By:
Tom Nordlie (352) 392-1773 x 277

Source(s):
John Arthington jarth@gnv.ifas.ufl.edu, (863) 735-1314, ext. 204
Findlay Pate pate@gnv.ifas.ufl.edu, (863) 735-1314, ext. 203

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ONA, Fla.—South Florida ranchers may improve calf production using a system developed by the University of Florida’s Institute of Food and Agricultural Sciences to increase conception rates in young cows by weaning calves early.

“Every cattleman’s goal is one calf per cow per year,” said John Arthington, a beef cattle management specialist with UF’s Range Cattle Research and Education Center in Ona. “Without increased supplementation, we don’t traditionally expect that kind of performance from cows two or three years old. But early weaning improves the odds.”

While most ranchers wean calves at about eight months of age, the UF system allows weaning at 60 to 100 days. Arthington said the system is designed specifically for Florida beef cattle.

“Most of our cattle are one-half to one-quarter Brahma, so they mature slowly,” he said. “When a young cow nurses, her energy demands are divided between body maintenance, growth and lactation. She loses weight, reducing body condition and making conception less likely.”

Researchers at the Ona center score cow body condition on a scale of one to nine, ranging from very emaciated to very obese. Arthington said a score of five or six is optimal for rebreeding. Research in Florida indicates that cows scoring at least five have an 89 percent chance of conception, while cows scoring three or less have a 31 percent chance.

“The worse the cow’s body condition, the more she can benefit from our system,” he said. “Early weaning should occur at the start of the breeding season so the cow can put on weight and have a better chance of conceiving.”

He said the UF system fits the schedule favored by most South Florida ranches, where cows are bred in winter and calves are born in fall. Under the UF system, early weaning takes place in January.

After weaning, calves are grazed on winter ryegrass supplemented with small amounts of commercial feed, Arthington said. The grass requires little fertilizer and no irrigation, and will grow modestly even under drought conditions.

“Ryegrass isn’t widely used for adult cattle because it doesn’t provide enough forage, but it’s ideal for our system,” he said. “These little calves eat only five to eight pounds of dry matter a day, and they’re too light to trample the forage base.”

Findlay Pate, director of the Ona center, said the UF system has been tested for two years, and should prove economical for cattlemen.

“Florida ranchers haven’t used early weaning in the past, because they needed a proven forage crop to keep feeding costs low,” said Pate, a beef cattle management specialist. “We’ve solved that problem, and the system has other advantages.”

He said early-weaned calves can be stocked five to the acre, so minimal land is required. Calf prices typically begin rising in January and peak in April, when ryegrass forage begins to disappear.

Calves gained almost two pounds per day on the UF system, comparable to weight gain in nursing calves, Pate said. Research indicates that early-weaned calves perform more efficiently in feed lots and are more likely to produce high-grade beef.

“We’re putting together an economic package so we can show cattlemen what our system offers from a bottom-line standpoint,” he said. “We’ve hired an economist and that will be his first order of business.”

Beginning in November, UF will test the system on commercial ranches, the first step toward field studies away from the Ona center. Pate said the research is supported solely with state funds.

“We consider this a very important project, so we’ll rely only on state funding,” he said. “At the same time, we’re trying to get this system out to cattlemen as soon as possible.”

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