Keeping those pesky flies away in summer isn’t just a job for the horsetail. Swedish researchers have determined that providing a climate-appropriate shelter in summer months is essential to equine welfare—not just for shade, but also for insect relief.

“(Study horses used) shelters … during even moderate summer weather, and offering protection, mainly because of insects, seems important,” said Elke Hartmann, PhD, of the Swedish University of Agricultural Sciences’ Department of Anatomy, Physiology, and Biochemistry, in Uppsala.

In their study, Hartmann and her fellow researchers observed eight Warmblood horses with free access to three kinds of shelters in their individual paddocks:

• A three-wall shelter (including two solid, transparent walls) with a roof;
• A shelter with roof and three open sides (metal bars only); and
• A three-wall shelter with no roof.

During each 24-hour test, the horses were allowed to choose between two of these three shelters in their paddock. For one day, they could choose between the first and second type of shelter, and for the other day, they could choose between the first and third shelter, Hartmann said