稀土和过瘤胃蛋氨酸不同组合对奶牛产奶性能与氮排泄的影响

Effect of different combination of rare earth and rumen-protected methionine on lactation performance and nitrogen excretion of dairy cows

试验旨在研究稀土和过瘤胃蛋氨酸不同添加水平组合对奶牛产奶性能与氮排泄的影响。选取体重(650±30)kg、2~3胎、泌乳天数(90±20)d及产奶量(30.06±3.34)kg相近的荷斯坦奶牛60头,随机分成10组,每组6头。对照组(C)饲喂基础日粮,9个试验组(LL、LM、LH、ML、MM、MH、HL、HM、HH)添加不同组合的RE和RPMet。RE分别添加20.5(L)、23.0(M)、25.5(H)g/(头·d);RPMet分别添加22.5(L)、25.0(M)、27.5(H)g/(头·d)。预试期15 d,正式试验期60 d。结果表明:LH、ML、MH、HL、HH组产奶量极显著高于C组(P<0.01),LL、MM、HM组显著高于C组(P<0.05),其中MH组产奶量提高幅度最大,较C组提高20.33%;MH组乳脂率显著高于C组(P<0.05);MH组乳体细胞数显著低于C组(P<0.05);LM、LH、ML、MM、MH、HL、HM、HH组氮总排泄量极显著低于C组(P<0.01),LL组显著低于C组(P<0.05)。本试验条件下,MH组,即23.0 g/(头·d)RE+27.5 g/(头·d)RPMet为最佳添加组合。

The experiment was to research the effect of different addition levels of rare earth and rumen-protected methionine on lactation performance and nitrogen excretion.Sixty cows with similar body weight(650±30)kg,parity 2~3,lactation period(90±20)d and milk yield(30.06±3.34)kg were divided into ten groups with six cows in each group.The test was divided into nine test groups(LL,LM,LH,ML,MM,MH,HL,HM,HH).The addition level of RE was 20.5(L),23.0(M),25.5(H)g/(head·d);the addition level of RPMet was 22.5(L),25.0(M),27.5(H)g/(head·d).The prefeeding period was 15 d,and the formal experiment period was 60 d.The results showed that the milk yield of LH,ML,MH,HL,HH groups were extremely higher than that of C group(P<0.01),LL,MM,HM groups were significantly higher than that of C group(P<0.05),and MH group increased the most,which was 20.33%higher than C group.The milk fat rate of MH group was significantly higher than that of C group(P<0.05),the number of milk cells of MH groups were significantly lower than that of C group(P<0.05).The total nitrogen excretion of LM,LH,ML,MM,MH,HL,HM,HH groups were significantly lower than that of C group(P<0.01),and that of LL group was significantly lower than that of C group(P<0.05).After comprehensive consideration of various indicators,the MH group 23.0 g/(head·d)RE+27.5 g/(head·d)RPMet was the best addition combinations.