Dried distiller acute s grains plus solubles supplementation improves low-quality tropical grass utilization on beef steers

HERNÁNDEZ, OLEGARIO; LÓPEZ, AGUSTÍN; GARCÍA, ELISA MARIANA; NAZARENO, MÓNICA AZUCENA; ARROQUY, JOSÉ IGNACIO

CIêNCIA RURAL

UNIV FEDERAL SANTA MARIA

Año: 2022 vol. 52

0103-8478

This study was designed to evaluate the effect of corn dried distiller´s grains (DDGS) supplementation on feed intake, total tractdigestibility, and ruminal fermentation of beef steers fed low-quality Guinea grass (Megathyrsus maximus, cv. Gatton panic). TwelveBraford crossbred steers were housed in individual pens (n = 4 steers/treatment), provided with three levels of DDGS supplement: 0%, 0.6%,or 1.2% BW. Steers were blocked by live weight and randomly assigned to treatments within the block. Corn DDGS supplementation increasedtotal OM intake (21.55, 40.23, and 56.69 g/kg BW0.75) and tract OM digestibility (46.33, 49.03, and 72.39 % DM). Total tract digestible OM,CP, NDF and EE intake also increase in response to DDGS supplementation. Forage OM intake decreased when supplementation level reached1.2 % BW. Also, ruminal pH decreased with DDGS supplementation level (6.88, 6.47, and 6.27). No differences were observed in total volatilefatty acids (VFA) concentration; however, the molar proportion of acetate decreased (77.98, 73.90, and 67.29 % Total VFA) as well as acetate:propionate ratio (4.38, 3.48, and 2.74). On the contrary, propionate proportions increased (18.32, 21.86, and 24.81 % Total VFA). Levels ofammonia and lactate were within suggested values for optimal fermentation and bacterial growth. Low-quality grass supplementation withcorn DDGS increased total OM intake and digestibility. Also, DDGS inclusion favorably altered volatile fatty acids profile by reducing theacetate to propionate ratio regarding forage-only diets.Key words: distiller´s grains plus solubles, forage, beef cattle, intake, supplementation.