Joe Davis has been a successful Thoroughbred racehorse trainer for 30 years and has always understood the common-sense correlation between healthy respiratory function and performance.

Oxygen transferred from the lungs to the bloodstream fuels muscle performance. The horse that can’t get enough air during peak exertion is fated to fizzle out going down the stretch.

Joe also knew that the stable environment – especially hay – is one of the worst contributors to poor respiratory health because even top-quality hay is loaded with tiny particles of dust, mold, bacteria and fungi. These irritate and inflame the thin, delicate lining of the respiratory system’s upper airway and lungs, restricting airflow and triggering coughs.

What Joe didn’t know is that high-temperature hay steaming can help. That is until he was approached to participate in an important study conducted by equine respiratory expert Laurent L. Couëtil, DVM, PhD, Diplomate ACVIM-LAIM, and Kathleen Ivester, DVM, PhD, Diplomate ACVS, and their team at the Purdue College of Veterinary Medicine in Indiana. Joe was one of four trainers recruited for research comparing the benefits of feeding dry hay, high-temperature steamed hay and haylage, and the impact of each feed on the quantity of dust and other breathable irritants in the stable environment.

“We needed to evaluate a fairly large group of horses and measure their exposure to dust and the amount of airway inflammation before and after changing their diet,” explains Dr. Couëtil.

The veterinarian’s many contributions to equine health include having led the way in establishing the term “Equine Asthma” as the label for conditions ranging from mild Inflammatory Airway Disease to Recurrent Airway Obstruction.

Happy To Participate

Joe was happy to have horses in his program at Indiana Grand Racing and Casino be among the 43 Thoroughbreds to participate in the study. Dr. Couëtil’s team measured dust exposure within the breathing zone of each horse, then performed a lung wash -- called a bronchoalveolar lavage or BAL -- to determine the type and number of inflammatory cells deep within the lung. Next, they randomly assigned each horse to either continue eating hay, steamed hay, or haylage for six weeks. Dust exposure measurements and lung washes were repeated at each three- and six-week interval. The research was conducted while horses continued their normal training and racing schedules. The findings haven’t been fully analyzed or published yet, but “Our data is very encouraging,” reports Dr. Couëtil.

For Joe, however, the results are already speaking for themselves in his horses improved respiratory health and appetite. So much so that the veteran trainer asked to keep the full-bale HG2000 hay steamer Haygain made available to his horses for the study.

“Especially in the summer when it’s dusty and windy, we’ve had some problems with coughing and general respiratory health,” Joe explains of his eagerness to have his horses in the study. He observed that steamed hay was especially helpful for a few of his horses that were “bleeders,” aka Exercise Induced Pulmonary Hemorrhage, which occurs relatively often in racehorses. One of those was a horse named A Little Irradic, who Joe had claimed for $10,000 not knowing that he had a severe case of this condition.

“We didn’t know until Purdue scoped him the first time for the study,” Joe recounts. The horse’s first post-race scope revealed a high neutrophil count that correlates to inflammation. After switching to steamed hay, “his last two scopes were clear,” the trainer relays. Plus, in one of the races before those clear scopes, A Little Irradic finished second in a run for a $75,000 purse.

During the intervals when his horses ate steamed hay, Joe also noticed a significant improvement in another relatively common condition: blisters on the throats of 2-year-olds. This often happens when youngsters come in from life in open pasture to the stable environment and time spent working on the track. “Their throats are irritated and they’re coughing just because they haven’t been exposed to so many things before,” Joe explains. These issues cleared up significantly after the 2-year-olds received steamed hay.

Better appetites were another big improvement the trainer saw in horses getting steamed hay. “It’s like salad to them,” he says. “They love it!” That means more nutrients for the horses and less waste of hay that Joe estimates has become 40% more expensive in the last three years.

A Seasoned Veteran’s Perspective

Though the data hasn’t been crunched yet, Joe needs no further evidence of steamed hay’s benefits. One of his racing accomplishments is having a horse, Union Bowman, that was a leading money winner up until the ripe old age of 11. “That’s very unusual in our world,” Joe explains of Union Bowman’s longevity. It’s also a testament to the trainer’s horsemanship and determination to provide the best for the horses running under his colors.

Now that the data collection phase of the research is completed, Joe is grateful to keep his horses on Haygain steamed hay continuously. Keeping the initial 10 horses on it during the study required two or three one-hour steaming cycles every morning, but the results made it well worth the slight extra effort and planning.

Our research has made it clear that the dust horses are exposed to when eating even the best quality hay can lead to mild equine asthma,” Dr. Couëtil explains.

The response of Joe’s horses to steamed hay didn’t surprise Dr. Couëtil. “Our research has made it clear that the dust horses are exposed to when eating even the best quality hay can lead to mild equine asthma,” he explains. “We have also found that even low levels of inflammation in the airway have a negative impact on performance, so it is important for the health, welfare, and performance of the equine athlete to minimize dust exposure.”

Joe plans to keep steaming and Drs Couëtil and Ivester plan to keep studying ways to detect, treat and manage equine airway inflammation. Along with helping horses, the Purdue program’s parallel goal is the use of the horse as a model of respiratory disease in humans.

The veterinarians express their gratitude to Grayson-Jockey Club Research Foundation for funding the study, to Haygain for donating hay steamers and to C&M Forage, LLC for donating the haylage. Haygain is honored to help with this important research impacting horses and people.