Influence of Energy Intake upon Reproductive Performance and Milk Production of Two-Year-Old Beef Heifers

Reproductive performance of the beef female is influenced by the level of energy fed both before and after calving. The interval from calving to the first post-partum estrus is lengthened by a low energy intake either before or after calving. Conception rate varies directly with the energy intake after calving. A limited amount of data suggests that different breeds of cows may have differential reproductive performance when subjected to a given environment. More knowledge of the effects of pre- and post-calving energy levels upon reproductive performance of beef females could lead to wiser and more efficient use of available resources. Valuable information might be gained by determining the response of different breeds to various energy levels. The experiment reported here was designed to measure the effects of two pre-calving and three post-calving levels of digestible energy on the reproductive performance of 2-year-old Hereford and Angus heifers. Advisor: J. N. Wiltbank and D. R. Zimmerma