404 Beef heifer development: Managing nutrition to optimize fertility

Abstract

Abstract Beef cattle longevity can be tied to reproductive performance. Developing heifers that will thrive in their environment, under specific management systems, is crucial for today’s producers. Management decisions influencing heifer fertility are numerous; however, the most commonly discussed and studied revolves around nutrition. The objectives of this presentation are to review our understanding of the influence of nutrition on beef heifer fertility and identify potential mechanisms which may improve heifer fertility and beef producer profitability. Also, we will identify management decisions that may impact body weight gain or efficiency of weight gain, thus impacting fertility. Management strategies delaying heifer growth patterns pre- or post-weaning have been reported to alter heifer reproductive performance. Additionally, developing heifers on native range compared to in the dry lot or confinement settings may alter growth rates/patterns, thus affecting the heifer’s ability to become pregnant, or maintain that pregnancy. Supplementing heifers with specific nutrient profiles has also been reported to improve pregnancy rates compared with non-supplemented or control animals. Previously, it was believed heifers are born with a finite number of follicles within their ovaries, and the depletion of the ovarian reserve occurs at a constant rate. Recent research has challenged this, reporting heifers developed on a stair-step growth program had an increased number of primordial follicles compared to constant gain developed heifers. Additionally, development system (native range vs. dry lot) appears to impact ovarian function. Continued research increasing our understanding of mechanisms involved in improving heifer fertility are warranted. These efforts will aid in identifying management strategies that will optimize animal reproductive performance.