DEGRADABILIDADE DA MATÉRIA SECA DO GRÃO DE SORGO COM TANINO PELA TÉCNICA IN SITU EM RUMINANTES

Abstract

We evaluated the effect of tannin on the degradability of sorghum dry matter depending on the levels of corn meal substitution per milled sorghum grains in steers concentrate. Sorghum grains were obtained by cutting the sorghum plant panicle with dry beans (87% DM) with the aid of pruning shears. Analyzes were done to determine the bromatologic composition of sorghum grain. To determine the degradability of dry matter were placed 25 g of sorghum grain in non-woven fabric bags (NWF - 100 g / m2), respecting the relationship of 20 mg of dry weight/cm² of surface. These samples were incubated in four crossbred steers with a body weight of 518,8 ± 30,6 kg, rumen fistulated and kept in individual pens with free access to water. The animals went through an adaptation period to the facilities and experimental diets for 14 days. They were fed with a total mixed ration diet ad libitum formulated and balanced so that presented a forage : concentrate ratio of 60:40.The treatments were constituted according to the levels of corn meal substitution per milled sorghum grain in the proportions of 0, 33, 67, 100% in the concentrate. The Dry Matter Degradability (DMD) was obtained after the samples remain in the rumen for 0, 6, 12, 24, 48, 72, 96, 120 and 144 hours. The DMD showed increasing trend for the levels of 0, 33, 67 and 100% of milled sorghum grains in substitution of corn meal in the diet. The levels 33 and 100% of replacement showed the most pronounced DMD up to 48 hours of incubation. While the levels 0 and 67 had higher degradability in between 48 and 144 hours of incubation. Therefore, the sorghum grain included in the proportions of 33 and 100% in the concentrate showed great availability of dry matter in the early hours of incubation. The level 67% of sorghum grain in the diet had the highest DM disappearance at 144 hours of incubation.