Valk H, Sebek L B
DLO-Institute for Animal Science and Health (ID-DLO), Department of Ruminant Nutrition, Lelystad, The Netherlands.
J Dairy Sci. 1999 Oct;82(10):2157-63. doi: 10.3168/jds.S0022-0302(99)75459-7.
For almost two lactations, 24 high-yielding, multiparous dairy cows were fed a basal diet and concentrate mixtures with three different P concentrations. The basal diet consisted of grass (silage or artificially dried), corn silage, wet beet pulp, straw, and concentrates. The concentrate mixtures differed only in P content by varying the amount of monosodium phosphate. The number of cows and the amount of dietary P, expressed as a percentage of current recommendations in the Netherlands were: 6 cows, 100% (P100); 9 cows, 80% (P80); and 9 cows, 67% (P67). This resulted in dietary P concentrations of 3.3, 2.8, and 2.4 g/kg of dietary DM for the P100, P80, and P67 treatments, respectively. The trial lasted for 21 mo, including two lactations and two dry periods. Feed intake of the P67 group was reduced significantly during the first dry period. Dry matter intake, milk yield, and body weight were all reduced with the low P treatment during the second lactation. Phosphorus had no effect on reproductive performance. Between P100 and P80, no effect on any of the variables in this trial was observed. Results suggests that the diet with 2.8 g of P/kg of dietary DM proved to be sufficient to meet the P requirement of dairy cows producing approximately 9000 kg of milk per lactation.
在近两个泌乳期内，对24头高产经产奶牛饲喂基础日粮和三种不同磷浓度的精料混合料。基础日粮由青草（青贮或人工干燥）、玉米青贮、湿甜菜粕、稻草和精料组成。精料混合料仅通过改变磷酸二氢钠的用量来改变磷含量。奶牛数量以及日粮磷含量（以荷兰当前推荐量的百分比表示）分别为：6头奶牛，100%（P100）；9头奶牛，80%（P80）；9头奶牛，67%（P67）。这导致P100、P80和P67处理的日粮磷浓度分别为3.3、2.8和2.4 g/kg日粮干物质。试验持续21个月，包括两个泌乳期和两个干奶期。P67组在第一个干奶期的采食量显著降低。在第二个泌乳期，低磷处理使干物质采食量、产奶量和体重均降低。磷对繁殖性能没有影响。在P100和P80之间，未观察到对本试验中任何变量的影响。结果表明，日粮磷浓度为2.8 g/kg日粮干物质的日粮被证明足以满足每泌乳期产奶约9000 kg的奶牛的磷需求。
