Pregnancy rate improves when you use visual heat detection and timed AI, says research from Florida and Wisconsin.

Some people believe that timed AI programs don't work very well in heifers, says Carlos Risco, of the University of Florida's College of Veterinary Medicine.

However, research conducted in Florida and Wisconsin shows that when you use visual heat detection with OvSynch or a modified OvSynch timed AI program, fertility is not affected in heifers. Similar to lactating dairy cows, the advantage of a timed AI program in heifers is that AI submission occurs sooner during the breeding period.

With the use of OvSynch for timed AI, you give a shot of GnRH on day one, a shot of prostaglandin on day seven, a second shot of GnRH on day nine, and then you breed 16 to 20 hours later. However, any heifer that shows visual signs of heat after the prostaglandin shot should be bred that day. Heifers that don't show visual signs of heat should continue on with timed AI, and are bred on day 10.

When you use visual heat detection and timed AI together, says Risco, pregnancy rate improves when compared to breeding on detected heat alone without the use of OvSynch. Florida researchers are now trying to determine the optimal protocol for timed AI in heifers.

Source: Carlos Risco, Universityof Florida