Estrus Detection Intensity and Accuracy, and Optimal Timing of Insemination with Automated Activity Monitors for Dairy Cows

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LeRoy, Craig
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University of Guelph

This thesis was conducted to evaluate automated activity monitors (AAM) for estrus detection and to identify the time interval after activity alert that optimizes pregnancy risk. A study was conducted on four dairy farms using one of two AAM systems for inseminations before 80 days in milk (DIM). Activity monitors identified 83% of cows in estrous by 80 DIM. Anovular or multiparous cows, cows with purulent vaginal discharge, or lame cows with body condition score ≤ 2.5 had higher odds of not being detected in estrus by 80 DIM. In a sample of inseminations based on AAM, only 3% were not in estrus based on serum progesterone concentration. The probability of pregnancy was higher for primiparous cows inseminated 0 to 8 hours after AAM alert but was not different for multiparous cows inseminated 0 to 8 h, 8 to 16 h or 16 to 24 h after AAM alert.

Activity Monitors, Estrus Detection