日粮蛋白质和赖氨酸水平对奶牛产奶性能的影响

Effect of Different Dietary Protein and Lysine Levels on Milk Performance of Dairy Cows

试验选择40头泌乳中期的荷斯坦奶牛,随机分为4组,饲喂4种不同蛋白质和赖氨酸水平的日粮,以测定4种日粮对奶牛产奶性能的影响。预试期10 d,正式期70 d。试验Ⅰ组(日粮CP 14.1%,Lys 0.60%)和试验Ⅲ组(日粮CP 12.6%,Lys 0.58%)产奶量明显高于试验Ⅱ组(日粮CP 14.1%,Lys 0.45%)和试验Ⅳ组(日粮CP 12.5%,Lys 0.44%)(P<0.05);试验Ⅰ组产奶量略高于试验Ⅲ组,试验Ⅱ组产奶量高于试验Ⅳ组但差异不显著(P>0.05)。各试验组之间的乳脂率、乳蛋白、乳糖、总固形物和体细胞(SCC)基本无变化(P>0.05)。综合分析表明,日粮CP水平从14.1%下降到12.6%时,维持相同的赖氨酸水平,奶牛产奶性能不受影响。奶牛日粮赖氨酸水平从0.60%降到0.45%,无论日粮蛋白质水平是否变化,奶牛产奶量下降。

Fouty Holstein cows were randomly allotted to four treatment groups and measured the effect of four diets on milk production performance with different protein and lysine levels. The cows were fed the experimental diets for ten days adaptation period followed by seventy days lactation trial. Four treatments took similar amount of diet DM（ P 〉 0. 05 ）. Milk production for treatment 1 and 3 were higher than that of treatment 2 and 4 （ P 〈 0.05 ）. Milk production for treatment 1 was similar to treatment 3, and that of treatment 2 was similar to treatment 4（ P 〉 0.05 ）. Milk fat, milk protein, milk sugar, total solid and SCC were not different among treatments. It concluded that milk performance of dairy cows had no change when dietary CP decreased from 14.1% to 12.6% and dietary lysine maintained the same level. When dietary Lys decreased from 0. 60% to 0. 45%, no matter how dietary CP changed, milk production of cows decreased.