Synchronized cattle breeding has long been ignored because of the time and effort it requires, but researchers at the University of Guelph’s Ontario Veterinary College believe it’s worth it. Now, they’re trying to prove it.

Prof. Walter Johnson, Department of Population Medicine, is working with DVSc student Alejandro Estrada to test various techniques of using controlled internal drug-release devices (CIDRs) to synchronize beef cattle breeding. The researchers want to determine the most effective method and timing for the process that gives farmers the best results with minimal hassle.

"Synchronized breeding is typically associated with a lot of work for beef farmers, because they have less intensive herd management and must round up the cows each time they treat them," says Johnson. "But it does have the potential to save farmers both time and effort."

Johnson says synchronization can help beef farmers achieve pregnancy in their cows’ short 60-90 window by making all cows receptive at the same time, eliminating the work associated with estrus detection. Instead of putting a bull into the pasture for the entire duration, breeding attempts can be funneled into a few days. Synchronization also makes artificial insemination a lot easier, offering access to superior genetics from better bulls.

But using CIDRs to synchronize ovulation can be time consuming too, because the herd must be rounded up more often to give treatments. So, Johnson and Estrada are working to find ways to make the process easier.

They looked at several variables to determine the most effective way to synchronize breeding. They varied the frequency of handling the animals for treatment, tested spring- and fall-breeding cows, and used different hormone combinations. In all cases, the estrous cycle was artificially reduced from 21 days to nine days (the cycle CIDRs work on). The nine-day cycle reduces the amount of hormone treatments needed and has no effect on the cow’s health or reproductive abilities.

The researchers found all test treatments produced conception rates of 63 to 90 per cent in a single artificial insemination attempt. That’s better than most synchronization programs and comparable to traditional method of natural service.

Results also show that cows need to be handled fewer times for treatment than originally predicted. This means fewer treatments and less rounding up is required, and the cows experience less stress.

In this study, cows were run through treatments three to five times, with all methods proving to be equally effective. No significant differences were found between breeding seasons, protocols used, or initial body weights of cows.

A complete analysis of the costs associated with using CIDRs and artificial insemination for beef farmers is still to come, but Johnson expects it will be an economical alternative to traditional insemination in the near future.

"Artificial insemination and breeding synchronization offer huge advantages for beef farmers," says Johnson. "It takes farmers a lot less time and effort to get a very good conception rate."

This research was sponsored by the Ontario Cattlemen’s Association and the Ontario Ministry of Agriculture, Food, and Rural Affairs.

The CIDRs were donated by Vetrepharm and some hormones were provided by Pharmacia and Upjohn.