Health Update

What Affects Heart Health In Event Horses?

- Sushil Dulai Wenholz

In both horses and humans, the autonomic nervous system is largely responsible for things we take for granted—regulating our cardiovascular, gastrointestinal and other systems without our conscious involvement. There are sympathetic and parasympathetic aspects of the autonomic system. The former is connected with a fight-or-flight response, while the latter is related to a “rest-and-digest” mode, explains Olivia Lorello, VMD, CVA, from the Swiss Institute of Equine Medicine at the University of Bern.

The two sides are meant to balance out. “When one is high, the other is low,” says Dr. Lorello. A chronic imbalance is a strong indicator of potential heart trouble. And that makes it an interesting area of study for the eventing world, which has been haunted in recent years by a number of heart-related equine fatalities.

Dr. Lorello and her colleagues wanted to begin defining normal values of autonomic tone markers and how they change over a competition season—something that to date has been incompletely described in event horses.

The team gathered two groups of warmbloods, all approximately the same age. The control group consisted of eight noncompeting horses and the test group consisted of 17 eventers competing at Preliminary through CCI*** levels. Not all horses completed the study for either rider-related or horse health-related reasons.