Authors: Dr. Ronaldo Cerri (University of British Columbia) and Meagan King, (Postdoc, University of Guelph)
Why are automated activity monitors (AAM) becoming more popular on Canadian dairy farms? DFC-funded research has shown that AAM can work just as well as synchronization programs while also predicting which cows will have better fertility.
Neck collars or leg pedometers are currently used on 10% of Canadian dairy farms as their main strategy for reproductive management (>50% of inseminations). Visual heat detection and timed AI are still used more than AAM, but this may change as hormone use is further scrutinized.
Two large field trials in Ontario and BC (funded by the Dairy Research Cluster 2, supervised by Dr. Ronaldo Cerri at the University of British Columbia and students Tracy Burnett, Augusto Madureira, and Liam Polsky) found that reproduction programs using AAM for heat detection are equally efficient as those relying heavily on synchronization protocols.
Breeding cows based on AAM data had similar pregnancy per AI and days open compared with a strict timed AI program (Presynch-Ovsynch). With goals to improve heat detection accuracy and the use of AAM data to make farm-level management decisions, Dr. Cerri’s research group studies how estrus events and intensity are related to ovulation, ovarian/uterine function, fertility, and performance in dairy reproduction programs.
The researchers also found that cows with high intensity heats and large changes in activity (during spontaneous and induced estrus) had greater pregnancy per AI and better fertility, compared to cows with low intensity heats who had more ovulation failure. Moreover, the top 25% highest-producing cows had heats with the lowest intensity and shortest duration. Older cows, those with low body condition, and those experiencing high temperature-humidity indices (above 65) showed less estrus behaviour as well.
In the BC field trial, each individual farm was a big source of variation in the performance of programs based on heat detection, likely because AAM are more prone to individual farm variations compared with established timed AI protocols. This means that the best reproductive program for each farm may differ based on their specific strengths, particularly whether they can better use AAM or injection-schedules properly and consistently. Anovular cows and those with poor leg health can also impair the performance of AAM reproductive programs.
Ultimately, differences in attitudes and preferences among Canadian dairy producers (highlighted in a nationwide survey by José Denis-Robichaud) should be considered when choosing the optimal reproduction management tools. For example, producers have differing views about reproduction hormones in terms of profitability and long-term effects on fertility. However, for farms already reaching 30 to 35% conception rates from breeding at estrus, doing that will still be more profitable than completing full synchronization protocols.