Effects of transportation procedures on salivary and plasma cortisol concentrations in cold-blood horses

Abstract

Summary: Horses are often transported. Road transport is stressful for horses and induces various rates of cortisol release related to breed and age. The aim of this study was to evaluate the stress level in cold-blood horses of different ages, in response transport over two different distances. The stress level was evaluated on the basis of cortisol concentrations in plasma and saliva samples taken during transportation procedures. A total of 36 cold-blood mares in the process of being sold and bought were included in the study. The horses were divided into four age-and distance-related groups. Twelve adult mares and 12 fillies were transported 50 km. The other two groups (six fillies and six adult mares) were transported 550 km. Samples were taken at rest, two times during the transportation procedure and 12 hours after transport 50 km or 24 hours after transport 550 km. Salivary and plasma cortisol concentrations increased during transportation procedures and remained elevated 12 and 24 hours after the end of transport. In conclusion, in cold-blood horses subjected to transportation, even 24 hours post-transport rest is insufficient to lower plasma and salivary cortisol concentrations to baseline values. Cold-blood, naive horses seem to be more sensitive to changes in location than to road transport. Saliva samples are useful for the determination of cortisol concentration in transported cold-blood horses.