饲喂高亚油酸玉米对奶牛瘤胃发酵、产乳量和乳成分的影响

选用 6头经产荷斯坦种乳牛分为对照和HLAC两组 ,以二乘反转法 ,研究了高亚油酸玉米 (HLAC)、对奶牛瘤胃发酵、产乳量和乳成分的影响。HLAC组用HLAC部分替换了对照组饲料中的普通玉米 ,两组日粮组成和营养成分基本相同。结果表明 ,HLAC的替换对瘤胃液氨氮浓度、挥发性脂肪酸浓度及其组成无显著影响 (P>0 .1) ,但纤毛虫总数显著增加 (P <0 .0 5 )。两组牛干物质采食量和产乳量无显著差异 ,但HLAC组乳脂率有下降趋势 (P <0 .1)、乳脂肪中C18:2比例小幅提高、C18:1比例显著提高 (P <0 .0 5 )、乳蛋白质率及其产量小幅增加、乳糖率和无脂固形物率及其产量显著提高 (P <0 .0 5 )。以上结果显示 :奶牛饲料中HLAC的使用可改善乳成分 ,并对瘤胃发酵产生一定影响

Effect of high linoleic acid corn on rumen fermentation, milk yield and composition in lactating dairy cows

Six lactating Holstein cows were divided into two groups (n=3) of control and HLAC, and used in a double reversal trial, to evaluate diet containing high linoleic acid corn (HLAC) on ruminal fermentation, milk yield and composition. In the HLAC diet, HLAC partially replaced the normal corn in the Control diet, and the two diets contained the same level of nutrients. The results indicated that the concentration of ammonia nitrogen, the concentration and formation of total volatile fatty acids were unchanged with HLAC, but total protozoal number increased(P<0.05). Although there existed no significant difference(P>0.1) in Dry matter intake and milk yield between the two groups, the percentage and production of lactose and the Solids-Not- Fat were increased significantly(P<0.05) with HLAC diet. With HLAC diet, percentage of milk fat tended to decrease(P<0.1), and C18:1 Proportion in milk fat increased significantly(P<0.05) and C18:2 Proportion in milk fat was unchanged. It is suggested that HLAC could improve the milk quality and has some effect on rumen fermentation.