Calves with weak calf syndrome are typically born with no noticeable problems, but are so weak that they may fall over on their side and usually come around slowly, according to Gregg Hanzlicek, director of production animal field investigations for the Kansas State University Veterinary Diagnostic Laboratory.
Hanzlicek points at disease or nutritional deficiencies as some of the causes of weak calf syndrome.
"BVD (bovine viral diarrhea) in the herd is sometimes associated with weak calves," he said. "From a nutritional standpoint, vitamin A deficiency or selenium deficiency in the dam have been associated with weak newborn calves."
Diagnostic tests can pinpoint BVD or vitamin A and selenium deficiencies, Hanzlicek said. These tests require tissue or blood samples from the calf or its dam, and they provide a way for the producer to determine why calves are born in a weakened situation.
Depending on the cause of the weakness, a high percentage of these calves sometimes do not survive, he said, which can damage producers economically given current record-high cattle prices.
Balanced nutrition offers prevention
Nutritional balance in cows and heifers prior to and during calving season is crucial, Hanzlicek said, especially during periods of cold temperatures. One of the main reasons for weak calves is that their mother consumed a diet deficient in energy and protein, although lack of protein in late gestation is usually the main culprit.
He said cows and heifers should have at least a body condition score 5 prior to calving. In the last trimester of gestation, the demands of the cow and her unborn calf are huge, and the demands increase even more in cold weather.
"We know that for calves born to cows that are less than a BCS 5, it takes them a much longer time to get up and nurse once they are born," Hanzlicek said. "All calves are born with a small amount of body fat they can use for energy. If they are born in a cold environment, they are trying to keep warm, but they don't have much body fat to use for energy. Therefore, they can get weak quickly."
Although it may be too late to prevent weak calves from nutritional imbalances for the current calving season, Hanzlicek said producers should still test forages to know the protein, energy and trace mineral content. The analysis process requires the producer to take samples of the hay they plan to feed during winter, have those samples tested by a lab, and work with a veterinarian or animal scientist to balance an appropriate diet for the herd.
Also discuss with a veterinarian or animal scientist how to appropriately adjust those rations for colder temperatures, he said, as cows and heifers will need more protein and energy during 10 degree Fahrenheit days compared to 30 and 40 degree days, for example.
Hanzlicek added that injectable products are available as a short-term remedy for diagnosed vitamin A or selenium deficiencies. They can be given to pregnant cows and heifers to supplement their unborn calves, but producers likely would not need them if they perform a forage analysis and feed an appropriately formulated diet.
Control and response
Prevention is more favorable than response, Hanzlicek said, but if producers are experience weak calf syndrome in their herds this calving season, they must get the calves up, warmed and nursing within a short time after birth.
During cold days, he said producers should consider warming the calves on the floorboard of a pickup, in a hot box or using a warm water bath. Research has shown that a heat lamp alone usually won't warm calves sufficiently.
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"We need to warm the calf up, but then we need to provide some type of oral energy for that calf, because it's hypothermia and perhaps hypoglycemia that explain the weakness," Hanzlicek said.
Providing oral energy doesn't mean giving the calves electrolytes, a remedy used to treat scours, he said. Even the highest-energy electrolyte products have a small amount of total energy, so he recommends colostrum or milk replacers to help treat weak calves.
"The reason why we like colostrum replacers is that likely the weak calf didn't get up and consume its colostrum," Hanzlicek said. "Colostrum contains the necessary antibodies to protect the calf, so we want to try to provide antibodies to them to protect them from scours and respiratory disease. It is best if we can get the colostrum in them within two hours after birth, certainly less than six hours after birth. In a cold spell, it may make sense to intervene earlier, maybe within the first hour."
"It's amazing once you warm them up and administer high-energy products how fast those cold, weak calves will get up on their own," he added. "Many times you can send them out with their mother the next day."