影响牛生长激素(BST)促乳作用的因素

牛生长激素 (BST)是一项新生物技术 ,它既安全实用又能提高生产效率 ,自上世纪三、四十年代发现其促进犊牛生长、增强泌乳作用以来 ,至今有 10 0 0多名科学家在全世界范围内对它已进行 15 0 0多次试验 ,涉及 30 0 0 0头奶牛 ,这些结果惊人相似 ,且被许多国家权威部门证实。但BST增产幅度在不同试验仍有差别 ,其原因多种多样 ,本文将对影响BST促乳效应的主要因素作一简述。1　BST剂量和使用方式研究表明 ,有几种因素可决定泌乳反应的强弱程度 ,其中最主要的是在血液循环中激素所能达到的浓度 ,这主要取决于应用激素的剂量和使用激素 (B…     

牛生长激素对泌乳奶牛胚胎移植的影响

牛生长激素可以提高奶牛人工授精的初次受胎率，这可能是由于bST对胚胎或生殖道功能产生影响。本试验的目的是研究胚胎移植生产中bST对胚胎或／和移植受体的潜在影响。对在人工授精的同时接受bST处理（和未接受bST处理（bST对照供体组，n＝８０）的荷斯坦奶牛进行超排获得胚胎。在第７天冲卵后观察胚胎发育的品质和阶段。可移植的胚胎经乙二醇冷冻用于直接移植。经bST处理的供体牛胚胎发育迅速，但对胚胎品质未有影响。作为受体的荷斯坦泌乳牛在发情期的第１天一部分接受bST（Posilac，５００mg，s．c；bST受体组，n＝９７），而另一…     

运动场环境对奶牛肢蹄健康的影响

试验研究运动场环境对于奶牛．月支蹄健康的影响,对15户奶牛养殖户饲养的221头成年泌乳牛的饲养方式、运动场地面及运动场饲养密度进行调查,通过一般线性模型的单变量方差分析奶牛肢蹄健康情况与运动场环境的关系。结果显示：在运动场地面局部潮湿、干燥的情况下,运动场密度在12．3—33．4m2／头范围时,其对奶牛肢蹄病发生无显著影响;而运动场地面为三合土、黄土、沙土及干粪时,其奶牛肢蹄病发病率极显著低于立砖地面的发病率。     

美国研究发现rBST可以减少奶牛对环境的影响

1993年,美国批准在奶牛中使用重组牛生长激素（rBST）。美国康乃尔大学最近进行的一项研究表明,给奶牛使用rBST不仅可以提高产乳量,而且可以大大减少对环境的影响。研究发现,与不使用rBST的牛群比较,用不到15．7万头奶牛可以生产出用100万头奶牛同样数量的牛奶。这可以节省49．1万吨玉米,     

国外牛生长激素使用情况评述及我国的对策

国外牛生长激素使用情况评述及我国的对策王建荣（上海市农业科学院畜牧兽医研究所上海２０１１０６）李伯良（中国科学院上海生物化学研究所上海２０００３１）１．国内外基因工程牛生长激素（ｒｂＳＴ）的研究开发概况（１）国外ｒｂＳＴ研究开发情况：牛生长激素自然状...     

Lead poisoning in cattle and its implications for food safety

The lead poisoning incidents in cattle investigated by the Veterinary Laboratories Agency between 1990 and 2003 are reviewed. Lead poisoning was most commonly encountered in young calves, but cattle of all ages were affected. The lead was derived mainly from lead paint, lead accumulator batteries and lead in soil from old mine workings. Paint was responsible for the majority of cases of poisoning in young calves; yearling animals were most at risk from discarded batteries, and adult cows were most commonly poisoned by geochemical sources of lead. There was a marked seasonal incidence, with most cases occurring after turnout in the spring and early summer.     

Bovine spongiform encephalopathy and the safety of milk from Canadian dairy cattle

The detection of bovine spongiform encephalopathy (BSE) in beef cattle closed Canadian beef export markets to 30 countries, including the USA, with devastating financial losses. The detection and confirmation of the fifth and seventh BSE-infected animals but first infected dairy cows extended the problem of risk management to Canadian dairy farmers. As the public are concerned about the safety not only of beef but also of milk and milk products that may contain disease-causing prions, this review examines the evidence for the safety of milk from studies on prions in milk or colostrum and their vertical and lateral transmission in various animal systems. The evidence indicates that the risk of contracting new variant Creutzfeldt-Jakob disease through the consumption of milk is negligible.     

Suspected botulism in dairy cows and its implications for the safety of human food

A large outbreak of suspected botulism occurred on a dairy farm. The affected animals were listless and showed signs ranging from hindlimb unsteadiness to lateral recumbency, although the most common presentation was sternal recumbency with an apparent hindlimb weakness when stimulated to rise. Postmortem examinations revealed no conclusive gross pathology or histopathology. The affected cattle were found to have neutrophilia and hyperglycaemia with no other consistent haematological or biochemical abnormalities. The combination of clinical signs, disease epidemiology and the ruling out of other differential diagnoses strongly supported a diagnosis of unconfirmed botulism; however, the source of toxin was not demonstrated. Botulism is a severe disease in human beings and there are uncertainties about the pharmacokinetics and pharmacodynamics of Clostridium botulinum toxins. In such circumstances, a precautionary approach to food safety is essential. Restrictions were placed on the movement of livestock and sale of milk from the farm premises until 14 days after the onset of the last clinical case.     

Effects of meloxicam on reproduction parameters in dairy cattle

This study was carried out in dairy cattle with the NSAID meloxicam to investigate possible drug effects on different reproductive parameters as well as on the progeny. Forty-one cows received intravenous injection of either meloxicam (Metacam^® 20 mg/mL solution for injection) or placebo at a dose volume of 7.5 mL/100 kg, corresponding to a dose of 1.5 mg meloxicam/kg, i.e. three times the recommended therapeutic dose. Treatment was performed in each phase of reproduction, i.e. once prior to breeding, twice shortly after breeding, once at the beginning of the second and third trimester of gestation and once at the end of the third trimester of gestation. Offspring of the cows were weighed and clinically examined for vitality at birth and after 28 days. No relevant difference between the meloxicam and control group was found in the reproductive performance of the cows or in the body weight development or vitality of the calves.     

关注食品安全 捍卫生命健康——访北京美正检测技术有限公司总经理龚利新

与生命和健康相关的职业是神圣的,保证食品安全、关注人类健康是企业家的责任。一个文明和谐的社会,必然是一个人人具有高度社会责任感的社会;一个优秀的企业,必然是具有强烈社会责任感的企业。北京美正检测技术有限公司(以下简称美正检测)自2015年成立以来,以“关注食品安全,捍卫生命健康”为企业使命。     

The effect of claw trimming on the hoof health of Swedish dairy cattle

A 2-year experiment on the effect of claw trimming on hoof health was performed in 77 Swedish dairy herds (3444 dairy cattle) selected on herd size, breed composition and membership in the official milk-recording scheme. In the autumn, cows within each herd were blocked according to breed, parity and stage of lactation and allocated to two treatments: autumn trimming (AT) or no autumn trimming (NAT). Outcome variables were claw measurements and prevalence of hoof lesions and lameness (measured at spring trimming) and the need for hoof treatments between scheduled trimmings. At spring trimming, NAT cows had longer and shallower claws than AT cows. The average net growth of the toe wall was greater for AT than for NAT cattle, with a marked variation between housing systems. Most hoof lesions present at AT had disappeared at the subsequent spring trimming. Controlled for clustering by herd-within-year and for the effects of individual-and herd-level covariates, AT cattle at spring trimmings had significantly lower odds of lameness (OR=0.66) and of haemorrhages of the sole or white-line (OR=0.86), sole ulcer (OR=0.59) and white-line fissure or double sole (OR=0.71)-but not of moderate-to-severe heel-horn erosion or dermatitis (OR=0.96). Acute hoof treatments between claw trimmings were more common in the NAT group (OR=2.02).     

Evaluation of a monitoring system for assessing animal health in dairy cattle

A monitoring system to assess animal health in dairy farms was developed and applied on 44 farms in an epidemiological study. The objective of the study was to evaluate the applicability of the system for long term monitoring of health data. For this purpose, the quality of the collected data and the acceptance of the system by farmers and veterinarians were investigated. Farmers recorded all health events using a form. Collected data was entered into a central database on a monthly basis. The recording of health data was easy to do and did not take a lot of time. Most of the farmers (89%) used less than 20 minutes per week for the recording. This time need was independent of the herd size. 66% of the farmers found it useful to record health data, especially for improving their overview on health of each single cow. Treatments were reported in 81% of the cases, inseminations and calving in 80% of the cases. All events were reported correctly and precise.