Monensin and protein supplements on methane production and rumen protozoa in bovine fed low quality forage

This study aimed at evaluating the effect of sodium monensin and protein supplementation in the enteric methane production and the population of ruminal protozoa in bovine fed Brachiaria brizantha Marandu cultivar hay. The treatments were: mineralized salt, mineralized salt with monensin, proteinenriched salt and protein-enriched salt with monensin. The experimental outline was in a 4 x 4 Latin square. The protein supplementation increased the dry matter intake and the total concentrations of rumen ciliate protozoa. Monensin eliminated the rumen fauna and reduced the methane production. Methane production was 19.13; 15.73; 24.35 and 11.52 g/kg of ingested DM when mineralized salt, mineralized salt with monensin, protein-enriched salt and protein-enriched salt with monensin were supplied, respectively. The association between the inputs allows for a reduction in the methane production without a reduction in dry matter intake.