Chronic lower airway diseases, such as recurrent airway obstruction (RAO) and inflammatory airway disease (IAD), are all too common in horses today. Reducing dust in the diet and environment can benefit these horses, but Purdue University researchers found that omega-3 fatty acid supplementation will reduce signs even further.

For the purpose of their study, the researchers used an algae-based omega-3 supplement that also contained vitamin C, methylsulfonylmethane (MSM), and a mushroom complex.

“Algae is the richest source of DHA (docosahexaenoic acid), and this is a vegetarian and renewable source of DHA (unlike fish, which is the other common source of DHA and EPA),” said Laurent Couëtil, DVM, PhD, Dipl. ACVIM, a professor in the Purdue University Department of Veterinary Clinical Sciences, in West Lafayette, Indiana.

Specifically, the team aimed to evaluate the algae supplement’s impact on horses with RAO or IAD housed in a low-dust environment, based on changes in visual analog scores (VAS) for cough, lung function, and bronchoalveolar lavage fluid (BALF).

In order to determine an effective dosage, Couëtil and his colleagues first conducted a pilot study of four healthy horses and four RAO-affected horses from Purdue’s herd. The team fed the algae supplement at the lowest recommended dose to one group and at double the dose to the second group. After two weeks, the team doubled both treatments. They collected blood every two weeks and concluded the study when the blood plasma’s omega-3 content plateaued, which was Week 4.

The researchers then conducted a nine-month clinical trial inv