Lying down and chewing cud is a crucial part of a cow’s digestive process, new research has confirmed, rather than a sign of laziness.
Cattle have evolved to graze without extensive chewing, in order to gather the greatest quantity of food in the shortest amount of time. Once their stomach (or rather their rumen) is full, cattle must rest in order to allow microorganisms to break down the fibrous material.
Read more at New South Wales Department of Primary Industries