Forage type affects the temporal methane emission profiles in dairy cows fed fresh forages

Methane (CH4) emission rates increase after feeding till a peak and then decrease until the next feeding. Understanding the CH4 emission patterns when animals are fed different forages and the drivers for variation in temporal CH4 emission may be a tool for using short-lived CH4 inhibitors efficiently in grazing systems when fed during milking only. The objectives of this study were: a) to compare the temporal CH4 emission profile of non-lactating cows fed plantain or ryegrass and, b) evaluate the relationship between feed nutrient intake and dry matter intake rate, with CH4 emissions accumulated during the first 3 h after feeding as a percentage of 24 h CH4 emissions. After the CH4 emissions peaked, they decreased more rapidly in PLT compared to RG fed cows. The cumulative CH4 emissions during the first 3 h after feeding as a percentage of 24 h emissions was 18 % greater in PLT than in RG fed cows, and 13 % greater in the afternoon compared to the morning. The soluble sugars concentration in the forage was the only feed feature with significant effect on the cumulative CH4 emissions during the first 3 h after feed delivery, whereas there was no relationship with dry matter intake during the first 3 h after feeding. In grazing systems forages resulting in greater CH4 emissions during the first 3 h after feeding as a percentage of 24 h emissions would be more suitable to be combined with short lifespan CH4 inhibitors.