Substituição do farelo de trigo por palma com ureia em dietas para novilhas

Abstract

Were evaluated the replacement of wheat bran (0, 33, 66 e 100%) by spineless cacti with urea plus ammonium sulfate (9:1) to dairy heifers fed diets based on sugar cane correct with urea. Were used 24 crossbred heifers Hosltein/Zebu in a randomized design, in which the initial weight of the animals was taken as covariate, Willians test was used as a tool to assist in recommending safe level when linear effect. The dry matter intake (kg/day and %BW), organic matter, neutral detergent fiber, total carbohydrates and total digestible nutrients showed a quadratic effect (P<0.05). To degradable rumen protein the effect was linear (P<0.05). In the digestibility of dry matter, organic matter, neutral detergent fiber and non-fiber carbohydrates was quadratic effect (P <0.05), and the digestibility of crude protein were increasing and linearly. For variables of plasma urea nitrogen concentration, urine urea excretion, nitrogen balance, microbial nitrogen synthesis and efficiency of microbial protein had no effect (P>0,05). Decreased linear effect (P <0.05) for animals' performance, in the Williams test indicated that the decrease in performance occurred at the level of higher replacement. The cactus with urea can replace up to 66% wheat bran diet based on sugar cane for growing heifers.