Back to Basics
While reproductive technologies are a great thing, a Virginia Tech specialist says reproductive efficiency goes back to management.
October 8, 2024
When cattle producers call or see Vitor Mercadante, they want to talk about timed artificial insemination (TAI) protocols and/or embryo transfer (ET). That’s a good thing. After all, the Virginia Tech beef extension specialist is a reproductive physiologist by training. However, at the Applied Reproductive Strategies in Beef Cattle (ARSBC) symposium in Athens, Ga., Sept. 4-5, 2024, Mercadante preached the basics before sharing the latest AI protocols.
Mercadante reminded the audience that the real goal of beef cattle production, at least for most, is to make money. For a cow-calf producer, that means putting a healthy, live calf on the ground year after year.
“We can take that to the next step where our goal is to wean a heavy, healthy calf that has the greatest genetic potential to perform,” he said. “Then we can add another level and that is to do it at the lowest cost possible to maximize profitability. Reproductive efficiency, it’s the key for profitability and productivity in cow-calf operations.”
That concept is so important, Mercadante urged producers to actually write down the definition of reproductive efficiency in their herd.
“I would define reproductive efficiency as optimizing pregnancy rates early in the breeding season — not just maximizing or optimizing pregnancy rates, but when cows become pregnant,” Mercadante said. “That’s important because that will determine when cows calve.”
Study after study shows calves that come in the first part of the calving season are generally the heaviest at weaning and, therefore, the most profitable, he added.
Next on his list is selecting and developing replacement heifers that have high fertility.
“You want to do all that at the lowest cost possible.” For purebred breeders, he added, “You want to select and develop bulls that have high fertility, bulls that will breed cows.”
“There’s not that one thing we can do to really achieve reproductive efficiency. It’s a combination of things, the things we do every day that help us achieve it.” — Vitor Mercadante
“There’s not that one thing we can do to really achieve reproductive efficiency. It’s a combination of things, the things we do every day that help us achieve it,” Mercadante emphasized. “Management is really important. Having a sound nutrition and animal health program is extremely important. Selection pressure for fertility, selecting animals that become pregnant, selecting bulls that will get cows pregnant, it’s all important. Then we can take advantage of reproductive technologies. I think we should do things in that order.”
If a producer’s animal health, nutrition and fertility goals are met, then Mercadante said they are ready to think about TAI. Before they order the CIDR®s, though, there are more specifics to consider.
“An analysis of several studies shows the greatest pregnancy rates to TAI were in mature cows with extended days postpartum, 72 days or more, and a greater than 5.0 body condition score (BCS),” he said (see Table 1). BCS is rated on a 1-to-9 scale with 1 being emaciated and 9 being obese.
Table 1: Factors affecting timed-AI pregnancy rate
Days postpartum and BCS equally important
“Pregnancy rate was similar for cows with postpartum days of more than 72 and a BCS of less than 5 compared to cows with postpartum days of less than 72 and a BCS of more than 5,” he said. “However, in both cases pregnancy rate was decreased significantly compared to cows that were more than 72 days postpartum and in a BCS of 5 or more.”
The Virginia Tech beef extension specialist still said, though, that success with TAI goes back to the very basics.
“We know it works and producers are taking advantage of it,” he said. “We hope more and more people can see the value of doing estrous synchronization. What most people do, however, is they'll jump to the reproductive technology right away. They’ll say, I want to AI, I want to do embryo transfer. Those are all good things. But if you don't have good management, if you don't have a solid nutrition plan and an animal health program, if you don't have selection pressure, those technologies are not miracles.”
Editor’s note: Becky Mills is a freelance writer and cattlewoman from Cuthbert, Ga.
Topics: Reproduction , Management , Events , News
Publication: Angus Beef Bulletin
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