Sometimes I wonder if my horses are part beaver! More than one evergreen pine, deciduous tree, lilac bush and burn pile has been chewed to splinters as if the horses are planning to construct a dam in the middle of the pasture. This is especially true with the two four year olds. They are turned out at least 8-12 hours each day where long stem forage is always available yet continue to naw on any post or rail not slathered in Cribox or covered in hot wire. Knowing full well that these horse's nutritional needs are being satisfied, I must assume that there are behavioral or even physical needs for this tree butchering. Wood chewing has long been observed as a destructive stable vice in horses, but can it be turned constructive to mitigate boredom? My mission this week was to reframe the research and/or discussion around wood chewing.
Wood chewing is terribly destructive to any equine facility. (And expensive too while lumber prices skyrocket!) I myself have brand new post and rail fencing, and the thought of teeth marks on any bit of it grates on my nerves. However, what if the answer to my problem is to embrace wood chewing as a common equine behavior rather than strategize for complete prevention? A recent guest lecture about enrichment opportunities for horses in confinement changed my problem solving trajectory. Alayne Blickle of Horses for Clean Water encouraged horse owners to provide non-toxic tree limbs and bushes as forms of entertainment for horses in confinement. I thought this was an excellent suggestion that seemed to point to a fundamental, if not essential, need for chewing.
First off, let's take a Google tour around the publicly available, peer-reviewed information on wood chewing. In my search for scientific inquiry, wood chewing came up surprisingly often especially in the management of racing horses. It was always framed as an unwanted stable vice. It was also surprising how common it really is across disciplines. The occurrence of wood chewing studied in Thoroughbred race horses, Standardbred race horses, eventers, dressage, endurance and pleasure horses consistently landed between 30-54% (Hanis et al., 2020; McGreevy et al., 1995; Waters et al., 2002)! That's 1 in 3 to 1 in 2 horses at any given modern horse facility. Stable vices such as wood chewing are not only ordinary, but have been around since horses were domesticated.
According to research wood chewing is correlated with...
1) amount of time stabled (positive relationship; redbo et al., 1998; McGreevy et al., 1995)
2) amount of roughage available (negative relationship; Redbo et al., 1998)
3) use and amount of pelleted feed/forage in diets (positive relationship, Redbo et al., 1998; Willard et al., 1977)
4) weaning, housing, and feeding strategies in young TBs (Water et al., 2010)
5) even the dominance ranking of the dams (Waters et al., 2010)
6) amount of exercise (negative relationships; Kyrzak et al., 1991)
My horses ALWAYS have long stem hay in front of them (a variety of grass species and alfalfa) along with salt blocks in every paddock and pasture. They are turned out in pairs for 8-12 hours a day. I know that their nutritional needs are being exceeded, and the two worst beavers only get 1.5 lbs a day of ration balancer. Therefore, I'm going to chalk it up to boredom, instinctual behavior, and losing baby teeth. I'm not going to stress about it!
So, if wood chewing is a relatively common behavior even for healthy horses, how can we redirect this activity from our nice barn structures, fence posts and rails to an alternative? For starters, I will be providing my young horses with non-toxic tree limbs from here on out especially in the winter and spring months when grazing is limited. Yes, there is a risk of wood splinters getting stuck in teeth and throats (there are tradeoffs for everything that we do with horses), but I think the risk is lower than my frustration and fear of fencing projects.
5 Ways to Redirect Unwanted Wood Chewing
Hot wire is your best friend- make sure to keep it hot and keep it secure! The most common mistake made with hot wire fencing is poor grounding.
Cribox Hydrophane™ is EXCELLENT (though a bit expensive to do all your wood fencing) ! The Farnam Chew Stop™ did nothing.
Wrap posts and rails with corrugated drain pipe or well secured chicken wire. The corrugated drain pipes are very safe, look good, and don't break the bank! (I did this at my previous boarding facility, and it worked great!)
Provide non-toxic shrubs, branches and stumps to redirect chewing in confinement areas. Contact your local county extension agency for poisonous plants list.
Provide other enrichment tools like salt licks, toys, feed balls, and slow feeders when appropriate.
My research on the topic of wood chewing has led me to two conclusion; first, wood chewing is relatively common, and secondly, it is NOT related to nutritional need beyond fiber intake and the desire to chew. There are many equine behaviors that get attributed to nutritional deficiency, but in my 14 years of experience I have not found research or anecdotal support for this theory. Behaviors such as wood chewing, copophragy, cribbing, and dirt licking are behaviors associated with boredom and a horse's natural instinct to explore their world with their mouths. Luckily, I have a lot of trees on the property that need trimming, so I won't be short of limbs to "feed" my horses.
Waters, A.J., C.J. Nicol, and N.P. French. 2002. Factors influencing the development of stereotypic and redirected behaviours in young horses: Findings of a four year prospective epidemiological study. Equine Veterinary Journal. 34: 572-579.
Redbo, I., Redbo-Torstensson, P., Ödberg, F., Hedendahl, A., & Holm, J.1998. Factors affecting behavioural disturbances in race-horses. Animal Science,66(2), 475-481. doi:10.1017/S1357729800009644
McGreevy PD, French NP, Nicol CJ. 1995. The prevalence of abnormal behaviours in dressage, eventing and endurance horses in relation to stabling. The Veterinary Record. 137(2):36-37. DOI: 10.1136/vr.137.2.36.
Hanis, F., E.L. Teik Chung, M.H. Kamalludin, and Z. Idrus. 2020. The Influence of Stable Management and Feeding Practices on the Abnormal Behaviors Among Stabled Horses in Malaysia. Journal of Equine Veterinary Science. 94:103230. ISSN 0737-0806,
W. E. Krzak, H. W. Gonyou, L. M. Lawrence. 1991. Wood chewing by stabled horses: diurnal pattern and effects of exercise, Journal of Animal Science. 69(3):1053–1058. https://doi.org/10.2527/1991.6931053x.
Willard, J.G., J. C. Willard, S. A. Wolfram, and J. P. Baker. 1977. Effect of Diet on Cecal Ph and Feeding Behavior of Horses. Journal of Animal Science. 45(1):87–93. https://doi.org/10.2527/jas1977.45187x