Intake and in vivo digestibility of Tetrachne dregei differed from autumn supplemented with a ruminal protein activator

Resumen

In order to evaluate the animal response of a ruminal protein activator in animals which intake a Tetrachne dregei summer grass, differed from autumn and ripe, with the purpose of improving the forages intake and the in vivo dry matter digestibility, two doses of a ruminal protein activator (200 and
400 g. head.d-1) and a control without the activator in 280 kg steers were studied in a metabolism shed. These animals received Tetrachne dregei controlled in a completely randomized design with three treatments, three repetitions and four sampling days for food intake and feces collection measurements. The average composition was of 5.7 and 40.6 % of crude protein, 73.1 and 32.5 % of neutral detergent fiber, for Tetrachne dregei and the ruminal protein activator, respectively. It was estimated 77.52 %
of degradable protein in the activator. The control animals, only fed with Tetrachne dregei had lower total dry matter intake, forage dry matter intake and dry matter digestibility with respect to the treated groups(P <0.001), without significant differences. The total dry matter intake, dry matter digestibility and the digestible dry matter intake, was increased in 18.9, 9.3 and 33.6 % respectively, compared to that obtained in the treated animals, (P <0.001) and the forage dry matter intake in 14.5 % (P <0.002), but there were not significant differences between doses. The ruminal protein
activator achieved high response to low doses, when increasing the intake of digestible organic matter and degradable protein significantly in 34 and 50 %, respectively (P <0.001).

Key words: protein supplementation, forages, low quality, protein activator