DRY COW DIET, MANAGEMENT, AND ENERGY-BALANCE AS RISK-FACTORS FOR DISPLACED ABOMASUM IN HIGH PRODUCING DAIRY HERDS

The objective of this study was to determine prepartum risk factors fo r displaced abomasum. The design was a prospective study of 1170 multi parous Holstein cows from 67 high producing dairy herds in Michigan. E ach farm was visited four times within a 6-wk period. At each visit, d ata on nutrition and management were collected. All multiparous cows w ithin 35 d of projected calving were assigned a body condition score, and blood was sampled to determine the concentration of nonesterified fatty acids in plasma. A multivariable linear regression model was use d to determine risk factors associated with the incidence of displaced abomasum during lactation on a herd basis. A multivariable logistic r egression model with random effect was used to determine risk factors for displaced abomasum on an individual cow basis. Significant risk fa ctors for displaced abomasum included a negative energy balance prepar tum (as estimated from plasma nonesterified fatty acids), a high body condition score, suboptimal feed bunk management prepartum, prepartum diets containing >1.65 Meal of net energy for lactation/kg of dry matt er, winter and summer seasons, high genetic merit, and low parity.