Rev. Erudite Redneck, B.S., B.S., M.A., M.Div.

I swear, my inner redneck is a fifth-grader. I simply cannot read stuff like this without snickerin', and I grew up in a home where one of my earliest chores were pickin' up feed sacks and spreadin' manure from behind feed troughs onto a vegetable patch, where the calves bawled for breakfast every mornin', the bulls were the Princes of the Pasture, and the cows were ... cows ...
--ER

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Aug. 12, 2004
NEW TEST HELPS IDENTIFY FERTILE BULLS
Writer: Steve Byrns, (325) 653-4576, s-byrns@tamu.edu
Contact: Dr. Bruce Carpenter, (432) 336-8585, bb-carpenter@tamu.edu

FORT STOCKTON -- It's been said that "a bull is half the calf crop" In
reality, that varies a lot more than many realize, said a livestock
specialist with Texas Cooperative Extension.

A bull that is a fertile and active breeder may sire 80 or more calves
in a season, whereas a less fertile bull will sire only a few or even
none, said Dr. Bruce Carpenter. A good bull offers genetic merit, but
fertility is paramount to getting those genes into the herd.

Carpenter, who is based at Fort Stockton, said the need becomes even
greater in single-sire herds where the fate of an entire calf crop from 25
or more cows may depend on only one bull.

He said the "Repro Test," recently demonstrated at Texas A&M's Beef
Cattle Short-Course in College Station, may help worried cattlemen get a
bit more sleep.

"The Repro Test detects a protein in bull semen called ‘fertility
associated antigen' or FAA," said Carpenter. "All else being equal (semen
quality, healthy bulls, etc.) FAA-positive bulls are 16 percent to 19
percent more fertile than those testing negative for the protein.

"FAA positive bulls settle more cows and they do it earlier in the
breeding season. The benefit of FAA positive bulls even helps with
artificially bred females, because research has shown they require fewer
services to become pregnant."

Until this year, Carpenter said, the fertility antigen test was tedious
and required a three-day laboratory procedure. The Repro Test, however,
can be conducted "chute-side" with results being ready within 20 minutes.

"The new test uses a lateral flow cassette, which looks like a home
pregnancy test," said Carpenter. "Cassettes cost about $30 each, but a
bull only needs to be tested once for FAA in his lifetime (after puberty).

The trait is believed to be moderately heritable in male offspring."
The test does not eliminate the need for annual bull exams and
fertility tests, he said, but it does add accuracy to the conventional
breeding soundness exam.

"The FAA test is not a cure-all," said Carpenter. "There are many
factors that can and do affect a bull's fertility. Breeding soundness
exams, while not perfect, are still the best way to predict an
individual's fertility. Exams should be done each year before breeding
season. Annual exams are necessary because things like semen quality can
change, or a bull may get sick or injured, compromising his breeding
potential."

According to Carpenter, the fertility associated antigen, formerly
called heparin binding protein, was identified 15 years ago at the
University of Arizona by Dr. Roy Ax.

"His lab did all the early basic research, literally at the molecular
level," Carpenter said. "When it came time to evaluate live breeding
animals, much of that research was conducted on Texas ranches. Texas A&M
scientists collaborated with Dr. Ax's lab to conduct some of the
large-scale breeding trials necessary to prove the test's effectiveness.

"To-date, 600 bulls and 15,000 cows have been evaluated.. Their
research findings leave little doubt about the desirable qualities of FAA
positive bulls."

For more information contact an Extension office or visit
www.reprotec.us

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