Abstract
The effect of level of energy on reproductive performance in mature Hereford cows was studied. Two levels of energy, 9 lb. of TDN per head daily (high) and 4.S lb. of TDN per head daily (low) were fed prior to calving. Following calving one-half the cows on the high ration and one-half on the low ration received 16.0 lb. of TDN per head daily (high-high and low-high). The remainder of the cows received 8.0 lb. of TDN per head daily (high-low and low-low). Results indicate that level of energy can markedly influence reproduction in the mature beef cow suckling a calf. The proportion of cows diagnosed pregnant during the experiment was 95%, 77%, 95% and 20% for cows fed the high-high ration, high-low ration, low-high ration and low-low ration, respectively. The difference among these groups was largely the result of a larger proportion of cows failing to show estrus on the low energy level after calving. Copyright © . .