富含棕榈酸的脂肪酸补充剂颗粒大小对奶牛生产性能的影响

Effects of Prill Size of a Palmitic Acid–enriched Fat Supplement on Performance of Dairy Cows

本试验的目的是评价富含棕榈酸的脂肪酸补充剂(PA)的颗粒大小对奶牛采食量、营养物质消化率和奶产量的影响。试验选取24头初产和经产荷斯坦牛进行重复4×4拉丁方设计,试验期21d。总的来说,与对照组相比,PA处理可增加乳脂含量、乳脂产量、3.5%乳脂校正乳产量、中性洗涤纤维消化率、C16乳脂肪酸的含量和产量、饲料效率,降低C16脂肪酸和总脂肪酸的消化率、从头合成的乳脂肪酸含量和预先形成的乳脂肪酸含量,但不影响干物质采食量、体重、体况得分、奶产量、乳蛋白产量和乳糖产量;与PA-SM处理组相比,PA-LG处理组趋向增加乳脂肪含量;与PA-MD处理组和PA-SM处理组相比,PA-LG处理组增加了C16脂肪酸的消化率;除此,与PA-MD处理组和PA-SM处理组相比,PA-LG处理组增加了C16脂肪酸的消化率。结果显示,PA可增加乳脂肪含量、乳脂肪产量和饲料利用率,减小的脂肪颗粒可降低脂肪酸消化率,但是在本试验的日粮条件和颗粒粒径的条件下,减小的脂肪颗粒对于动物生产性能没有影响。

The objective of our experiment was to evaluate the effects of prill size of a palmitic acid-enriched fatty acid supplement （PA） on feed intake, nutrient digestibility and production responses of dairy cows. Twenty-four primiparous and multiparous Holstein cows were assigned to replicated 4x4 Latin squares balanced for carryover effects with 21-d periods. PA treatments increased milk fat content, milk fat yield, 3.5~/, fat-corrected milk, neutral detergent fiber digestibility, and improved feed efficiency compared with control. Compared with coi^trol, PA treatments did not affect dry matter intake, body weight, body condition score, or yields of milk, protein, and lactose. Compared with control, the PA reduced the digestibility of 16-carbon fatty acids and total fatty acids, and the contents of de novo synthesized milk fatty acids and preformed milk fatty acids. In contrast, PA treatments increased the content and yield of 16-carbon milk fatty acids compared with control. However, PA-LG tended to increase milk tat content compared with PA-SM, and it increased 16-carbon fatty acid digestibility compared with PA-MD and PA-SM. Additionally, PA-LG increased total fatty acid digestibility compared with PA-MD and PA-SM. Results demonstrated that PA increased milk fat content and yield, and feed efficiency. Reducing prill size decreased fatty acid digestibility, but it had no effect on animal pertbrmance under the dietary conditions and prill sizes evaluated.