There are a number of reasons cattlemen choose to castrate calves before marketing, the primary reason is market demand and economics.

Although the practice of castration is widely utilized within the industry, the timing and method used for castration can vary considerably between operations. Factors that may impact timing of castration include producer philosophy, product marketing claims, weather, and availability of resources such as facilities or labor.

Some cattlemen believe that delayed castration improves growth in nursing calves. This belief is also endorsed by some castration tool manufacturers who claim that delayed castration creates significant weight gain advantages at weaning compared to calves that were castrated shortly after birth. Since producers are paid on a weight basis, most cattlemen opt to market their calves at weaning. Consequently, differences in weaning weight can mean differences in profitability. Most research literature suggests that castrating calves shortly after birth has minimal to no effect on weaning weight.

The issue of age at castration was examined in a Florida setting to ascertain if timing of castration resulted in significant differences in growth rate and weaning weight in nursing calves. Calves born in December to March were divided into two groups and castrated at different times:  Early (average of 36 days of age in March/April) or Late (average of 131 days of age in June).

Calves had similar birth weights and by May the Early castrated calves continued to have similar body weights compared to calves that had not been castrated. This implies that calves castrated at or near birth had overcome any potential growth delays related to castration by the time body weight measurements were initiated.