Convenient, efficient and tight breeding of a cowherd has become much more feasible with the advent of timed artificial insemination (TAI), says David Patterson, University of Missouri (MU) Extension beef specialist.

MU researchers have led the nation in perfecting breeding protocols for heifers, which always have been more difficult to breed, Patterson says.

“We now have a 14-day protocol accepted nationally for use with heifers. The protocol, Show-Me Synch, can jump-start pre-pubertal heifers,” he says.

The protocol uses a CIDR (controlled internal drug release), a vaginal insert containing the natural hormone progesterone, which controls the breeding cycle. The CIDR protocol replaces MGA, a synthetic hormone that imitates progesterone and is mixed in feed rations.

A comparison study with more than 400 heifers at Circle A Ranch at Lineville, IA, showed that CIDR brought 92% of heifers into heat, compared with 85% when fed MGA ration. This ranch had long success getting heifers to eat the right amount of MGA ration; first-time users of MGA rations are rarely that successful, he says.

“You just get a lot more for your buck when using the CIDR protocol,” Patterson says.

Approved TAI protocols for 2010 are included in the back of all AI stud catalogs. “Just make sure you are looking at the current protocols. They change year to year,” Patterson says.

“When you use TAI, you also cut work at calving time,” Patterson says. While not all calves are born on one day, they will arrive within about 10 days, reducing the time spent checking cows at night.

“Synchronization facilitates TAI but also allows more cows to conceive earlier in the breeding season,” he says.

In field demonstrations with 7,000 cows in 70 herds, the conception rate on the first day of the breeding season averages 62%, he reports. Most cows missed on the first breeding day are bred in their next heat, 21 days later. That concentrates more than 90% of the cows into a three-week season.

Research at the MU Thompson Farm, Spickard, MO, shows TAI steadily moves average calving dates earlier each year, even in a well-managed herd artificially inseminated for years. Those extra days early in the season means more pounds of calf at weaning time.

Patterson says TAI allows owners of even small herds to use the top bulls in the nation available through AI stud services that sell semen. Those bulls have proven records on traits that are needed in a cow herd.

“If you go to the time and trouble to synchronize and AI your cows, use the tested bulls with proven records with high accuracy,” he says.

The bottom line is that bringing better genetics to the farm increases the value of the calves, and eventually the cow herd, he says.
-- MU news release