Prediction of Dry Matter Intake by Cattle in Feedlot

Dry matter intake (DMI) is the most important variable affecting animal performance (Waldo and Jorgensen, 1981). This is especially the case for beef cattle, considering their economic importance, their complex digestive systems and their particular metabolic functions (Forbes, 2007). Feed intake restrictions can prevent the fulfillment of nutritional requirements. As most of the nutrients in beef cattle diets are used to meet their maintenance requirements, small alterations in feed intake may lead to limitations in the efficiency of the productive processes. Consequently, the growth rate will decrease, the genetic potential for weight gain will not be reached and the profitability of livestock activities will be jeopardized. In addition, problems associated with feeding stress, health and digestive disorders may arise. The factors that control feed intake are complex and multi-factorial, and there is no consensus on how ruminants regulate this important activity (Forbes, 2007). Interactions between several factors, such as diet, animal, environment and management, are primarily responsible for the lack of accuracy in DMI prediction equations (McMenimam et al., 2009). To plan an efficient feeding program capable of providing the best feed formulation to meet nutritional requirements, it is necessary to predict the level of voluntary intake of growing beef cattle under ad libitum feeding with great precision and accuracy.