There are a number of different ways to get heifers bred quicker once they are moved into a breeding pen, says Vance Kells of Circle Bar Heifer Ranch in Satanta, Kan. Here are some of the strategies that he uses:
- Feed MGA (melengestrol acetate) to heifers for 14 days. Seventeen days after the last day of MGA feeding, give a prostaglandin shot. Watch for heats and breed accordingly. Use timed-AI 72 hours after the prostaglandin shot on any heifers that were not artificially inseminated off of an observed heat.
- Use a CIDR (a progesterone-releasing insert) in conjunction with a shot of GnRH on day 1. Follow that with a shot of prostaglandin on day 7. Watch for heats and breed accordingly, then use timed-AI on the remaining heifers 72 hours later.
- Give a prostaglandin shot on day 1; watch for heats and breed for the next 96 hours. Ten days later, give another prostaglandin shot to animals that are not bred.
- "Walk and chalk" animals in the breeding pen daily for 10 days. Breed off of natural heats. On day 11, give a shot of prostaglandin to any heifers that are not yet bred.
"On our heifer ranch we have done all of the above," Kells says. "For the last five years we have been using option #4. It fits our time frame the best."
Kells says he has had great success using this approach, with 98-99% of all heifers bred within the first 17 days of being in the breeding pen.
"All of the above programs work," he says. "It just depends on which shot schedule (you use) or how aggressive you want your AI program to be."
Kells will give a virtual tour of Circle Bar Heifer Ranch at the 2012 Dairy Calf & Heifer Conference, March 20-21, in Visalia, Calif. The general session is sponsored by Pfizer Animal Health. To register for the conference, click here.