Abstract: [Objective] To explore the effects of adding glycyrrhetinic polysaccharide to the early lactation diet on the production performance and serum indexes of dairy cows. [Method] This experiment used a random number table method to divide 60 cows with similar physical health,age,and parity during early lactation（21 days postpartum） into 4 groups,with 15 cows in each group.Each group had 3 replicates,with 5 cows in each replicate,including the control group,experiment I,experiment II,and experiment III groups.The early lactation cows in the control group were only fed with a basic diet.On the basis of feeding the basic diet,the early lactation cows in the experimental group I,II,and III were added 0.3%,0.6%,and 0.9% to the basic diet,respectively.The production performance indexes and serum indexes of the early lactation cows were tested within 21 days of the formal experimental week of this experiment. [Result] Compared with the control group,the dry matter intake,milk production,and weight changes of early lactation cows in experiment I,experiment II,and experiment III groups were significantly increased,and the difference was significant（P<0.05）;The feed conversion rate of early lactation cows in experiment I,experiment II,and experiment III groups were significantly decreased,and the difference was significant（P<0.05）;the total antioxidant capacity,content of superoxide dismutase and glutathione peroxidase in the serum of early lactation cows in experiment I,experiment II,and experiment III groups were significantly increased,and the difference was significant（P<0.05）;the content of malondialdehyde in the serum of early lactation cows in experiment I,experiment II,and experiment III groups decreased significantly（P<0.05）. [Conclusion] Adding glycyrrhetinic polysaccharide to the early lactation diet can improve the production performance of cows and have good antioxidant capacity,with the optimal dosage of glycyrrhetinic polysaccharide being 0.9%.

Key words: early lactation, glycyrrhiza polysaccharide, cow, production performance, serum indicator