公牦牛与当地家牦牛交配，可充分发挥野血牦牛耐粗饲、耐寒、生长发育快的优势，是一条在现行畜牧业体制下复壮家牦牛的简便措施。通过该地区牦牛生产性能现状的评估，将为牦牛杂交改良、本品种选育、政府部门的宏观决策提供理论依据。     

Analyses of Genetic Diversity and Phylogeny of mtDNA D-loop from Yak in Karakoram-Pamir Area

This experiment was conducted to clarify the genetic diversity,genetic differentiation and phylogenetic status of yak in Karakoram-Pamir area.The mtDNA D-loop region sequence was selected as a molecular marker,and the sequence and genetic diversity of the mtDNA D-loop region of yak in Karakoram-Pamir area were analyzed by PCR direct sequencing and bioinformatics methods.The yak sequence in GenBank was used.The maximum likelihood method was used to construct the phylogenetic tree and the intermediary network relationship.The results showed that the mtDNA D-loop sequence of yak in Karakoram-Pamir area was rich in A and T bases,with AT content of 61.2%,and there were 63 polymorphic loci,accounting for 7.04% of the total number of nucleotides.The results indicated that A and T bases were rich in the mtDNA D-loop sequences at 61.2%.There were 63 mutation sites,accounting for 7.04% of all nucleotides,The average haplotype diversity (Hd) was 0.806,the average nucleotide diversity (π) was 0.01528,and the average nucleotide difference (K) was 13.509,indicating that the yak was rich in genetic diversity in Karakoram-Pamir area;Through phylogenetic analysis,there were two branches in yak in China,forming two branches and six small clades.The yak in Karakoram-Pamir area involved in this study had two different maternal origins.Additionally,yak in the Karakoram-Pamir area was less shared with other breeds of yak haplotypes.In the branch C,the yak group in the Karakoram-Pamir area accounts for a large proportion and was shared with wild yak.The yak population in Karakoram-Pamir area had a unique genetic background,which might be the result of early domestication of wild yaks.It was suggested to increase the identification of yak breeds and the formulation of breed standards in this area,and strengthen the protection of yak genetic resources in this area.According to the current situation of the population,wild blood yaks were introduced for purification and rejuvenation to prevent breed degeneration and decrease of genetic diversity.The introduction of foreign yak breeds and disorderly hybridization were reduced to ensure the characteristics of this breed of high-quality yak breed resources.     

野牦牛及青海地方牦牛品种全线粒体基因组母系遗传多样性、分化及系统发育分析

旨在从分子水平上探究野牦牛及青海地方牦牛品种的母系遗传多样性、群体遗传结构、亲缘关系和遗传背景。本研究在测定青海省4个地方牦牛品种(即青海高原、环湖、雪多和玉树牦牛)22条全线粒体基因组(Mitogenome)序列的基础上,从GenBank下载了已公布的野牦牛及上述4个地方牦牛品种的142条相应序列,使用BioEdit 7.2.5、Arlequin 3.11和Network 10.1等软件对共计164条线粒体基因组序列进行综合分析。结果显示：1)根据序列间核苷酸变异共确定了115种单倍型,其中野牦牛和青海地方牦牛品种分别拥有22种和93种单倍型;在野牦牛和青海高原、环湖、雪多、玉树牦牛中分别检测到22、26、18、23、19种特有的单倍型。遗传多样性分析显示,野牦牛单倍型多样度最高(0.992 8±0.014 4),且高于4个青海地方牦牛品种的单倍型多样度(0.973 1±0.007 7);4个青海地方牦牛品种单倍型多样度大小依次为：雪多牦牛(0.988 5±0.012 6)、玉树牦牛(0.975 8±0.018 7)、青海高原牦牛(0.973 0±0.016 6)和环湖牦牛(0.939 3±0.027 8)。2)野牦牛与环湖牦牛之间的固定分化指数值(F_ST值)最大(0.041 2),分化程度最高,而与玉树牦牛间的F_ST值最小(-0.008 8),分化程度最低。青海4个地方牦牛品种中,雪多牦牛与青海高原牦牛之间F_ST值最大(0.035 8),分化程度最高,而雪多牦牛与环湖牦牛间F_ST值最小(0.011 2),分化程度最低。3)聚类分析显示,4个青海地方牦牛品种各自为1类,存在明显的母系遗传差异。相比而言,环湖牦牛和雪多牦牛聚类较近,青海高原牦牛和玉树牦牛聚类较近,而野牦牛与玉树牦牛聚类关系更近,各品种(群体)间的聚类结果与其分化程度、地理分布一致。4)系统发育分析表明,115种单倍型分布在3个大的母系遗传分支(即Mt-Ⅰ、Mt-Ⅱ和Mt-Ⅲ),其中Mt-Ⅰ支系所占比例为72.17%,由A、B、E和F 4种单倍型组构成;Mt-Ⅱ支系包括C、D和H 3种单倍型组,占26.09%;而Mt-Ⅲ支系只包含G单倍型组,由雪多牦牛和野牦牛所拥有,所占比例为1.74%,提示牦牛有3个母系起源。综上所述,野牦牛和青海4个地方牦牛品种均具有丰富的母系遗传多样性,其多样性水平由高到低依次为野牦牛、雪多牦牛、玉树牦牛、青海高原牦牛和环湖牦牛。青海4个地方牦牛品种间及与野牦牛间的遗传分化程度均较弱,但各自拥有特有的母系遗传信息,存在明显的母系遗传差异。野牦牛和青海家牦牛品种由3个母系支系组成,推测牦牛有3个母系起源。     

Seasonal changes in spermatogenesis and immunolocalization of inhibin/activin subunits in the wild male ground squirrel (Citellus dauricus Brandt)

The objective of this study was to investigate the seasonal changes in spermatogenesis and the immunolocalization of the inhibin alpha and inhibin/activin (betaA and betaB) subunits during the breeding and non-breeding seasons in the wild male ground squirrel. The testicular weight and size and seminiferous tubule diameter were measured, and histological observations of testes were performed. The sections of the testes were immunostained by the avidin-biotin-peroxidase complex method (ABC) using polyclonal antisera raised against porcine inhibin alpha, inhibin/activin betaA and inhibin/activin betaB during the breeding and non-breeding seasons. There were marked variations in testicular weight and size and seminiferous tubule diameter between the breeding and non-breeding seasons, and all types of spermatogenic cells, including spermatozoa, were found in the breeding season. In addition, immunoreactivity was also detected for the inhibin alpha, betaA and betaB subunits in Sertoli and Leydig cells during the breeding season, but immunostaining was only present for the inhibin alpha and inhibin/activin betaB subunits in Sertoli cells during the non-breeding season. These results suggest that seasonal changes in testicular weight and size and seminiferous tubule diameter of wild ground squirrels are correlated with changes in spermatogenesis, and the cellular localization of the inhibin/activin subunits showed season related changes in the breeding and non-breeding seasons.     

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.     

牦牛育种工作的创新发展

牦牛是分布在青藏高原及周边地区特有的家畜.长期以来托牛业管理方式粗放,生产性能低下.大通种牛场进行导入野牦牛基因改良家托牛的育种研究,培育成功了世界上第一个牦牛新品种"大通托牛",并实施一系列综合技术措施,对托牛业发展有积极的促进作用.     

Hormonal and histological studies in a 61XXY bull.

A Friesian bull with bilateral testicular hypoplasia was diagnosed as having a pure 61XXY karyotype. The bull displayed normal sexual behaviour but was azoospermic. At 17 months, the animal's peripheral plasma androgen levels appeared to be lower than normal, and one testicle removed one month later showed small seminiferous tubules totally lacking in germ cells. The Leydig cell volume of this testis was well within the normal range but the tubule length was rather short. At 33 months of age an increase in peripheral plasma androgen levels was noted. In the remaining testis there had been both a considerable rise in Leydig cell volume and a fall in tubule length. These findings may be explained by the interaction of three factors; the effects of the abnormal karyotype, the increased maturity of the animal at 33 months and the reaction of the remaining testis to unilateral castration.     

导入野血牦牛群体的遗传变异和基因分化

采用聚丙烯酰胺凝胶电泳法和火焰光度法对家牦牛和３个含野血牦牛群体ＴＦ,ＨＢ,Ｈｐ,ＫＥ,ＡＭＹ１和ＲＢＣＬＤＨ１６个基因座多态性的研究表明：家牦牛与３个含野血牦牛群体具有同样的多态性特征,但群体的遗传变异随野牦牛血比例的增多而减少。含野血牦牛群体之间的亲缘关系大于家牦牛,再大于野牦牛,但总群体所发生的基因分化程度很小（２７４８％）。     

Growth and Development of The Kunlun Type of Wild Yak

The observation of body height and weight of 10 captured wild yak shows the body height and weight of the wild yak at three and four months old were similar with that of domestic yak. At their 24 months old, the body height and weight were higher by 26.9 % and 62.5 % than that of the domestic ones. The results indicate that, once adapted to the half-shed and half-grazing conditions, the tamed Kunlun type of wild yak with superior genetics would grow and develop faster than the domestic yak at elder ages.     

Meat characteristics of Qinghai yak and semi-wild yak

Six domestic yaks aged 6 years, comprising three culling male and three culling female yaks, from the Qinghai Lake area and three male semi‐wild yaks aged 6 months from Datong Yak Farm were used to detect the levels of amino acids, mineral elements, residual heavy metals and pesticides in yak meat. The results showed that there was little difference in amino acid levels for different types of yak by age and sex. The meat of the adult male yak was 7.35 mg/kg higher in calcium (P < 0.05) and 124 mg/kg higher in phosphorus (P < 0.01) than that of the adult female yak. There was an obvious difference in zinc content, and there was also a significant difference for copper and sulfur between adult male and female yaks (P < 0.01). Iron was 8.85 mg/kg higher in semi‐wild yaks than in domestic yaks, but there were no differences for other minerals. The levels of residual heavy metals and residual pesticides were well within those allowed by the National Standard of China. Furthermore, the data showed that introducing wild yak’s blood did not result in a quality change in the domestic yak meat. Yak meat from Qinghai Plateau has the characteristics of being non‐polluted and rich in amino acids in comparison with local yellow cattle meat.     

饲养管理方式对甘南牦牛繁殖力及杂交后代影响的研究

[目的]为了研究加强种公牛和母牦牛的饲养管理对母牦牛的繁殖效果和杂交后代生长发育的影响.[方法]本试验用大通牦牛和其冻精杂交甘南牦牛,通过对试验组的种公牛、母牦牛和杂交后代进行补饲、延长放牧时间和提前断奶等措施,研究了203头母牦牛的繁殖效果和其杂交后代的生长发育情况.[结果]表明,自然交配试验组发情率、受胎率、繁殖成活率分别比对照组提高9.19%、11.03%、14.10%,流产率和犊牛死亡率降低3.3%、3.87%;人工授精组发情率、受胎率、繁殖成活率分别提高6.74%、5.48%、10.52%,流产率和犊牛死亡率降低4.07%、4.62%.加强母牦牛的饲养管理,所产犊牛的初生重比传统饲养管理条件下母牦牛所产的犊牛初生重公母分别增加2.92 kg和2.07 kg,提高19.80%和14.22%.6月龄体重分别增加12.82 kg和12.23 kg,提高17.45%和16.88%.[结论] 用大通牦牛改良甘南牦牛,采用人工授精和自然交配都有良好的效果,加强种公牛、母牦牛饲养管理是提高牛群繁殖力的有效方法,对后代生长发育影响明显.     

牦牛HOXA1基因的时空表达及其对机体调控机制的研究

试验旨在获得牦牛HOXA1基因序列并进行生物信息学分析,同时分析其组织表达谱和时序表达谱,为进一步研究多脊椎骨形成的原因及其机制奠定基础。通过RT-PCR技术克隆多脊椎骨牦牛HOXA1基因,利用半定量RT-PCR技术检测该基因在多脊椎骨牦牛组织中的表达情况,利用实时荧光定量PCR技术检测该基因在多脊椎骨牦牛不同发育时期各组织中的表达情况。RT-PCR结果表明,多脊椎骨牦牛HOXA1基因序列全长为885 bp,其中开放阅读框（ORF）为870 bp,编码290个氨基酸。同源性分析表明,牦牛与普通牛、野牦牛、人、野猪、马、家鼠、黑猩猩、原鸡和野猪的同源性为75.4%～98.1%。组织表达分析表明,HOXA1基因在心脏、肝脏、脾脏、肺脏、肾脏、大肠、小肠、肌肉、胃、卵巢、子宫、输卵管、乳腺、睾丸中均有不同程度的表达;时序表达分析表明,随着年龄的增长HOXA1基因在多数组织中的表达量呈逐渐升高趋势。     

肃南县牦牛导入青海大通牛场野牦牛血液复壮效果调查

[目的]通过引进野血种公牦牛改良当地牦牛可有效遏止牦牛退化,进一步巩固和改善我县牦牛品种质量,恢复其原有的优良生产性能和品种特征,提高经济效益.[方法]本文以野牦牛和家牦牛杂交后代与家牦牛后代为研究对象,分别测定了杂种牦牛和家牦牛的初生、6月龄、18月龄体尺、体重.[结果]显示,在同等条件下,1/4野血牦牛初生、6月龄、18月龄体尺、体重均显著高于同龄家牦牛,经t检验差异极显著（P＜0.01）.[结论]用野血牦牛改良家牦牛,是目前更新复壮家牦牛群体的有效途径之一,能获得很强的杂种优势,对提高经济效益,增加农牧民收入,保护生态环境都具有十分重要的意义.     

Expression Pattern of HOXA1 Gene and Its Putative Regulating Mechanism of Yak

The aim of study was to obtain the yak HOXA1 gene sequence and related bioinformatics information,and analyze its expression spectrum and temporal expression profiles for providing related information of the formation of multiple vertebrae and its mechanism.RT-PCR technology was applied to clone the yak HOXA1 gene,semi-quantitative RT-PCR technique was used to detect the gene expression level in multiple organisms,and Real-time quantitative PCR technique was used to detect the gene expression level in the organisms in different development periods.The results showed that the obtained HOXA1 gene was 885 bp including the ORF of 870 bp,encoding 290 amino acids.The yak HOXA1 gene shared a homology of 75.4% to 98.1% with ordinary cow,wild yak,human,wild boar,horse,mice,chimpanzees,jungle fowl and wild boar.There were different expression level of HOXA1 gene in heart,liver,spleen,lung,kidney,large intestine,small intestine,muscle,stomach,ovaries,uterus,fallopian tubes,breast and testicular tissue.With the growth of the yak,HOXA1 gene expression level in tissue also increased.     

1／2野血初产牦母牛产奶性能测定

在半哺乳情况下，对３头１／２野血初产牦母牛进行了１８５天泌乳性能测定。结果；１／２野血初产牦母牛产奶２２７．５３ｋｇ，乳脂率６．６０％，比当地实初产家牦母牛奶量增加２３．６１ｋｇ，乳脂率提高０．３０％，折合４％标准乳量３２．８２ｋｇ。