In 1984, Lynn Brewer was pictured in the April issue of Progressive Farmer magazine with his gray quarter horse mare, Roanie. At the time, he was cattle manager at Oak Hill Farm, a 1,500-cow commercial operation in Leesburg, Georgia.
The article talked about how Brewer used one injection of prostaglandin to synchronize herd cows, as well as 500 replacement heifers, and then bred them by artificial insemination (AI). At that time, this was new technology, and Brewer was an early adopter.
Times have changed a little. Today, Brewer partners with a sorrel -- this one named Dot -- from the same home-bred family as Roanie. He rides herd at Wil-Mil Farms, a 490-cow purebred Angus operation in Georgia. At 76, Brewer admits to moving a little slower. But, he's still focused on practices that pay, including AI and herd synchronization, which he and herd owner Henry Griffin rely on today just as much as he did in 1984.
Back in the day, at Oak Hill, Brewer says he saw how synchronization helped the crossbred herd.
"A bunch of calves were born during the first part of the season thanks to that technology," he notes. "We didn't have to stay up as many nights during calving season, and we didn't get as tired."
He also saw increased weaning weights, better quality and more uniformity in calf crops. He preconditioned and backgrounded 550- to 600-pound weaned calves, with gains at 2 pounds. He was able to sell them in truckload lots, often to repeat buyers who liked what they saw. That same pattern of success shows on Wil-Mil steers today. Calves that don't meet Brewer's and Griffin's standards for seedstock are castrated, preconditioned and sold in uniform truckload lots, where they, too, are bringing in plenty of repeat buyers.
As for bulls and heifers that do make the cut here, AI-sired calves are a valuable commodity. Griffin says last year, AI-sired heifers sold for an average of $2,750 a head. Commercial bull-bred heifers sold for $1,850 each.
On bulls, Griffin develops them to 2-year-olds for his annual sales. They typically sell for $3,500 to $4,000, a nice premium over feeder steers.
SYNCHRONIZATION A GAME CHANGER
University of Georgia reproductive physiologist Pedro Fontes is a staunch advocate of AI and synchronization, both in commercial and purebred beef herds. For approximately $20, he says producers can get genetics from a bull in the top of the breed for traits ranging from calving ease to marbling.
Since these bulls have been used on hundreds or even thousands of females, he adds: "We know what to expect from their offspring with high accuracy. With a cleanup bull, we can estimate how the offspring will perform based on expected progeny differences [EPDs], but the accuracy is not as good."
A genetic boost is valuable, but Fontes says for most cattle producers, the shift to herd synchronization is where the real game changer lies.
"Synchronization means not only that we can AI the whole herd at a predetermined time, but it allows us to increase the number of cows pregnant early in the breeding season," he explains. It saves the producer hours of twice-a-day heat-checking to target AI to the right point in a cow's cycle, and it means 40 to 60% of cows in a herd will get pregnant the first day of the breeding season. That means more time to recover from calving before the next breeding season, making it more likely they rebreed on time, increasing profitability.
There is also a connection between synchronization and weaning weights. It's basic but often missed that because a majority of calves are born earlier in the season, they are older and hence significantly heavier come weaning time. Those extra pounds are a direct addition to the bottom line.
Potential replacement heifers also benefit from a good synchronization program, Fontes notes.
"Heifers born earlier in the calving season are older at breeding. Consequently, a greater percentage of them will reach puberty sooner, breed earlier in the season and become early-calving cows. We're setting them up for success."
At the North Florida Research and Education Center in Marianna, Florida, where Fontes did part of his graduate research, Cliff Lamb, now at Texas A&M, led a case study evaluating the use of reproductive technologies on subsequent values of the calf crop. He started with a herd that only used natural service during a 120-day breeding season. Estrus synchronization and AI were used in combination with a gradual decrease in the length of the breeding season. Early-bred heifers were used as replacements, and open cows were culled every year.
Over six years, Lamb was able to shorten the breeding season from 120 days to 70 days. The pregnancy rate increased from 81 to 93%, and calf value increased by $169.26, based solely on weaning weights and using a $1.49 price per pound as the benchmark.
These are the sort of facts that lead Fontes to recommend synchronization even if a producer doesn't AI the herd. "There are synchronization protocols for natural service," he explains. "You don't benefit from the genetic aspects of AI, but you benefit from altering the calving distribution."
Since more cows or heifers will come into heat at the same time with a synchronization program, it's important to give preference to experienced bulls. Fontes says to play it safe by planning on a ratio of one bull to no more than 20 to 25 cows. And, make sure your bulls pass a Breeding Soundness Exam every season.
A SEVEN-DAY PROTOCOL
At Wil-Mil, AI adds too much value to calves to be left out, so they stick with the AI-synchronization combination. Currently, they use the 7-Day CO-Synch + CIDR protocol. On Day 0, a gonadotropin-releasing hormone (GnRH) injection is given and a controlled internal drug release device (CIDR) containing progesterone is inserted in the vagina of the cow or heifer. On Day 7, an injection of prostaglandin is given, and the CIDR is removed. After 60 hours for cows (54 hours for heifers), insemination proceeds with another injection of GnRH.
The cost for the 7-Day CO-Synch protocol is around $18 to $20 a head for the drugs. That doesn't include labor, the AI technician's fee or the semen.
"We tried the 14-day CIDR program, but we got about the same results, around 50% pregnant, as we did with the seven-day program," Brewer says. They tried heat-checking after they removed the CIDR and only breeding animals that showed standing heat, but he says that didn't really boost conception rates.
AI and synchronization, for all their benefits, aren't a cure-all for every deficit in a cow herd. It's important cows be in good condition, at a body condition score (BCS) of 5.0 to 6.0. As for heifers, the rule of thumb is to wait to breed them until they are at 60 to 65% of their expected mature weight.
At Wil-Mil, managing toward conception includes a complete herd health program starting at birth and continuing through the animal's life.
Brewer and Griffin keep cows and heifers in breeding shape with Tifton 85 bermudagrass and pearl millet grazing in the warm months, and rye and oat grazing during the December to February breeding season. At breeding, they supplement mature cows with hay, Tifton 85 baleage and a total mixed ration including gin trash, dried distillers grain, peanut hulls and peanut skins.
First-calf heifers get extra attention. They start feeding them a little prior to calving to help build up extra reserves for what is a stressful period in their reproductive lives.
"I believe if you keep a herd healthy and comfortable, a lot of things will take care of themselves. It doesn't take an Einstein. You just have to be willing to do it every day," Brewer says.
Fontes agrees, adding: "A successful AI program requires a willingness to try. If you don't have the facilities and labor, there are folks who provide that service and can even bring portable chutes and corrals."
Then or now, commercial or purebred, gray or sorrel mare, Brewer says AI and synchronization are still worth the trouble when it comes to keeping a herd on track. Some things, thankfully, don't change.
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