I was absolutely exhausted. I was also, and I was aware of it at the time, just a little bit crazy. When I finally did get a break, I crashed for days.
So what does this have to do with writing about horses? Well, if you think about historical periods in which the concept of the vacation was nonexistent and most of the human population struggled nonstop to scrape a living, it clarifies the state of mind that many of your characters would be in. It also explains the extravagance of religious and cultural festivals. Those were a chance for everyone to catch a break from the daily grind and even, if they were lucky, to get a little rest.
If they were even luckier, some of the animals got a rest, too: from tilling the fields, hauling the wagons, even going to war. A holiday for the humans could mean a holiday for the horses (and donkeys and oxen and hunting dogs).
Or not. If horses were being ridden or driven in the processions, they were definitely working, especially if they were carrying or pulling heavy loads.
A horse can pull a wheeled vehicle up to about six times his own weight, and more of course if he’s hitched with one or more other horses. He can carry up to a quarter of his weight; more than that and he’s likely to be in trouble. Carriage horses tend to be larger than riding horses, though this isn’t invariable, and even a tiny Mini horse can pull a small cart. However for most purposes, the coach or dray horse in your novel will run from 1200 to over 2000 pounds. The riding horses will range from 900 to about 1400 pounds on the average, if they’re designed to carry adult humans. Smaller horses and ponies will for the most part carry less weight and smaller riders, though the small ponies of the Shetland Isles and the pony-sized (under 14 hands or 48 inches) horses of Iceland have regularly carried grown men. Those are sturdy little animals, tougher and stronger by the inch and the pound than horses.
But even the toughest island pony can’t go on forever without relief. Horses like humans benefit from breaks in the routine. Too long of course and they lose condition–like human athletes and laborers–but a day or two every so often is a great restorative.
This applies even more to periods of prolonged or heavy exertion: marathon treks across country, long marches interspersed with battles, lengthy cattle drives, competitive circuits in which horses perform to the maximum over short, intense periods such as races, three-day events, or horse shows. The more intense the exertion, the more carefully the horse has to be conditioned up to it, and the more important it is that he be given time to rest after it.
Pushing too hard and too long can have some similar effects to those that you’ll see in a human, and some that are distinctive in horses. Exhaustion, damage to muscles and joints, weakening of the immune system, all can happen to horses as well as humans.
So can something called broken wind, which is the equine form of chronic obstructive pulmonary disease (COPD) . For the most part equine COPD occurs in cold climates, where horses are kept for long periods in closed barns with constant exposure to dust, mold, and bacteria. It shows up less often where horses live outside in the clean air, though some horses can develop allergies in any place and climate. As for those horses in Victorian novels whose wind was broken after a nightlong, nonstop gallop in horrible weather followed by inadequate or nonexistent care, see above regarding weakened immune systems. In an era without vaccinations, horses would be highly susceptible to respiratory infections and much more likely to suffer damage to the lungs resulting in COPD.
A horse with COPD will be said to have heaves, which is basically asthma, and will have a similar set of reactions to a human with this chronic disease. A “heavey” horse is not hard to detect; if he’s had the syndrome for a while, in addition to the wheezing, he’ll have a chronically tucked up belly and a horizontal groove which is called a “heave line.” He can only be worked lightly if at all, and has to be kept carefully protected from dust and allergens–which usually includes feeding him something other than grass or hay (both of which are loaded with allergens).
Even if the horse’s wind remains sound, if he’s been used long and heavily without a break, over time he’ll develop arthritis that will eventually cripple him. In the shorter term, and much more dangerously, if he is pushed relentlessly, especially on hard or rough ground, the circulation in his legs and feet will be damaged to the point that the inner structures of the feet give way. This is called founder, or more technically laminitis. Mild cases are treatable, and modern veterinary science can do wonderful things with medication and foot care. In older days, founder would generally be a death sentence.
A mildly foundered horse in a lower-tech society might be diagnosed by noticing signs of pain or tenderness in the feet (especially in front). The horse might stand with his forelegs propped in front of him to relieve the pain. An experienced horseman will feel heat in the hooves, and detect a digital pulse at the fetlocks. He may try to reduce the pressure by standing the horse in a running stream or lake, or in cool mud.
If the horse is severely foundered, the horseman will be able to feel the point of the coffin bone coming through the sole. When that happens, the horse can’t be saved.
Other complications of overwork include colic, which I’ve blogged about before, and “tying up” or muscle spasms, which can be chronic or even fatal. Tying up is a form of weekend warrior’s disease–often seen on Monday morning in horses ridden heavily all weekend and left standing around with little or no exercise the rest of the week. It’s just as important to get regular exercise as it is to get regular breaks–to develop condition and then keep it, with sensible management and a clear understanding of how a horse’s body and mind are put together.
That doesn’t mean that in an age when the horse was the main form of transportation, that horsemen didn’t know how to keep that transport running. They would have to make judgment calls and, when necessary, sacrifices. A messenger rides the feet off his horse in order to the news to the city that will be destroyed otherwise; a knight drives his horse to the charge again and again until the horse falls. These are legitimate sacrifices, provided the writer knows that’s what they are–and isn’t writing the horse as a motorcycle that whinnies (early, often, and at times when no actual horse would do that).