Effect of molasses-based liquid supplements on digestibility of creeping bluestem and performance of mature cows on winter range.

Abstract

Poor quality of tropical range forage leads to excessive weight loss and poor reproductive performance of beef cows. This research measured 1) the digestibility by steers fed creeping bluestem (Schizachyrium scoparium var. stoloniferum) diets supplemented with cane molasses (0 or 20% of diet DM) and(or) added CP (no added CP, urea, or soybean meal) and 2) the performance of mature cows grazing creeping bluestem range and supplemented with 1.6 kg/(cow.d) (DM basis) of either molasses-urea or molasses-cottonseed meal-urea, each containing 30% CP (DM basis). Bluestem averaged 4.7% CP and 37.0% in vitro OM digestion. In the digestion trial, diets supplemented with molasses had greater (P < .01) apparent OM digestibility but lower (P < .01) apparent NDF, ADF, and hemicellulose digestibilities than diets not supplemented with molasses. Apparent OM digestibility of diets supplemented with soybean meal was greater (P < .05) than that of diets supplemented with urea but not different (P > .05) from the control. While grazing range, mature cows supplemented with molasses-urea lost less (P < .05) body condition (-1.7 vs -1.3) than cows supplemented with molasses-cottonseed meal-urea. Treatment did not affect cow weight loss on range (P = .85) or pregnancy rate (P = .51). Cows supplemented with molasses-urea tended to wean a heavier calf (P = .09). When fed at 1.6 kg/(cow.d) to mature cows grazing range, a molasses-based supplement containing urea was of equal value to one containing a natural protein.