Some abstracts do not have video files because ASAS was denied recording rights.
1258
Estrus detection intensity and accuracy, and optimal timing of insemination with automated activity monitors for dairy cows
The objectives were to assess: the ability of automated activity monitoring (AAM) to detect estrus for first insemination; the accuracy of detection; and the optimum interval from the onset of estrus to insemination. Four commercial farms were studied over 1 year; 2 employed the AfiAct (Afikim) system and 2 the Heatime HR (SCR Inc.) system. Cows were inseminated between 55 and 80 DIM based on AAM only, then supplemented with timed AI (TAI). Blood progesterone was measured in 1014 cows at weeks 5, 7, and 9 postpartum; purulent vaginal discharge (PVD) was assessed at week 5 and lameness and BCS at week 7. Overall, AAM detected 83% of cows in estrus by 80 DIM. Cows that had 3 serum P4 < 1 ng/mL, had PVD, or were both lame and had BCS ≤ 2.5 were less likely to be detected in estrus by 80 DIM (62, 68, 53%, respectively). Blood samples were collected on the day of 445 AI based on AAM and 323 TAI. The proportion of cows not in estrus (P4 > 1 ng/ml) on the day of AI was similar (P = 0.35) between AAM (4 ± 1.8%) and TAI (3 ± 1.2%). Activity data were extracted from AAM software for 1454 AI. Onset of estrus was calculated using the same (AfiAct) or similar (for the proprietary SCR algorithm) criteria as the AAM system. Producers recorded the time of AI. The interval from onset of estrus to AI was categorized as 0 to 8, 8 to 16, or > 16 h. There was no effect of AAM system on the probability of pregnancy per AI, but there was an interaction of interval with parity. For multiparous cows, the probability of pregnancy per AI was 31%, which did not differ (P = 0.7) with the interval to AI. For primiparous cows, the odds of pregnancy were greater if AI occurred 0 to 8 h (49%) than 8 to 16 h (36%) or > 16 h (31%) after the onset of estrus. AAM can detect estrus for first AI in just over the length of 1 estrus cycle for over 80% of cows, but the remainder would likely require intervention. For multiparous cows, performing AI based on AAM once per day would not affect pregnancy per AI, but for primiparous cows AI within 8 h of the onset of estrus may be advantageous.
Keywords: reproduction, management