Association analysis between bilateral convergent strabismus with exophthalmus and milk production traits in dairy cattle

Bilateral convergent strabismus with exophthalmus (BCSE) is characterized in cattle by a symmetrical antero-medial rotation and protrusion of the eyeballs. This eye defect is caused by an inherited, centrally insufficient function of the eye muscles recti laterales and retractores. In German Brown cattle a monogenic, autosomal dominant inheritance proved to be most probable in complex segregation analysis. In our study running between October 1993 and May 1995 a total of 200 affected German Brown cows was studied. The investigation of the association between milk production traits and BCSE was based on 10,960 German Brown cows. The analysis revealed no significant differences between affected and non-affected cows, nor between cow families with and without affected members. There was no indication of an association between milk production traits and occurrence of BCSE within cow families. Linkage or pleiotropy of the BCSE locus with quantitative trait loci for milk production traits may be rather unlikely.     

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.     

中国不同牛种DGAT1基因遗传多样性及经济性状关联分析研究进展

乙酰辅酯A∶二酰甘油酰基转移酶(DGAT1)是甘油三脂合成过程中唯一的关键酶,对动物机体脂肪代谢、沉积起重要作用,已成为研究奶牛泌乳性状和肉牛主要经济性状的重要候选基因之一。近年来,随着相关研究的不断深入,研究者普遍认为DGAT1基因对奶牛的产奶量、乳脂率、乳蛋白率、乳糖率、乳脂肪酸及空怀天数、输精次数、初配年龄等繁殖性状均有显著影响,且与肉牛体脂也存在相关性。作者主要介绍了DGAT1基因的遗传多态性及其与经济性状关联分析在中国各地区不同品种奶牛、肉牛、水牛和牦牛上的研究进展,指出该基因对奶牛的产奶性能及肉牛的肉质性状、生长性状具有重要的调控作用。但由于环境条件、品种及选育背景等因素影响,DGAT1基因遗传多态性对不同地区不同牛群体的经济性状影响不尽相同。因此,要将DGAT1基因实际应用在品种选育工作中还需明确该基因对研究群体的具体遗传效应,并结合其他候选基因进行综合分析。     

Breed performance in organic dairy farming in Northern Spain

Organic farm management combines best environmental practices, a high level of biodiversity, preservation of natural resources and high animal welfare standards. To meet these criteria, farmers must have livestock well adapted to local organic conditions and information about how different breeds and crosses perform under different conditions. The objective of this study was to compare the performance of different pure breeds and cross-breeds of cattle in organic dairy systems in Northern Spain. The data analysed were obtained from monthly records kept between 2010 and 2016 on organic farms registered in the regional milk recording system. Analysis of various traits indicated that the Holstein-Friesian breed suits the organic production system in the study region. Although the reproductive performance of Holstein-Friesian cows was poorer (in terms of number of services per conception) than that of cross-breed and Brown Swiss cows, the Holstein-Friesian produced more milk and lived longer. In addition, there was no difference in calving type or calving ease between the different breed groups. The better milk fat and protein yields produced by the crosses may be useful traits for farmers interested in milk transformation. The advantage of continuing to use Holstein-Friesian cattle is that the breed is predominant worldwide, and the genealogy is well documented. If Holstein-Friesian cattle continue to be used, the main priority will be to search for well-adapted bulls (particularly for pasture-based conditions) and to elaborate a genetic merit index for organic and pasture-based systems with the aim of predicting and minimizing genotype × environment interactions.     

Genetic effects on beef heifer puberty and subsequent reproduction.

Significant genetic variation exists within and between breeds of beef cattle for age at puberty (AP). In general, faster-gaining breed groups of larger mature size reach puberty at a later age than do slower-gaining breed groups of smaller mature size; breeds selected for milk production reach puberty at younger ages than do those breeds not selected for milk production. Heterosis, independent of heterosis effects on weight, influences most measures of puberty in females and scrotal circumference (SC) in males. Crossbred heifers reach puberty at younger ages and heavier weights than their straightbred counterparts. Scrotal circumference has been shown to be an excellent indicator of AP in yearling bulls. Furthermore, a favorable genetic relationship exists between SC in bulls and AP of female offspring. Beef cattle breeders may take a direct approach to breeding for AP and subsequent reproduction by directly selecting for measures of fertility such as SC. However, an indirect approach, involving selection for an array of traits that provide an appropriate "genetic environment" for the expression of fertility (i.e., size, milk production, calving ease) may be preferred. Although seedstock producers are limited to making change through within-breed selection, commercial producers can take advantage of both within- and between-breed selection as well as crossbreeding to achieve the same goal.     

中国荷斯坦牛PIK3CB基因多态性及其与繁殖和产奶性状的关联分析

【目的】 探究磷脂酰肌醇-4,5-二磷酸3-激酶催化亚单位β（PIK3CB）基因多态性及其与中国荷斯坦牛繁殖和产奶性状的关系。【方法】 通过混池测序对中国荷斯坦牛PIK3CB基因进行单核苷酸多态性（SNP）位点筛选,采用竞争性等位基因特异性PCR （KASP）技术在1 160头健康泌乳中国荷斯坦牛中进行SNP分型并进行群体遗传学分析,采用线性模型进行SNP与11个繁殖和产奶性状基于单位点和单倍型组合的关联分析。【结果】 在PIK3CB基因中共检测到了17个SNPs,筛选出7个SNPs用于后续分析。关联分析发现,7个SNPs与多个目标性状存在显著或极显著的关联（P<0.05;P<0.01）;位于外显子区域的g.130433743 A>G位点AA基因型个体和位于可变剪接区域的g.130448069 G>A位点GG基因型个体,其经产牛首末次配种间隔、产奶量、乳蛋白量和乳脂量最低,体细胞评分最高,上述基因型个体具有较短的首末次配种间隔,而产奶性能相对较差;g.130387717 G>A位点AA基因型个体,其初配日龄和青年牛首末次配种间隔最低,产奶量、乳蛋白量和乳脂量最高,该基因型个体的繁殖和产奶性能均较好,上述3个SNPs位点可作为中国荷斯坦牛繁殖和产奶性状的候选位点重点关注。单倍型分析发现,PIK3CB基因的g.130387717 G>A、g.130430832 A>－、g.130433743 A>G、g.130433982 C>T、g.130446073 C>T和g.130448069 G>A 6个SNPs紧密连锁形成一个单倍型块,且与多个目标性状存在显著或极显著关联（P<0.05;P<0.01）,其中H2H3和H2H4单倍型组合个体的繁殖和产奶性能较好,为优势单倍型组合。【结论】 中国荷斯坦牛PIK3CB基因存在丰富的遗传变异,其多态性与繁殖和产奶性状存在关联,g.130433743 A>G、g.130448069 G>A和g.130387717 G>A位点可作为潜在分子标记,为中国荷斯坦牛的平衡育种提供理论依据。     

中国荷斯坦奶牛RPL23A、ACACB基因3个SNPs检测及其与产奶性状的关联分析

旨在开展奶牛群体高乳成分功能基因的验证与筛选,利用微流控芯片自主选育技术分析北京地区母牛群体高乳蛋白、高乳脂基因频率,同时分析基因多态性及其与产奶性状的相关性。本研究对北京地区8个大型奶牛场1 596头中国荷斯坦奶牛RPL23A、ACACB基因的多态性进行了检测,所有个体均为3胎以内的泌乳牛,收集每头牛所有测定日的产奶量、乳脂率、乳蛋白率等数据,同时对3个多态位点不同基因型与产奶性状进行了关联分析。RPL23A基因的SNP位点g.20146771G>A,在第一泌乳期,与产奶量、乳脂量、乳脂率和乳蛋白量均达到极显著关联（P<0.01）,第二泌乳期,g.20146771G>A与5个产奶性状均呈极显著关联（P<0.01）。ACACB基因的SNP位点g.63962768C>T,在第一泌乳期,与产奶量、乳脂量、乳脂率和乳蛋白量均呈极显著关联（P<0.01）,在第二泌乳期,与产奶量、乳脂量、乳脂率和乳蛋白率呈极显著关联（P<0.01）。结果表明,RPL23A、ACACB基因可以作为影响中国荷斯坦奶牛产奶性状的候选基因用于标记辅助选择,以上基因位点可能通过直接或间接的途径影响奶牛的乳脂或乳蛋白性状,对产奶性状起到重要调控作用。本研究为荷斯坦奶牛后续的标记辅助选择奠定了良好基础。     

Association between single nucleotide polymorphisms (SNPs) and milk production traits in Italian Brown cattle

Italian Brown is a cattle breed largely exploited in the production of many dairy products in Italy, including typical and traditional cheeses. For this reason, the improvement of selection methods is of economic relevance while a deeper understanding of the genetic mechanisms regulating milk production is of general scientific interest. We selected a total of 561 samples, representing virtually all Italian Brown bull population, to test for association between milk production traits and 29 known genes harbouring 106 single nucleotide polymorphisms (SNPs). After filtering, a total of 31 SNPs in 22 candidate genes and 473 bulls were retained. Associations between each SNP and milk traits were tested by a mixed model approach, obtaining seven significantly associated SNPs, two of which (in β-Lactoglobulin) associated with all traits, and four (in Chemokin receptor I, αs1 casein, k casein, fatty acid synthase, thyroid hormone responsive and Oxytocin prepropetide genes) associated with at least one trait.     

瑞士褐牛蜘蛛腿综合征致病位点检测方法的建立

牛蜘蛛腿综合征（Arachnomelia Syndrome,AS）是一种常染色体隐性遗传病,现主要见于德系西门塔尔牛和欧洲瑞士褐牛。患病犊牛先天骨骼系统严重畸形,出生即死亡或出生不久死亡。已证实瑞士褐牛蜘蛛腿综合征是由编码亚硫酸盐氧化酶的基因SUOX外显子4上一个单碱基插入突变c.363-364insG所致。本研究首次建立了瑞士褐牛蜘蛛腿综合征致病基因突变位点分子筛查的方法：荧光引物PCR产物电泳法和PCR产物直接测序法。使用荧光引物PCR产物电泳法对10个品种187头牛样本进行该突变位点的基因型分型,没有发现携带该致病基因的个体。荧光引物PCR产物电泳法判定基因型快速可靠,实验成本较低,适合大规模群体的检测。由于我国曾多次进口瑞士褐牛遗传物质,可能将该致病基因引入本地牛群体。因此对我国相关牛群开展AS隐性不利基因的筛查是必要的,尤其是针对种公牛进行筛查,可避免该致病基因在群体的传播造成重大经济损失。     

牛催乳素基因及其单核苷酸多态性与产奶性状关系的研究进展

SNPs是目前遗传标记研究的一大热点,牛催乳素(prolactin,PRL)基因是与产奶性状相关的重要候选基因。PRL基因上的SNPs与牛的产奶量、乳脂量、乳蛋白量、乳脂率、乳蛋白率等性状存在某种关联,可用于牛的标记辅助选择(MAS)育种。笔者从PRL的结构与功能、基因的定位及作用机制、PRL上的SNPs与产奶性状关系的研究等几个方面进行了综述。     

Mitochondrial respiratory metabolism and performance of cattle

Two groups of cows were sampled to study variation of mitochondrial metabolism. The first group included 10 lactating and five gestating Holstein cows, representing available phenotypic extremes for milk yield. The second group included 13 Angus, 13 Brangus and 13 Hereford cows, representing available extremes within breeds for growth breeding value ratios. Consistently poor mitochondrial samples were obtained from gestating cows; these were excluded from analyses. Linear correlations of Holstein mitochondrial respiratory activities with sire-predicted difference for milk and milk fat ranged from -.35 to .15. Correlations of dam and cow indices and cow yields for milk with acceptor-stimulated mitochondrial respiration, oxidative phosphorylation efficiency (adenosine diphosphate:oxygen ratio [ADP:O ratio]) and adenosine triphosphate (ATP) synthesis rate were .25 to .48, consistently higher than for milk fat, -.06 to .17. No differences among beef breeds in mitochondrial respiration rates, coupling of respiration to phosphorylation, ADP:O ratio or ATP synthesis rate were detected by repeated measures analyses of variance. No patterns were evident among correlations of the mitochondrial characteristics and growth and milk traits in beef cattle. These initial findings indicate that variability in the mitochondrial respiratory activities measured has less relation to weaning and yearling growth traits of beef cattle than to milk yield of Holstein cattle.     

甘南牦牛杂交改良现状与措施

甘南牦牛应突出肉用价值,把肉当作主攻方向,作为主导支柱产品。开展牦牛与普通牛的种间杂交,是提高牦牛业生产水平和经济效益的重要途径。在二元杂交试验中,若杂交目的主要以生产肉或提高役力,改良牛的父本,应选择短角牛、夏洛来牛、西门塔尔牛、海福特等肉乳兼用和肉用良种牛,具有明显杂优效果;若杂交的目的主要是生产牛奶和酥油,则父本以黑白花奶牛等与牦牛交配产生黑犏杂一代的组合为最佳;若杂交的目的主要是奶肉兼用,则一代奶用二代肉用。甘南地区犏牛繁殖的主要目的是产奶。因此,牦牛种间杂交育种的主要方法是采用良种牛冻精(娟姗牛等)与母牦牛进行人工授精等方法生产良种犏雌牛。     

Maternal effects due to cytoplasmic inheritance in dairy cattle. Influence on milk production and reproduction traits

The objectives of this study were to determine the importance of effects of cytoplasmic origin on milk production and reproduction traits.Cow families at the experimental farm originated from randomly collected calves from 240 herds in two breeding districts. Cytoplasmic origin was defined as the first animal in the traced, maternal lineage. Milk production of 290 cows in first lactation from 1976 to 1982 was used. Reproduction records of the same cows as nulliparous and primiparous could be analysed in cow families.Cytoplasmic origin was a significant (P < 0.01) source of variation in kg fat plus protein, and milk returns (Dfl.) after adjustment for district of origin of the cytoplasmic source, sire's breed, calving year and season, breeding values of sires and material grandsires, and age at calving. Cytoplasmic origin accounted for maximal 10% and 13%, respectively, of the phenotypic variation in the two traits.Cytoplasmic origin was not a significant source of variation in nulliparous and primiparous reproduction traits after adjustment for effects of sire's breed, calving year and season. Although not significant, the cytoplasmic components accounted for 10 to 4% of the phenotypic variation in number of inseminations per first conception and for −0.04% to 13% of the phenotypic variation in age at first calving for the first and second generation, respectively. Some of these cytoplasmic components accounted for more phenotypic variation in reproductive traits of nulliparous heifers than most additive genetic components found in the literature.The effects of cytoplasmic inheritance on production and reproduction traits might have an impact on breeding policies in dairy cattle.     

Lactation curves and estimated feed conversion ratios for Simmental,Brown Swiss and Tyrol Grey in Kosovo

Abstract

A total of 2516 test-day milk production records of three dual-purpose cattle breeds, Simmental (S), Brown Swiss (BS), and Tyrol Grey (TG), having their first lactation in Kosovo, were analysed with a repeatability test-day mixed model with the aim of comparing lactation curves and feed conversion ratios of the three breeds. The BS had the highest yield, followed by S and TG. The TG cows tended to have flatter lactation curves than the other breeds. However, as the breeds differed in size, they were also compared throughout lactation for their estimated feed conversion ratios, defined as metabolic body weight per kg of milk (proportional to expected maintenance requirements per kg of milk produced, under certain assumptions). On this criterion BS still ranked highest, while S and TG had similar feed conversion ratios.     

PCR-SSCP analysis of leptin gene and its association with milk production traits in river buffalo (Bubalus bubalis)

Leptin gene has been found to be associated with various economic traits including milk production and fat quality in dairy animals. In the present study, we investigated genetic variations in intron 1 region of leptin gene in riverine buffaloes (Bubalus bubalis) using polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) and sequencing methods and associated them with milk traits. The study revealed three SSCP variants A, B and C among a total of 301 buffaloes from nine breeds. The frequency of variant C was found invariably high among all the breeds except in Marathwada buffalo. Variant A was found to be absent in Chilika, Nili-Ravi, Nagpuri and Pandharpuri breeds and also had the lowest frequencies in Mehsana, Jaffarabadi, Murrah and Toda breeds. Sequencing of SSCP variants revealed a total of five polymorphic sites, with three haplotypes. Statistical analysis revealed significantly high fat percentage at 150?days in SSCP variant B in Mehsana buffaloes. However, the associations of SSCP variants of leptin gene with total milk yield, 305?days milk yield and total fat yield were found to be non-significant. The present study is the first report on association analysis of leptin gene polymorphisms with milk production and milk quality traits in river buffalo.     

Relative merits of various Bos taurus dairy breeds for cross-breeding with Bos indicus cattle

Data extracted from reports on cross-breeding of Bos taurus and Bos indicus cattle for milk production were used to compare the merits of various Bos taurus breeds for this purpose. The study was restricted to projects in which two or more taurus breeds had been used simultaneously, and to records on F₁ crosses. The only taurus breeds represented were Friesian, Brown Swiss and Jersey.Brown Swiss crosses were the oldest and Jersey crosses the youngest at first calving; both differed significantly from Friesian crosses. In milk yield Friesian crosses were the highest and Jersey crosses the lowest, and again all differences were significant. Jersey crosses had significantly shorter calving intervals than the other crosses.The ranking of the crosses was very consistent across projects. The difference in milk yield between Friesian and Jersey crosses increased proportionately with level of production.     

中国荷斯坦牛RPL23A和ACACB基因对产奶性状的遗传效应分析

作者所在团队前期通过奶牛乳腺上皮组织转录组测序及荷斯坦公牛全基因组重测序研究发现RPL23A和ACACB基因是奶牛乳蛋白和乳脂性状的候选功能基因,本研究旨在探究这两个基因是否对奶牛产奶性状具有显著遗传效应。以北京地区7个牧场的1059头中国荷斯坦母牛为试验群体,采集尾根静脉血并提取基因组DNA,通过飞行时间质谱方法检测SNP位点基因型,利用SAS9.4软件的MIXED过程进行关联分析。结果表明,RPL23A基因的SNP位点g.20146771C>T与第1泌乳期5个产奶性状达到显著或极显著关联(P=0.0001~0.0416),其优势等位基因为T;ACACB基因的g.63878254T>C位点与第1泌乳期产奶量、乳脂量和乳蛋白量呈极显著关联(P<0.01),其优势等位基因为C;g.63962768G>A位点与第1泌乳期产奶量、乳脂量、乳脂率和乳蛋白率关联显著或极显著(P=0.0001~0.0391),其优势等位基因为A。综上,RPL23A基因主要影响中国荷斯坦牛产奶量和乳蛋白,ACACB基因对产奶量和乳脂具有显著遗传效应,3个SNP位点可考虑作为遗传标记用于标记辅助选择培育奶牛高乳蛋白乳脂新品系和选育提高。     

Evaluation in beef cattle of six deoxyribonucleic acid markers developed for dairy traits reveals an osteopontin polymorphism associated with postweaning growth

The objectives of this study were to 1) estimate the allelic frequencies in US beef cattle of 6 DNA markers reported to be associated with variation in dairy production traits; and 2) evaluate the association of these markers with beef production traits. Several genetic markers have been associated with milk yield or composition, including polymorphisms in secreted phosphoprotein 1 (SPP1; also called osteopontin), growth hormone receptor (GHR), casein S1 (CSN1S1), diacylglycerol O-acyltransferase 1 (DGAT1), peroxisome proliferator-activated receptor gamma co-activator-1alpha (PPARGC1A), and ATP-binding cassette subfamily G (white) member 2 (ABCG2). Allelic frequencies for these 6 markers, and their association with 21 phenotypes, were evaluated in 2 crossbred beef cattle populations that sample influential industry sires. Five of 6 markers were segregating in beef cattle populations; the exception was ABCG2. The SPP1 marker was associated with yearling weight (P = 0.025), live weight at slaughter (P = 0.016), postweaning ADG (P = 0.007), and HCW (P = 0.007) in a large, multisire population representing the 7 most populous beef breeds in the United States. Postweaning growth trait associations were confirmed in an independent population of similar construction, including sires from tropically adapted breeds. The SPP1 marker was associated with yearling weight (P = 0.034), live weight at slaughter (P = 0.011), and postweaning ADG (P = 0.015) and showed a trend toward association with HCW (P = 0.083) in this population. Whereas DGAT1, GHR, and CSN1S1 polymorphisms showed association with some traits in individual populations, the lack of consistent predictive merit between populations indicates they may not be suited for beef cattle selection. No significant associations were observed for the PPARGC1A marker and any of 21 recorded traits, indicating this marker had no apparent value in selection for the beef cattle traits tested in these populations. The SPP1 marker had consistent associations and effect sizes (10.5 to 11.5 kg of live weight at slaughter) in both populations, providing strong evidence for utility of the SPP1 marker for postweaning growth in beef cattle.     

肉牛早期断奶试验研究

[目的]旨在研究早期断奶技术对不同品种肉用犊牛生长发育的影响,[方法]本试验在草原牧区应用犊牛代乳料产品开展了不同品种犊牛的早期断奶工作,[结果]表明:安杂牛、新褐杂牛、荷斯坦牛三组间日增重差异不显著(P>0.05),安杂组增重成本8.25元/kg,新褐杂增重成本组9.27元/kg,荷斯坦组增重成本9.62元/kg,但...