Case Study: The effects of photoperiod on feeding behavior of lactating dairy cows in tie-stalls

To determine the effects of photoperiod management on behavior of dairy cows, 30 lactating cows were subjected to a long-day (16 h/d light) or short-day photoperiod (8 h/d light). Feeding behavior was observed and feed refusals were collected before and after a 21-d adaptation to photoperiod treatment. Feeding behavior data were summarized for 4 daily time periods based on light schedule, and no effect of light treatment was observed for DMI, lying time, or overall feeding behavior. However, in time period 4 (1600 to 1900 h), the long-day treatment decreased lying time (28.3 vs. 37.7 min/h) and tended to increase eating time (17.5 vs. 9.03 min/h). There was also a tendency for the long-day treatment to reduce daily feed sorting. Providing supplementary light may reduce sorting and increase distribution of eating activities throughout the day, and the change in feeding pattern may be affected by the time of day the supplementary light is provided.