Suckling range beef calf production demonstrates periodicity despite consistency of management. Performance of calves within 33- to 50-d intervals from birth to weaning over nine seasons demonstrated maximum interval growth of approximately 1 kg d^-1, but average seasonal growth rates varied from 0.79 to 0.99 kg d^-1.Maximizing available forages for the final 33 d preweaning could minimize seasonal variations in calf production.