半胱胺和稀土组合添加对奶牛产奶性能和氮排泄的影响

Effects of Combination of Cysteamine and Rare Earth on Lactation Performance and Nitrogen Excretion of Dairy Cows

本文旨在研究半胱胺(CS)和稀土(RE)不同水平组合对奶牛产奶性能和氮排泄的影响。选取体重、胎次、产奶量、乳成分及泌乳期相近的荷斯坦奶牛80头,随机分为10组,每组8头。对照(C)组饲喂基础日粮,9个试验组添加不同水平组合的CS和RE。CS分别添加13(L)、15(M)、17(H)g/(d·头);RE分别添加20.5(L)、23(M)、25.5(H)g/(d·头),组成LL、ML、HL、LM、MM、HM、LH、MH、HH 9个试验组。预试期15 d,正试期60 d。结果表明:试验组的产奶量均高于C组(P<0.01),HM组的产奶量高于ML组(P<0.01)及LL组、MH组、HH组(P<0.05),与其余试验组差异不显著;HM组和MH组乳体细胞数低于C组(P<0.01),HM组和MH组与其余试验组无显著差异,其余试验组与C组无显著差异;各试验组氮排泄量均低于C组(P<0.01),HM组低于LL组、ML组、HH组(P<0.01)和HL组、MH组(P<0.05),与其余试验组无显著差异。综合上述指标,以HM组合,即CS 17 g/(d·头)、RE 23 g/(d·头)为最佳组合。

This experiment was conducted to determine the effects of different combinations of cysteamine(CS)and rare earth(RE)on lactation performance and nitrogen excretion of dairy cows.Eighty Holstein lactating cows with similar weight,parity,milk yield,milk composition and lactation days were selected and randomly divided into 10 groups with 8 cows in each group.The control group(C)was fed a basal diet,and 9 experimental groups were supplemented with different levels of CS and RE.The addition level of CS is 13(L),15(M),17(H)g/(d·head);the addition level of RE is 20.5(L),23(M),25.5(H)g/(d·head),consisting of 9 different test groups of LL,LM,LH,ML,MM,MH,HL,HM,HH.The pre-experiment period is 15 days and the formal experiment period is 60 days.The results showed that in milk production,the test group was higher than C(P<0.01),HM was higher than ML(P<0.01),LL,MH,HH(P<0.05);the number of breast cells in HM and MH was lower than that in C(P<0.01);Nitrogen excretion was lower in each test group than that in C(P<0.01),HM was lower than LL,ML,HH(P<0.01)and HL,MH(P<0.05),and there was no significant difference from other test groups.Comprehensive indicators,HM group,CS 17 g/(d·head)and RE 23 g/(d·head)are the best combinations.