关中母马血清白蛋白位点与受胎率关系的研究

采用聚丙烯酰胺凝胶电泳技术，测定了３８匹关中母马血清白蛋白遗传多态性，结果证实了ＡＬｂ位点不同基因型与受胎率的关系，发现ＢＢ型母马的第１个情期受胎率极显著的高于ＡＡ型和ＡＢ型；Ｂ基因为优势基因，Ｂ基因对Ａ基因的替代效应为８．３６％，最后制定出优势基因Ｂ对基因型育种值的回归方程。     

中国荷斯坦牛乳蛋白分子遗传多态性和产奶性状相关性的研究

从北京两个主要牛场共采得１８７头中国荷斯坦奶牛的血样,提取基因组ＤＮＡ,通过ＰＣＲ－ＲＦＬＰ方法对Ｋａｐｐａ酪蛋白、Ｂｅｔａ乳球蛋白（βｌｇ）和Ａｌｐｈａ乳白蛋白（α－ｌａ）进行了基因型的鉴定,并结合产奶性状进行统计分析,结果表明,牛群中上述３种乳蛋白基因的基因频率分别为Ｋ－ｃｎＡ７９％,Ｋ－ｃａＢ２１％,β－ｌｇＡ４３％,β－ｌｇＢ５７％,α－ｌｇＢ１００％,Ｋ－ＣＮ和β－ｌｇ基因位眯对产奶量没     

中国无角美利奴羊血红蛋白多态性研究

测定分析３４只中国无角美利奴育成公羊的血红蛋白多态性和生产性能结果表明：中国无角美利奴育成公羊血红蛋白基因型分为ＨｂＡ、ＨｂＢ、ＨｂＡＢ三型,受基因ＨｂＡ、ＨｂＢ控制;血红蛋白基因型为ＨｂＡＢ的羊剪毛后体重显著高于基因型为ＨｂＡ的羊,而与基因型为ＨｂＢ的羊差异不显著。     

杜洛克FUT1基因多态性及其与产仔性能的关联分析

采用PCR-RFLP方法对杜洛克FUT1基因多态性进行分析。结果发现:杜洛克FUT1基因开放阅读框307位点经Hin6Ⅰ酶切后,检测到AA、AG和GG3种基因型,AA基因型的频率为0.157,A基因的频率为0.353。分析这3种基因型与杜洛克产仔性能间的关联性。结果表明:抗性纯合子AA基因型的个体1～5胎每个胎次的产仔数均值均高于AG和GG基因型,且第1胎和第4胎的产仔数均值显著高于AG和GG基因型(P<0.05),AA基因型对产仔性能而言是有益基因型。     

撒坝猪血清酯酶多态性与日增重关系的研究

本研究采用垂直板聚丙烯酰胺凝胶电泳法对１０２头撒坝猪的血清酯酶（Ｅｓ）多态性进行了检测，计算了该位点的基因型频率，基因频率及遗传多样性指数，并用普通方差分析和二因素有互作的最小二乘模型对不同酯酶基因型与几个阶段日增重的关系进行了分析。结果表明，撒坝猪血清酯酶三种基因型ＡＡ、ＡＢ和ＢＢ的频率分别为０．２４５１、０．５９８０和０．１５６９。两个等位基因Ａ和Ｂ的基因频率分别为０．５４４１和０．４５５９。该位点的遗传多样性指数为０．４９６２。在三种基因型中，ＢＢ型个体的２～６月龄平均日增重显著高于其它两种类型，且酯酶基因型与性别之间的互作效应明显，显示了猪的血清酯酶多态性作为２～６月龄平均日增重的遗传标记以进行标记辅助选择的可能性     

柴达木马血清白蛋白多态性的研究

采用聚丙烯酰胺电泳对１３１匹柴达木马血清白蛋白的多态性进行研究。结果：（１）柴达木马血清白蛋白基因座有ＡＬＡ＾Ａ和ＡＬＢ＾Ｂ两个等位基因，基因频率分别为０．４１２２和０．５８７８；（２）柴达木马存在ＡＬＢ ＡＡ，ＡＬＢ ＡＢ和ＡＬＢ ＢＢ三种基因型，以ＡＬＢ ＡＢ为优势基因型；（３）基因杂合度为０．４８４６，有效等位基因数为１．９４个。     

夏洛来杂种羊及其亲本的血红蛋白遗传多态性

采用聚丙烯酰胺凝胶电泳对夏洛来杂种羊及其亲本的血红蛋白多态性进行了遗传检测。结果表明：参试羊表现出ＨＢＡＡ，ＨＢＢＢ和ＨＢＡＢ三种基因型，各群体均以杂合子ＨＢＡＢ为优势基因型，ＨＢ＾Ｂ为优势基因，ＨＢ＾Ｂ频率在０．５１５２￣０．６４２８之间，没有发现ＨＢ＾Ｃ基因；群体基因频率分析和亲子配对资料的遗传分析均证实，绵羊ＨＢ受常染色体位点上两个共显性等位基因的控制，各羊群ＨＢ基因的杂合度在０．５左右。     

猪囊尾蚴B抗原的克隆及鉴定

本实验从猪囊尾蚴虫体中提取 Ｒ Ｎ Ａ， 根据已发表的 Ｂ 抗原（ Ａｇ Ｂ） 核苷酸序列设计一对引物， 用 Ｒ Ｔ Ｐ Ｃ Ｒ 扩增出 Ａｇ Ｂ 全基因， 以ｐ Ｕ Ｃ１１９ 为载体克隆， 转化到大肠杆菌 Ｊ Ｍ８３ 中， 经分析鉴定所扩增片段为 Ａｇ Ｂ 基因。     

海兰褐鸡血清白蛋白和运铁蛋白的多态性

采用聚丙烯酰胺凝胶电泳法对５５只引入乐都的海兰褐鸡血清白蛋白和运铁蛋白的多态性进行研究。结果发现：（１）被检海兰褐鸡血清白蛋白有ＡＬＢ ＢＢ，ＡＬＢ ＢＣ二种基因型，以ＡＬＢ ＢＢ型为优势基因型（９０．９１％），ＡＬＢ＾Ｂ和ＡＬＢ＾Ｃ等位基因频率分别是０．９５４５和０．０４５；（２）运铁蛋白只有ＴＦ ＢＢ一种基因型；（３）ＡＬＢ和ＴＦ两位点的平均基因杂合度（Ｈ）和有效等位基因数（Ｎｅ）分别为０．０     

中国肾型IBV毒株的基因型及其S1基因的巢式PCR

用本研究建立的ＩＢＶＳ１基因的巢式ＰＣＲ方法鉴定了国内５个肾型传染性支气管炎病毒（ＩＢＶ）分离株。以此５个分离株及３个标准毒株的ＲＴ－ＰＣＲ产物（１７４９ｂｐ，含Ｓ１基因）为模板，１对内部引物经巢式ＰＣＲ都获得１７２９ｂｐ的产物，另１对内部引物的巢式ＰＣＲ有大小不同的产物（１６７８ｂｐ或０．５、０．６ｋｂ）。参照以前的ＲＦＬＰ分析结果，探讨了中国肾型ＩＢＶ毒株的基因型状况。     

北京地区荷斯坦牛乳蛋白多态性与产奶性能的相关分析

本研究选取北京市 4个牛场共 73 1头健康荷斯坦奶牛 ,利用聚丙烯酰胺凝胶垂直板状电泳(PAGE)对其乳蛋白进行分型 ,采用基因替代模型来分析乳蛋白多态性与奶牛产奶性能间的关系。结果表明 :αsl CN座位B基因对产奶量的替代效应最大 ,为 62 4kg ;β CN座位A1基因对A2 基因的替代使乳脂率提高 0 .1 2 % ,但产奶量降低 70kg ;κ CN座位和 β Lg座位A基因对B基因的替代效应分别对乳蛋白率、乳脂率有显著效应 ,使二者分别降低 0 .2 0 %。     

Genetics and physiology of leptin in periparturient dairy cows

In dairy cattle, the increase in milk yield has been accompanied by a more negative energy balance (EB) during early lactation and a decrease in fertility. As the hormone leptin is involved in regulation of nutritional status and reproductive function this hormone is an interesting protein to investigate during the periparturient period in dairy cattle. This study was performed to get insight into the function of leptin during the periparturient period and to perform an association study between polymorphisms in the bovine leptin gene and leptin receptor gene and fertility as well as production traits. Leptin concentrations in the periparturient cow undergo remarkable changes; leptin concentrations were high during late pregnancy and declined to a nadir at parturition. Genetic analysis of the leptin gene indicated that a combination of three polymorphisms located at a 135 bp region of the leptin promoter explained most of the variance in prepartum leptin concentrations. The two extreme genotype combinations could be used to investigate the function of leptin concentrations in pregnant cows. A polymorphism located on intron 2 of the leptin gene explained a significant part of the variation in milk yield. On the promoter region of the leptin gene an SNP was detected that was associated with first postpartum luteal activity (FPLA). This SNP could be a candidate marker for fertility in dairy cows. Another SNP on the leptin promoter was associated with energy balance and dry matter intake (DMI) where a higher dry matter intake occurred together with a higher energy balance. Two genotype combinations of the aforementioned three associated SNPs were defined which had a good milk yield together with a good energy balance and fertility. Calculations of an economical value per trait have to validate if one of these genotype combinations would be a possible candidate to be used in selection.     

The proteolytic activity of milk fat, whey and casein for iodinated, extrinsic bovine IgG1, IgG2, SIgA and IgM

Purified, iodinated bovine immunoglobulins (Igs) were incubated with fresh Guernsey milk or with the casein, fat and whey fraction of such milk for up to 12 hr at 37 degrees C. Igs incubated in whole milk, showed little evidence of proteolysis in either the whey, fat or casein fractions although the amount of radioactivity which became associated with the latter two fractions prevented adequate analysis. When the individual milk fractions were first prepared and then incubated with iodinated Igs, we found no evidence for proteolysis of any Ig in whey or casein but ca. 25% breakdown or dissociation of the IgM and SIgA which had been incubated with milk fat. Breakdown of these Igs in fat was not inhibited with benzamidine-HCl, sodium azide or EDTA. These data show that: only those Igs which associate with milk fat are degraded or dissociated by it and the Ig fragments described from cows milk or recovered during studies on Ig transport cannot be ascribed to the proteolytic activity of fresh milk.     

西农萨能奶山羊CSN1S2基因多态与产奶量、体尺指标的相关分析

利用PCR2RFLP技术对69只西农萨能奶山羊的CSN1S2基因进行多态性分析。扩增产物为310bp的CSN1S2F基因片段,被Alw26I限制性内切酶消化后表现多态性。F等位基因为310bp,N等位基因为179和131bp,相应地,FF基因型为310bp,NF基因型为310,179和131bp,NN基因型为179和131bp。在该群体中,F等位基因频率为010870,N等位基因频率为019130,处于Hardy2Weinberg平衡状态。将西农萨能奶山羊CSN1S2F基因座不同基因型与平均产奶量进行相关分析,结果表明:CSN1S2的不同基因型对平均产奶量有显著影响,NN基因型个体产奶量最高,FF基因型个体产奶量最低,且FF基因型个体平均产奶量显著低于NN基因型个体(P<0105)。将西农萨能奶山羊CSN1S2F基因座不同基因型与体尺指标进行相关分析,结果表明:在初生重和体高指标上,NF基因型个体显著优于NN基因型个体(P<0105);在体斜长和管围指标上,NF基因型个体略优于NN基因型个体,但差异不显著(P>0105);在成年体重和胸围指标上,不同的基因型个体间无差异。     

An independent confirmation of a quantitative trait locus for milk yield and composition traits on bovine chromosome 26

Several reports have demonstrated that bovine chromosome 26 (BTA26) harbours significant or suggestive quantitative trait loci (QTL) for milk production and composition traits in dairy cattle. Our previous study showed that a C/T substitution in the bovine TCF7L2 gene on BTA26 was significantly linked to QTL for protein yield (PY) in a Canadian dairy cattle population. Actually, this polymorphism was one of the markers derived from a genome‐wide screening of QTL for milk PY using an amplified fragment length polymorphism technique combined with a DNA pooling strategy. In the present study, 990 Holstein bulls with complete genotype and phenotype data from 14 sire families were analysed to confirm, if the QTL effects exist in other populations. Statistical analysis revealed that this marker was significantly associated with PY, protein percentage, milk yield and fat yield (FY) (p < 0.001) in the US Holstein population. These results indicate that this QTL region has a pleiotrophic effect on different milk traits and is portable in different populations.     

IgE reactivity to milk components in dogs with cutaneous adverse food reactions

We investigated the IgE reactivity to crude and purified milk antigens in the sera of 112 dogs with cutaneous adverse food reactions (CAFRs). Of the 112 dogs, 33 (29%) had specific IgE for crude milk antigens. In the dogs with milk-specific IgE, IgE reactivity to casein, bovine serum albumin (BSA), α-lactalbumin, β-lactoglobulin, and bovine IgG were 81%, 85%, 39%, 27%, and 35%, respectively. Casein and BSA may be important allergens in dogs with CAFRs. Some canine vaccines contain casein hydrolysate as a stabilizer and the pooled serum with anti-casein IgE showed IgE reactivity to the vaccines containing it. Information about IgE reactivity to casein in dogs with CAFRs could be useful for predicting adverse reactions to the vaccines including casein hydrolysate.     

The effect of beta and kappa casein genes on milk yield and milk composition in different percentages of Holstein in crossbred dairy cattle

The objective of this study was to compare the genotype, and composite genotype frequency, and the association between beta and kappa casein genes and milk yield (MY), percentage of fat (%Fat), protein (%Prot), and solids non‐fat (%SNF) between two groups of crossbred Holstein: G1 ≤ 87.5% Holstein = 89 cows and G2 > 87.5% Holstein = 142 cows. Five genotypes of beta casein gene were observed. A1A2 and A1B were the most and rarest frequency, respectively, in both groups. Five genotypes of kappa casein gene were found. The highest and the lowest frequency were AA, and BB and BE, respectively, in both groups. Composite genotype A1A2AA was the most frequent in both groups. Linkage disequilibrium (LD) between two genes was detected. Significant differences of frequencies between both groups of both genes were not found. The association of the genes and the traits was different between G1 and G2. Negative effects on the traits were found in both groups. In addition, the stronger effect of the beta casein gene was observed in most of the traits. The conclusions were that different %Holstein caused different significant effects of these genes. A study of the association of these genes within each percentage of Holstein is strongly recommended.     

The polymorphism in the β4-defensin gene and its association with production and somatic cell count in Holstein-Friesian cows

The aim of this study was to find a polymorphism of the bovine β4‐defensin gene and search for its association with milk yield and composition and with the somatic cell count in milk. The data were from the years 1999 to 2004 on 212 Holstein‐Friesian (HF) dairy cows, descended from 70 sires. Based on the sequence of the bovine β4‐defensin gene (GenBank no. AF008307 ) the primers were designed for the amplification of the 924‐bp or 393‐bp long fragments. The 924‐bp long fragment was sequenced and the sequence was compared with that available in the GenBank. Ten putative nucleotide sequence polymorphisms were found in the intron of the bovine β4‐defensin gene. One of them, a C→T transition at position 2239, that creates a new NlaIII (Hin1II) restriction site, was genotyped with polymerase chain reaction‐restriction fragment length polymorphism (PCR‐RFLP) in a cohort of 212 HF cows. The CC genotype was the most common (72%). The heterozygous CT genotype was found in 26% of the genotyped cows and four cows (2%) were TT homozygotes. In order to determine the relationship between the polymorphism of the β4‐defensin gene and milk production traits a multi‐trait repeatability test‐day animal model was used. The Derivative‐free Multivariate analysis program was used for computation. The differences between estimates for genotypes were checked using Student's t‐test. The model included the animal genotype, year‐season of calving and parity as fixed effects and the animal additive genetic effect and permanent environmental effect of individual cows as well as dates of the tests as random effects. Significant associations were found between the RFLP‐NlaIII and milk fat, protein and lactose contents. Also, a significant effect was shown of the defensin genotype on the somatic cell count in the milk.     

Comparison of milk yield in dairy cows with different degrees of lameness

OBJECTIVE: To compare milk yield among cows classified as nonlame, moderately lame, and lame and to examine the relationship between severity of lameness and milk yield in cows classified as lame during the first 100 days after parturition. DESIGN: Longitudinal study. ANIMALS: 465 Holstein cows. PROCEDURE: Cows were examined weekly during the first 100 days after parturition and assigned a lameness score by use of a 6-point locomotion scoring system (ie, 0 to 5). Milk yield was compared among cows classified as nonlame, moderately lame, and lame. Among cows classified as lame (locomotion score > or = 4), milk yield was compared for cows with low, medium, and high cumulative locomotion scores. Cows classified as lame were further examined on a tilt table for diagnosis and treatment of lameness. RESULTS: 84 (18%), 212 (46%), and 169 (36%) cows were classified as nonlame, moderately lame, and lame, respectively. Among cows in their second or later lactations, milk yield in lame cows was significantly lower than that in moderately lame and nonlame cows. In addition, among cows classified as lame, milk yield was significantly lower in cows with high locomotion scores during the first 100 days after parturition, compared with cows with low scores. Most (58%) cows classified as lame had laminitis. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicate a linear relationship between increasing degree of lameness and decreasing milk yield among cows in their second or later lactations. The locomotion scoring system used in this study may be a useful management tool that veterinarians and dairy farmers could adopt for early detection of lameness in dairy cows.     

和田多胎红羊泌乳规律初步研究

本研究旨在探明和田多胎红羊泌乳规律,提高双羔成活率。选取6只产双羔和田多胎红羊母羊为试验动物,检测其产后1~28 d泌乳量、乳成分变化规律;测量产后第1天母羊乳房体尺指标,并与泌乳量进行相关性分析。结果显示,和田多胎红羊产后1~28 d总泌乳量为29.87 kg,平均每日泌乳量为1.07 kg,泌乳量在第1~3天上升速度最快,在第21天达到峰值1.23 kg,泌乳曲线方程为：y=537t^0.477e^-0.033t;乳脂、非脂乳固体、密度、乳糖、固形物、蛋白质指标在和田多胎红羊母羊产后1~3 d快速下降,7~28 d趋于稳定,且6项指标第1天与第7、14、21、28天均差异极显著（P<0.01）;和田多胎红羊母羊产后第1天与第14、21、28天的泌乳量之间相关性不显著（P>0.05）,产后第2天与第28天的泌乳量相关性不显著（P>0.05）,其他均显著相关（P<0.05）;母羊产后第1、2、3、7天泌乳量与乳房宽呈显著相关（P<0.05）,母羊产后第14、21、28天泌乳量与乳房体尺指标相关性不显著（P>0.05）。以上研究结果为和田多胎红羊新类群种质特性、选育、饲料配制、羔羊早期断奶等提供理论依据。