维生素b
B族维生素
奶牛
维生素
限制
营养物
食品科学
生物
动物科学
生物技术
生物化学
内分泌学
机械工程
生态学
工程类
作者
C.L. Girard,M. Duplessis
出处
期刊:Canadian Journal of Animal Science
[Canadian Science Publishing]
日期:2022-06-01
卷期号:102 (2): 201-210
被引量:5
标识
DOI:10.1139/cjas-2021-0065
摘要
Dairy cow diets are generally balanced for energy and major nutrients with B vitamins generally assumed not to be limiting, in spite of their role as coenzymes, essential to many metabolic reactions in protein, carbohydrate, and lipid metabolism. Assuming adequacy of B-vitamin supply may explain some of the discrepancies between the outcomes of metabolic prediction models and measured cow performance. In lactating dairy cow, the amount of B vitamins from the diet and synthesized by the ruminal microbiota is generally sufficient to prevent deficiency symptoms and, as such, is assumed to fulfill requirements. However, reports of beneficial effects of B-vitamin supplementation on dairy cow performance suggest that B-vitamin supply is sometimes lower than its needs, as an insufficient B-vitamin supply decreases metabolic efficiency by driving a shift toward alternative metabolic pathways with greater energy cost. Using information on folates and vitamin B 12 illustrated how meeting dairy cow needs for B vitamins should not be overlooked in formulation of rations for lactating dairy cattle. The present review discusses current knowledge and indicates areas presently impeded by the lack of research results, especially the limitations on the ability to estimate B vitamin need and supply.
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