Loosely Tied Heads Improve Respiratory Health During Transport

Without question, transport brings about stress in horses, with maximal stress noted in the first 30 minutes, making shipping an important welfare concern. Furthermore, transporting horses is associated with health concerns, including injury, gastrointestinal disorders, respiratory tract infections, and pneumonia.

“One factor that may contribute to bacterial contamination of the airways and respiratory issues is head position during transport. An elevated head position may interrupt the horse’s natural tracheal clearance mechanisms, contributing to accumulation of secretions in the trachea and pneumonia or pleuropneumonia,” explained Catherine Whitehouse, M.S., a Kentucky Equine Research nutrition advisor.

To assess head position, specifically head height, during transport, six Thoroughbreds experiencing long-distance transit (870 miles or 1,400 km over 22 hours) were tied facing forward with either a short or long rope.^* The short rope was 20 inches (50 cm) long and prevented horses from lowering their heads below withers height. The long rope was 37 inches (95 cm) long and allowed horses to lower their heads to carpus (knee) level. Hay and feed were offered to all horses during transit, positioned at a height of 35 inches (0.9 m) and 63 inches (1.6 m) from the floor for the long- and short-rope groups. Water was offered every four hours during a mandated 30-minute rest for the drivers.

 Tracheal washes were obtained seven days before transit and again immediately after returning from transit. Bacteria in those washes were counted using “colony-forming units.”

Horses were also observed via video cameras in the trailer during transport.

During the long-distance transport, the research team noted the following:

• Horses in the long-rope group spent approximately 50% of their time with their heads down;
• Both groups spent the same amount of time eating during transport;
• Horses did not drink during the rest stops, which was thought to lead to the observed 5% weight loss noted in both groups of horses;
• Horses exhibiting “licking,” which was viewed and validated as a sign of stress, was higher in the short-rope group;
• Bacterial numbers were increased more than 100 times in the short-rope group after 22 hours of transport, whereas no increase in bacterial numbers was noted in the long-rope group.

“Horses with loose head restraint showed lower signs of stress and had fewer bacterial loads after transport than horses transported with tight head restraint,” stated Whitehouse.

The researchers further suggested that this strategy of using a long rope likely protects horses against transport-associated respiratory disease.

In addition to head position, having hay in the breathing zone of horses also poses a respiratory health risk, potentially resulting in exacerbation of equine asthma. It is therefore important to provide clean, dust-free hay during transport.

“To support respiratory health in horses that either travel frequently or over long distances, consider supplementation with omega-3 fatty acids, as well as vitamins E and C. These supplements offer many health and performance benefits but should be incorporated into the diet several weeks or months before travel for best results,” recommended Whitehouse.

^*Takahashi, Y., H. Niwa, Y. Ebisuda, K. Mukai, T. Yoshida, S. Raidal, B. Padalino, and H. Ohmura. 2024. Increased freedom of head movement mitigates stress and bacterial load in the airways of horses during transport. Frontiers in Veterinary Science 11:1477653.