Effects of active yeast on lactation performance,plasma biochemical,antioxidant,and immune indexes of lactating yaks in warm season

LAI Meiling; LIU Dazhong; XIU Yuhe; WANG Hong; LUOSANG Dunzhu; BASANG Wangdui; JIANG Nan

doi:10.13557/j.cnki.issn1002-2813.2025.17.004

Abstract：The experiment aimed to investigate the effects of active yeast on the lactation performance,plasma biochemical,antioxidant,and immune indexes of lactating yaks in the warm season.A total of 12 Niangya yaks from Jiali County,with the same parity,similar calving dates,and a body weight of(200±30)kg,were selected and randomly divided into two groups,with six replicates per group and one yak per replicate.The control group received conventional supplementary feeding,while the active yeast group was supplemented with 100 g/d of active yeast per yak(yeast cell count ≥200 million/g)on the basis of conventional supplementary feeding.The pre-test period was seven days and the formal test period was 35 days.The results showed that compared with the control group,the active yeast group had significantly increased milk yield in lactating yaks on the 18th day of the formal test period(P＜0.05),significantly increased milk fat percentage and milk lactose percentage on the 35th day(P＜0.05).On days 18th and 35th,the concentrations of plasma triglycerides(TG)and glucose(GLU),as well as the activities of total superoxide dismutase(T-SOD)and glutathione peroxidase(GSH-Px)were significantly increased in the active yeast group(P＜0.05),while the concentrations of urea nitrogen(BUN)and malondialdehyde(MDA)were significantly decreased(P＜0.05).On the 18th day,the content of plasma immunoglobulin M(IgM)was significantly increased(P＜0.05).The study indicates that supplementing active yeast can effectively increase the milk yield of lactating yaks in the warm season,improve milk composition,and enhance the body's antioxidant capacity and immune function.