A dead two-year old Angus heifer was submitted to the South Dakota Animal Disease Research and Diagnostic Laboratory for examination by Jennifer Poindexter-Runge, DVM, Ree Heights, S.D. in February of 2007. This was the third dead heifer out of 25. Clinical signs in the group of heifers included weight loss, depression, disorientation and death. Cattle presented weak and mildly neurologic (mild proprioceptive deficits/wanted to turn one way more than another), but had no overt signs of illness. They progressed to recumbency and death.
Necropsy examination revealed a thin carcass, large pale liver and a large male fetus in the uterus. Microscopic examination of liver revealed severe diffuse hepatic lipidosis. No viral or bacterial pathogens were identified. Fecal exams were negative for parasite ova. The liver contained 42.76% fat. “The findings in this case were suggestive of pregnancy toxemia. The feed ration and late gestation were likely contributing factors,” says Dale Miskimins, DVM, MS, South Dakota Animal Disease Research and Diagnostic Laboratory. “A complete necropsy is needed on this type of case,” Miskimins says.
Miskimins says the fat content of the liver was very high at 42.76%. Cows with >34% lipid have severe fatty liver disease, 25%–34% are moderately affected, and 13%–25% are mildly affected.
Poindexter-Runge expected that leptospirosis might be diagnosed, and had also thought about moldy corn. “All of the heifers were in similar body condition at about a 4–4.5 body condition score,” she says. She notes that this can also be seen in fat cattle. Poindexter-Runge believes a low level of energy intake compared to nutritional demands of the fetus and large and multiple fetuses may also be a factor in pregnancy toxemia.
“I would think you would see it more in heifers due to increased nutritional demands of a fetus and a heifer’s growth,” Poindexter-Runge notes. “But cows are also affected at a lower incidence.”
Poindexter-Runge says if affected cattle are appetent, increase their carbohydrate intake with grain. When inappetant, a feeding concentrate or propylene glycol can be force fed. She notes that a 5% dextrose infusion may also be used.
“I suggested to the owner to put them on 8 lbs of corn and we seemed to stop any other clinical signs from occurring,” she says.