中国荷斯坦牛HH4遗传缺陷单倍型分子筛查

HH4(Holstein Haplotype 4)是在荷斯坦牛群中发现的一种隐性遗传缺陷单倍型,由1号染色体上GART基因g.1277227AC单碱基错义突变引起,隐性基因纯合时引起胚胎早期流产,严重威胁着奶牛养殖者的经济效益。本研究利用飞行时间质谱技术对北京地区332头荷斯坦公牛样品和1 151头母牛样品进行了检测分析,结果表明,在所检测的荷斯坦牛群体中,未发现HH4携带者个体,即均为正常个体。提示HH4单倍型对我国荷斯坦牛群影响较小,在奶牛场的选种选配中可以不予考虑,但在遗传物质引进的时候应重点关注,避免引入有害基因。     

遗传缺陷单倍型HH3检测方法的建立与应用

遗传缺陷单倍型HH3(Holstein Haplotype 3)由牛8号染色体上SMC2(structural maintenance of chromosomes 2)基因的T/C突变引起的隐性遗传疾病,其隐性纯合子可导致胚胎死亡,而HH3携带者个体表型正常。本研究建立了竞争性等位基因特异性PCR(KASP)检测遗传缺陷单倍型HH3的方法,该方法可快速、高通量的检测遗传缺陷单倍型。本研究共随机检测了北京地区158头荷斯坦母牛,发现HH3携带者个体6头,携带率3.8%,有害基因频率1.9%。本研究为遗传缺陷单倍型的分子筛查提供了借鉴,同时为奶牛场进行合理的选种选配提供了依据。     

国内荷斯坦种公牛HH4遗传缺陷基因筛查

HH4是新近在荷斯坦牛中发现的一种遗传缺陷,其分子机理为牛1号染色体上的GART基因编码区内的1个A/C错义突变。该遗传缺陷呈隐性遗传、突变等位基因纯合时,导致胚胎早期死亡。本研究针对HH4建立了基于PCR-RFLP技术的分子检测方法。结果表明:通过对466头国内荷斯坦种公牛进行基因筛查,发现6头携带者,均可以追溯到共同的祖先公牛Besne Buck。建议我国今后进口荷斯坦种牛时,对个体进行系谱分析和遗传缺陷基因分子检测,避免引入有害基因;同时,对国内现有荷斯坦公牛群体进行HH4筛查,明确标注每头公牛的携带状态,以便在生产实践中合理选种选配。     

荷斯坦牛HH5遗传缺陷基因快速检测方法的建立及应用

HH5是新近发现的一种荷斯坦牛隐性遗传缺陷基因,其分子机理为9号染色体上138kb大片段缺失,造成二甲基腺苷转移酶1(TFB1M)基因丢失。TFB1M基因在核糖体小亚基合成中发挥重要功能,故缺陷纯合子胚胎在发育早期死亡,造成母牛流产。HH5基因的共同祖先为1957年出生的一头加拿大著名公牛,其因在世界范围内广泛扩散,奶业发达国家已将其列为常规检测的遗传位点。本研究首先通过Sanger测序分析HH5缺陷基因,发现除了已知的138kb大片段缺失外,还存在一个9bp插入片段(TGATTACAA);该基于此特征序列,设计等位基因特异性PCR分型方法,PCR产物经琼脂糖凝胶电泳即可快速分型。笔者所在团队对北京郊区某奶牛场372头荷斯坦母牛检测,发现HH5携带者12头,携带率为3.23%。本研究为我国荷斯坦牛HH5遗传缺陷基因筛查提供了一种准确便捷的分子检测方法。     

中国荷斯坦牛凝血因子XI缺陷症遗传分析

凝血因子XI缺陷症（FactorXIdenciency）是荷斯坦牛的一种常染色体单基因控制的隐性遗传缺陷。该病的遗传基础是由位于牛第27号染色体的凝血因子XI基因外显子12上发生的一段76bp序列插入。本研究采用PCR方法对我国13个主要公牛站的571头荷斯坦公牛的凝血因子XI基因进行了全面检测,未发现隐性有害基因携带者和纯合个体。     

北京地区荷斯坦牛白细胞黏附缺陷症的检测分析

牛白细胞黏附缺陷症(BLAD)是由常染色体上CD18基因单碱基突变(A→G)引起的隐性遗传疾病,患病牛只机体免疫力降低、易患病,影响其生产性能的表现。本研究采用限制性片段长度多态性聚合酶链反应方法(PCR-RFLP),检测了北京502头荷斯坦母牛CD18编码基因第二外显子的多态性。结果表明,3个奶牛场中共检测到2种基因型——AA和AG,未检测到GG基因型。检测群体BLAD基因携带率为3.1%,说明北京地区规模化奶牛场使用的公牛冻精中BLAD基因没有得到彻底净化,导致母牛群体中BLAD基因携带率在3.0%以上。在奶牛育种和生产中,应有计划的淘汰携带BLAD基因的个体,净化京郊荷斯坦奶牛群体。     

北京地区奶牛HH6遗传缺陷基因分布初探

随着人们对奶牛选育程度的加强,奶牛遗传缺陷问题逐渐凸显。HH6是新近发现的一种荷斯坦牛遗传缺陷,其致病机理为16号染色体上SDE2基因编码区内发生了一个从A到G的突变,SDE2是真核生物中维持基因组稳定必需的蛋白质,突变使得该蛋白的功能受到抑制,进而导致了胚胎在几次细胞分裂之后便死亡,即造成母牛流产。这一突变最初来源于一头1987年出生的美国公牛,该公牛及其后代的冻精在世界范围内被广泛的使用。为了分析HH6在北京地区荷斯坦牛中的分布情况,本研究利用KASP SNP分型技术和微流控芯片技术结合的新型检测技术,研发出可准确检测HH6的方法,可实现在2.5h内对96个样本分型。随后对100头公牛和466头母牛随机样本检测,结果在公牛中未检出携带者,而母牛群携带率为1.93%。尽管HH6在当前牛群中分布并不广泛,但仍需将其纳入常规种牛遗传检测当中并实施科学选配,以免该缺陷在国内牛群中传播,造成更大的损失。     

中国荷斯坦公牛CN和DUMPS遗传缺陷检测及系谱分析

旨在研究中国荷斯坦牛中瓜氨酸血症(Citrullinemia,CN)和尿苷酸核酶缺乏症(Deficiency of uridinemonophosphate synthase,DUMPS)2种遗传缺陷的携带者比率及系谱来源,并构建更简便的检测方法。本研究通过PCR-RFLP方法对参加我国联合青年公牛后裔测定和良种补贴项目的591头荷斯坦公牛进行了大规模CN和DUMPS的遗传缺陷检测,并构建了奶牛CN隐性有害基因的AS-PCR检测技术。结果,共发现2头CN和1头DUMPS隐性有害基因携带者公牛,携带者比例分别为0.34%和0.17%。经过系谱追溯,2头CN携带者公牛均为澳大利亚公牛Linmack Kriss King-CN后代,DUMPS携带者公牛为美国公牛Skokie sensation Ned后代。基于此,我国有必要尽快建立荷斯坦牛隐性遗传缺陷监控体系并进行系谱标注,通过青年公牛预选和选种选配,避免携带者公牛进入后裔测定和良种补贴项目,以逐步降低我国奶牛群体中隐性有害等位基因频率。     

北京地区荷斯坦母牛群体HH1遗传缺陷基因抽样调研

HH1(holstein haplotype1)是近年来在荷斯坦牛群中发现的一种遗传缺陷,其致病机理是牛5号染色体APAF1(apoptotic peptidase activating factor 1)基因上的C/T突变,导致编码谷氨酰胺的密码子突变为终止密码子,纯合时个体致死,大多数表现为妊娠早期流产。本研究运用竞争性等位基因特异性PCR(KASP)方法,共随机检测了北京地区158头荷斯坦母牛,发现HH1携带者20头,携带率为12.66%,提示HH1在我国荷斯坦母牛群体中存在一定的比例,牛场有必要定期对HH1携带者进行筛查并合理选种选配。     

中国荷斯坦牛脊椎畸形综合征的研究现状与展望

脊椎畸形综合征(CVM),是由在荷斯坦牛群中发现的一个隐性遗传缺陷基因所导致的,其纯合时可以造成妊娠奶牛流产、死胎或畸形,危害着奶牛业的健康发展.在荷斯坦牛群中发现的脊椎畸形综合征引起了各国奶牛育种协会和育种者的关注,奶业发达国家开展了相关的研究工作,纷纷报道了在本国奶牛群中发现了脊椎畸形综合征的存在,都相应建立了种公牛遗传缺陷基因的分子检测方法和育种方案,有效降低了CVM对奶业发展的危害.本文就我国荷斯坦牛脊椎畸形综合征的研究和应用状况进行了综述,主要介绍了CVM背景、传播途径、危害性、控制措施及展望等方面的内容,以供同行参考.     

Normal cross-sectional anatomy of the bovine digit: comparison of computed tomography and limb anatomy

The purpose of this study was to define the structures of the digits and hoof in Holstein dairy cattle by using computed tomography scan (CT scan). Transverse, sagittal and dorsoplantar CT images of two isolated cattle cadaver digits were obtained using a Siemens ARTX2 Somatom. The CT images were compared to corresponding frozen cross-sections. Relevant anatomical structures were identified and labelled at each level. The CT images provided anatomical detail of the digits and hoof in Holstein dairy cattle. Transversal images provided excellent depiction of anatomical structures when compared to corresponding frozen cross-sections. The information presented in this paper would serve as an initial reference to the evaluation of CT images of the digits and hoof in Holstein dairy cattle.     

Magnetic resonance imaging of the normal bovine digit

The purpose of this study was defining the normal structures of the digits and hoof in Holstein dairy cattle using Magnetic Resonance Image (MRI). Transverse, Sagital and Dorsoplantar MRI images of three isolated cattle cadaver digits were obtained using Gyroscan T5-NT a magnet of 0.5 Tesla and T1 Weighted sequence. The MRI images were compared to corresponding frozen cross-sections and dissect specimens of the cadaver digits. Relevant anatomical structures were identified and labeled at each level. The MRI images provided anatomical detail of the digits and hoof in Holstein dairy cattle. Transversal images provided excellent depiction of anatomical structures when compared to corresponding frozen cross-sections. The information presented in this paper would serve as an initial reference to the evaluation of MRI images of the digits and hoof in Holstein dairy cattle, that can be used by radiologist, clinicians, surgeon or for research propose in bovine lameness.     

Low Incidence of an Altered Endometrial Epidermal Growth Factor (EGF) Profile in Repeat Breeder Holstein Heifers and Differential Effect of Parity on the EGF Profile Between Fertile Holstein (Dairy) and Japanese Black (Beef) Cattle

A high incidence (about 70%) of alteration in endometrial epidermal growth factor (EGF) profile, i.e., loss of 2 peaks on days 2–4 and 13–14, has been linked to a reduced fertility in multiparous repeat breeder Holstein cows. However, the EGF profile in Holstein heifers and other breeds (types) of cattle has not been investigated. In study 1, EGF concentrations were determined using endometrial tissues obtained by biopsy on days 3, 7 and 14 from 84 fertile Holstein heifers to obtain a normal range and 53 repeat breeder Holstein heifers to estimate incidence of alterations in the EGF profile. In repeat breeder heifers, EGF concentrations were similar to fertile controls on 3 days and five animals (9.4%) had an altered EGF profile with EGF concentrations below the normal range on days 3 and 14. In study 2, EGF concentrations on day 3 were repeatedly examined from the nulliparous period to the third postpartum period in 28 Holstein (dairy) and 47 Japanese Black (beef) cattle. The effect of parity on EGF concentrations on day 3 was different between Holstein and Japanese Black cattle. In Japanese Black cows, the EGF concentrations were consistently high throughout the study period, while in Holstein cows, the EGF concentrations decreased after the second calving. In conclusion, unlike multiparous repeat breeder Holstein cows, an altered EGF profile may not be a major cause of repeat breeding in Holstein heifers, and the peak EGF concentrations around day 3 may decrease even in fertile populations of multiparous dairy cows, but not in beef cows.     

影响荷斯坦奶牛产犊间隔的因素及其研究进展

产犊间隔（calving internal,CI）又称胎间距,即两次产犊间的时间间隔,能够综合反映奶牛发情、配种、妊娠和产犊等繁殖性能,是衡量奶牛繁殖性能的一个重要指标,同时也是影响奶牛产奶量和产犊数量的重要因素,对奶牛养殖经济效益具有直接影响。最新研究显示,适宜产犊间隔与牛群泌乳能力相关,泌乳能力越高,适宜产犊间隔应越长。但是,即使中国规模化牛场产奶量已经有了大幅提升,中国大多数牧场还在追求更短的产犊间隔。为此,作者对影响荷斯坦奶牛产犊间隔的因素及其研究进展进行概述,并简要阐述了产犊间隔对牛场经济效益的影响,以期为中国荷斯坦奶牛养殖确定适宜产犊间隔提供一定的借鉴和理论依据。     

不同品种牛乳营养成分含量及脂肪酸含量和组成测定比较研究

[目的] 比较中国荷斯坦奶牛、荷斯坦奶牛和西门塔尔牛乳中常规营养成分含量、矿物质元素含量及脂肪酸含量和组成的差异。[方法] 选取中国荷斯坦奶牛、荷斯坦奶牛和西门塔尔牛各6头,每头奶牛收集200 mL生鲜乳样品,利用乳成分分析仪测定乳中常规营养成分含量,通过原子吸收分光光度计测定乳中矿物质元素含量,应用气相色谱仪测定乳中脂肪酸含量和组成。采用统计学方法对不同品种牛乳中的营养成分含量及脂肪酸含量和组成进行比较。[结果] 中国荷斯坦奶牛生鲜乳中乳脂含量显著（P<0.05）高于荷斯坦奶牛,乳蛋白含量显著（P<0.05）高于荷斯坦奶牛和西门塔尔牛;中国荷斯坦奶牛生鲜乳中乳钙含量显著（P<0.05）高于荷斯坦奶牛,乳锌含量显著（P<0.05）高于荷斯坦奶牛和西门塔尔牛。中国荷斯坦奶牛生鲜乳中豆蔻酸含量显著（P<0.05）低于荷斯坦奶牛,油酸和亚油酸含量显著（P<0.05）高于西门塔尔牛;中国荷斯坦奶牛生鲜乳中饱和脂肪酸含量显著（P<0.05）低于西门塔尔牛,不饱和脂肪酸含量显著（P<0.05）高于西门塔尔牛。[结论] 中国荷斯坦奶牛乳中部分营养成分和矿物质元素含量接近或优于荷斯坦奶牛和西门塔尔牛,脂肪酸含量和组成与荷斯坦奶牛相近,脂肪酸组成优于西门塔尔牛。     

育成荷斯坦奶公牛与其他3个品种牛的肉品质比较研究

通过对育成荷斯坦奶公牛与西门塔尔牛、新疆褐牛及新疆土种牛肉品质部分指标的比较分析研究,旨在探讨荷斯坦奶公牛的肉品质。选择在相同营养模式下18月龄左右4个品种牛各3头进行屠宰,取右半边胴体的背最长肌作为肉品质试验样品,分别对牛肉的肉品质、常规营养成分及氨基酸含量进行测定和分析。结果表明,荷斯坦奶公牛肉色、失水率、系水力、熟肉率、大理石花纹等指标均优于新疆褐牛、新疆土种牛,次于西门塔尔牛;荷斯坦奶公牛嫩度优于新疆土种牛;粗蛋白质、粗灰分含量分别为20.14%、1.11%,且各品种间差异均不显著(P>0.05),干物质含量为26.30%,显著高于新疆褐牛和新疆土种牛(P<0.05),低于西门塔尔牛(P>0.05),粗脂肪含量为10.04%,显著高于其他品种牛(P<0.05);荷斯坦奶公牛含有人体需要的各种氨基酸,其中蛋氨酸、谷氨酸、甘氨酸、组氨酸、牛磺酸等含量丰富,氨基酸组成比例良好。     

Comparison of enzyme activities in plasma and leukocytes in dairy and beef cattle

Concentrations of plasma glucose, immunoreactive insulin (IRI) and free fatty acid (FFA) and activities of enzymes related to energy metabolism and lactate dehydrogenase (LDH) isoenzyme pattern in plasma and leukocytes were investigated in lactating Holstein cows (dairy cattle) and fattening Japanese Black Wagyu x Holstein steers (beef cattle). IRI concentrations and LDH and malate dehydrogenase (MDH) activities in the plasma of beef cattle were significantly higher than those in dairy cattle. The cytosolic ratio of MDH/LDH activity in the leukocytes of beef cattle was significantly higher than that of dairy cattle. These findings might be associated with the different energy metabolism between dairy and beef cattle.     

奶牛性别鉴定的研究与应用

选取牛雄性性别决定基因SRY (sex region of Y chromosome),根据基因序列设计特异引物,应用PCR技术对5头荷斯坦奶牛DNA样品进行扩增,鉴定其性别;并对设计的引物灵敏度进行检测;对已有的公、母各20头荷斯坦奶牛DNA样品进行PCR盲检,获取奶牛高灵敏度特异性引物,用于奶牛性别鉴定。结果表明,4头公牛DNA样品可以扩增出目标条带(66 bp),1头母牛DNA样品无法扩增出条带,阴性对照扩增无条带;最佳引物灵敏度为1.6 pg/μL,可以很好地满足性别鉴定需要。40头个体中,20头个体DNA样品可以扩增出条带,其余20头个体DNA样品无法扩增出条带,检测结果与实际性别对比准确率为100%。试验结果表明,设计的引物灵敏度比较好,能够满足奶牛性别鉴定的需要。     

Development of genetic evaluation for milk production traits of Holsteins in Japan

The procedure used for the genetic evaluation of dairy cattle in Japan has developed from a lactation sire–MGS model to a multiple‐lactation random regression test‐day animal model. Genetic evaluation of Holstein bulls in Japan began in 1989 with the use of field‐style progeny testing; dairy herd improvement program data from all over Japan were used, along with a sire and maternal grandsire model. In 1993, an animal model was introduced to estimate breeding values for yield and type traits. A random regression test‐day model was first applied in 2010. In the business of breeding dairy cattle, it is very important to users that estimated breeding values are reliable and stable among subsequent routine evaluations. With experience in the genetic evaluation of dairy cattle in Japan, Japanese researchers have found ways to improve the stability of estimated breeding values. These modifications involve changes in data editing, development of evaluation models, changes to the structures of unknown‐parent groups, awareness of the problems of predicting lactation yield from partial test‐day records, and adjustment for heterogeneity within herd variances. Here, I introduce developments in, and our experiences with, the genetic evaluation of yield traits of Holstein cattle in Japan.     

Refined mapping of twinning-rate quantitative trait loci on bovine chromosome 5 and analysis of insulin-like growth factor-1 as a positional candidate gene

Twinning in cattle is a complex trait that is associated with economic loss and health issues such as abortion, dystocia, and reduced calf survival. Twinning-rate QTL have been detected previously on BTA5 in the North American Holstein and Norwegian dairy cattle populations and in a USDA herd selected for high twinning rate. In previous work with the North American Holstein population, the strongest evidence for a QTL was obtained from analysis of an extended, multiple-generation family. Using additional animals, an increased density of SNP marker association tests, and a combined linkage and linkage disequilibrium mapping method, we refined the position of this QTL in the North American Holstein population. Two sets of twinning-rate predicted transmitting abilities estimated during 2 different time periods in the North American dairy cattle population were used to provide validation of results. A total of 106 SNP and 3 microsatellites were used to scan the genomic region between 5 and 80 Mb on BTA5. Combined linkage-linkage disequilibrium analysis identified significant evidence for QTL within the 25- to 35-Mb and 64- to 70-Mb regions of BTA5. The IGF-1 gene (IGF1) was examined as a positional candidate gene and an SNP in intron 2 of IGF1 was significantly associated with twinning rate by using both data sets (P = 0.003 and P = 1.05 x 10(-6)). Replication of this association in other cattle populations will be required to examine the extent of linkage disequilibrium with the underlying quantitative trait nucleotide across breeds.