Methane emission by cattle supplemented with additives in Brazil

摘要

Energy is a limiting factor to life and productive functions of animals. The knowledge of gas production by animals according to the diet demonstrates the partial efficiency of energy utilization as an important indicator of feed utilization. Virginiamycin is a non-ionophore antibiotic, with potential effect on improvement of ruminal fermentation and features indicative of an increase in dry matter intake. This antibibiotic acts by penetrating the bacterial cell wall, binding to the 50 S ribosomal subunit and blocking protein synthesis through the inhibition of peptide bond formation (Cocito, 1979). Monensin, an ionophore antibiotic, has antimicrobial activity against Gram positive bacteria and subsequent alterations in ruminal fermentation products, namely an increase in propionate at the expense of acetate and methane (Nagaraja et al, 1997). This study aimed to evaluate the inclusion of additives monensin, virginiamycin and its combination on methane emission determined by respirometric chamber in Fl Crossbred Holstein x Gir bulls.