奶牛干乳期营养水平及饲养管理技术的研究

奶牛完成一个泌乳期,到分娩前两个月应停止泌乳,称干乳期。加强这一时期奶牛营养水平及饲养管理技术的研究,对提高奶牛一生的产乳量具有十分重要的意义。有数据表明,无干乳期连续挤奶的牛比有干乳期的牛,在同样的饲养条件下,第二胎产奶量下降25%,第三胎则下降38%;且随胎次的增加,不干奶的牛产奶量下降的幅度更大。     

最适奶牛维生素营养

近年来,人们对于维生素在调节反刍动物免疫力和健康水平所起的作用日益关注,本文目的在于讨论最佳维生素营养(Optimum Vitamin Nutrition,OVN)在奶牛健康、繁殖和奶质方面的作用。 1 VE和乳房健康 乳腺炎是一种在奶牛中常见的疾病,而且在     

奶牛的维生素营养

奶牛是一种草食家畜，以青粗饲料为主，其维生素来源比较丰富，加之瘤胃微生物能够合成多种维生素，因而在奶牛日粮中往往容易忽视补充维生素，中国奶牛饲养标准中也仅仅规定了维生素A及胡萝卜素的需要量。但在实际生产中，由于不同季节青饲料的不均衡性以及奶牛产奶性能的提高或奶牛繁殖等需要，如不注意补充维生素，将会严重影响奶牛的健康、     

维生素E对鸡的营养免疫作用

维生素Ｅ是家禽营养中一种重要的微量营养素，具有多种多样的生物学作用。近来的研究结果表明：维生素Ｅ除了具有一般的营养作用外，还能提高机体免疫功能，是鸡免疫系统发育所必需的，也是维持免疫功能达到最佳状态的重要物质；它能保证鸡免疫器官的正常发育，对体液免疫、细胞免疫和细胞因子产生有益的影响，提高机体抵抗疾病的能力。１维生素Ｅ对鸡免疫功能的影响１．１免疫器官 法氏囊、胸腺和脾脏是鸡的主要免疫器官。缺乏维生素Ｅ将阻碍免疫器官的发育。根据结构与功能原理，当免疫器官发育受到抑制时，其免疫功能也会受到损伤。Ｍａ…     

奶牛维生素A的营养研究

主要总结了最近维生素A与奶牛营养的研究,探讨维生素A和奶牛营养之间的关系。     

高产奶牛B族维生素营养的研究现状

本文阐述了B族维生素中叶酸、VBl2和胆碱的功能、代谢途径、它们的相互关系及对高产奶牛生产性能的影响。在组织代谢中，叶酸与胆碱能为奶牛体组织提供一碳基团，用于能量与蛋白质代谢、嘌呤与DNA的合成，而改善奶牛的生产性能。但叶酸提供甲基需要VBl2参与，而胆碱与蛋氨陵在提供甲基上能够互补，它们在代谢过程中相互联系和相互制约。它们的具体代谢途径、作用机制还不完全清楚。     

奶牛营养中维生素E的研究进展

维生素E是一种有效的抗氧化剂，可提高机体免疫力。本文结合VE的生物学功能综述其对奶牛繁殖、疾病、乳品质等的影响。     

商业生产条件下的最佳维生素营养

日粮中添加维生素不再只是为了预防缺乏症的问题。最近的研究表明，日粮含较高水平的维生素可使现代动物表现其遗传潜力。维生素与氨基酸不同，氨基酸可按其限制性分类，而对维生素则应予以综合考虑。     

Fat-soluble vitamin nutrition for dairy cattle

The need for supplementation of dairy cow diets with fat-soluble vitamins depends on the amount of vitamins naturally present in the diet, the availability of dietary vitamins, and the vitamin utilization rate of the animal. Fresh forage contains ample amounts of the vitamin A precursor beta-carotene as well as vitamin E. Irrespective of the dietary amount, however, the availability of vitamins A, D, and E, as well as beta-carotene, can be adversely influenced by poor fat digestion, as commonly occurs due to enteric disease in young calves. In addition, high-grain diets appear to increase the amount of ruminal vitamin destruction and may thus increase vitamin requirements. The vitamin utilization rate may be increased by inflammation as well as dietary and environmental factors. The factors influencing vitamin availability and utilization rate should be considered when formulating rations. Because the vitamin requirement is variable, blood concentrations of vitamins should be monitored when conditions such as poor fertility, weak calves, and poor immune response are present.     

纤维在奶牛生产中的营养作用

纤维是奶牛的一种必需营养素,它在奶牛的泌乳、繁殖等生理活动中都起到了非常重要的作用。搞清楚纤维在奶牛生产中的作用原理、生产中的添加量以及怎样高效率的利用纤维等问题将对提高奶牛单产、提高经济效益有重要意义,此文就这些问题作了综述,供奶牛养殖者参考。     

维生素A在家禽营养中的作用

养殖业中饲料大约占养殖业成本的50％—70％。经过20年的飞速发展，养禽业正步入稳产阶段，此阶段家禽企业制胜的关键一方面在于规模化经营(规模效益)和现代管理手段的实施，另一方面则来自于饲料成本的降低。VA自1947年首次人工合成以来，现已成为饲料行业中必不可少的原料，VA的价格高，占维生素成本比重较大，当今饲料和预混料生产厂家都十分注重畜禽日粮中VA的添加，企业找到VA的适宜添加量，既有利于节省成本，又能得到较好的生产效果。本文对VA在家禽营养中的作用进行了全面的论述，希望能引起家禽生产企业对VA使用的注意。     

高产奶牛的营养与饲养

根据中华人民共和国《高产奶牛饲养管理规范》，高产奶牛的定义为：305天产奶量6000千克以上，含脂率3．4％(或与此相当的乳脂量)的牛群或个体奶牛。该标准是1985年制定的，6000千克这在目前，虽然已算不上“高产”，但国家制定该“规范”的目的是：维护高产乳用牛的健康，延长使用年限，充分发挥其产奶性能，降低饲养成本，增加经济效益。然而，在     

影响奶牛泌乳量的因素及高产措施

提高奶牛产奶量、最大限度地增加经济效益是所有养牛户追求的目标。笔者结合近几年章丘市奶牛饲养的实践经验，把影响奶牛泌乳量的因素及高产措施，总结出以下几点：１遗传因素 奶牛的泌乳力首先取决于遗传，它是影响泌乳量的内在因素。主要有品种和个体因素，不同品种牛的产乳量差异很大，一般乳用牛的产乳量高于乳肉役兼用牛，而乳用牛中高度培育品种高于地方品种。在个体因素方面，同一品种的不同个体，在相同的生命时期，相同的饲养管理条件，其泌乳力也会有差别。因此在选择品种时，根据实际情况和经济效益决定是选择乳用型，还是选择…     

Protein nutrition of dairy cattle

Abstract

In the June 1998 issue of the New Zealand Veterinay Journal, a clinical review was published focusing on aspects of the protein nutrition of dairy cattle (Westwood et al., 1998 Westwood, CT,, Lean, IJ, and Kellaway, RC. 1998. Indications and implications for testing milk urea in dairy cattle: A quantitative review. Part 1. Dietary protein sources and metabolism. New Zealand Veterinary Journal, 46: 87–96. [Taylor &; Francis Online], [Web of Science ®] , [Google Scholar]). The authors wrote: “Most species of rumen bacteria can use ammonia for growth, but some, particularly bacteria which ferment cell wall carbohydrates, use or have obligate requirements for amino acids and peptides (Russel et al., 1992 Russel, JB,, O’Connor, JD,, Fox, DG,, Soest, PJ, van and Sniffen, CJ. 1992. A net carbohydrate and protein system for evaluating cattle diets. I. Ruminal fermentation. Journal of Animal Science, 70: 3551–61. [PubMed], [Web of Science ®] , [Google Scholar])”.     

Triennial Lactation Symposium: Opportunities for improving milk production efficiency in dairy cattle

Increasing feed costs and the desire to improve environmental stewardship have stimulated renewed interest in improving feed efficiency of livestock, including that of US dairy herds. For instance, USDA cost projections for corn and soybean meal suggest a 20% increase over 2010 pricing for a 16% protein mixed dairy cow ration in 2011, which may lead to a reduction in cow numbers to maintain profitability of dairy production. Furthermore, an October 2010 study by The Innovation Center for US Dairy to assess the carbon footprint of fluid milk found that the efficiency of feed conversion is the single greatest factor contributing to variation in the carbon footprint because of its effects on methane release during enteric fermentation and from manure. Thus, we are conducting research in contemporary US Holsteins to identify cows most efficient at converting feed to milk in temperate climates using residual feed intake (RFI), a measure used successfully to identify the beef cattle most efficient at converting feed to gain. Residual feed intake is calculated as the difference between predicted and actual feed intake to support maintenance and production (e.g., growth in beef cattle, or milk in dairy cattle). Heritability estimates for RFI in dairy cattle reported in the literature range from 0.01 to 0.38. Selection for a decreased RFI phenotype can reduce feed intake, methane production, nutrient losses in manure, and visceral organ weights substantially in beef cattle. We have estimated RFI during early lactation (i.e., to 90 d in milk) in the Beltsville Agricultural Research Center Holstein herd and observed a mean difference of 3.7 kg/d (P < 0.0001) in actual DMI between the efficient and inefficient groups (±0.5 SD from the mean RFI of 0), with no evidence of differences (P > 0.20) in mean BW, ADG, or energy-corrected milk exhibited between the 2 groups. These results indicate promise for using RFI in dairy cattle to improve feed conversion to milk. Previous and current research on the use of RFI in lactating dairy cattle are discussed, as well as opportunities to improve production efficiency of dairy cattle using RFI for milk production.