BULLER STEER SYNDROME REVIEW

The buller steer syndrome is found among confined and pasture-kept cat tle, The buller behavior occurs when a steer is repeatedly mounted ('' buller'') and ridden by its pen mates (''rider'') until it is injured or killed. The usual practice is to remove the animal being ridden. Th e ridden animals are typically grouped together in a ''buller'' pen wh ere little or no mounting is observed. The buller steer syndrome, in t oday's dollars is estimated at US $70 per steer and thus represents a significant economic loss. Factors associated with an increase in the rate of bulling include: submissive behavior, pheromones, warm weather , large group sizes (over 200-250 head per pen) and other stressful ev ents (mixing, handling, temperature, dust). Buller steer physiology ha s been studied, with few concrete conclusions. Exogenous estrogen may increase and androgens may decrease the behavior, The vomeronasal orga n was not found to be involved in the behavior since lesions to this s econdary olfactory organ did not influence bulling rates. A concerted effort is needed to systematically study this problem for economic and welfare reasons. (C) 1997 Elsevier Science B.V.