UConn study links poor coat condition to higher parasite loads

A student works with a horse in the UConn stables
(c) Jason Sheldon / UConn)

Poor coat condition in horses has long been associated with heavy parasite burdens. A new
study from the University of Connecticut provides fresh evidence supporting this link and introduces a new tool to help assess it.

Led by Associate Professor Jenifer Nadeau in UConn’s Department of Animal Science, researchers developed a skin and coat condition scoring system to evaluate horses alongside their parasite levels. The work, published in the Journal of Equine Veterinary Science, builds on ideas that suggest that outward appearance may reflect an animal’s parasite resistance.

In the study, UConn’s herd of Morgan and Thoroughbred horses was regularly evaluated by students as part of the university’s hands-on equine science program. Faecal egg counts were collected to measure strongyle parasite loads, while separate teams of students, blinded to those results, scored each horse’s skin and coat condition.

The findings showed a clear trend: horses with higher parasite loads were significantly less likely to have good hair lustre. Although factors such as breed, age, housing, and season also influenced coat condition, parasite burden remained a strong predictor. Thoroughbreds, for example, tended to score lower than Morgans across several skin and coat categories.

The new scoring system may provide horse owners, managers, and even animal control agencies with a practical tool to help identify horses struggling with parasite-related issues or neglect. It can complement existing faecal testing by offering a quick visual assessment that may signal when further investigation is needed.

Nadeau plans to continue investigating how parasite levels change throughout a horse’s life and how coat condition can be used as an additional indicator of health. The study reinforces a message well known to equine professionals: paying close attention to coat quality can provide valuable clues about what’s happening inside the horse.

For more details, see:

N. DeBel, J. Johnson, A. Simoneau, B. Sweeney, G. Stearns, M. Amalaradjou, E. Gibbs, T. Moore, J. Nadeau,

The effect of parasitic load on skin and hair coat condition in Morgan and Thoroughbred horses,

Journal of Equine Veterinary Science, (2025) Vol 148, 105546

 

https://doi.org/10.1016/j.jevs.2025.105546

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