摘要
本研究旨在对部分生产牛群的日粮氮泌乳转化效率进行测定,分析影响因素,为提高奶牛日粮氮泌乳转化效率的应用技术研究提供依据。试验采用牛场实地调查的方法,对7个规模奶牛场的18个牛群的日粮氮泌乳转化效率进行测定,并对其影响因素进行主成分分析。结果表明,18个牛群产奶量分布为6.00～28.40kg.d-1,日粮粗蛋白水平分布为11.47%～18.34%。对18个牛群氮平衡分析结果表明,日粮粗蛋白氮摄入量分布为185.72～653.00g.d-1.头-1,粪、尿、乳粗蛋白氮排出量分别占到摄入量的25.58%～42.73%、25.04%～74.65%和12.26%～27.99%;日粮真蛋白氮摄入量分布为160.06～582.20g.d-1,粪、尿、乳真蛋白氮排出量分别占到摄入量的24.10%～43.18%、29.17%～75.54%和10.77%～30.98%。粪、尿排出氮占摄入粗蛋白氮比例与产奶量呈负相关,乳分泌氮占摄入粗蛋白比例与产奶量呈正相关。摄入粗蛋白泌乳转化效率主要受日粮CP水平、DMI和产奶量的影响,由18个牛群测定数据建立的回归方程:MNECP(%)=36.96-1.45CP(%)-0.83DMI(kg.d-1)+1.11产奶量(kg.d-1),R2=0.87。用已发表的21组数据对该方程进行了检验,实测值与预测值差异不显著。结果提示,奶牛日粮粗蛋白泌乳转化效率的分布在12.26%～27.99%,真蛋白为10.77%～30.98%;日粮蛋白泌乳转化效率主要受产奶量、日粮CP含量和DMI的影响,其中与产奶量呈正相关,与CP含量和DMI呈负相关。
The aim of the study was to determine the dietary nitrogen conversion efficiency of dietary nitrogen, and analyze its influential factors and provide the basis for improving the dietary nitrogen conversion efficiency in lactating cows. Dietary nitrogen conversion efficiencies were measured in 18 lactating Holstein herds distributed in 7 farms. The factors influencing the dietary nitrogen conversion efficiencies were identified by principal component analysis （PCA）. The results showed that the average daily milk yield of the 18 herds ranged from 6.00 to 28.40 kg·d-1 and dietary CP （crude protein） ranged from 11.47% to 18.34%. The nitrogen balance analysis results indicated that CP nitrogen intake ranged from 185.72 to 653.00 g per cow per day, CP in feces comprised 25.58%-42.73% of dietary CP, that in urine comprised 25.04%-74.65% of dietary CP, that in the milk comprised 12.26%-27.99% of dietary CP. The true protein intake ranged from 160.06 to 582.20 g·d-1 per cow, and 24.10%-43.18% were secreted in feces, 29.17%-75.54% were excreted in urine, and 10.77%-30.98% were used for milk production. The percentage of nitrogen in feces and urine was negatively correlated with milk yield, and that in milk was positively correlated with milk yield. Dietary CP level, DMI and milk yield were the major factors affecting dietary CP nitrogen conversion efficiency for milk protein synthesis. The multiple regression equation was MNECP（%） = 36.96-1.45 CP （%）-0.83 DMI （kg·d-1）＋ 1.11milk yield（kg·d-1）,R2=0.87. The equation was verified using 21 sets of data collected from published paper, and the difference between the measured and predicted efficiencies was non-significant （P〉0.05）. The results indicated that the crude protein conversion efficiency was 12.26%-27.99% in lactating dairy cows, true protein conversion efficiency was 10.77%-30.98%. Dietary protein conversion efficiency was mainly affected by lactation milk yield, dietary CP content and DMI, which was positively correlated with milk yield, but negatively correlated with DMI and CP content. The results will provide the basis for the application of technologies to improve the dietary nitrogen conversion efficiency for milk protein synthesis in lactating cows.
出处
《畜牧兽医学报》
CAS
CSCD
北大核心
2012年第11期1833-1840,共8页
ACTA VETERINARIA ET ZOOTECHNICA SINICA
基金
国家奶业产业技术体系(CARS-37)
关键词
泌乳奶牛
日粮氮
氮效率
乳蛋白
lactating cow
dietary nitrogen
nitrogen conversion efficiency
milk protein
作者简介
艾金涛（1985-），男，山东济南人，硕士生，主要从事反刍动物营养研究，E—mail：a198519972000@163．com
通讯作者：苏鹏程，E-mail：clark@sdau．edu．cn
通讯作者：王中华，E—mail：zhwang@sdau．edu．cn
