Aditivo a base de extratos vegetais como alternativa à monensina sódica na dieta de vacas de corte terminadas em confinamento

Abstract

The objective of the present study was to evaluate the effect on performance and ingestive behavior of herbal extract additive as an alternative for monensine on feedlot cull cows diet. Twenty four cull cows, Charolais (CH) vs. Nellore (NE) crossbred, being each treatment composed by eight animals, between then one CH; one NE; one ¾ CH e ¼ NE; one ¾ NE e ¼ CH; two 11/16 CH e 5/16 NE and two 11/16 NE e 5/16 CH, with initial age and live weight of 7 years and 423 kg, respectively, were used. The roughage:concentrate ratio was of 62:38, constituted by sorghum silage and concentrate composed by wheat bran, corn, limestone and sodic chlorate. The experimental diets were: EVE basic diet + 5 mg of herbal extract additive; MON - basic diet + 300 mg of monensin and CON control group, without additive. The herbal extract used was Rumex® and monensin was obtained with Rumensin®. The quantity of additive used was the higher one recommended by manufacturers. Feedlot period was of 64 days. The complete randomized experimental design was used, wit a 3 x 2 factorial arrangement (3 diets and 2 racial predominance) and the averages were compared by t test with 5% and 10% of probability. No interaction between diet and racial predominance was observed and additives inclusion didn t affect animal s performance and food intake. Animals with Charolais racial predominance (CRP) obtained higher weight gain (P<.05) and dry mater intake (P<.10) and better feed conversion (P<.10) then Nellore racial predominance (NRP) animals. The EVE diet proportioned higher (P<.05) rumination time, number of ruminal chews per bolus, rumination time per bolus.