Effects of entropy and parity on lactation performance, feed intake, eating time, and bunk preference of dairy cows

Understanding individual differences in cows' preference for feed or feeding environment may be important for adjusting management practices to meet their needs, improving animal welfare, and the efficiency of the production system. Our objectives were to (1) evaluate cows' preferences for visiting feed bunks and (2) assess the effect of parity on feed intake and eating time patterns. Data from 10 feeding trials conducted between 2019 and 2023 at the University of Wisconsin-Madison were compiled and used for this retrospective study. Conditional entropy measurement was used to generate an index that classifies cows' preferences for visiting feed bunks from least random to most random. A generalized linear model was used to evaluate the effects of normalized entropy values on lactation performance, feed intake, eating time, and bunk preference using a Tweedie distribution. A mixed effects model was fitted to the data. The model included parity as fixed effect and study as a random effect. No effects of bunk preference on performance-related parameters were observed. Dairy cows with a less predictable bunk preference could maintain milk and component-corrected yields compared with animals showing more predictable behavior. However, cows with less predictable preference needed to change their feeding behavior to adapt within their environment across different trials, such as feeding management, social hierarchy, and feed sorting. This suggests that dairy cows can engage in exploratory behavior that appears to provide them with information about the nutritive value of the feed available. In addition, relationships between dominant-subordinate cows can also greatly affect the feeding behavior of less dominant animals. Expectedly, older cows showed greater milk and component-corrected yields in the current study. Furthermore, parity affected feed intake and eating time patterns of high-producing animals, where younger animals appear to eat slower in smaller but more frequent meals throughout the day compared with older cows. These findings suggest that dairy cows of different ages should be housed separately, potentially minimizing competition among animals.