不同粗饲料组合对原料牛乳脂肪酸组成和含量的影响

Effect of Different Forage Combination on the Fatty Acid of Raw Milk

本试验旨在研究不同粗饲料组合对荷斯坦奶牛原料乳脂肪酸的影响。试验采用单因素随机试验设计,将18头体重、年龄、胎次相近,处于泌乳中期的健康荷斯坦奶牛分为3组,每组6头。在全混合日粮(TMR)饲喂基础上调整粗饲料中干草比例,为对照组(TMR+羊草100%)、试验组1(TMR+羊草50%+苜蓿50%)、试验组2(TMR+羊草50%+苜蓿25%+秸秆25%)。在试验开始第1天、第25天、第50天采集奶样,用气相色谱法测定原料牛乳脂肪酸。结果表明:(1)试验组1和对照组的t10,c12-CLA含量差异显著(P<0.05)。(2)试验组1和2较对照组C20:1分别下降了16.67%和33.33%。(3)对照组和试验组1的C14:1/C14:0均呈下降趋势,而试验组2的C14:1/C14:0是先下降再上升(P<0.01)。(4)对照组n3/n6比值增加趋势变缓,试验1组对n3/n6比值的增加效果最强,试验组2次之。

This study was conducted to research the effects of different forage combination on the fatty acids of cows＇ raw milk. Eighteen Holstein Cows were randomly assigned to three treatments, with similar body weight, milk yield and days in milk. The three treatments were： TMR＋Chinese wild-rye 100%（control group）; TMR＋ Chinese wildrye 50% and alfalfa hay 50%（treatment group 1）; TMR＋Chinese wildrye 50%, alfalfa hay 25% and corn straw 25%（treatment group 2）. Milk samples of Holstein Cows were taken at the 1st, 15th and 50th days of the experiment period. The fatty acids were determined by gas chromatography. The results were as follows：（1） The contents of t10, c12-CLA in treatment group 1 and treatment group 2 showed significant difference（P0.05）.（2） The contents of C20：1 in treatment group 1 and treatment group 2 were reduced by 16.67% and 33.33% than the control group respectively.（3）The values of C14：1/C14：0 in the control group and treatment group 1 showed the declining trend, while it was down firstly, and then increased in treatment group 2.