When calves are weaned prior to or during the breeding season (45 to 100 days of age), reproductive performance can be improved. Weaning prior to breeding is practiced among females that are at high risk of conceiving late in the calving season or not conceiving at all. These are usually thin cows or first-calf heifers. Research conducted in Oklahoma showed that weaning calves of very thin (body condition score 3 to 4) first-calf Hereford heifers as early as 6 to 8 weeks of age can increase conception rate and reduce the postpartum interval. In that study, first-calf heifers whose calves were weaned early had a 38-percentage unit advantage in conception rate during the breeding season that immediately followed; plus, the first-calf heifers were 87 pounds heavier on the normal weaning date. Average calving date was 18 days earlier the following calving season; thus, their calves were 18 days older at weaning the next year. In addition to raising more calves, there is substantial long-term benefit to maintaining a relatively short calving season that in some cases may only be practically achieved by early weaning. Assuming 1.75 pounds average daily gain for the last 18 days prior to weaning, this would equate to 32 more pounds per calf at weaning the following year. If the calves were worth $120/cwt., females whose calves were early weaned would produce 38 more calves per 100 females and generate almost $40 more per calf weaned the following year.

The improved reproductive performance comes at a cost. Calves must either be sold at a very light weight, or retained and sold later. Neither of these options will likely generate as much short-term net income as leaving the calves with their mothers until normal weaning time; however, the long-term benefits of early weaning may well exceed the reduction in short-term profit.