饲粮全棉籽比例对奶牛泌乳性能及乳脂脂肪酸组成的影响

本试验旨在研究饲粮全棉籽比例对奶牛泌乳性能和乳脂脂肪酸组成的影响.试验采用4×4拉丁方试验设计,选择8头泌乳早期的经产中国荷斯坦奶牛(产奶量、胎次、产犊日期接近,健康无疾病),分为4组,每组2个重复,每个重复1头牛.A组饲喂基础饲粮,B、C和D组分别饲喂含5％、10％、15％全棉籽的试验饲粮.每期试验28 d,其中预试期为7d,正试期为21 d.结果表明:随着饲粮全棉籽比例的增加,奶牛产奶量有提高趋势(P＞0.05),校正乳产量极显著提高(P＜0.01).全棉籽极显著地提高了奶牛的乳脂率(P＜0.01),对乳蛋白率、乳糖率和乳非脂固形物率无显著影响(P＞0.05).全棉籽极显著降低了饱和脂肪酸( SFA)的含量(P＜0.01),不同程度地提高了乳中多不饱和脂肪酸( PUFA)和单不饱和脂肪酸(MUFA)的含量(P＜0.05或P＜0.01);短链脂肪酸和中链脂肪酸含量都显著降低(P＜0.05),长链脂肪酸含量有不同程度的提高(P＜0.05或P＜0.01).结果提示,饲粮中添加全棉籽可以提高奶牛产奶量,优化乳脂脂肪酸组成,改善乳脂品质,并以10％为泌乳早期奶牛最佳饲粮全棉籽比例.

Dietary Whole Cottonseed Percentage Affects Lactation Performance and Fatty Acid Composition of Milk Fat in Dairy Cows

This experiment was conducted to study the effects of dietary whole cottonseed(WCS) percentage on lactation performance and fatty acid composition of milk fat in dairy cows.A 4×4 Latin square design was used.Eight Holstein cows in early lactation with similar milk yield,parity and time of parturition were selected and assigned randomly into four groups with two replicates in each group and one cow per replicate.Cows in group A were fed a basal diet,and cows in groups B,C and D were fed experimental diets conteined 5%,10% and 15% WCS,respectively.Each period lasted for 28 d with 7-d adaptation period and 21-d formality period.The results showed as follows: with the increasing of WCS percentage,milk yield of dairy cows tended to be increased(P>0.05),and FCM yield was significantlly increased(P<0.01).Milk fat percentage was significantly increased by WCS(P<0.01),and percentages of milk protein,lactose and milk non-fat milk solids(SNF) were not significantly affected(P>0.05).Saturated fatty acid(SFA) content was significantly decreased by WSC(P<0.01),contents of poly-unsaturated fatty acid(PUFA) and monounsaturated fatty acid(MUFA)were also significantly increased(P<0.05 or P<0.01);short-chain fatty acid(SCFA) and middle-chain fatty acid(MCFA) were significantly decreaed(P<0.05);long-chain fatty acid(LCFA) content was significantly increased(P<0.05 or P<0.01).These results indicate that dietary WCS can increase milk yield,optimize fatty acid compositon of milk fat and improve milk fat quality.For dairy cows in early lactation period,the optimal percentage of WCS in the diet is 10%.