Program Your Calves for Success
Steps you can take to make your calves the best they can be.
October 22, 2024
You likely go to great lengths to pick the best bull for your cow herd. It’s the same for choosing your replacement heifers and deciding which cows to keep or cull. Yet there’s another step to make sure your calves reach their full genetic potential.
The fancy term is fetal programming. It simply means the development of the calf partly depends on the nutrition available to its dam during gestation. Let the body condition score (BCS) of the cow slip too much and it can affect everything from her calf’s immune system to her heifer’s fertility to her steer calf’s carcass grades.
Fetal programming first came to light in humans. During a blockade of Holland during World War II, food was cut off to the Dutch. Years later, scientists discovered that babies born after their mothers were severely malnourished during gestation developed health problems as adults.
Philipe Moriel, a University of Florida animal scientist based at the Range Cattle Research and Education Center in Ona, told attendees at the 2024 Applied Reproductive Strategies in Beef Cattle (ARSBC) symposium in Athens, Ga., Sept. 4-5, that the same holds true in beef cattle.
“By changing the nutrition, you can change how that calf develops.” — Philipe Moriel
“By changing the nutrition, you can change how that calf develops,” he said.
Initially, researchers and cattle producers focused on nutrition during the last two months of gestation, because that’s when 75% of calf growth happens.
“Now we know that this is not the most important time. All of the trimesters are important,” said Moriel. While the nutrient requirements for the pregnancy itself are almost zero the first trimester, those first three months are when the pancreas, liver, brain and ovaries are formed.
“Every tissue has a different time, or different window, for development,” he explained.
For example, muscle tissue is formed during mid- and late gestation, and it develops in two different ways. During mid-gestation, the number of muscle fibers increases. During late gestation, muscle mass increases just from the size of each of the fibers.
“Once that calf is born, the number of muscle fibers are set,” said Moriel. “That means if you have a major restriction during gestation, to the point that it decreases the number of muscle fibers after birth, you might never have a chance to compensate.”
Then there is the all-important adipose tissue, or fat. It is formed during the last three months of gestation. Shortchange a cow then, and her calf’s marbling scores can suffer.
Mining the research
Carcass weight and quality aren’t the only traits affected by fetal programming. Moriel cited two University of Nebraska studies that looked at age of puberty and pregnancy rate of heifers from nonsupplemented and supplemented cows. In the 2007 study, age of puberty was actually a bit shorter, although not statistically significant, in heifers born to the nonsupplemented cows. However, pregnancy rates were lower, 80% compared to 93%, for the heifers born to nonsupplemented cows.
In the 2010 study, days to puberty were longer, 366 compared to 352, for the nonsupplemented group and pregnancy rate was less, 80% compared to 90%.
Whether your cow-calf operation is in Florida or Montana, supplementing cows every day is a chore — a big one. Moriel has help for that.
“Frequency of supplementation can be reduced to one or three times a week without sacrificing BCS at calving,” he said, citing a study conducted at Ona. He did add, however, that calf weight at weaning was less from cows that didn’t get supplementation, as well as those whose dams were only supplemented one to three times a week.
Editor’s note: Becky Mills is a freelance writer and cattlewoman from Cuthbert, Ga.
Angus Beef Bulletin EXTRA, Vol. 16, No. 10-B
Topics: Feedstuffs , Management , Nutrition , Reproduction
Publication: Angus Beef Bulletin
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