Be sure your horse is hydrated
January 30, 2019
It's like clockwork. When Stacy Tarr, DVM, brings his 20-year-old gelding up to take care of his recurring lameness, the old horse will drink one full tub of water every night.
"If I come out and there is more than an inch of water in that tub, that's unusual," Tarr said, and the veterinarian takes note.
Water consumption is crucial to good health, and changes in it often signal other health problems.
"You need to know how much water your horse normally drinks," Tarr said. "The exact amount is going to vary between summer and winter, but it is pretty consistent."
Winter weather often compounds the task of physically getting water to your horse, as well as getting your horse to drink water, especially in freezing conditions.
"What I worry about over the winter is that in order to maintain their body heat, horses have to eat more roughage," Tarr said. "That's how their internal furnace works: the hay and roughage they eat ferments and creates body heat. They are eating more to stay warm.
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"But horses often don't drink enough when it gets cold," he added. "Eating more roughage and not consuming as much water leads to dehydration and impaction-caused colics."
Impaction colic caused by dehydration can happen over several days or weeks, especially if a horse is chronically not drinking enough water.
"That's my biggest concern in winter," Tarr said. "The best prevention is to know your horse and how much water he drinks."
Experts vary on what constitutes a normal range of adequate water intake for the average horse. Depending on size and individual metabolism, normal consumption for a mature horse can range from six to 12 gallons per day.
"It can be hard to tell whether or not your horse is getting enough to drink," Tarr said, "especially if he is watering out of a creek or a lake, or if you use automatic waterers."
Manure consistency is variable and, in Tarr's experience, is not a good indicator of dehydration. One basic way to test if a horse is dehydrated is to check skin turgor, or firmness.
"If you gently pinch the loose skin below the eye or on the neck, in a couple of seconds the skin should flatten right back out again," he explained. "That indicates good turgor and adequate water content. If the skin stays tented up or pinched, it's because the horse is dehydrated.
"However, the only way to confirm how dehydrated a horse might be is to draw blood and do a packed cell volume test and check the red blood cell count in the blood. If it's too concentrated, it's because he doesn't have enough fluid in his blood circulation."
Horses must have constant access to fresh water, Tarr said. Drinking water that is close to freezing temperature also reduces a horse's core body temperature.
"When it's cold out, if the water is warmer, horses drink more," Tarr said. "If they drink from a [freezing] water tank, they just don't get as much."
Research at the University of Pennsylvania School of Veterinary Medicine's New Bolton Center proved it in 1994. Its herd of feral ponies drank 40 percent more heated water when offered a choice between that and near-freezing water. The study showed that ideal water temperature is between 40 and 65 degrees Fahrenheit.
Heating options include automatic waterers with built-in heaters; however, like watering from a creek or lake, they don't allow you to monitor how much water your horse is actually drinking like a bucket or a trough would. In addition, automatic waterers still need to be checked daily to make sure they are running and not freezing over. Floating tank heaters and models that sit on the bottom of the tank are options, but those types of heaters need to be regularly checked for electrical problems, too. The researchers at New Bolton Center found that carrying out buckets of heated water was the easiest way to get it to their feral herd.
Regardless of the method, keep the water fresh, Tarr said.
"Bigger tanks will freeze less than a smaller one," he said. "Our tanks are of the size where horses drink it down, so [the tanks] don't get stagnant and fill with ice. We fill our [200- to 250-gallon] tanks twice a day.
"It's best to heat the water if you can. If not, keep a sharp shovel handy."
–Quarter Horse News