Release of methane and of carbon dioxide by dairy cattle

Abstract

153 two-days measurements on gaseous exchange of lactating cows were evaluated in order to quantify the release of methane and carbon dioxide by dairy cattle as affected by several parameters of feeding and performance. All animals received nutrients according to requirements with respect to their live-weights (450 kg to 725 kg) and milk yields (7.5 kg/d to 25.7 kg/d) using common dietary ingredients. Methane release averaged at 300 g/head and was particularly depending on the intake of crude fiber and of ether extract (CH{sub 4} (g)=63 + 80xCF (kg) + 11xNfE (kg) + 19xCP (kg) - 195xEE (kg)). Methane formation increased with higher live-weight and with higher milk per kg of milk produced, the relative methane excretion decreases with increasing yield in an asymptotic manner. The yearly emission of 600 kg cow at a milk yield of 5000 kg/year was estimated to account for 108 kg with a further methane release of 8 kg and of 5 kg per further 100 kg of live-weight and per 1000 kg further milk yield per year, respectively. Methods to reduce methane release by ruminants are discussed. Carbon dioxide release averaged at 9.7 kg/d and head and was depending on milk yield (feed intake) as well as on live-weight (CO{sub 2} (kg/d) = 0.2 + 0.14xmilk yield (kg/d) + 0.061x W (kg{sup 0.75})). (orig.).