Discriminability and preference among milking machine functions by dairy cows

An attempt was made to assess discomfort to the cow associated with milking machine function. Seven cows were presented with conditional discrimination tasks between alternative stimuli, using operant conditioning procedures. No discrimination between stimuli was evident. When allowed to choose between wide and narrow pulsation ratios, the 7 cows failed to do more than respond randomly. Four of the cows who were given a choice between potentially more or less aversive stimuli, pulsation vs. zero pulsation, showed no clear preference. The data suggest either that cows cannot discriminate within the experimental range of machine functions, i.e. that no measurable preference existed, or, under the experimental methods used, that cows could not learn the conditional discrimination required.