饲粮磷水平对西门塔尔杂交后备母牛营养物质表观消化率的影响

摘要

本文旨在研究饲粮磷(phosphorus,P)水平对后备母牛营养物质表观消化率的影响.选用体况良好、体重(369.5±37.8)kg的杂交后备母牛[西门塔尔牛(♂)×中国黄牛(♀)]24头,随机分为6组,每组4头,定量(3.50 kg/d)饲喂6种不同磷水平的精饲料,粗饲料(玉米青贮)自由采食.各试验组精饲料磷水平分别为0.38%、0.45%、0.50%、0.56%、0.61%和0.67%(干物质基础).试验期为30 d,预试期20 d,正试期10 d,收集正试期后7 d饲料和粪样.测定饲料样及粪样中干物质(dry matter,DM)、粗蛋白质(crude protein,CP)、中性洗涤纤维(neutral detergent fiber,NDF)、酸性洗涤纤维(acid detergent fiber,ADF)、磷和淀粉含量.结果表明:精饲料磷水平对牛DM、CP、NDF和ADF采食量均无影响(P＞0.05);各组牛磷采食量随精饲料磷水平的升高而提高,1、2、3、4、5组依次为0.37%、0.41%、0.44%、0.47%、0.50%、0.54%,除4组和5组外,其余各组之间差异显著(P＜0.05);饲粮DM、淀粉和CP的表观消化率均没有受到磷水平的影响(P＞0.05),5组饲粮NDF和ADF表观消化率最高.结果提示,饲粮磷水平0.37%可满足后备母牛对磷的需要;当饲粮磷水平为0.50%时,可以较好满足后备母牛消化饲料中NDF和ADF的需求.%The aim of this study was to evaluate the effects of dietary phosphorus (P) level on apparent digestibility of nutrients in replacement heifers. Twenty-four healthy crossbreed heifers (Simmental × Chinese yellow cattle) with the body weight of (369.5 ±37.8) kg were selected and randomly assigned to six groups with four heads per group. The experiment groups were fed concentrations in equal amounts (3.50 kg/d) with six levels of P, which were 0.38％, 0.45％, 0.50％, 0.56％, 0.61％ and 0.67％ ( dry matter basis), respectively, and the roughage was ad libitum. The experiment lasted for 30 days, which were divided into a 20day preliminary trial period and a 10-day trial period. Feed and feces samples were collected during the last 7 days of trial period. The samples were tested for the contents of dry matter (DM), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), P and starch. The results showed as follows: the P level of concentrate had no significant influence on the feed intake of DM, CP, NDF and ADF ( P ＞ 0.05 );the P intake increased as the increasing of P level of concentration, and the values of group 1, 2, 3, 4 and 5 were 0.37％, 0.41％, 0. 44％, 0.47％, 0.50％ and 0.54％, respectively, among which the difference were significant except group4 and 5 ( P ＜ 0.05); the levels of concentrate P had no significant influence on DM, starch and CP apparent digestibility ( P ＜ 0.05 ); the NDF and ADF apparent digestibility of group 5 were the highest. The results indicate that 0.37％ of P level can satisfy the P need of replacement heifers, and 0.50％ dietary P is optimum for NDF and ADF digestion in replacement heifers. [Chinese Journal of Animal Nutrition ,2011,23 (4) :589-596]