Solid supplementation and energy sources for grazing beef cattle: digestion and metabolism

Abstract

ABSTRACT The objective of this study was to determine the influence of different forms and energy sources for energy protein supplementation for grazing cattle on nutrient intake digestibility, ruminal fermentation, microbial protein synthesis, nitrogen utilisation, urea and creatinine metabolism. Five rumen cannulated crossbred steers were used in a 5 × 5 Latin square experiment design of 21-d periods. Steers were randomly designated to one treatment sequence: BSES (bran sorghum energy supplement); BCES (bran corn energy supplement); BPFES (bran protect fat energy supplement); SBES (solid block energy supplement); SMES (solid molasses energy supplementation). Animals were individually allocated in paddocks covered with Urochloa brizantha and were offered a concentrate at 400 g/100 kg of LW. Steers fed with bran supplements had higher supplement intake and total digestible nutrients compared to steers fed with solid supplements. The animals that received starch-based energy source in supplements had lower concentration of acetate and total volatile fatty acids compared to steers supplemented with protected fat source. Steers fed solid supplements had higher nitrogen excretion compared to steers fed bran supplements. The bran supplements were superior to solid alternatives. Addition of protected fat positively influenced the digestion of grazing beef cattle.