Limit-feeding corn as an alternative to hay for gestating beef cows.

Three experiments were conducted to determine the efficacy of limit-feeding corn-based diets as an alternative to hay for beef cows in gestation and early lactation. Seventy or 71 mature, pregnant Simmental crossbred cows (average weight = 589 +/- 10 kg) were used in each trial. Each of 29 or 30 cows was fed approximately 5 kg of whole shelled corn, 1.2 kg of a pelletted supplement, and 1 kg of hay daily from November to April to meet nutritional needs for gestation. The remaining 41 cows were fed first-cutting round-baled hay free choice. Cows with ad libitum hay intake consumed approximately twice as much feed as cows limit-fed the corn-based diet. Body weight change during the winter was not affected (P > .10) by feeding system in Trials 1 and 2. Limit-feeding the corn-based diet had no detrimental effects on subsequent cow performance or conception rate or on calf weaning weight following summer grazing on pasture. The cost to feed a cow hay was nearly double that of limit-feeding corn-based diet. Two additional experiments were conducted to determine the effect of supplemental monensin (200 mg/d) on performance of gestating Simmental-Angus first-calf heifers fed corn-based diets. In Trial 4, monensin-supplemented heifers were fed 10% less corn than control heifers. In Trial 5, both groups were fed equal amounts of feed. No adverse effects of feeding the corn-based diets were observed. It was concluded from these trials that corn-based diets can meet the nutrient requirements of pregnant beef cattle without adverse effects on production and at a lower cost than feeding hay.