RISK-FACTORS ASSOCIATED WITH LAMENESS IN LACTATING DAIRY-CATTLE IN MICHIGAN

A prospective cohort study was conducted to determine specific risk factors that may be associated with lameness in lactating dairy cattle. The data for this study were from the National Animal Health Monitoring System (NAHMS) project from June 1986 to August 1987. Possible risk factors evaluated included the parity of the cow, herd size, housing type, exclusion of dry hay from the diet, bedding type and frequency of bedding changes. This study included 45 of the 54 randomly-selected herds that participated in the NAHMS project. Data were obtained from individual animal records and two herd management surveys completed by the producer at each farm. The results of the analysis show that for each 1 year increase in parity there was more than a 30% increased risk of becoming lame (odds ratio = 1.4; CI = 1.2-1.4). A herd size of 50-99 cattle was also associated with lameness in lactating daily cows (odds ratio = 4.6; CI = 1.2-12.7).