利用BLUP法估计荷斯坦种公牛的抗热应激育种值

以公牛女儿数大于10头为限制因子，建立线性模型Y=xb＋za＋e，对带有抗热应激$441标记的荷斯坦种公牛育种值进行了估计。结果表明：带有抗热应激S441标记的荷斯坦种公牛的平均育种值大于没有标记的群体均值。$441可以作为一种荷斯坦种公牛抗热应激分子标记应用于品种选育和生产中。应用CNDHI软件评估了2007～2011年公牛的最佳线性无偏差预测值，并依据年度均值作出遗传趋势，为选种和遗传评估提供依据。     

乌鲁木齐种牛场荷斯坦种公牛产奶性能的种用价值评定

目的:估计新疆乌鲁木齐种牛场荷斯坦牛产奶性状的遗传参数及育种值,为该场荷斯坦种公牛的选种选配计划提供理论依据。方法:以新疆乌鲁木齐种牛场2009~2015年间荷斯坦泌乳母牛的产奶性能记录资料为基础,运用DMUAI-REML算法及动物模型BLUP法,对荷斯坦牛产奶量及乳成分进行单性状方差组分及育种值估计。结果:牛场荷斯坦种公牛后代母牛的产奶量、乳脂率、乳蛋白率、乳糖率及非脂固形物的遗传力分别为0.14、0.13、0.14、0.09、0.11。6头种公牛里估计得到产奶量育种值最高的是65206012号种公牛,乳脂率、乳蛋白率、乳糖率、非脂固形物育种值最高的是11101917号种公牛。结论:使种公牛生产性能评定的更准确,需综合考虑产奶量和乳成分等性状,最终对种公牛进行选育选配。     

利用动物模型最佳线性无偏预测法估计西门塔尔种公牛精液性状育种值研究

利用贵州省家畜冷冻精液站西门塔尔种公牛2006、2007、2008年采精量、鲜精活力、冻精活力和合格冻精产量7172条记录,建立动物模型,利用MTDFREML软件对种公牛的单个精液性状育种值进行估计,对育种值排序做秩相关分析,并跟据各性状的不同遗传特点,计算种公牛综合育种值。结果表明,各性状育种值排序有所差异;综合排名前10位的公牛依次是6021、2190、6019、6075、6059、6053、452、439、6051和6063。为该站种公牛的选择提供了一定的依据。     

出生胎次对奶牛产奶性能影响的研究

一、引言依据女儿产奶量来估计公牛育种值是目前选留种公牛中所采用的主要方法。女儿产奶量不仅受遗传因素的影响,而且还受到环境因素的影响,因此如何能更好地剔除环境因素则显得十分重要。目前所采用的方法是仅剔除场年季效应。奶牛出生时母亲胎次的大小(即母亲各胎次分娩的女儿)是否对女儿成年后产奶性能有所影响,是否需在估计公牛育种值时予以剔除一直众说纷纭。在中内外以往的文献报道中尚未见到有关出生胎次对奶牛产奶性能影响的实例报道。本文对2194条产奶记录进行了处     

用BLUP方法估计北京市黑白花种公牛育种值的研究

本文利用北京市奶牛研究所提供的2872头母牛的第一泌乳期记录,用BLUP方法估计了17头公牛的关于泌乳量和乳脂率两个性状的复合育种值。所用的模型包含牛场-年-季节效应(固定)、观察值对女儿初产月龄的回归、公牛效应(随机)、公牛组效应(固定)和随机误差。研究结果表明,BLUP方法是适用于我国奶牛业的实际情况的,在一个省市内进行公牛比较,有一台微处理机就能解决全部计算问题,因此这一方法是值得在我国加以研究和推广的。     

美国和西德乳用种公牛的后裔鉴定方法

一、美国种公牛后裔鉴定方法美国对种公牛后裔鉴定所采用的方法与评定母牛的育种值的方法非常相似,是直接利用其女儿的育种值来评定父亲的遗传性能的。最初曾简单地利用女儿的平均数值作测定,后来,随着人工授精的普遍开展,种公牛后裔鉴定的方法也得到了改进。现在采用“美国农业部——奶牛改良协会”同群比较法。这个方法     

泌乳母牛305天奶量估计方法初步研究

<正> 一、前言在估计乳用种公牛的育种值时,采用同期同龄比较法,虽然可以消除一般环境的差异,却无法克服各女儿实际泌乳天数不同的影响,因此必须先将各女儿的实际产奶记录作泌乳天数的校正。但是,由不同作者提出来的泌乳天数的校正系数,固各自所搜集的原始资料及统计方法的不同,其实际误差都不很理想,适用范围也有很大的局限性。我们在总结、比较现有泌乳天数校正系数的制定方法及实际应用的基础上,根据最小二乘法原理,对泌乳母牛305天奶量的估计方法作了研究,推导出一组相应的计算公式。现将初步结果报告于后。     

我国种公牛遗传评估体系

遗传评定是指对奶牛个体的遗传素质——育种值进行估计，它是进行种牛选择的依据。在奶牛育种中，育种值估计，尤其是公牛的育种值估计，占有十分重要的地位。目前，世界大多数国家采用的奶牛育种值估计方法——测定日模型，与过去所采用的其它方法相比，主要优点是：能更有效地消除系统环境因素的影响：能充分利用所有亲属的信息：具有严格的统计学特性；可同时进行公牛和母牛的育种值估计。测定日模型由加拿大圭尔夫大学Larry Schaeffer教授于1993年率先提出，目前在加拿大和欧洲等奶业发达国家得到应用。     

奶牛繁殖性状的育种值估计

利用北京市8个荷斯坦奶牛群的头胎繁殖性状资料，用BLUP法估计了公牛繁殖力的育种值。利用20头公牛的2299头与配母牛头胎繁殖性状资料．估计了公牛雄性繁殖力的育种值。利用19头公牛的2001头女儿的头胎繁殖性状资料．估计了公牛雌性繁殖力的育种值。分别比较了考虑场、年、季之间互作效应的和未考虑场、年、季之间互作效应的育种值估计准确性．分析了不同场、不同输精年份、不同输精月份对公牛繁殖力的影响。结果表明，考虑场、年、季之间互作效应时的准确性最高．未考虑时的准确性最低；本文中不同场、年、季水平对公牛繁殖力的影响是显著的。结论：估计公牛繁殖性能的育种值时，应事先或模型中加以剔除这些固定效应。     

中国从加拿大奶业网引进奶牛测定日模型遗传评估系统已开始启用

中国农业大学、中国奶业协会联合与加拿大奶业网（CDN）于2006年在北京签署了奶牛测定日模型遗传评估系统的引进协议。2007年中国奶业协会已应用此系统对部分有后裔测定成绩的种公牛进行了个体遗传评估．这标志我国奶牛遗传评估系统已有新的突破。传统动物模型奶牛遗传评估系统存在一定的缺陷，主要包括需要通过测定日记录估计泌乳期记录，估计的过程本身存在较大的误差：对只作用于一定泌乳阶段的系统环境效应．无法在模型中直接考虑：假设性状的育种值在一个泌乳期内保持不变等。为解决上述问题．1993年加拿大圭尔夫大学著名教授Larry Schaeffer首次提出了测定日模型．其原理是利用奶牛泌乳测定日记录直接估计奶牛泌乳测定日育种值，进而得到泌乳期育种值。目前世界上奶业发达国家加拿大、德国、荷兰等国家均采用测定日模型对奶牛进行个体遗传评定。     

部分中国荷斯坦种公牛脊柱畸形综合征携带状况的检测和分析

摘本研究旨在对部分中国荷斯坦种公牛脊柱畸形综合征(Complex vertebral malformation,CVM)致病基因的携带状况进行筛查.应用错配PCR突变分析技术(PCR mismatch amplification mutation assay,PCR-MAMA)建立了针对CVM致病基因的特异性检测方法.利用PCR-MAMA法检测了154头荷斯坦种公牛,发现了24头CVM阳性个体,阳性率为15.58％.结果显示,应对中国荷斯坦种公牛进行全面的针对CVM的检测.     

Variants of somatotropin in cattle: gene frequencies in major dairy breeds and associated milk production

The amino acid sequence of bovine somatotropin (bST) varies at position 127 where either valine or leucine is found. The frequencies of leucine₁₂₇ and valine₁₂₇ bST gene alleles in cows (n = 302) and sires (n = 70) from major dairy breeds (Holstein, Brown Swiss, Guernsey, Jersey, and Ayrshire) were determined using DNA extracted from whole blood or spermatozoa. A 428 base pair fragment of the bST gene was amplified using polymerase chain reaction (PCR) and variants of the bST gene were detected as polymorphisms by Alu I restriction endonuclease digestion of PCR products. Restriction enzyme DNA fragments for the leucine₁₂₇ variant were 265, 96, 51, and 16 base pair and for the valine₁₂₇ variant were 265, 147, and 16 base pair as a polymorphism of bST was present in the 147 base pair DNA fragment. Frequencies of leucine₁₂₇ and valine₁₂₇ alleles for cows (n=302) were 1.0 and 0 for Brown Swiss, .93 and .07 for Holstein, .92 and .08 for Guernsey, .79 and .21 for Ayrshire, and .56 and .44 for Jersey, respectively. In Holstein sires used for artificial insemination (n=70), the frequency of leucine₁₂₇ and valine₁₂₇ alleles was .96 and .04. Estimates of transmitting ability for milk production tended to be greater for Holstein cows that were homozygous for leucine₁₂₇ bST and Jersey cows that were homozygous for valine₁₂₇ bST whereas Holstein sires with different bST genotypes were similar. In summary, frequencies of alleles for the bST gene were not similar in different dairy breeds and estimates of milk production were correlated with bST gene variant in cows but not sires.     

Performance ofBos taurus×zebu crossbreds under village conditions

Summary Data on first lactation performance of 751 Holstein×zebu and Jersey×zebu crossbred heifers of various grades were collected under rural field conditions in Maharashtra. The heifers were the progeny of seven Danish Holstein (Sortbroget Dansk Malkekvæg) sires, 33 homebred Holstein sires, six Danish Jersey sires and 35 homebred Jersey sires. The least-squares analysis showed that the location and genetic group within the two classes of crossbreds significantly affected the milk yield. In pooled data the 7/8 Holstein crossbreds produced by homebred sires were significantly superior to other genetic groups of either Holstein or Jersey inheritance. The milk yield increased with increasing level of homebred Holstein inheritance and with Jersey inheritance. Danish Holstein sires were the best to produce the halfbred Holstein crosses. The differences in the genetic groups accounted for 20% of the phenotypic variance in 305-day milk yield and for 2% of the variance of the lactation length in the crossbred population. It is inferred that the optimum level of exotic breed inheritance in Maharashtra would be above 50% and that the genetic group of the dams needs to be considered when evaluating the performance of a sire's progeny.

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Rendimiento de Cruzamientos deBos Taurus×Cebu Bajo Condiciones Aldeanas

Resumen Se colectaron datos sobre la primera lactancia de 751 novillonas Holstein×Cebu y Jersey×Cebu bajo condiciones de campo en Maharashtra. Las novillonas pertenecian a la progenie de siete Holstein Daneses (sortbroget Danks Malkerase) sires, 33 sires Holstein locales, seis sires Jersey Daneses y 35 sires Jersey locales. El análisis de cuadrados mínimos mostró, que la localización y grupo genético dentro de dos clases de cruzamientos, afectó significativamente la producción de leche. Los datos globales mostraron, que las Holstein 7/8 provenientes de sires locales, fueron significativamente superiores a otros grupos genéticos, tanto Holstein como Jersey. La producción de leche se incrementó paralelamente a la herencia Holstein de sires locales, asi como de sires Jersey locales. Los sires Holstein Daneses fueron los mejores para producir los cruces Holstein. Las diferencias entre los grupos genéticos influyeron en un 20% de la variación fenotípica en 305 días de lactancia y en 2% de la variación del período de lactación en la población cruzada. Se infiere, que el nivel óptimo de herencia de razas exóticas en Maharashtra sería superior al 50% y que el grupo genético de las madres reproductoras tiene que ser evaluado conjuntamente con el de los machos.

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Performance Des Croisements de Taurins (Bos Taurus) Et de Zebu En Elevage Villageois

Résumé Les données concernant les performances de première lactation de 751 génisses croisées Holstein×Zebu et Jersiais×Zebu, de différents degrés ont été recueillies sur le terrain dans des conditions villageoises dans le Maharashtra. Les génisses étaient les descendantes de sept taureaux Holstein danois (sortbroget Dansk Malkerace), de 33 taureaux Holstein indigènes, de 6 taureaux Jersiais danois et de 35 taureaux Jersiais indigènes. L'analyse des moindres carrés a montré que le lieu et le groupe génétique à l'intérieur des deux classes de métis avaient une influence significative sur le rendement laitier. Dans les fichiers de données, les métisses 7/8 Holstein engendrées par des taureaux indigènes étaient très supérieures aux autres groupes génétiques d'ascendance Holstein ou Jersiaise. La hausse de la production de lait était parallèle à la hausse de l'héritage de sang Holstein indigène et à celle de l'héritage de sang Jersiais. Les taureaux Holstein danois étaient les meilleurs pour la production de demi-sangs Holstein. Les différences dans les groupes génétiques étaient responsables de 20 p. 100 de la variance phenotypique de la production laitière de 305 jours et de 2 p. 100 de la variance de la durée de lactation dans la population métisse. Il en découle que le niveau optimal de sang importé à Maharashtra se situerait au dessus de 50 p. 100 et que le groupe génétique des mètres doit être pris en considération quand on évaluée les performances de la descendance d'un taureau.

     

Pregnancy Rates to Fixed Embryo Transfer of Vitrified IVP Bos indicus,Bos taurus or Bos indicus × Bos taurus Embryos

The pregnancy rates obtained after the transfer of cryopreserved in vitro‐produced (IVP) embryos are usually low and/or inconsistent. The objective of this study was to evaluate the pregnancy rates of Holstein, Gyr and Holstein × Gyr cattle after the transfer of vitrified IVP embryos produced with X‐sorted sperm. Seventy‐two Gyr and 703 Holstein females were subjected to ovum pickup (OPU) sessions, followed by in vitro embryo production using semen from sires of the same breeds. Embryos (1636 Holstein, 241 Gyr and 1515 Holstein × Gyr) were exposed to forskolin for 48 h prior to vitrification. The pregnancy rate achieved with Gyr dam and sire was 46.1%, which was similar (p = 0.11) to that of Holstein dam and Gyr sire (40.3%). Crossing Gyr dams with Holstein sires resulted in a pregnancy rate of 38.9% and did not differ (p = 0.58) from the pregnancy rate obtained with the cross between Holstein dams and Gyr sires. The rate obtained with Holstein dam and sire was 32.5%. The average pregnancy rate was 36.6%, and no difference was found in the proportion of female foetuses (88.8%, in average) among breeds (p > 0.05). In conclusion, transfer of cryopreserved X‐sorted embryos represents an interesting choice for dairy cattle. Despite the small differences between pregnancy rates, we highlight the efficiency of this strategy for all of the racial groups studied.     

应用微卫星DNA标记分析荷斯坦母牛系谱可靠性及影响因素

为了评估当前中国荷斯坦牛群体的系谱准确性,本研究选择15头种公牛及来自21个牛场的2 220头女儿牛,借助牛3号染色体(BTA3)上17个微卫星标记,对女儿-公牛标记基因型是否错配进行分析。结果,按照错配标记数大于等于3个为系谱错误的标准,本研究所涉及的母牛群中系谱错误率为16.62%。经对影响系谱错误的因素分析表明,场效应是主要的影响因素,不同场间系谱错误比例差异较大;由于公牛女儿在各牛场中分布不均匀,导致公牛效应也达到显著。研究结果提示在中国荷斯坦牛群体进行亲子鉴定是亟需和必要的。     

荷斯坦牛泌乳曲线的拟合分析

通过对安徽荷斯坦牛泌乳曲线进行拟合分析，结果 Wood模型对泌乳曲线的拟合精度为（R^2)=0.2336-0.5661；若剔除第1个泌乳月，对2-10个泌乳月利用Wood模型再次拟合，拟合精度则显著提高，达到0.9左右，使用f(t)=∑i=1^5αit^i-1模型拟合泌乳曲线，拟合精度达到0.9442-0.9955。     

Risk factors for umbilical hernia in Holstein heifers during the first two months after birth

OBJECTIVE: To determine risk factors associated with identification of an umbilical hernia during the first 2 months after birth in Holstein heifers. DESIGN: Case-control study. ANIMALS: 322 Holstein heifers born in a single herd (45 with an umbilical hernia and 277 without). PROCEDURE: Risk factors that were examined included sire, whether the dam had a history of umbilical hernia, milk yield, duration of gestation, whether the dam had a history of dystocia, whether the heifer had a twin, birth weight, total serum protein concentration, and whether the heifer had an umbilical infection. Logistic regression was used to analyze risk factors. RESULTS: Heifers born to sires with > or = 3 progeny with an umbilical hernia were 2.31 times as likely to develop an umbilical hernia as were heifers born to sires with < or = 2 progeny with an umbilical hernia. Heifers with umbilical infection were 5.65 times as likely to develop an umbilical hernia as were heifers without umbilical infection. CONCLUSIONS AND CLINICAL RELEVANCE: Sire and umbilical infection were associated with risk of an umbilical hernia during the first 2 months of life in Holstein heifers. Attributable proportion analysis indicated that the frequency of umbilical hernias in Holstein heifers with umbilical infection would have been reduced by 82% if umbilical infection had been prevented.     

Genetic and phenotypic parameters for conformation and yield traits in three Swiss dairy cattle breeds

This study presents genetic parameters for conformation traits and their genetic and phenotypic correlations with milk production traits and somatic cell score (SCS) in three Swiss dairy cattle breeds. Data on first lactations from Holstein (67 839), Brown Swiss (173 372) and Red & White breeds (53 784) were available. Analysed conformation traits were stature and heart girth (both in cm), and linear scores of body depth, rump width, dairy character or muscularity, and body condition score (only in Holstein). A sire model, with relationships among sires, was used for all breeds and traits and variance components were estimated using AS‐REML. Heritabilities for stature were high (0.6–0.8), and for the linear type traits ranged from 0.3 to 0.5, for all breeds. Genetic correlations with production traits (milk, fat and protein yield) and SCS differed between the dairy breeds. Most markedly, stronger correlations were found between SCS and some conformation traits in Brown Swiss and Red & White, indicating that a focus on a larger and more ‘dairy’ type in these breeds would lead to increased SCS. Another marked difference was that rump width correlated positively with milk yield traits in Holstein and Red & White, but negative in Brown Swiss. Results indicate that conformation traits generally can be used as predictors for various purposes in dairy cattle breeding, but may require specific adaptation for each breed.     

Genetic parameters for direct and maternal calving ease in Walloon dairy cattle based on linear and threshold models

Calving ease scores from Holstein dairy cattle in the Walloon Region of Belgium were analysed using univariate linear and threshold animal models. Variance components and derived genetic parameters were estimated from a data set including 33 155 calving records. Included in the models were season, herd and sex of calf × age of dam classes × group of calvings interaction as fixed effects, herd × year of calving, maternal permanent environment and animal direct and maternal additive genetic as random effects. Models were fitted with the genetic correlation between direct and maternal additive genetic effects either estimated or constrained to zero. Direct heritability for calving ease was approximately 8% with linear models and approximately 12% with threshold models. Maternal heritabilities were approximately 2 and 4%, respectively. Genetic correlation between direct and maternal additive effects was found to be not significantly different from zero. Models were compared in terms of goodness of fit and predictive ability. Criteria of comparison such as mean squared error, correlation between observed and predicted calving ease scores as well as between estimated breeding values were estimated from 85 118 calving records. The results provided few differences between linear and threshold models even though correlations between estimated breeding values from subsets of data for sires with progeny from linear model were 17 and 23% greater for direct and maternal genetic effects, respectively, than from threshold model. For the purpose of genetic evaluation for calving ease in Walloon Holstein dairy cattle, the linear animal model without covariance between direct and maternal additive effects was found to be the best choice.     

A hereditary disposition for bovine peripheral nerve sheath tumors in Danish Holstein cattle

Background

Peripheral nerve sheath tumors (PNSTs) are frequently found in Danish cattle at slaughter. Bovine PNSTs share several gross and histopathological characteristics with the PNSTs in humans with heritable neurofibromatosis syndromes. The aim of the present study was to investigate a possible hereditary disposition to PNSTs in dairy cattle by statistical analysis performed on data from 567 cattle with PNSTs. Furthermore, a preliminary genome-wide association study (GWAS) was performed on DNA isolated from 28 affected and 28 non-affected Holstein cows to identify loci in the bovine genome involved in the development of PNSTs.

Results

PNSTs were significantly more common in the Danish Holstein breed than in other breeds with 0.49% of Danish Holsteins slaughtered during an eight-year-period having PNSTs. PNSTs also occurred significantly more frequently in the offspring of some specific Holstein sires. Examination of three generation pedigrees showed that these sires were genetically related through a widely used US Holstein sire. The PNSTs included in GWAS were histologically classified as neurofibroma-schwannoma (43%), schwannoma (36%) and neurofibroma (21%) and derived from Holstein cows with multiple PNSTs. A single SNP on chromosome 27 reached genome-wide significance.

Conclusions

Gross and histological characteristics of bovine PNSTs are comparable to PNSTs in humans (schwannomatosis). Danish Holsteins are genetically disposed to develop PNSTs but the examined materials are insufficient to allow determination of the mode of inheritance.