When it comes to colostrum, 2 quarts is not enough, says Jerry Olson, technical services veterinarian with Pfizer Animal Health. Calves need to consume at least 100 grams of immunoglobulin to prevent failure of passive transfer. Because of the variation in immunoglobulin concentration, he recommends feeding 1 gallon of colostrum within four hours of birth. This compensates for colostrum with low-immunoglobulin concentrations and helps ensure that calves have the opportunity for good passive transfer.