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

Abstract

The objective of this study was to determine risk-factors affecting increase in physical activity during estrus and pregnancy per artificial insemination (P/AI) in lactating dairy cows. Cows were monitored continuously by 2 automated activity monitors [a collar-mounted accelerometer (HT; Heatime, SCR Engineers, Netanya, Israel) and a leg-mounted pedometer (BO; Boumatic Heat-seeker-TX, Boumatic Dairy Equipment, Madison, WI)]. When an increase in activity was detected, body condition score (BCS) and blood samples were collected, ovaries were scanned by ultrasonography, and, if the cow was eligible for breeding, artificial insemination was performed. Milk production and health-related data were recorded throughout the experimental period. Pregnancy diagnosis was performed at 42 ± 7 d of gestation. Data were analyzed using Pearson correlation, ANOVA, and logistic regression. A total of 1,099 true events of estrus from 318 lactating Holstein cows were recorded, averaging 3.46 ± 1.1 events per cow. Positive predictive value for estrus episodes detected by the HT and BO systems were 89.6 and 85.5%, respectively. Mean peak activity at estrus (PA) recorded by the HT system was 71.6 ± 20.7 index-value, and 334.3 ± 155.7% relative increase by the BO system. Compared with primiparous, multiparous cows expressed estrus with lower PA (69.3 ± 0.8 vs. 75.9 ± 1.1 index for HT; 323.9 ± 6.0 vs. 354.8 ± 8.48% for BO) and shorter duration (DU; 10.7 ± 0.2 vs. 12.0 ± 0.3 h); DU was measured by HT only. Lower BCS was associated with decreased PA measured by both systems, estrus DU, and P/AI. Peak activity was weakly correlated with milk production on the day of artificial insemination (r = -0.20); however, when categorized into quartiles, the highest-yield cows had lower PA and DU. Follicle diameter was not correlated with PA or DU, but cows with greater concentrations of estradiol had higher PA. Cows with greater PA in both systems had greater P/AI than those with lower PA (36.5 vs. 24.6% for HT, 33.5 vs. 21.4% for BO). In conclusion, measurements of estrus events captured by automated activity monitors are correlated with BCS, parity, and secondary behavior signs related to estrus. Surprisingly, estrus intensity and duration were only weakly correlated with milk production, preovulatory follicle diameter, and concentrations of estradiol at estrus. Cows that had measurements of high-intensity estrus were significantly more fertile than low-intensity estrus.

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

“…Duration of activity episodes varied between 11 and 19.1 h (Table 1). Thereby, multiparous cows expressed lower intensity (Reith et al, 2014a) and peak activity (Madureira et al, 2015) as previously shown by López-Gatius et al (2005) who calculated that each additional lactation number caused a 21.4% decrease in locomotion. Negative effects of high milk production on activity were reported by Yániz et al (2006) and López-Gatius et al (2005) who observed a 20048.7 ± 0.6 (SE) HeatWatch Free-stall barn/concrete flooring Roelofs et al (2005) 11.8 10.0…”

“…Body reserves are mobilized to compensate for NEB and contribute to higher loss of BW and body condition score (BCS) (Liefers et al, 2003) which in turn affects fertility by fewer cows showing initiated estrus. In a recent study conducted by Madureira et al (2015) the BCS of an estrual cow affected significantly peak activity, as animals with BCS ⩽ 2.5 expressed less intense estrus patterns. In addition, NEB has been related to delayed resumption of ovarian activity, prolonged postpartum anestrus (Liefers et al, 2003), a greater incidence of irregular cycles (Wathes et al, 2007), decreased conception rates and increased pregnancy loss (Wiltbank et al, 2006).…”

“…Activity increases markedly in cows approaching estrus (e.g. Valenza et al, 2012;Reith et al, 2014a;Madureira et al, 2015), indicating a reliable prediction of sexual restlessness. Cows were between 2.3 and 6 times (Redden et al, 1993;Gaillard et al, 2016) as active at the time of estrusmostly defined as day 0as when not in estrus.…”

“…Activity meters using acceleration technology are attached to the neck collar of each cow (Madureira et al, 2015;Gaillard et al, 2016) and measure continuously horizontal accelerations related to upward movements of cow's head and neck during walking and mounting behavior (Reith et al, 2014a). Data present average activity shown as a general activity index which can be stored in 1-h (Gaillard et al, 2016) or 2-h intervals each day (Reith et al, 2014a;Madureira et al, 2015). Specially developed algorithms based on deviations of the current measured data from the stored activity pattern are used to separate cow's day-to-day activity from activities associated with estrous behavior.…”

Changes of locomotion activity in the Holstein dairy cows during estrus

“…The comparable results of the increased locomotion activity of Holstein dairy cows in the estrus period in comparison with the reference period before estrus were detected also by our research (32.2 %). Significantly higher differences in the locomotion activity, when comparing the period before estrus with the values of this indicator in the estrus period, expressed by the level of the locomotion activity in the interval of two hours (u/2h), were recorded by Favero (1984) and Silper et al (2015) at the level of (77.3 u/2h), or Madureira et al (2013) who detected the average cows´ activity in the estrus period at the level of 72.8 u/2h. Fundamentally different results, based on their experiments, are stated by Firk et al (2002) who did not confirm the significant growth of the cows´ locomotion activity in the estrus period.…”