Sentence:  The annual incidence of <WSD>buller</WSD> steers within the feedlot industry is reported to fall between 2 and 4 percent, but the incidence per pen can be quite variable ranging from 0.0 percent to 11.2 percent per pen (Taylor et al., 1997). 
Meaning of the word marked with <WSD> tags:  A steer that allows itself to be mounted by bulls when in the crowded conditions of a feedlot.