UTICA, Ill. — Synchronizing cows can help cattlemen control
their calving season.
“We want the cows to show estrus at a period of time, so you
can breed them within a specific time,” said Teresa Steckler, University of
Illinois Extension commercial agriculture specialist.
“By synchronizing, you can concentrate your labor, time when
you’re going to A.I. and have them all bred at one time,” Steckler said at “The
Keys to Profitability and Sustainability in a Changing Beef Industry” meeting
sponsored by the U of I Extension.
“I find it astounding that A.I. has been around since the
early ‘60s, but today we only have about 15 percent of our cow-calf operations
using A.I,” she said. “I understand some guys don’t have the facilities, but you
can synch the girls, use a bull and tighten up your calving season.”
Utilizing a synchronization program will cost some money,
and every protocol behaves slightly different.
“Not every cow will respond the same,” the specialist noted.
“And consider your labor and determine if you have time to heat check or if you
want to A.I. all the females at once.”
The body condition score of the females is very important
for these programs.
“Cows with less than 4 to 4.5 body condition score will have
a 10-percent decrease in pregnancy rates, so you need to make sure your cows are
in good shape.” Steckler said.
No one synchronization program is perfect for every herd.
“That’s why we’re always doing research to make them
better,” she said.
A University of Kentucky study compared the value of calves
from an estrus synchronization program and A.I. to a natural program.
“The percent of calving in the first 30 days is probably the
most important number, and the A.I program was 85 percent versus the natural at
62 percent, or a 23-percent difference,” Steckler said. “And the weaning age is
10 days greater for the A.I calves, and that’s at least 20 pounds.”
Therefore, cattlemen can gain money by utilizing an estrus
synch and A.I. program. The calf weight weaned per cow exposed was 508 pounds
versus 399 pounds for the natural program.
“If you have 109 additional pounds of calf weaned per cow
exposed, at $1.45 per pound, that’s an additional $158,” Steckler said. “Minus
$16 for the cost of A.I., that’s $142 of added value.”
Cattlemen have several options for using A.I. — heat
detection, heat detection and timed A.I. or timed A.I.
“I hate heat detecting, so I like timed A.I., but there’s
several things you need to take into consideration,” Steckler said. “It depends
on your goals. A CO-Synch plus a CIDR will cost $23 to $27, but you can do one
shot of prostaglandin and watch for estrous, and that’s $2.50 to $3.”
Timed A.I. programs are advantageous because they reduce the
cost of labor and cattlemen can manage animals in groups instead of
“Don’t use a cow protocol for heifers, and don’t use a
heifer protocol for cows because there is a big difference in the timing,” she
“The Ovsynch program is not used in the beef industry very
much. It is primarily a dairy program.
“The CO-Synch seven-day program plus CIDR is probably the
most widely used program in the beef industry, and it works very well,” Steckler
“I like the five-day CO-Synch plus CIDR. “I’ve been working
with a producer in southern Illinois, and he achieved a 75-percent pregnancy
rate on 3 year olds two years in a row.”
Research shows using a CO-Synch program when cows have a 4.5
or less body condition score results in a 30-percent pregnancy rate; from 4.5 to
5 score, a 41-percent rate; and 5.5 or greater, pregnancy rates of 59 percent.
“That’s a 29-percent difference in the A.I. conception rate.
We can’t afford that kind of loss,” Steckler said.
There are two major differences between a five-day and
seven-day CO-Synch program.
“The CIDR is only left in five days, but you have to run the
females through the chute twice for the second prostaglandin shot,” Steckler
“I took a guy in southern Illinois with a 62-cow herd from a
90-day calving season to a 60-day the first year. The second year, it was down
to 55 days, and third year a 45-day calving season, with one shot of
prostaglandin and a bull.”
For natural breeding, Steckler recommends one mature bull
for every 25 to 30 cows.
“We run three sets of two bulls, and we leave them in with
the cows for no more than two weeks at a time,” she said. “We use one young bull
and one old bull, and the bulls always have a two-week rest interval.”
Steckler provided data from a Virginia herd that included
640 cows that had spring and fall calving.
“This herd was synchronized, and they used A.I. for multiple
generations. The calf crop was retained through harvest, only A.I.-sired heifers
are maintained as replacements and cleanup bulls have excellent (Expected
Progeny Differences), but low accuracies,” she said.
The farm used the Ovsynch protocol and divided the herd into
four groups — A.I. sired crossed with A.I. sired dam, A.I. sired crossed with
non-A.I. sired dam, natural sired crossed with A.I. sired dam and natural sired
crossed with non-A.I. sired dam.
“The things that really stand out to me are the calves that
were natural sired and crossed with non-A.I. sired dam were on feed 189 days and
61 percent graded choice versus the calves that were A.I. sired and crossed with
A.I. sired dam were on feed 170 days and 97 percent graded choice,” the
specialist said. “If you’re paid on the grid, that’s quite a bit of difference —
$797 versus $972 per calf.”
In addition, A.I. sired calves born to dams that were
products of A.I. returned 22 percent more to the ranch in calf value compared to
natural service calves from nature service dams, Steckler added.