Supplementing Monensin and Rumen Undegradable Protein to Late-Gestation Heifers

Summary with Implications This study evaluates the effects of supplementing late-gestation heifers with rumen-undegradable protein and monensin on weight gain, feed efficiency, and reproductive performance, and subsequent impact on progeny. We hypothesized that supplementation would enhance growth and feed efficiency, ultimately improving cow and calf performance. Previously synchronized artificially inseminated heifers were fed ad libitum hay for 89 d prior to calving. Feed was top dressed with chelated mineral with or without monensin, dried distillers’ grains, or dried distillers’ grains and monensin. Supplementation with rumen undegradable protein increased growth rate and decreased calving difficulty with no further effects on cow or calf performance.