不同日粮蛋白能量水平对伊犁马产奶性能和乳成分的影响

试验采用2因子4水平饱和D-最优回归设计以研究日粮粗蛋白和消化能对伊犁马泌乳后期产奶量、乳成分的影响,通过响应曲面回归分析获得伊犁马泌乳后期适宜粗蛋白和消化能的需要量.选取年龄11～12周岁、体重410 kg±30 kg、胎次4～5胎,处于第3泌乳月的伊犁马30匹,随机分为6个试验组,每组5个重复.单栏定量饲养,分别饲以6种不同DE和CP水平的日粮,试验期60 d.试验结果显示,随着粗蛋白和消化能摄入的增加,日估计产奶量逐渐增加,其中以日粮4组（CP 1 352 g/d,DE 25.5 Mcal/d）最大,为8 156 mL/d.日粮4组的乳脂率、乳蛋白率、锌、锰在各组中最高,分别为0.99％、1.77％、1.12 μg/mL和28.96 ng/mL,而体细胞数和磷最少,分别为10.60×10^3个/mL和0.32 mg/mL.乳糖、总固体物、钙和铜含量在各组间均无显著差异（P＞0.05）.日产奶量与粗蛋白和消化能的回归关系为：日产奶量（mL/d）=-1.052 1×10^5 ＋581.678 3×DE＋116.6012×CP-0.111 0×DE×CP-0.037 2×CP^2-1.958 5×DE^2 （P＜0.05）.研究结果提示：DE和CP日摄入量影响处于泌乳后期伊犁马的产奶量和乳成分,400 kg体重伊犁马泌乳后期DE和CP的适宜需要量分别为108.05MJl/d和1 419.32g/d.

Effects of Dietary Protein and Energy Levels on Performance and Milk Composition of Yili Mares

In this trial,two-factor 4 levels of saturated D-optimal design was used to study the effects of crude protein （CP） and digestible energy （DE） on milk performance and milk composition of Yili horse in late lactation stage,and a suitable CP and DE requirements through the response surface methodology were obtained.Thirty Yili mares aging 11～12 years with weighing 410 kg ± 30 kg,parity of 4～5 in third lactation month were selected and randomly divided into six groups with five repeats in each group.All horses were fed with six rations containing different levels of DE and CP for 60 d.The results showed that with the increase of CP and DE intake,estimated daily milk production increased gradually,and the group 4 （with CP 1 352 g / d,DE 25.5 Mcal / d） reached the maximum of 8 156 mL/d.Meanwhile,the contents of fat,protein,zinc and manganese in mare milk of group 4 were the highest among the groups,and the values were 0.99%,1.77%,1.12 μg/mL and 28.96 ng/mL,respectively,and somatic cell count and phosphorus concentration were the least,were 10.60 × 10^3 counts/mL and 0.32 mg/mL.The lactose,total solids,calcium and copper contents in each group were not significantly different.The regression expression of CP,DE and the daily milk yield was：daily milk yield （mL/d） =-1.024 4 × 10^5＋2 330.102 8 × DE＋114.350 2 × CP-0.454 2 × DE × CP-0.036 452 × CP^2-32.498 9 × DE^2 （P 〈 0.05）.The results suggest that DE and CP daily intake affect milk yield and milk composition of Yili mares in late lactation stage,the suitability requirements of DE and CP for 400 kg weight Yili mares at late lactation stage are 108.05 MJl / d and 1 419.32 g/d.