Cows"eat grass, squeeze out milk."Compared with monogastric animals,cattle have four stomach chambers, namely rumen,reticulum,Omasum and abomasum;compared with non ruminant animals,the rumen of cattle can not secrete digestive juice,but contains a large number of microorganisms and ciliates.Because of the structural and physiological characteristics of bovine digestive system,the clinical diseases of bovine digestive system are complex and varied,especially rumen heave,forestomach relaxation and omasum obstruction,which seriously endanger dairy production.Correct diagnosis of common digestive system diseases of dairy cows and taking targeted prevention and control measures can effectively reduce the loss of farmers.