Short communication: Chronology of different sexual behaviors and motion activity during estrus in dairy cows.

In studying the efficiency of a variety of methods for estrus detection in a large dairy herd, we suspected a definite sequence of estrus signs. Consequently, we observed a subset of animals continuously between 0400 and 2400 h, making a note of the precise timing and frequency of each sexual behavior. Sixteen Holstein-Friesian cows, >20 d postpartum, were equipped with motion activity-sensing neck collars and had milk progesterone profiles monitored simultaneously. The duration between the first and last observed estrus behavior was (mean ± SE) 14.0 ± 1.9 h, with a range 8.5 to 28.75 h. The duration of standing to be mounted (STBM) was 4.68 ± 1.49 h, with a range of 0.25 to 18.25 h. Sniffing the vulva of another cow occurred on average 5.5 ± 1.3 h (range = 0.25-18.25 h) before the first STBM. By ranking the first appearance of each behavior, we established that sniffing was followed by the active behaviors of mounting another cow and not accepting a mount, as well as the passive behaviors of being sniffed and STBM by another cow. Chin resting occurred before not accepting a mount and STBM. All these behaviors were observed in the reverse order after the last STBM. The mean profile of motion activity revealed an increase in motion activity with the onset of exploratory behaviors, and highest values occurred within the period of STBM. Such distinct behavioral sequences may be controlled by changes in peripheral progesterone and estradiol concentrations, as well as by subtle independent mechanisms via pheromones in differing concentrations or divergent composition.

Association of production diseases with motor activity-sensing devices and milk progesterone concentrations in dairy cows.

We have previously established that the efficiency of identifying oestrus with activity-sensing devices can be compromised by common production diseases; the present study was undertaken to determine how these diseases may affect device readings. A total of 67 Holstein-Friesian cows, >20 days postpartum, were equipped with activity-sensing neck collars and pedometers, and simultaneous milk progesterone profiles were also monitored twice a week. The influences of common production stressors on maximum activity and progesterone values were analysed. Approximately 30% potential oestrus events (low progesterone value between two high values) remained unrecognised by both activity methods, and progesterone values in these animals were higher on the potential day of oestrus when both activity methods did not detect an event (0.043 ±â€¯0.004 versus 0.029 ±â€¯0.004 ng/mL; P = 0.03). Data from a subset of 45 cows (two events each) were subjected to mixed models and multiple regression modelling to investigate associations with production diseases. Cow motor activity was lower in lame cows. Maximum progesterone concentrations prior to oestrus increased as time postpartum and body condition score (BCS) increased. There were also fewer days of low progesterone prior to oestrus associated with increases in BCS and maximum progesterone concentrations prior to oestrus. In conclusion, lameness was associated with lower activity values, but this suppression was insufficient to account for lowered oestrus detection efficiency of either device. However, associations were identified between production diseases and progesterone profiles.