The objective of this study was the evaluation of the locomotion activity of heifers and Holstein dairy cows during estrus. We have analyzed the locomotion activity using the Heatime RuminAct device on 180 cows (32 heifers and 148 dairy cows) and we evaluated a total of 633 estrus cycles during the reference period of 3 days before estrus, 3 days after estrus, and on the day ofestrus occurrence. The datawere analyzed using the DataFlowTM II program. The locomotion of cows was expressed in the units of locomotion activity in 24 h (u.24 h⁻¹). During the reference period of 3 days before estrus, the cows showed locomotion activity of 558 u.24 h⁻¹, with an increase in locomotion activity on the day of estrus of 836 u.24 h⁻¹, and, during the reference period of 3 days after estrus, the level of locomotion activity decreased to 537 836 u.24 h⁻¹, which is a similar level of locomotion activity to the reference period before estrus. Through the statistical analysis, we evaluated the impact of parity, lactation stage, milk yield, and individuality on changes in locomotion activity during estrus and throughout the reference period, and we found a significant effect of parity (F = 13.41, p < 0.001) on changes in the locomotion activity of dairy cows during estrus. Based on these results, this research offers fresh perspectives on assessing specific factors affecting the locomotion activity of dairy cows during estrus through the practical application of electronic systems for estrus detection on dairy farms.

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.

The study aimed to explore if milkability parameters could reliably predict the dimensions of teat structures and their milking-induced changes. Ultrasonography repeatedly measured the teat structures of 48 Holstein cows from mid to late lactation. We found that milking-induced changes in each structure are affected by different milkability parameters. Regression models for teat canal change and length change were significant, and variability was found to be 46.03% and 21.50%, respectively. Similarly, the teat structure’s dimensions significantly affected milkability parameters, which differed for each structure. However, regression models only explained between 3.36% (teat length) and 7.59% (cistern) of variability. The prediction potential, performed based on milkability, is limited if the initial dimensions of structures are not provided. If teat dimensions were measured at the beginning of the production life, automatically collected milkability data could be used to calculate milking-induced changes incurred with each milking and the development of teat dimensions over the production life. If perfected, this tool could provide alerts about critical milking-induced changes and risky teat conformation traits, as they have a proven effect on udder health and are reliable indicators of milking effectiveness.