西门塔尔牛产奶量与其体型线性性状的相关、通径分析

本文通过对某牛场20头西门塔尔牛产奶量与其体型线性性状进行相关、通径分析,结果表明:尻长、乳房深、体高、胸围、乳头长与其产奶量呈弱正相关;尻宽与产奶量接近于中等正相关;尻长、尻宽、乳头长是影响产奶量的重要性状,且是正向作用;体高、胸围是影响产奶量的重要性状,起负面作用;尻长、尻宽对产奶量的直接作用大.     

西门塔尔牛奶产量与其体型线性性状的相关,通径分析

本文通过对某牛场２０头西门塔尔牛产奶量与其体型线性性状进行相关、通径分析,结果表明：尻长、乳房深、体高、胸围、乳头长与其产奶量呈弱正相关,尻长、尻宽、乳头是影响产奶量的重要性状,且是正向作用;体高、胸围是影响产奶量的重要性状,起负面作用;尻长、尻宽对产奶量的直接作用大。     

西门塔尔奶牛产奶量与其体型线性性状的相关、通径分析

本文通过对某牛场２０头西门塔尔牛产奶量与其体型线性性状进行相关，通径分析。结果表明，尻长、乳房深、体高、胸围、乳头长与其产奶量呈弱正相关，尻宽与产奶量接的于中等正相关、尻长、尻宽、乳头长是影响产奶量的重要性状且是正向人艇，体高、胸围是影响产奶量的重要性状起负面作用，尻长、尻宽对产奶量的直接作用大。     

荷斯坦牛体型线性性状对305d产奶量的通径分析

随机抽取荷斯坦牛395头,测量体高、体斜长、胸围、腹围、管围、尻高、尻宽、腰角宽、乳房深度、后房高度、前房附着、乳头长度、乳头外径等13个体型线性性状,收集395头奶牛305d产奶量,进行荷斯坦奶牛体型线性性状对305d产奶量的通径分析,建立体型线性性状对305d产奶量的最优回归方程.结果显示,前房附着、乳头外径与305d产奶量相关极显著(P<0.01),体斜长、后房高度、乳房深度与305d产奶量的相关系数达到显著水平(P<0.05),其余均不显著(P>0.05);体斜长、胸围、尻宽、后房高度和前房附着对305d产奶量的通径系数达到显著水平(P<0.05),并且以直接影响为主导.以体斜长、胸围、尻宽、后房高度和前房附着建立对305d产奶量的最优回归方程y=7601.7470+33.3901x2-_18.3858x3-97.7271x7+71.9464x10-18.5792x11其拟合精度达到0.95以上.     

荷斯坦奶牛体型线性性状对305天产奶量的通径分析

进行荷斯坦奶牛体型线性性状时305 d产奶量的通径分析,建立体型线性性状对305 d产奶量的最优回归方程.随机抽取荷斯坦奶牛395头,测量体高、体斜长、胸围、腹固、管围、尻高、尻宽、腰角宽、乳房深度、后房高度、前房附着、乳头长度、乳头外径等13个体型线性性状,收集395头奶牛305 d产奶量.结果表明:前房附着,乳头外径与305 d产奶量相关极显著(P0.05);体斜长、胸围、尻宽、后房高度和前房附着对305 d产奶量的通径系数达到显著水平(P相似文献   

荷斯坦牛体型线性性状与产奶量的相关性研究

本研究对新疆荷斯坦奶牛的产奶量与体型线性性状进行了相关、通径分析。结果发现，荷斯坦奶牛的乳房纵沟深、后乳房宽、后乳房高与产奶量呈中等正相关；体高、体长、尻宽、尻长与产奶量呈弱相关；后乳房宽、乳房纵沟深是直接影响产奶量的重要性状。     

荷斯坦奶牛体型线性性状与产奶量的相关性分析

对新疆荷斯坦奶牛的产奶量与体型线性性状进行了相关。通径分析。结果表明，荷斯坦奶牛的乳房纵沟深，后乳房宽，后乳房高与产奶量呈中等正相关，体高，体长，尻宽，尻长与产奶量呈弱相关；后乳房宽，乳房纵沟深是直接影响产奶量的重要性状，且是正身作用；后乳房高对产奶量起负面影响。其间接作用大。     

金川牦牛体躯结构及产肉性状的通径分析

旨在探讨金川牦牛重要结构及产肉性状间的线性相关,以便筛选间接选择性状。利用30头金川牦牛共14个性状,分别以体重、体高、胸围、胴体重、净肉重5个性状为因变量,其他性状为自变量,进行通径分析。结果表明:(1)针对体重,胸围、坐骨端宽、体高等的直接作用较大,胸围、胸围与体斜长、坐骨端宽等的决定程度较大,胸深、胸围、体高等的决策系数较大;(2)针对体高,胸深、胸围、体重等的直接作用较大,胸深、胸深与胸围、胸深与体重等的决定程度较大,体重、胸围、尻高等的决策系数较大;(3)针对胸围,尻高、体斜长等的直接作用较大,尻高、尻高与体斜长、坐骨端宽等的决定程度较大,尻高、体斜长、胸深等的决策系数较大;(4)针对胴体重,体重、坐骨端宽、尻高等的直接作用较大,体重与胸深、体重与体斜长、体重与体高等的决定程度较大,体重、尻高、胸围等的决策系数较大;(5)针对净肉重,体重、体高、胸深等的直接作用较大,体重与胸深、体重与体斜长、体重与体高等的决定程度较大,体重、胸深、体高等的决策系数较大。结论:各因变量的间接选择性状为:体重—胸围、坐骨端宽等,体高—体重、胸围等,胸围—体斜长、尻高等,胴体重—体重、尻高等,净肉重—体重、胸深等。     

6月龄地中海水牛体重与体尺指标的相关性分析

本文旨在探究6月龄地中海水牛体重与体尺指标之间的相关性,构建多元回归方程,研究影响地中海水牛的主要体尺指标。选取公水牛98头,母水牛88头共186头健康的6月龄地中海水牛,测定其体重、体高、十字部高、体长、胸深、胸宽、胸围、腹围、尻宽、尻长及管围,构建多元回归方程并分析其相关性。结果显示,体重与各体尺指标之间均呈现不同程度的相关性,6月龄地中海公水牛体重与胸宽、胸围、尻宽、尻长、管围呈极显著正相关,其中体重与胸围的相关性最大（P=0.560）。6月龄地中海母水牛的体重与体高、十字部高、体长、胸深、胸宽、胸围、腹围、尻宽、尻长及管围之间均呈极显著正相关,其中与管围相关性最大（P=0.736）。6月龄地中海水牛的体重与体高、十字部高、体长、胸深、胸宽、胸围、腹围、尻宽、尻长及管围之间均呈极显著正相关,其中与胸围相关性最大（P=0.649）。根据构建的多元回归方程其相关系数r可知,6月龄地中海水牛的体重与体尺指标之间存在较强的回归关系,其中母水牛的各体尺指标与体重的相关性高于公水牛,可通过构建的多元回归方程进行体重的测算。     

非遗传因素对新疆褐牛体尺性状的影响

旨在探讨非遗传因素对新疆褐牛体尺性状的影响。根据伊犁地区3个牧场2013—2017年间544头新疆褐牛的体尺性状记录,分析不同年份、胎次、场、季节对新疆褐牛体高、体斜长、胸围、腹围、胸底宽、尻宽、尻长、坐骨端宽、后腿宽度、后腿厚度、后腿高度、后腿半围共12个体尺性状的影响,并进行了多重比较。结果:GLM一般线性方差分析结果显示不同年份对新疆褐牛12个体尺性状均影响极显著(P<0.01);不同场对新疆褐牛胸围、腹围、胸底宽、尻宽、后腿宽度、后腿厚度、后腿半围影响极显著(P<0.01);不同季节对新疆褐牛胸围、尻宽、坐骨端宽、后腿宽度、后腿厚度、后腿高度影响极显著(P<0.01);不同胎次仅对后腿高度影响极显著(P<0.01)。多重比较结果显示,不同年份对新疆褐牛的尻长、后腿厚度、后腿半围影响极显著(P<0.01);不同场对新疆褐牛体高尻长、坐骨端宽、后腿厚度有极显著的影响(P<0.01);不同胎次对新疆褐牛后腿高度、后腿半围有极显著的影响(P<0.01);不同季节对新疆褐牛尻宽、后腿宽度影响极显著(P<0.01);4个非遗传因素对新疆褐牛体高、体斜长、胸围、胸底宽、尻宽有显著影响(P<0.05)。     

浅谈人工乳、代乳料应用与推广

随着人们生活水平不断提高,对奶的需求也在逐步增加,乳牛饲养在辽宁省迅速发展起来.为满足市场需求解决供求之间的矛盾,在大力发展乳牛数量的同时,要不断改进乳牛的培育方法.     

牦牛乳及乳制品、犏牛和黑白花奶牛乳的脂肪酸组成分析

用气相色谱 质谱联用仪(GC MS)对牦牛乳、黑白花奶牛乳、犏牛乳及牦牛乳制品（奶油、酥油、曲拉、酸奶）中的脂肪酸组成进行了测定。结果表明,牦牛乳中功能性脂肪酸,如共轭亚油酸（CLA）、亚油酸（LA）、α 亚麻酸（ALA）、γ 亚麻酸（GLA）占总脂肪酸的比重均显著高于犏牛乳和黑白花奶牛乳（P＜0.05）;犏牛乳中ω 6/ω 3 PUFA的比值（1.55）略高于牦牛乳（1.54）,差异不显著（P＞0.05）,但都在最佳膳食平衡比值范围内,黑白花奶牛乳中ω 6/ω 3多不饱和脂肪酸（PUFA）的比值（11.33）超过了推荐最佳比值。加工处理能够改变乳制品脂肪酸的构成,如牦牛乳奶油中检测出原奶中所不含的一种亚油酸（18:2Δ8c,11c）。酥油主要以不饱和脂肪酸（UFA）为主,而曲拉主要以饱和脂肪酸（SFA）为主,牦牛酸奶中没有检测到GLA。     

Detection of staphylococcal enterotoxins in milk and milk products

For food evaluation the determination of the number of Staphylococcus aureus (hereinafter S. aureus) colonies is insufficient in view of present scientific knowledge. The results, advantages and shortcomings of diagnostic methods are demonstrated on an example of three methods of detection of staphylococcal enterotoxins in milk and milk products. 133 strains were investigated by the method of biotyping of S. aureus strains. Four strains of S. aureus were included in biotype A, seven xin-producing strains were isolated seventeen times by detection of 96 S. aureus strains were not included in any biotype, the other strains belonged to biotypes C and E. This method can be used as an auxiliary method of evaluation of foods containing S. aureus bacteria. The agar-gel precipitation method of enterotoxin detection in isolated strains of S. aureus has just restricted validity. The enteroto-strains. The main shortcoming of this method is a fact that the result concerning the isolated strains need not be identical with the result of enterotoxin detection in food. Direct assays of staphylococcal enterotoxins in milk and milk products using an enzymoimmunological method seem to be the most promising, mainly due to their high sensitivity (0.0001-0.001 micrograms.ml1-) and other advantages. Positive and negative results are presented on an example of two model trials with winter sheep milk cheese.     

Tropical milk production systems and milk quality: a review

We reviewed information on dairy cattle production systems in the tropics, the factors involved, and their influence on milk composition. Genetic factors had greater influence on milk production; specialized breeds produced more milk, and there was an inverse relation between the content of fat, protein, total solids, and the amount of milk produced. Season was related to the availability of forage, and the type of grazing system. Greater pasture area increased individual production, while a greater supply of feed concentrate did not increase milk production. The number of calvings positively affected milk production through the fifth calving, with subsequent declines in production. Milk production increased to a maximum and then declined as lactation progressed. Specialized systems had higher production and better hygienic milk quality; milking and container equipment are critical for maintaining milk sanitary quality. Factor interaction is highly complex, preventing the generation of specific recommendations and general principles applicable to the specific conditions for each system.

     

生乳与巴氏杀菌乳中糠氨酸含量及其测定方法研究

本试验研究了生乳与巴氏杀菌乳中糠氨酸含量及其测定方法,并提出糠氨酸作为巴氏杀菌乳中复原乳成分的标示物质,可鉴定巴氏杀菌乳中是否掺入复原乳.研究结果表明,生乳中糠氨酸含量应低于7 mg/100 g;乳粉中糠氨酸含量大于135 mg/100 g;不含复原乳的巴氏杀菌乳中糠氨酸含量应小于12 mg/100 g.使用高效液相色谱(HPLC)紫外检测糠氨酸平均偏差＜5%(n=5);回收率为98.2%.     

破骨细胞与奶牛产乳热

奶牛产乳热是奶牛围产期的多发病,在养殖生产中造成了重大危害。研究发现,产乳热的发生与分娩前后血钙浓度降低有关。甲状旁腺激素(PTH)、降钙素(CT)和1α,25-(OH)_2D_3可直接或间接地调控破骨细胞(OC)的形成、活化和骨吸收功能,从而调控骨钙动员和血钙浓度,很可能与产乳热的发生息息相关。本文就PTH、CT和1α,25-(OH)_2D_3在产乳热中调控OC的可能机制作一综述。     

Mycobacterium paratuberculosis and milk

The possibility that milk from cattle with Johne's disease could be a potential vehicle of transmission of Mycobacterium avium subsp. paratuberculosis (M. paratuberculosis) to humans has been the focus of a UK government-funded research programme at Queen's University, Belfast since 1993. The main findings of this research programme are reported and practical advice about the most appropriate methods for the isolation/detection of this organism in milk is given. The findings of several milk surveys during which optimised sensitive detection methods were employed (decontamination with 0.75% cetyl pyridinium chloride for 5 h prior to culture and a novel immunomagnetic PCR technique) have revealed that detectable levels of M. paratuberculosis are present in bulked raw cows' milk in the UK at both the farm level and at dairy processing plants prior to pasteurisation. Furthermore, results of three different experimental approaches to assess the effect of pasteurisation time/temperature conditions on the viability of M. paratuberculosis (laboratory pasteurisation studies, a national survey of commercially pasteurised milk, and processing of naturally infected milk through commercial-scale pasteurising plant) provide firm evidence that this organism is capable of surviving commercial milk pasteurisation on occasion. Hence, both raw and pasteurised cows' milk are potential vehicles of transmission of M. paratuberculosis to humans.     

The national milk safety program and drug residues in milk.

There are a number of factors that must be considered in any attempt to control animal drug residues in milk and milk products. Dairy herds vary greatly in number of cows. Milk from individual cows and farms is pooled, diluting drug residues that may be present in the milk from a single treated cow. Management techniques, including the handling, administration, and record keeping of animal drugs, vary greatly from one dairy to another. It is important that both veterinarians and nonveterinarians adhere to adequate milk discard times for animal drugs used to treat dairy animals. Observance of appropriate safeguards at the farm level, such as record keeping and clearly identifying treated animals, is critical for controlling and preventing the presence of illegal animal drug residues. Within the framework of the Federal Food, Drug, and Cosmetic Act and the Public Health Service Act, the FDA is working with state and other regulatory agencies and industry to better ensure the absence of illegal animal drug residues in milk and milk products. Preventive measures concentrate on minimizing the need to administer animal drugs to lactating cows, and diverting milk containing drug residues from the human food supply. Monitoring programs concentrate on screening milk and tracing violations to the individual producer. Minimizing illegal drug residues in milk and milk products requires close cooperation between farmers, veterinarians, the dairy industry, the pharmaceutical industry, and regulators.