Some cattle herds saw an increase in weak calf syndrome last year, and Washington State University researchers are working to figure out why.
They recommend ranchers ensure their herds are receiving a higher amount of protein prior to calving.
Calves are born normal or weak, and typically die within hours to days of birth, said John Wenz, WSU associate professor and a member of the field disease investigation unit.
The cause of the syndrome is unclear, Wenz said.
WSU sent out a survey to ranchers. In phase one, with 165 respondents, 20 percent of herds had experienced at least one weak calf born during calving season in 2015-2016. In 2017, the number increased to 42 percent.
In phase two of the study, ranchers gave more detailed information about 47 herds, half of which reported a problem. The percent of calves lost to the syndrome rose from 0.05 percent in 2015-2016 to 1.5 percent in 2017, Wenz said.
“One and a half of a hundred calves being lost, that impact doesn’t seem that great,” he said. “But there’s a range for those 47 herds that went anywhere from one calf out of 100 to 35 percent.”
The percentage of deaths attributed to weak calf accounted for about half of calf death-loss, Wenz said.
“Every calf lost is lost income,” he said. “If it is only one out of 100, but if it’s doubling your normal death loss, at least in a bad year, that impact can be substantial.”
The syndrome tends to come and go, Wenz said.
WSU will work with herds that reported a problem to identify risk factors, Wenz said.
First-calf heifers have the highest risk, with an average about 2.3 percent experiencing weak calf, compared to .05 percent of cows that are 3 to 8 years old. About 1 percent of cows that are 9 years or older experience weak calf, Wenz said.
But in 2017, a bad year for the syndrome, older cows were hit harder, seeing a 450 percent increase, Wenz said, compared to a 214 percent increase in 3 to 8 year olds and to first-calf heifers, which saw a 35 percent increase, Wenz said.
The researchers are weighing a University of Idaho study from 1972 that identified a relationship between syndrome effects and the amount of crude protein fed before calving. Feeding lower amounts of protein seemed to be identified with more weak calf, particularly during winter, Wenz said.
If they’ve had problems with weak calf before, Wenz said, ranchers should conduct a forage analysis, raising crude protein percentage up to 12 percent about 60 days before calving. He also recommends more intense care for calves that don’t get up right away.
It’s possible that reduced activity for the herds due to extreme weather could play a part, he said. Delayed calving could also be a factor. Antecdotally, some ranchers have told Wenz that cows that don’t get enough exercise have more calf troubles.
“There’s no data on that, but it’s an intriguing idea,” he said. “It’s all speculation at this point.”