Use of feed additives in Nelore cattle fed with high forage diet: Experiment I, Experiment II and experiment III.

Abstract

Food additives used in ruminant nutrition are tools that can improve the conversion of forage to animal protein and increase nutrient utilization efficiency. There is an important gap to be filled by research involving the use of molecules capable of altering the fermentation process in ruminants fed diets containing high forage content. Narasin is a molecule released in the market in 2016 and little is known about its effects on animals fed diets containing forage and long-term use. With regard to Lasalocida and Virginiamicina, the published work still leaves us to be desired with regard to the effects of prolonged use on ruminal microbiology and consequent effect on the fermentation and digestibility of the nutrients in animals consuming high content of forage measured daily. In addition, there is lack information on the comparison between these three additives in the same experiment. Therefore, we propose to perform three experiments: Experiment I: We will evaluate the effects of the use of Narasina, Lasalocida and Virginiamicina on the ruminal microbial population, fermentation parameters, apparent nutrient digestibility and blood parameters of 32 male Nellore cattle with ruminal cannula, divided in 4 treatments (Control, Narasina, Lasalocida and Virginiamicina) during 140 days; Experiment II: Following the work carried out in experiment I, the effect of Narasina, Lasalocida and Virginiamicina on the ruminal microbial population, ruminal fermentation parameters, apparent nutrient digestibility and blood parameters will be evaluated up to 28 days after the last administration of treatments; Experiment III: In order to evaluate the performance of cattle fed with high forage in the treatments presented in the experiment I, 160 Nellore cattle, with a mean age of 13 months, divided into 40 bays will be used, with 10 bays per treatment over 140 days. In this scenario, alterations in the ruminal fermentation process that increase the energy efficiency of this process, which may result in an increase in the digestibility of the fibrous fraction, would have a direct impact on the forage production system of beef cattle. (AU)