Rotavirus and Cryptosporidium shedding in dairy calf feces and its relationship to colostrum immune transfer.

Twenty Holstein calves received 2 L of colostrum twice within 12 h after birth; the first feeding occurred within 2 h of parturition. The increase in adsorption efficiency was related to the gamma globulin provided in the first colostrum feeding. Absorption efficiency ranged from 2.4 to 46.1%. The number of sheddings of rotavirus and Cryptosporidium by the calves during their first 4 wk of life was associated with serum gamma globulin concentration 24 h after birth and absorption efficiency. Absorption efficiency and body weight combined accounted for 60.4% of the variation in the number of sheddings; heavier calves shed more than lighter calves. During the first 4 wk, calves that shed more frequently gained less weight; weight gain was also associated with serum gamma globulin levels 24 h after birth. Colostrum composition varied between quarters of the same cow. Total protein and gamma globulin content of colostrum from the rear quarters was higher than from the front quarters. The association between number of sheddings and absorption efficiency suggest that calves should not be fed colostrum containing less than 9 g/100 ml of total protein.