Methane production of dairy cows fed cereals with or without protein supplement and high quality silage

Abstract: Ruminants produce methane during the fermentation of feed in the rumen. This release of methane represents not only an energetic loss for the animal but also contributes to the global warming because methane is released to the atmosphere. To mitigate the methane production from ruminants, and in particular from cows, feeding strategies need to be studied. The objective of the thesis was to evaluate the quantity of methane produced in diets with or without protein concentrate combined with two silages differing in protein content (17% vs. 13%). An experiment using a Latin squares design with six Swedish Red cows in two orthogonal blocks was performed to study three different treatments: treatment AC with silage A (2/3 early harvested silage + 1/3 red clover) and cereal, treatment AP with silage A, cereal and protein supplement and treatment BC with silage B and cereal. Each period lasted three weeks with two weeks adaptation to the diet and last week as a measurement period. There were no differences in methane production in absolute terms between treatments, and the average methane production of the cows was 473 g/d. Milk production and methane production per kg milk did not differ between treatments. Significant differences were found only between treatments AP and BC in methane production per kg of protein intake (104.7 g/kg vs. 203.3), per kg of MJ intake (1.6 g/kg vs. 2.0) and per kg of starch intake (492.1 g/kg vs. 228.5).