Methane production in lactating dairy cows fed diets containing different lipidic supplements was estimated by the use of a prediction equation. Diets were evaluated by estimating daily methane output, methane output per kg of milk production and methane output per unit of dry matter intake and per unit of organic matter digested in the rumen. The addition of lipids different sources of were efficient to reduce daily methane output, methane produced per unit of milk production and per unit of dry matter intake. The estimative of the energy losses was similar to that described in the literature, which was between 3.86 to 7.6% of gross energy intake. The concentrate rations without lipidic sources resulted in more daily methane production. The intake of corn silage resulted in higher of energy losses and produced more methane per unit of milk, feed intake and feed digested. In Brazil, methanogenesis by ruminants could be reduced by the utilization of lipid supplement, especially in regions where these lipidic sources are cheap and abundant.