Horse transport and housing has an effect on the animals’ stress levels, according to Shannon Garey, a PhD candidate under the direction of Theodore Friend, PhD, PAS, Dipl. ACAABS, of Texas A&M. Garey presented results of an ongoing study on equine stress at the 2009 Equine Science Society meeting May 29-31 in Keystone, Colo.

Researchers measured cortisol, a stress hormone, in yearling horses that had never been transported, both before and during a six hour ride in a semitrailer. The horses rode either in groups or in individual stalls.

They found that grouping during transport made no significant difference; all horses were equally stressed by hauling. All levels returned to normal within two hours after the haul.

After the transport trial, the researchers moved the horses from group housing to individual stalls. This change caused a nearly 3x increase in cortisol. After 35 days of being stalled, the horses’ cortisol remained elevated above the pre-hauling levels.