In designing their herd synchronization program, Justin and Nathan Spickler credit fellow Angus breeder Troy Vollmer, Wing, ND, with sharing his experiences with synchronization and artificial insemination (AI) in his herd. Vollmer and the Spicklers have followed the Select Sync protocol outlined in the annual Select Sires AI directory.

The Spicklers typically synchronize heifers five days before the cows, and follow these steps for both groups:

  • Day 0: Administer a GNRH shot.
  • Day 5: Begin heat detection and AI, which continues for seven days.
  • Day 7: Administer prostaglandin.
  • Day 9 and 10: Majority of the cows begin to show standing heat and are AI’d.
  • Day 11 and 12: A few stragglers will cycle.

“We’ve followed this AI protocol for several years. We only AI cows or heifers with observed heats; we don’t time breed anything,” Justin says.

He reports they typically see an 85% response to the protocol from day 5 to day 12, and usually have a 70%-75% AI conception rate.  

“The result is that 60% of our calf crop is sired by AI bulls,” Justin says. Cows are put with bulls after the AI protocol is finished. “We usually average about 75% of calves born in the first 21 days, and 90% in the first 42 days, with the balance in the last cycle. With this sync protocol, we’ve switched from a 63-day breeding season to a 68-day season. As a result, we allow our cows one chance at an AI conception and three chances at natural conception with the bulls.”

The Spicklers say the grouped calving season made possible by synchronization has been a boon for management.

“We get a lot of calves in a 10-day window in late March. So, instead of 10-15 calves/day, we’ll get 15-25 calves. In early April, calving slows down for a week, allowing us time to get sale cattle ready for our May sale,” Justin explains. By mid-April, they can also turn the remaining cows and heifers on grass to calve in the pasture.

Kindra Gordon is a freelance writer based in Whitewood, SD.