A study was conducted to evaluate the effects of preconditioning beef calves. In 1982, each of two producers allocated 100 cow-calf pairs to the study while in 1983, 130 cow-calf pairs were included on Farm 1 and 151 on Farm 2. In 1982, approximately even numbers of cow-calf pairs were randomly assigned to either a preconditioning (PC) or a regular (RG) program. These same groups were maintained in 1983. The length of the period from early weaning to shipment (preconditioning period) was 30 d (PC30) in 1982 and either 30 or 42 d (PC42) in 1983. At the end of the preconditioning period, calves from both farms were shipped to the same feedlot for 68- and 95-d tests in 1982 and 1983, respectively. PC calves gained faster than RG calves during the preconditioning period in five of the six farms by year by treatment situations. Preconditioning calves for 42 d rather than 30 d had no effect on either preconditioning gain or farm to feedlot weight loss. The cost of preconditioning ranged from $29.65 to $38.77 head−1 for PC30 calves and from $41.95 to $49.08 head−1 for PC42 calves. The price differential required by the cow-calf producer to break-even on PC calves ranged from + 5.0C kg−1 for PC30 calves to + 11.0C kg−1 for PC42 calves. Weaning treatment had no effect on either pregnancy rate the following year or on calving interval. In 1982 RG calves gained 0.13 kg d− more in the feedlot than PC30 calves. In 1983 PC30, PC42 and RG calves gained similarly. Treatment for illness of PC30 calves during the feedlot phase was 13.7% lower than RG calves in 1982. In 1983, treatment rate was reduced 42.0% for PC30 calves and 60.6% for PC42 calves. Preconditioning for 42 d rather than 30 d had no effect on feedlot growth or health performance. Cost of gain was 5.0C kg−1 less for PC calves than for RG calves in both 1982 and 1983. Key words: Calves (beef), weaning (early), preconditioning, farm, feedlot
The effects of maternal calving date and calving interval on growth performance of beef calves
