Abstract: The aims of this study were to study the effect of different dosages of Astragalus polysaccharide (APS) on antibody level of Holstein cows vaccinated with footandmouth disease vaccine and hence to provide a reference for the clinical usage of APS.Forty Holstein cows with similar age,parity and weight were randomly divided into 4 groups (10 per group).0 g,5 g,10 g and 15 g of APS were added in the concentrated food each day for 7 days,respectively.At the 4th day,the Holstein cows in each group were inoculated with serotype Asia 1 and O footandmouth disease vaccine.The levels of type Asia I and type O foot-and-mouth disease antibody were measured at the day 0,4,18,32,46 and 104.The results showed that APS can increase the level of foot-and-mouth disease antibody after vaccination (P<0.05),which was in accordance with dosage of APS.The study suggested that APS can be used as an immunopotentiator to prevent and cure the footandmouth disease of Holstein cow.

Key words: Astragalus polysaccharides, cows, foot-and-mouth disease, antibody