A producer and a veterinarian in western Kansas recently called in the expertise from the Production Animal Field Investigation Unit with the Veterinary Diagnostic Laboratory at Kansas State University to help solve the mystery surrounding deaths of several calves on a drought-stricken ranch.
Gregg Hanzlicek, director of the unit and a veterinarian in the diagnostic laboratory, said the local veterinarian had eliminated all contagious diseases as the cause of the deaths.
“We knew this area had been through two to three years of drought,” Hanzlicek said. “We found a well-managed herd, with the calves getting plenty of milk. But we did notice very little grass for the animals to graze on.”
The calves were grazing on multiple weeds. The weeds showing evidence of grazing were collected and sent back to Kansas State for analysis.
“The weeds were all nontoxic, except for one, a Senecio species that causes acute to chronic liver toxicity, which was identified by toxicologist, Dr. Deon van der Merwe,” he said. Pathology reports showed that the calves died from liver toxicity.
In a drought situation where there isn’t grass, animals will graze other species of plants that they don’t normally consume.
He advised moving the cattle off of the pasture and weaning the calves early.
“In a drought situation, producers usually don’t have this alternative. Supplement some type of feed every other day or so, enough to keep them full so they don’t eat other plants they don’t normally consume,” he advised.
In this case, the producer is providing sorghum-sudan as an alternative feed source.
Hanzlicek advised calling in a local veterinarian to investigate any unknown cause of calf deaths.