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Veterinary Teaching Hospital

by Josh Babcock, College of Veterinary Medicine

When Sue Morris sent her 17-year-old trail horse, Tracker, on a trailer bound for Washington State University’s Veterinary Teaching Hospital, she wasn’t sure he would survive the two-hour trip from Mead, Washington.

Tracker, a 17 year old Tennessee Walker.

“His respirations increased, he was sweating, and of course it was a bad day; it was 99 degrees,” Morris said. “I honestly didn’t think he was going to make it. I actually made plans to have him cremated four days before he came to WSU.”

Tracker’s liver was close to failing; and with his red blood cell count gravely low, his body was struggling to provide oxygen to vital organs and tissues.

It was suspected the 1,250-pound Tennessee walking horse needed an emergency blood transfusion.

“Something made his liver stop working and without the liver you can’t make it,” said Macarena Sanz, the lead veterinarian on the case. “When we see liver disease this severe, its rare to see them recovering. I didn’t think he was going to make it; I think we all felt that way.”

Since Tracker didn’t eat much for a few days, his liver mobilized fat cells that were causing inflammation. This condition is severe and can cause liver failure and death if left untreated.

Upon arrival, WSU equine veterinarians had two initial priorities. First: support the patient. Second: identify a compatible blood donor in case an emergency blood transfusion was needed.

Fortunately, Tracker’s red blood cell count remained stable that initial night. The medicine team administered dextrose, a calorie-dense simple sugar, via an IV line to allow the liver to rest. This was key not only to prevent further liver damage but to minimize fat mobilization that occurred as a result of Tracker not eating.  

In addition to dextrose, Tracker received a powerful anti-inflammatory, which helped reduce the inflammation in Tracker’s liver and additional medication to reduce scar tissue which could limit  liver function later on.

Tracker’s abnormal fat deposition and muscle wasting was most telling for Dr. Sanz.

Due to his age and these signs Dr. Sanz suspected Tracker had pituitary pars intermedia dysfunction, also known as equine Cushing’s disease, although the equine condition is very different than that of other species. Horses with PPID produce many abnormal hormones which lead to different clinical signs (excessive sweating, increased urination and water intake, laminitis, lethargy among others). As this condition also exacerbates liver inflammation, the medicine team began administering medication to treat the condition immediately.

“He perked up a little bit,” Sanz said. “We decided to wait on the blood transfusion and see how he did overnight.”

WSU equine veterinarians and fourth-year veterinary students monitored Tracker’s health that night, and consistently for the next two weeks.

Tracker’s liver also began to shrink to a normal size as the inflammation subsided as a result of treatment. 

It took 10 days, but gradually Tracker began to eat again and go for short walks. His liver also resumed its normal size.

“We don’t usually see many cases like these where they pull through,” Dr. Sanz said.

Tracker is now back at home in the mountains near Mead, with Morris, a mare named Annie and another gelding, Hugo.

He’s even galloping again, when he wants.

Sanz said the referring veterinarian’s care and their prompt referral gave WSU’s equine veterinarians a critical head start.

“Saving a horse like this is the best part of what we do, and it is always reminds us why we love what we do,” she said.

Jenny, a 3-year-old quarter horse from Spokane, Wash., ingested one of the most toxic substances known before she arrived at Washington State University’s Veterinary Teaching Hospital last month.

Jenny, a 3-year-old quarter horse, with veterinarians and technicians that helped her.

Today, three weeks later, the horse that may have been just a few bites away from death, has now headed home.

Jenny was poisoned by Clostridium botulinum, a deadly bacterium that produces the neurotoxin responsible for botulism.

When ingested by horses, the neurotoxin attacks the neuromuscular nerve junctions and blocks the release of acetylcholine, a chemical that tells the peripheral muscular system how to function; the condition is rapidly fatal and often leads to respiratory arrest.

“If enough of the toxins bind to enough neuromuscular junctions, the peripheral muscular system will eventually not get the message to breathe,” Jen Gold, lead veterinarian on the case, said.
Due to this, the bacterium is considered by the Centers for Disease Control as a bioterrorism threat due to its toxicity.

Dr. Gold said Jenny is fortunate she didn’t ingest more toxins.

“She didn’t get a huge dose,” Gold said. “A higher dose and she wouldn’t have made it.”

Like in most botulism cases, when Jenny arrived at WSU, she was unable to eat or swallow, her abdomen was bloated, she was weak, short-strided, and her pupils were dilated.
A test of Jenny’s stomach contents came back positive for botulism type C.

Gold treated Jenny with an antitoxin for botulism type B (the only antitoxin available to treat the condition) and penicillin. The horse was provided food via an IV until she was able to eat and drink again. 

Gold said Jenny is one of the lucky ones.

In nearly 20 years she’s seen about as many Botulism cases; this is just the second horse that has ever survived.

Gold said horses often die within 72 hours of ingesting the toxin and consulting a veterinarian sooner than later always gives the horse the best chance at survival. Dilated eyes that are unable to contract are often the condition’s biggest giveaway. 

Gold said the quick actions by Jenny’s owners likely saved the horse’s life.

“This case was really about her owner getting on it and bringing her to us,” Gold said. “She likely would have died otherwise.”

Most importantly, avoid strenuous exercise in smoky conditions

Silhouette of horse in orange smoky air.

“The best advice is don’t ride,” said Jen Gold, a WSU equine veterinarian. Dr. Gold said due to smoke inhalation, horses should not exercise in smoky conditions. “Physical activity, especially any strenuous exercise could be detrimental to the health of your horse,” Dr. Gold said.

Smoke contains a myriad of chemicals and acidic gases that can be harmful to animals of all sizes, as well as humans. According to the Environmental Protection Agency, those harmful air pollutants include carbon monoxide, benzene, and formaldehyde, to name a few. In addition, fine particulates in smoke can trigger asthma attacks, respiratory illness and infections in animals. The Air Quality Index established by the EPA to track the number of these particulates in the air can be helpful in protecting your horse. While the air quality rating is mostly geared for human health, Dr. Gold said when particulate levels exceed 150 it is unsafe for horses to exert themselves.

Dr. Gold said it is important for owners to watch for nasal discharge, coughing, sneezing, or difficulty breathing in your animals. In smoky conditions, these could be signs of inflammation or a respiratory infection, in which case it would be best to catch it early and consult a veterinarian.

Horse and large animal owners should also keep food and water free of the toxic particles in the air. Dr. Gold said changing water every few hours and before water appears unclear is priority. “If a horse drinks tainted water, they are likely not going to want to drink that water again, which is problematic in these conditions,” Dr. Gold said. “The same goes for their food.” By drinking water, horses keep their airways moist and free of the smoke’s particulates. Rinsing hay or other feed with water lightly will help clear the food of the smoke’s particles. Dr. Gold recommends changing water at the same time as water because horses tend to drink most within about two hours of eating.

“When you find yourself in these conditions just think about how you stay comfortable and try to do the same for your horse,” she said.