The objective of our bull and replacement heifer development programs is to provide sufficient feed to allow for animals to be functional at breeding time, but avoid over conditioning that may contribute to excessive weight loss during breeding and have detrimental effects on longevity. Over the last 20 years, ADG from weaning to yearling weight measurement in our development programs for bulls and heifers has been 2.4 and 1.0 lbs/d, respectively. Yearling weights averaged 1023 and 720 pounds, for bulls and heifers respectively. These values are a function of the feeding protocols not the genetic potential. What is the economic incentive for feeding breeding animals more than needed, especially if it may be detrimental for future production? Bigger animals need more feed every day just to maintain their weight than smaller animals, whether the difference in size is due to genetics or management. This is one reason why bulls and heifers that are developed at very high rates of gain do not maintain body weight when put out on native range conditions like those existing in Eastern Montana. Reproductive efficiency is not good in animals losing weight. Evidence of the calving ease and growth potential in our herd is provided by average weights at birth and weaning for bulls and heifer over the last 20 years of 76.3 and 625, and 70.5 and 565, respectively.
The diet fed to bulls has been free choice availability of grass and alfalfa hay with access to dormant pasture. Corn and protein supplement (if needed) is worked into the diet overtime. Maximum level of corn fed is maintained at approximately 20% of the diet on an as fed basis to protect against detrimental effects of a high starch diet.