Comparison of visual and computerized estrous detection and evaluation of influencing factors

The aim of this study was to compare the automatic estrous detection system (AED) Heatime® with visual estrous detection (VED). The study was conducted on 139 Holstein Friesian cows in one dairy herd in Northern Germany. The cows were fitted with activity collars from d 21 postpartum until d 40 of gestation and a 30-min visual estrous observation was conducted three times a day. In addition, as a separate part of the VED, estrous detection by exclusive consideration of standing estrus (SE) was investigated. Ovulation detected by regular trans-rectal ultrasonography and serum progesterone analyses served as gold standard to calculate estrous detection rate (EDR) and reliability rate (RR) for each of the three estrous detection systems (AED, VED and SE). Change in body condition antepartum and postpartum, lameness, milk yield and milk fat- milk protein- ratio (FPR) on the expression and detection of estrus were investigated. Estrus was more precisely detected by the AED (EDR: 85.1%) than by VED (EDR: 52.2%) and SE (EDR: 22.3%) (P < 0.05). The RR when using the three methods did not differ (P > 0.05). Changes in body condition, lameness, milk yield or the FPR were not associated with the estrous detection rate by the AED. The estrous detection rate by VED in lame animals (EDR: 24.2%) was, however, less than in cows without any lameness (EDR: 52.7%; P < 0.05). In conclusion, the AED Heatime® system can be effectively used for estrous detection and can be used to more precisely detect estrus than with VED.