Improving Re-Breeding Through Protein Supplementation

Research conducted at Fort Robinson in 1960 and following studies have demonstrated that good body condition supports successful reproduction in both young and older cows. The recommendations from these studies have emphasized the feeding of energy to assist thin cows back into condition. However, in the extensive range conditions of the West, the ranch is intended to supply dietary energy through the range vegetation. When we look at the costs associated with calf production many ranchers have production costs above the national average. Many of these high cost producers have higher than average purchased feed costs. It would be advantageous for ranchers to have an alternative nutritional strategy, to achieve reproductive management goals. Nutritional schemes that use small, biologically potent, easy to deliver and cost effective supplements would be widely adopted if available. The question to be asked is “Can the factors associated with good body condition on reproduction be mimicked by the diet in young thin cows?” This question has been the basis of our research program at New Mexico State University. The purpose of this paper is to describe how protein may act as a switch to turn on the reproductive system of thin young cows to breed back sooner after calving. We know that 2 and 3 year old cows ranging on native pastures after calving can lose weight at a rate close to 1 pound per day. This is due to an imbalance of nutrient demand (especially milk production) compared to nutrient intake. Usually late winter and spring forage is not abundant and low in nutritive value. Keeping in mind that our goal is to reduce cost of supplementation, “Is it possible to minimize the negative effects of weight loss on reproduction in young range cows with supplements