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

Effects of Dietary Phosphorus Levels on Apparent Digestibility of Nutrients in Simmental Crossbreed Replacement Heifers

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(neutraldetergent fiber,NDF)、酸性洗涤纤维(ac id 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 20-day 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（P0.05）;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（P0.05）;the levels of concentrate P had no significant influence on DM,starch and CP apparent digestibility（P0.05）;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.