Animal Science Department


Date of this Version

December 2003


Published for Proceedings, The Range Beef Cow Symposium XVIII December 9, 10, and 11, 2003, Mitchell, Nebraska.


Range livestock operations are continually challenged with the need to maintain sustainable production systems. Improvements in the herd’s biological efficiency are important considerations for the sustainability of beef cattle production. In a broad sense there are two levels at which improvements can be made, the cow and the calf. Considering that the majority of income for the typical cow-calf operation comes from the sale of the calf being produced, the calf would be a logical production unit to target for improvement. However, the key factor influencing total calf production is reproductive efficiency of the cow herd. Sound nutritional programs are pivotal to achieving the highest reproductive rates and increasing efficiency of beef cattle production. Strategic nutritional inputs may afford beef cattle managers the opportunity to produce beef cattle more efficiently and become more sustainable. In this regard, provision of supplemental fat to reproducing beef cows has been purported to improve production traits of the cow-calf unit. The purpose of this paper is to summarize expected responses of the cow and calf to dietary fat by compiling data available in the refereed (peer-reviewed) literature and from experiments conducted at the University of Wyoming. The goal will be to develop recommendations that will assist beef cattle managers determine whether or not supplementing fat to the cow herd has potential to improve biological efficiencies, and thus, improve sustainability of their beef cattle operations.

The most important factor affecting profit in a cow-calf enterprise is reproduction. In reviewing several sources of information, Bellows et al. (2002) estimated that reproductive diseases and conditions cost beef cattle producers $441 to $502 million in lost income yearly. Seventy-five percent of these costs were attributed to female infertility and dystocia and the failure to produce a healthy, viable neonatal calf. Therefore, the focus of this paper will be on supplementing fat to the beef cow during the most critical points of her annual production cycle (i.e. late gestation and early lactation). The initial discussion will focus on supplementing fat as a strategy to increase the probability of conception. The subsequent discussion will concentrate on how supplementing fat to the cow affects the calf. Researchers conducting the studies reviewed in the following discussion formulated the high-fat diets to provide equal energy and protein to that of the control diets so that responses could be directly attributed to the fat supplement.