The University of Missouri Extension dairy team is cautioning dairy producers to practice elevated biosecurity in light of a recent disease outbreak in Texas dairy country, in and near the Texas Panhandle from Dalhart to Lubbock, as well as in New Mexico. While the source of the outbreak is unknown, it has affected several dairy farms, observable through sudden decreases in milk production (up to 30 pounds per day), reduced feed intake and changes in manure consistency.

“Cows exhibiting symptoms are often mid-lactation, in second or greater lactation,” said Reagan Bluel, MU Extension dairy field specialist. “Milk has often been misdiagnosed as mastitis in the beginning as it becomes thick in consistency. Manure changes as the rumen motility decreases, varying from dry to tacky stools.”

While very few animals have died because of the undiagnosed condition, many have been culled when they fail to rebound in milk production.

The Texas Animal Health Commission (TAHC), USDA and Texas A&M Veterinary Diagnostic Lab are working on cases with dairy veterinarians in the affected areas.

According to TAHC, clinical signs include decreased herd level milk production; acute sudden drop in production with some severely impacted cows experiencing thicker, concentrated, colostrum like milk; decrease in feed consumption with a simultaneous drop in rumen motility; abnormal tacky or loose feces, and some fever.

Impacted herds have reported older cows in mid-lactation may be more likely to be severely impacted than younger cows and fresh cows or heifers. Dry cows and heifers do not appear to be affected. In addition, some herds have reported pneumonia and clinical mastitis cases as secondary sequelae.

The TAHC, USDA, Texas A&M Veterinary Diagnostic Laboratory (TVMDL), and dairy veterinarians, along with other partners, are also working closely to coordinate an efficient plan to monitor and evaluate affected dairy cattle, develop a case definition, and conduct additional diagnostics.

“A strong emphasis on enhanced biosecurity measures is encouraged,” TAHC wrote in a recent letter about the illness. “As monitoring and evaluation is underway, limiting people on and off premises and prioritizing diligent biosecurity practices is critical. When more information is available, additional guidance regarding preventative measures at the dairy level will be shared.”

Enhanced biosecurity efforts include requiring clean clothes and wearing rubber or disposable boots for anyone visiting the farm as well as recording the visitors for tracing purposes if an outbreak occurs. Veterinarians should be contacted immediately if a herd exhibits any of the symptoms.