Effects of Supplementation on Intake and Utilization on Harvested Forages

A frequent question asked by beef cattle producers is what supplement should be used. Prior to asking this question, it should be determined if a supplement is necessary. To answer this question, the nutrient requirements of the animal to meet the desired production level must be established. Next, it should be determined if current feed resources will meet these needs. It may be possible to shift grazing practices or to adjust feeding levels and meet the requirements. Once it is established that a supplement must be used, then the supplement that will improve the utilization of the base diet should be selected. With the wide array of supplements that are marketed, the different methods of feeding, and the differences in price and ingredients, choosing a supplement can be difficult. A good understanding of the principles of nutrition and digestion by beef cattle, the quality of the forage to be supplemented, the supplement composition, and associative effects that the supplement has on the forage will aid in determining the supplement that will provide the most benefit. Readers should refer to the previous paper in this proceedings for a discussion on basic nutrition of ruminants. This paper is written with the assumption that the primary component of the diet is forage. The data presented will be discussed assuming that the goal is for optimum utilization of the forage to meet the nutrient requirements of the animal at a given production level. This paper will also focus on the aspects of interactions of nutrients that are available to the microorganisms in the rumen and the resulting associative effects of the supplements on forage utilization. Economics of the feeding program will not be considered, however depending on the price of the forage and the supplement, it may be more economical to disregard the supplement\u27s affect on forage utilization and to provide a majority of the nutrients through the supplement