The relationship between activity clusters detected by an automatic activity monitor and endocrine changes during the periestrous period in lactating dairy cows

Abstract

The aim of this study was to determine the relationship between observed estrous-related behavior, activity clusters (AC; detected by automatic activity monitor), endocrine profiles, and ovulation time. Twenty-one cows in estrus (after 2 cloprostenol treatments, 11 d apart) and 12 nonsynchronized cows, to establish Heatime (SCR Engineers Ltd., Netanya, Israel) herd baseline activity, were enrolled. Cows had Heatime monitors applied 3 wk before the trial to establish their own baseline activity level. Cows in standing estrus had ultrasonography and phlebotomy carried out every 4 h to determine dominant follicle size, endocrine profiles, and ovulation time. After ovulation, these procedures were repeated once on d 3 to 6. Heatime alerted estrus in 90% of cows, and incorrectly alerted 17% of AC. The mean±SEM duration for standing estrus was 9±1 and 13±1 h for estrous-related behavior. Estrous-related behavior began after the start of the proestrous estradiol-17β (E2) increase (59±6.5 h). Cows with longer durations of raised proestrous E2 had longer intervals from its onset to the start of standing estrus and AC. The AC duration increased with longer durations of estrous-related behavior. Higher peak E2 occurred with longer standing estrus and estrous-related behavior. As E2 concentration decreased after the peak, 90% of cows still had estrous-related behavior. Duration of estrous-related behavior increased with higher average E2 concentration during the last 8 h before the start of the LH surge. During this surge 90% of cows had all of their standing estrus. As yields increased, so did the magnitude of the preovulatory FSH surges. Higher surges occurred with shorter standing estrus and estrous-related behavior. Cows with shorter LH surges had longer standing estrus. Peak LH preceded the AC peak (6.6±0.8 h). Duration of overlap between the AC start and the LH surge end ranged between 0 and 14 h; 1 cow had none. No association was found between the AC characteristics with the E2, LH, or FSH profiles. In conclusion, the relationship between the timing of the E2 increase and estrous activity may be mediated by other factors (GnRH surge). Estrous-related behavior, but not endocrine profiles, was related to AC duration. Timing of standing estrus during the LH surge ensures that mating allows sperm maturation before ovulation. Based on the interval from the start of an AC to ovulation (27±1 h), the optimum time to artificial insemination is, on average, between 9 and 15 h after the AC start.

Factors affecting expression of estrus measured by activity monitors and conception risk of lactating dairy cows

“…The true episodes were verified from ovarian structures and are in agreement with recent studies reporting 72 (Aungier et al, 2012) and 90% (Aungier et al, 2015) PPV of estrous detection using the same technology (HT). At-Taras and Spahr (2001) found a similar PPV for a pedometer system.…”

“…In spite of the differences in estradiol concentrations found when cows were divided in categories by estrus activity, the PA measured by both AAM systems was only weakly correlated with concentration of estradiol in plasma. A recent study by Aungier et al (2015) observed no correlation between activity clusters measured by AAM and FSH, LH, and estradiol profiles. However, a greater peak concentration of estradiol in plasma was in fact associated with standing and estrusrelated behaviors.…”

“…The expression of estrus behavior is triggered by high concentrations of estradiol-17β produced by the preovulatory follicle (Allrich, 1994;Forde et al, 2011). It is reasonable to assume based on this and other studies (Walker et al, 2008;Aungier et al, 2015) that some level of dependence exists between PA at estrus and estradiol concentrations in plasma, but the influence of other risk factors is probably greater than previously thought. One factor that has not been addressed in this or previous studies is the effect that sampling at random times of the day may have on estradiol concentrations, considering the acute changes in ovarian steroid concentrations observed in postprandial periods (Vasconcelos et al, 2003).…”

Review: Behavioral signs of estrus and the potential of fully automated systems for detection of estrus in dairy cattle

“…Ovarian functions (follicle development, ovulation, luteinisation and luteolysis) are regulated by endocrine hormones secreted by the hypothalamus (gonadotropin-releasing hormone (GnRH)), anterior pituitary (FSH and LH), ovaries (progesterone, estradiol and inhibin) and the uterus (prostaglandin F2 α (PGF2 α )) (Aungier et al, 2015). Elevated concentrations of estradiol secreted by the pre-ovulatory follicle in turn promote a GnRH surge and allowwhen progesterone levels are lowthe expression of behavioral estrus and the release of LH to cause ovulation ( Figure 1).…”

“…Data are read by an antenna and automatically transferred via IR signal to the herd management software providing lists and graphs to control reproductive (and health) status of individual cows (Reith et al, 2014a) (Figure 2). Aungier et al (2015) showed that the start of estrus-related behavior was 6 h before the start of an activity cluster recorded by Heatime ® (SCR Engineers Ltd, Netanya, Israel) and finished 3 h after the start of the activity cluster. In their investigation the system alerted estrus in 90% of cows and incorrectly identified 17% of the total number of clusters.…”