Intake and digestibility of low and high quality forage diets by purebred and cross-bred steers of tropically adapted breeds

摘要

To improve the overall value of calves from the southern U.S. beef cow herds, tropically adapted Bos indicus and Bos taurus breeds are being evaluated. The objectives of these studies were to determine the impact of tropically adapted breed type on dry matter intake (DMI) and digestibility of low- (LQ) and high-quality (HQ) diets. In Exp. 1, steers sired by tropically adapted beef breeds (Boran, Brahman, and Tuli) had similar DM and N digestibility coefficients as steers sired by Gelbvieh bulls for both HQ and LQ diets. In Exp. 2, DMI of a LQ diet was increased when supplemental protein was fed at 0.4% of BW. Steers with 25% Senpol or Tuli breeding had greater DMI than steers with 25% Brahman breeding or purebred Romosinuano steers. We concluded that previously developed concepts describing the interaction of low quality forage diets and protein supplementation is applicable to the breeds types used in this experiment. In these experiments, alternative sources of tropical adaptation in beef cattle were explored. New tropically adapted beef breeds can be incorporated into U.S. cow herds. The resulting prodigy can enter existing production systems without changing management strategies.