The effects of nutrition on reproductive performance of beef cattle.

The concept of feeding for optimal reproductive performance is not new. The effects of prepartum and postpartum nutritional levels on return to postpartum estrus and conception rates was reported in 1962. The effect of body condition regardless of nutrition regimen was first reported in 1975. Body condition scoring has become a popular topic for Extension and practitioner sponsored producer meetings. To effectively promote a management change that requires increased cash flow and does not have an immediate return requires demonstration of cost-effectiveness. This requires knowledge of the biologic information and transformation of that knowledge (through partial budget analysis) into additional profit for the producer. Controlling reproduction through proper nutrition at critical times of the reproductive cycle requires: 1. Calving and breeding seasons of 60 days. 2. Cows to be in moderate to good body condition at calving (BCS 5-7). 3. Cows to be slightly gaining at the beginning of the breeding season. 4. Cows to be bred to fertile bulls. 5. Evaluation and correction of body condition well in advance of the actual impact of BCS on reproductive function. 6. Producer to be prepared to initiate "alternate" plans (i.e., early weaning or 48 hour calf removal).