Abstract: [Objective] To explore the effects of adding LBP to diets on the production performance and serum indexes of early lactation cows. [Method] 80 early lactation cows (within 21 d postpartum) with similar litter size were selected and randomly divided into 4 groups of 20 replicates each, with 1 cow in each replicate, which were the control group, experimental groups A, B and C. The control group was fed with normal diet, while experimental groups A, B and C were fed with LBP, and the control group was fed with normal diet. The control group was fed a normal diet, while the experimental groups A, B and C were supplemented with 1%, 2% and 4% LBP in the basal diet, respectively. The changes in body weight, feed intake, lactation and milk quality were measured after 21 d of continuous feeding, and the effects of LBP on oxidative stress were measured in serum. [Result] The average daily weight gain and average daily feed intake of experimental groups B and C were significantly higher than those of control group and experimental group A (P<0.05). Differences in feed-to-weight ratios between treatments were not significant (P >0.05). There was no significant effect of different treatments on milk fat rate and milk protein rate (P>0.05), but with the increase of LBP addition, the somatic cell counts of test groups A, B and C were significantly lower than those of the control group (P<0.05). GSH-Px, SOD and T-AOC were significantly higher in test B and C groups than in control and test A groups (P<0.05), and MDA content was significantly higher in control and test A and C groups than in test B group (P<0.05). [Conclusion] Addition of 2% LBP to the diet helps to improve the performance of dairy cows and reduce the number of somatic cells in milk, which is helpful to improve the antioxidant capacity of the cow's organism.

Key words: lycium barbarum polysaccharide, dairy cow, lactation, oxidative stress