Lopez H, Kanitz F D, Moreira V R, Wiltbank M C, Satter L D
Department of Dairy Science, University of Wisconsin, Madison 53706, USA.
J Dairy Sci. 2004 Jan;87(1):139-45. doi: 10.3168/jds.S0022-0302(04)73151-3.
The objective of this study was to measure cow response to feeding of two dietary concentrations of P, one of which was close to recent National Research Council requirements, and the other of which was well in excess of the requirement. Diets containing 0.37 or 0.57% P (dry basis) were fed to Holstein cows for the first 165 d of lactation, and occasionally longer until cows were confirmed pregnant approximately 60 d after insemination. At calving, cows were randomly assigned to experimental diets. The number of cows completing a minimum of 165 d of lactation was 123 for the 0.37 and 124 for the 0.57% P groups. Cows were housed in a stanchion barn and fed one of two transition diets, each formulated to contain one of the P treatments for the first 3 wk of lactation, and then cows were moved to a free-stall barn where the experimental diets were group fed. Milk production, milk fat, and milk protein averaged 35.1 kg/d, 3.92%, and 2.90% for the 0.37% P diet, and 34.9 kg/d, 3.98%, and 2.91% for the 0.57% P diet. None of these measures were different between treatments. Blood serum P concentrations on d 50 and 100 of lactation averaged 6.1 and 6.2 mg/dL for the 0.37% P diet, and 6.8 and 6.9 mg/dL for the 0.57% P diet. No treatment differences were detected in milk production, cow health, or body condition score.
本研究的目的是测定奶牛对两种不同磷浓度日粮的反应，其中一种接近美国国家研究委员会近期的要求，另一种则远超过该要求。在泌乳期的前165天，给荷斯坦奶牛饲喂含0.37%或0.57%磷（干基）的日粮，偶尔会延长饲喂时间，直到奶牛在输精后约60天确认怀孕。产犊时，奶牛被随机分配到实验日粮组。完成至少165天泌乳期的奶牛数量，0.37%磷组为123头，0.57%磷组为124头。奶牛被饲养在一个栓系牛舍中，在泌乳期的前3周，饲喂两种过渡日粮中的一种，每种日粮都含有一种磷处理方式，然后奶牛被转移到一个自由牛舍，在那里对实验日粮进行群体饲喂。对于含0.37%磷的日粮，牛奶产量、乳脂率和乳蛋白率平均分别为35.1千克/天、3.92%和2.90%；对于含0.57%磷的日粮，分别为34.9千克/天、3.98%和2.91%。这些指标在不同处理之间均无差异。泌乳期第50天和第100天的血清磷浓度，含0.37%磷的日粮平均分别为6.1毫克/分升和6.2毫克/分升，含0.57%磷的日粮平均分别为6.8毫克/分升和6.9毫克/分升。在牛奶产量、奶牛健康状况或体况评分方面，未检测到处理差异。
