Fear of people by cows and effects on milk yield, behavior, and heart rateat milking

To examine the ability of cows to recognize people and the effects of the f ear of people by cows at milking, cows (n = 14) were handled by two people; one handled the cows gently, and the other handled them aversively. The ha ndlers wore clothes of different color. After handling, the cows stood furt her from the aversive handler than from the gentle handler. When the handle rs changed the color of their clothing, the cows did not discriminate betwe en them. The gentle handler stood close to the cows for one milking, and th e aversive handler stood close to the cows for another milking. For two con trol milkings, neither handler was present. Measurements included milking d uration, milk yield, residual milk, heart rates, incidence of movement, and kicking behavior of the cows. Compared with control milkings, the presence of the gentle handler did not change milk yield or residual milk. The pres ence of the aversive handler increased residual milk by 70%. Kicking behavi or of cows during milking was reduced with either handler present, and kick ing during udder preparation was reduced with the aversive handler present. For cows that best discriminated between the handlers, the presence of the aversive handler increased movement and heart rate during milking. For cow s that did not discriminate well between the handlers, the presence of eith er handler increased heart rate and decreased movement during milking. Cows recognized individual people, and the fear of people who are present durin g milking may reduce milk yield.