Evaluating Rumination Time Changes During Estrus in Dairy Cows

This study evaluated the impact of estrus on changes in rumination over 24 h using data from the DataFlow™ II program and the Heatime RuminAct device, encompassing 634 estrous cycles of dairy cows. During the reference period, three days before estrus, cows spent an average of 511 min per day ruminating. One day before estrus, the total rumination time decreased to 503 min per day. During estrus, rumination time further decreased to 481 min, reflecting a reduction of 31 min per day (6.2%) compared to the pre-estrus reference period. After estrus ended, we observed an immediate increase in rumination time, with post-estrus levels comparable to pre-estrus values. Using a linear model, we assessed the influence of the herd and individual cows on changes in rumination time during estrus compared to the reference period. Our findings confirm the notable impact of estrus on rumination in dairy cows. The reduction in rumination time was most pronounced in heifers (−66 min, −13%), followed by first-lactation cows (−36 min, −7%) and multiparous cows (−16 min, −4%). The influence of the lactation stage was significant, with cows in early lactation showing a greater reduction in rumination compared to cows in later stages. Additionally, high-milk-yielding cows exhibited slightly lower rumination times during estrus, reflecting the interplay between diet composition and energy demands. These results underscore the role of parity, lactation stage, milk yield, and individual differences in shaping rumination behavior during estrus. Behavior-monitoring systems proved valuable for detecting estrus and managing reproduction in dairy herds. Our results showed a notable 6.2% reduction in rumination during estrus, highlighting its potential as a reliable indicator in regions like Slovakia, where economic challenges impact dairy farming sustainability.