Files
Abstract
A three-year grazing trial was conducted to evaluate pearl millet [Pennisetum glaucum (L.) R.Br. (PM)] and brown-midrib pearl millet (BMR) with and without supplementation of soybean [Glycine max (L.) Merr.] hulls (0.75% of body weight (BW); PM+S and BMR+S, respectively) in a forage-finished beef production system in the southeastern U.S. Sixteen 0.81-ha pastures were randomly assigned to one of four finishing treatments in a completely randomized, 2x2 factorial design. Each year, Angus-cross bred steers (n = 32; 3-yr average BW = 439 ± 75 kg) were randomly assigned to treatment and finished for 64, 90, and 84 d during the summers of 2016, 2017, and 2018, respectively. Forage nutritive value samples and estimates of forage mass were taken at initiation, termination, and every two weeks throughout the grazing trial. Average daily gain (ADG) was calculated from fasted weights taken at grazing initiation and termination. Steers were harvested in September of each year and carcass data were collected 24 h postmortem. Striploins were removed from the right side of each carcass, vacuum packed, and allowed to age for 21 d. Striploins were fabricated into 2.54-cm steaks and allocated to meat quality and simulated shelf-life analyses. All data were analyzed using PROC GLIMMIX in SAS v. 9.4. All data from 2016 were omitted due to a lack of pearl millet in
treatment pastures. Treatments had no effect (P > 0.05) on forage mass. No differences (P > 0.05) were observed for relative forage quality and total digestible nutrients and forage variety had no effect (P > 0.05) on animal performance, hot carcass weight, dressing percent, nor ribeye area. However, supplemented steers exhibited greater (P < 0.001) ADG than non-supplemented steers. Slight differences (P = 0.0278) were observed for carcass lean L* values which were reflected in lean maturity and color (P = 0.0234 and P = 0.0361, respectively). No other treatment differences (P > 0.05) were observed. Results indicate pearl millet is a viable forage option for forage-finished beef systems and soybean hull supplementation improves animal performance over forage alone with minimal impacts on carcass characteristics, meat quality, and shelf-life.