Symposium Paper: Pre-Calving Nutrition and Management Programs for Two-Year-Old Beef Cows

Abstract

AbstractA female replacement program is needed in beef production enterprises to replace cows that have been culled for various reasons. Replacement females may come from either internal or external sources. Regardless of the source, management and nutrition play a large role in the successful development of these replacement females. In either case, females must be grown, mated, calved, and re-mated to enter the cow herd successfully. In most production systems in the US and Canada, replacement females are mated to calve at 2yr of age. These females have not yet reached their mature BW (MBW) at first calving. Consequently, higher nutritional and management demands are placed on these females following first calving. In addition to nutrient requirements for maintenance, lactation, and reproduction, these females also have nutrient requirements for growth. It is generally accepted, based on numerous research trials and production observations, that pre-calving nutrition [which is fundamentally reflected in body condition score (BCS) at calving] has a major impact of the length of the postpartum anestrous period. Recent and on-going research has identified potential opportunities to positively manipulate physiological processes in young cows through feeding elevated undegradable intake protein (UIP) or gluconeogenic precursors. Studies in animal behavior related to grazing and foraging indicate that opportunities and interactions for improved nutritional status exist by incorporating principles of animal learning and behavior into heifer development programs. Low-cost strategies designed to meet the nutritional demands of young cows and management programs designed to optimize reproductive performance will facilitate successful replacement programs.