Determinants of estrous behavior in lactating Holstein cows

Area of Science:

• Animal Science
• Reproductive Biology
• Behavioral Science

Background:

• Estrus expression is crucial for successful artificial insemination in dairy cattle.
• Understanding factors influencing estrus detection is vital for optimizing herd reproductive performance.
• Previous research has explored various physiological and environmental factors affecting estrus.

Purpose of the Study:

• To investigate the impact of environmental surface and physiological factors on estrus expression in lactating Holstein cows.
• To determine the influence of postpartum interval, season, and milk yield on estrous behavior.
• To assess the effect of observation surface (dirt vs. concrete) on estrus duration and activity.

Main Methods:

• Ovariectomized Holstein cows were repeatedly challenged with progesterone and estradiol benzoate to induce estrus.
• Estradiol benzoate injections were administered following a progesterone pessary removal to synchronize estrus.
• Estrous behavior was observed at 8-hour intervals on both dirt and concrete surfaces, with a minimum of three cows observed together.

Main Results:

• Standing and mounting behaviors were not significantly affected by postpartum interval, season, or milk yield.
• Mounting behavior showed an increase from the first to the sixth estrus challenge.
• Estrus duration, mounting activity, and standing activity were significantly greater on dirt surfaces compared to concrete surfaces.

Conclusions:

• The surface on which cows are observed has a profound effect on estrous behavior expression.
• Postpartum interval, season of year, and milk yield appear to be of minor importance in influencing estrus expression under these experimental conditions.
• Optimizing observation surfaces could enhance estrus detection rates in dairy herds.