Better heifer breeding

John Barnhart knows time is money in today’s cattle business. That’s why the Vienna, Mo., cattleman values breeding technology like fixed-time artificial insemination (FTAI).

“Fixed-time AI gives us the opportunity to get in there and breed a lot of females in a hurry,” Barnhart says. “And, the labor savings is tremendous. It’s one of those things where we can go in and literally be done [breeding] in about two days.”

An AI program without estrus synchronization could take 20-25 days. “It certainly eliminates a lot of headaches,” Barnhart says, “and, really gives us an option to increase the genetic base for our cattle herd. Plus, it improves the quality of our cow herd. It’s just been a tremendous difference in our whole operation.”

Barnhart works closely with University of Missouri Extension beef specialist Professor Dave Patterson, as well as Genex Cooperative, in establishing the right fixed-time AI protocol for his operation.

Fixed-time AI protocols allow all cows in a herd to be bred in one day. Proven AI sires add quality, while timed breeding adds uniformity to the calf crop.

Cows and heifers call for different synchronization protocols. Traditionally, heifers cause more management problems by way of reduced fertility, increased dystocia, greater nutrient needs and longer post-partum intervals. However, a new 14-day protocol involving split-time AI works best for most heifers.

Research conducted by Patterson and MU graduate assistant Jordan Thomas examined the timing of gonadotropin releasing hormone (GnRH) administration with split-time AI (STAI) following controlled internal drug release (CIDR)-based protocols to synchronize estrus and ovulation in beef heifers and cows.

According to Patterson, postponing AI and GnRH administration for heifers that fail to show heat by 66 hours allows more time for ovulation before insemination and might also minimize fertility differences between bulls. The technique allows more heifers and cows to exhibit estrus before insemination, as determined by activation of an Estrotect heat detection aid, applied at prostaglandin.

Patterson says GnRH administered at AI is not necessary for heifers that express estrus prior to 66 hours.

GnRH administration can be done concurrently with AI at 90 hours for heifers that fail to express estrus. Patterson says it is likely that improvements in pregnancy rates are due primarily to expression of estrus during the 24-hour delay period.

“If you use STAI, it can essentially maximize the proportion of the females that show estrus prior to being inseminated, and you end up getting pregnancy rates that are very similar to estrus detection protocols,” Patterson says.

Compared to FTAI protocols, Patterson says pregnancy rates are about 5% higher with the STAI approach. “You also have the confidence of knowing what your estrus response actually is at the time of breeding,” he says.

And with no GnRH being administered to heifers that express estrus by breeding, the STAI approach actually offers a cost savings to producers.

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