Colostrum is high-protein milk that's produced by the mother for a few days after giving birth. Colostrum contains many antibodies and increases the calves' resistance to disease. Weaning is a stressful time for calves. That stress can be heightened by production practices such as castration. Animals are castrated primarily to reduce the danger of handling males, who are often aggressive, if they're allowed to reach sexual maturity uncastrated.
Castration also improves the taste and tenderness of beef.
Meat from uncastrated cattle can be tougher and may carry an unpleasant odor. G-CSF stimulates bone marrow to produce white blood cells that fight infections. In tests, cows were injected with the compound daily from days three through seven after calving. On the sixth day, the cows were challenged with a bacteria and their reactions were monitored for several more days. Half of the cows receiving G-CSF did not become infected.