Mystery Illness is Now Affecting Dairy Cows in Texas, New Mexico As Industry Searches for Answers

Dairy farmers in the Texas Panhandle and New Mexico are grappling with quite the mystery. Something is causing milk production to nosedive, and veterinarians and state officials can’t pinpoint what it is. In affected cowherds, the issue impacts nearly 10% of the animals, causing reduced feed consumption and a 10% to 20% decline in milk production. 

A Texas dairy farmer told Farm Journal the mystery illness acts similar to the flu and impacts only older cows. Currently, the majority of cases are being reported in Texas and New Mexico. However, the American Association of Bovine Practitioners (AABP), the nation's largest cattle veterinary association, told Farm Journal they have some veterinarian members in Kansas who have also reported symptoms, but those reports are unconfirmed. 

“It appears that the disease peaks in about three to four days and lasts 10 to 14 days. Older dairy cattle appear to be more clinically affected, with a more severely affected lactation,” says Dr. Fred Gingrich, cattle veterinarian and executive director of AABP. “And although it's not consistent with every herd, it appears that it's mostly affecting animals that are in mid- to late lactation. It's pretty unusual that we have something going on in older animals, and it's not in fresh cows."

Gingrich says AABP understands the need for urgency in finding answers for dairy producers. 

“We understand right now that the primary impact of this disease is economic. These herds lose about 20% of their milk production for 14 to 21 days, which is a huge economic loss," Gingrich says. “I think we always like to look for the bright side in a situation, and we don't appear to have mortalities associated with this disease. That's not happening, which is really great.”

As the industry works to uncover the factors causing the disease, Gingrich says what makes pinpointing the cause so difficult is trying to decipher what the main symptoms of the illness are versus the secondary symptoms and related issues.  

“It's not a pneumonia outbreak, as far as we can see, and it's not a mastitis outbreak. I think that some of those things that we're seeing on farms are probably secondary to the initial agent that's causing cows to go off feed, and every dairy farmer knows that a cow that doesn't eat is at risk to get other syndromes and other diseases. I think that's what's occurring right now.” he adds. 

Gingrich says diagnostic labs have already done several tests, along with more pending samples. “Right now, the test results are what we would call inconclusive,” he says. “There's nothing conclusive as an exact diagnosis as to whether this is caused by a pathogen of a bacteria or a virus."

What We Know 

According to the Texas Animal Health Commission (TAHC), here’s a summary of what the industry knows at this time:

• The symptoms of the illness last between 10 and 14 days.
• The exact cause of the illness is undiagnosed and still unknown.
• Clinical signs include a sudden drop in milk production.
• Some severely impacted cows are producing thicker, more concentrated, colostrum-like milk.
• The problem causes a drop in feed consumption with a simultaneous drop in rumen function, accompanied by 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, fresh cows or heifers.
• Dry cows and heifers do not appear to be affected.
• Some herds have reported pneumonia and mastitis.

Texas officials say they are working with USDA to further monitor and evaluate reported cases.

 “We're trying to rule out infectious diseases in anything that might be related to  feed or water or any kind of supplementation that these animals are receiving,” Dr. Lewis R. “Bud” Dinges, TAHC executive director and Texas state veterinarian, told Farm Journal.

“We’re trying to gather some management data as far as what herds are affected, what's common to all the herds that are affected, and trying to do a good epidemiologic investigation here," Dinges says. "It doesn't appear to be an infectious disease, and we haven't seen anything to prove that we need to stop movement on these cattle as of right now.”

Signs to Look For 

Gingrich says both dairy producers and veterinarians should be on high alert and stay vigilant with biosecurity measures. 

If you’re a dairy producer, Gingrich says these are some signs to look for: 

• Rapid onset of cows that aren't eating
• Either a drop in rumen activity or more feed in the bunk at the end of the day
• A substantial loss in milk production 

“These things are key,” says Gingrich. “Don’t just think you might have a bad batch of feed or that you have a respiratory outbreak and just need to vaccinate. If you see any of these issues, immediately call your veterinarian. I think that is important. I think the other thing that is important is, as with any disease, make sure you're documenting it with good recordkeeping on who's affected, when they are affected, et cetera. Good recordkeeping on sick cows applies to any disease. So I would encourage you to do that, as well."

TAHC officials say they are working to find answers and will also continue to test.  

“The unknown is not what we want to hear,” says Dinges. “We're working on this around the clock to find an answer to what’s causing this in these cows.”