A method for estimating a greenhouse gas emission from a ruminant in a loose housing environment, and in a predetermined time period from T0 to Tdesired, the method including: determining a model emission rate function EM(t) for the ruminant determining the moments of eating feed by the ruminant, at least during the predetermined time period, as a series of points in time {T1, T2, T3, . . . , Tn} constructing the estimated real emission rate function ER(t) on the basis of the model emission rate function and the moments of eating feed, and integrating ER(t) from T0 to Tdesired. Also provided is a greenhouse gas emission estimation device, arranged to perform this method. In the device and method, use is made of the insight that knowing the eating moments can fine-tune calculations for establishing greenhouse gas emissions from the animals.