EFFECT OF LONG-TERM ADMINISTRATION OF A PROLONGED RELEASE FORMULATIONOF BOVINE SOMATOTROPIN (SOMETRIBOVE) ON CLINICAL LAMENESS IN DAIRY-COWS

A matched case-control study design was used to assess the effects of long-term administration of a prolonged release formulation of bovine somatotropin (sometribove) on clinical lameness and limb lesions in da iry cows. Cows treated with sometribove for at least 2 lactations (cas es) and nontreated dairy cows matched by herd, parity, age, and stage of lactation (controls) in 8 herds were evaluated for clinical lamenes s (as assessed by gait abnormality) and limb lesions by 2 observers, u sing a standardized scoring procedure at a single herd visit. Although a high proportion of the study cows were clinically lame (43%), an as sociation was not detected between chronic administration of sometribo ve and prevalent lameness. Of 21 types of limb lesions identified, 2 w ere positively associated and 2 were negatively associated with long-t erm sometribove use. Superficial laceration of the tarsus (odds ratio [OR] = 2.1) and superficial swelling of the metatarsophalangeal joint (OR = 4.5) were positively associated with sometribove treatment, wher eas femoral lesions (on = 0.2) and superficial lacerations of the femu r (OR = 0.14) were negatively associated with sometribove treatment.