本试验主要目的是研究饲喂经高温高压处理的油菜籽对放牧牦牛乳生产性能和乳脂肪酸的影响。选择15头母牦牛，随机分为3组：对照组（N组，放牧）；低饲喂量组（L组，放牧加饲喂油菜籽100 g/yak·d）和高饲喂量组（H组，放牧加饲喂油菜籽200 g/yak·d）。结果表明：（1）与对照组相比，饲喂100 g/yak·d油菜籽对牦牛的乳生产性能和乳脂 肪酸没有影响,饲喂200 g/yak·d油菜籽能显著提高乳产量以及各乳成分的产量(P＜0.05);（2）棕榈酸（C16∶0）、硬脂酸（C18∶0）和油酸（c-9-C18∶1）是放 牧牦牛乳脂中含量较高的3种脂肪酸，饲喂油菜籽显著提高乳脂中硬脂酸（C18∶0）的含量(P＜0.05);（3）N、L和H组中共轭亚油酸（conjugated linoleic acid, CLA）含量分别是1.23％、1.15％和1.18％,饲喂油菜籽对各组CLA的含量和脱饱和酶指数无显著影响，牦牛乳中c-9,t-11-CLA的含量较高，平均为总CLA含量的98.60%。

The objective of this study was to evaluate the effects of rapeseed treated by high temperature and pressure on milk performance and milk fatty acids of grazing yaks. Fifteen yaks were randomly divided into the following 3 treatments: control group (group N, pasturing), low level group (group L, pasturing plus feeding 100 g/d rapeseed per yak), high level group (group H, pasturing plus feeding 200 g/d rapeseed per yak). The results showed that: (1) compared with the control group, there was no influence on milk performance and milk fatty acids by feeding 100 g/d rapeseed per yak. When the yaks were fed 200 g/d rapeseed, milk yield and content of milk components were significantly increased (P<0.05); (2) palmic aicd （C16∶0）,stearic acid （C18∶0） and oleic acid （c-9-C18∶1） were the abundant fatty acids of milk fat of grazing yaks and feeding rapeseed could significantly enhance the content of stearic acid in milk fat (P＜0.05); (3) conjugated linoleic acid (CLA) contents of milk fat were 1.23%, 1.15% and 1.18% in the control, group L and H, respectively. CLA contents and desaturase indices showed no significant difference among groups and the content of c-9,t-11-CLA in yak milk was relatively higher, which was 98.60% of the total CLA content.