3Reinhardt T A, Hustmyer F G. Role of Vitamin D in the immune system [J]. J Dairy Sci ,1987,70:952.
4Wuryastuti H,Stowe H D,Bull R W,et al. Effect of vitamin E and selenium on immune responses of peripheral blood .colostrum and milk leukocytes of sows [J]. J Anim Sci , 1993,71:2464-2472.
