A recent study from the U.S. Department of Agriculture's Agricultural Research Service demonstrates that castration prior to weaning can reduce stress on calves.

Scientists measured levels of haptoglobin, a blood chemical indicating injury-related stress on calves castrated at different ages. They used 36 weeks as the typical weaning and castration age, and compared earlier dates. Haptoglobin levels were higher in calves castrated at 36 weeks than those castrated at 33 weeks or at birth. Surgically castrated calves also showed higher levels of haptoglobin compared with those castrated by banding.