Characterization of Pelvic, Foot and Tail Biometrics Using 3D-Kinematic Analysis during The Proestrus-Ovulation Period in Naturally Cycling Primiparous Dairy Cows Housed in a Tie-stall System

ABSTRACT The objective of this study was to investigate 3D-kinematics as a method for determining if primiparous dairy cows display differences in behaviour biometrics during the estrus period as ovulation approaches in a tie-stall system. The second objective was to evaluate the accuracy of behaviour biometrics as estrus alerts. Fourteen primiparous dairy cows (n = 14) were studied as part of a split-plot over time design. 3D-kinematic assessment took place during proestrus-estrus-ovulation period, Follicular diameter, corpus luteum (CL) diameter and estradiol (E2) concentrations served as physiological parameters to indirectly estimate the estrus period (d -1). The frequency of Pelvic tilts, Pelvic shifts left (Pelvicsl), Pelvic shifts right (Pelvicsr), Total pelvic shifts; TPelvicS), Foot strikes left (Foot strike L), Foot strikes right (Foot strike R), and Total feet strikes (TFootS) were recorded. Additionally, the frequency of Micro tail left (TailLMicro), and right (TailRMicro) movements, Middle tail left (TailLMid), and right (TailRMid) movements, Macro tail left (TailLMacro), right (TailRMacro) movements were also recorded. The overall length of estrous cycle in primiparous dairy cows in this study was 21.66 ± 3.09 (LSMeans ± SEM days). The largest Follicular diameter (LSMeans ± SEM; 17.04 ± 0.59 mm) and E2 (17.43 ± 1.76 pg/mL) occurred 24 h before ovulation. The frequency of some behaviour biometrics increased (LSMeans ± SEM Events/5min) at d -2 including Pelvic tilts (19.75 ± 8.67 Events/5min), Pelvicsl (20.26 ± 13.64), and TPelvicS (20.82 ± 8.79) compared to baseline (d -4, Pelvic tilt; 13.10 ± 8.32, Pelvicsl; 3.71 ± 2.52, and TPelvicS; 6.34 ± 2.72). Other significant patterns observed include a decrease at d -1 in the frequency of TFootS (9.86 ± 1.98), TTailMicro (7.30 ± 3.62), TTailMid (1.82 ± 1.01), and TTailMacro (1.66 ± 1.01) movements followed by an increase in frequency at d -4 (TFootS; 14.44 ± 2.78, TTailMicro; 14.57 ± 7.23, TTailMid; 6.07 ± 3.27, and TTailMacro; 1.84 ± 1.12). The accuracy of each behaviour biometric as a potential estrus alert was analyzed using J index values with balance sensitivity – specificity (J index, Se–Sp) levels (ROC curves analysis). Feet strikes had the greatest accuracy (0.50; 0.90-0.6) followed by Pelvic tilts (0.37; 0.78-0.59), Foot strikes L (0.33; 0.44-0.89), TailLMid (0.30; 1.00–0.30), TailLMacro (0.41; 1.0–0.41) and TFootS (0.34; 0.67-0.68). Our results indicate that naturally cycling, primiparous dairy cows housed in tie-stalls exhibit behavioural fluctuations such as the estrus period approaches, which can be used as estrus alerts.