Aditivos ionóforos e não ionóforos na dieta de tourinhos na fase de recria e terminação

Abstract

Brazil is one of the main beef producing countries, with the largest commercial herd. However, their productivity rates are still low compared to other countries, so to meet the expectations of the population demand for meat products, practices that improve performance such as the use of nutritional additives become indispensable for the development of beef cattle. with shorter production cycle. In this context, the objective of this work was to evaluate the performance, carcass characteristics and meat quality of bulls using the different additives (Flavomycin; Salinomycin; Virginiamycin) in their supplementation. The project was approved by the Animal Use Ethics Committee of the Universidade Federal Rural do Rio de Janeiro under protocol number 23083.010360 / 2016-18. Twenty-four Nellore bulls with average initial body weight (BW) of 303 kg were used. During the rearing phase, protein/energy supplement supplied in the amount 3 g / kg body weight / animal was used in the four treatments as proposed below: T1 - Control treatment (supplementation without the addition of additive); T2 - Supplementation + Flavomycin (40 mg / animal / day); T3 - Supplementation + Virginiamycin (45mg / 100kg BW) and T4 - Supplementation + Salinomycin (120mg / animal / day). Twelve Massai grass paddocks (three per treatment) managed in a continuous stocking system lasting 92 days during the dry season (May to August) were used. After reaching 355 kg BW the animals entered the finishing phase, when they were allocated in individual stalls receiving the additives from the previous phase and using sugarcane silage in a roughage: concentrate 30:70 ratio. The animals were evaluated every 28 days for their performance and dry matter intake. When they reached the average weight of 510 kg they were slaughtered in a commercial refrigerator. Subsequently, carcass yield and daily carcass gain were measured. The carcasses were transferred to cold room at a temperature of 1 ° C, and remained for 24 hours. Then, the Longissimus lumborum muscle was removed to measure the meat qualitative parameters: pH, temperature, color, cooking weight loss, shear force and centesimal composition. A completely randomized design with four treatments and three replications in the rearing phase was adopted, each pair of animal per paddock was considered an experimental unit, at the end the animals were confined individually and each animal was considered an experimental unit, totaling six replications per animal. treatment. An analysis of variance was applied, with significance, the test for comparison of means was applied using the Tukey test. The use of flavomycin, virginiamycin or salinomycin for Nellore cattle resulted in similar growth performance, carcass characteristics and meat quality. No evidence of benefit to rearing and finishing animals has been observed to support the use of additives at the doses used.