年龄及泌乳阶段对荷斯坦奶牛日粮钙、磷表观消化率的影响

本文对不同阶段荷斯坦育成牛(12月龄、18月龄、24月龄)、泌乳牛(1、2、5、9泌乳月)及围产期牛(围产前期、围产后期)的日粮Ca、P表观消化率进行了比较研究。试验奶牛饲喂生产日粮,各阶段育成牛日粮Ca含量为8.8~9.4g/kg,P含量为3.1~3.2g/kg;各阶段泌乳牛日粮Ca含量为10.2~10.6g/kg,P含量为5.6g/kg;围产期牛各阶段Ca含量为10.6~14.0g/kg,P含量为3.8~5.6g/kg。研究结果表明,24月龄和12月龄育成牛日粮Ca、P表观消化率差异不显著(P0.05),Ca表观消化率均显著高于18月龄(P0.05),P表观消化率极显著高于18月龄(P0.01)。泌乳牛日粮Ca、P表观消化率随泌乳期的延长而降低,1泌乳月、2泌乳月奶牛日粮Ca、P表观消化率显著高于5泌乳月、9泌乳月奶牛(P0.05),1泌乳月与2泌乳月及5泌乳月与9泌乳月之间的日粮Ca、P表观消化率差异均不显著(P0.05)。围产后期奶牛日粮Ca、P表观消化率显著高于围产前期奶牛日粮Ca、P表观消化率(P0.05)。研究结果显示,奶牛日粮Ca、P表观消化率受需要量和供给量的影响,适当控制日粮Ca、P含量可以提高其利用效率。

The Influence of Growth and Lactation Periods on Apparent Digestibilities of Dietary Calcium and Phosphorus in Holstein Cows

Apparent digestibilities of dietary calcium and phosphorus were compared among heifers（12,18,and 24 month old）,lactating（1,2,5,and 9 month in milk）,and peripartal（prepartum,and postpartum）Holstein cows in the present study.Cows were fed farm-made production diets.The calcium and phosphorus contents for heifers were 8.8-9.4g/kg and 3.1-3.2g/kg respectively,for lactating cows were 10.2-10.6g/kg and 5.6g/kg respectively,and for peripartal cows were 10.6-14.0g/kg and 3.8-5.6g/kg respectively.The results indicated that dietary calcium（P0.05）and phosphorus（P0.01）digestibilities of 18 month heifers were lower than those of 12 and 24 month heifers,and digestibilities of the later two heifer groups were insignificant（P0.05）.For lactating cows,calcium and phosphorus digestibilities decreased with the advancement of lactation period.Calcium and phosphorus digestibilities of cows 1 and 2 month in milk（MIM）or 5 and 9 MIM was similar（P0.05）,but the digestibilities of 1 and 2 MIM cows were higher than those of the 5 and 9 MIM cows（P0.05）.Postpartum cows had higher calcium and phosphorus digestibilities than that of the prepartum cows（P0.05）.The results implied that dietary calcium and phosphorus digestibilities changed with the requirement and dietary supply,and there is possibilities to elevate dietary calcium and phosphorus availabilities by proper control of there dietary contents.