Nutritional performance and metabolic characteristics of cattle fed tropical forages with protein and starch supplementation

Effects of protein supplementation, with and without starch on nutritional performance metabolic characteristics cattle fed low- medium-quality tropical forages were evaluated using 4 cannulated steers distributed according to a × Latin square. Experimental periods divided into two subperiods. In the first subperiod, animals received low-quality hay medium-quality. Supplementation schemes in second subperiod: (300 g crude – CP/d); CP/d) (225 g/d); g/d) supplementation. Without forage provided higher intake, digestibility, nitrogen balance (NB) efficiency utilization (EFNU). Comparing subperiods, supply supplements depressed but did not affect intake. increased NB, EFNU serum concentration IGF1 forage. Protein supplementation increases retention animals, an effect attributed mainly anabolic stimuli. However, this is more prominent when are forages. No positive impact animal metabolism was obtained combination supplemental starch.