You can carefully place a bucket of sparkling clean water under a horse’s nose, but you can most definitely not make them drink. Especially when they’re in the trailer – where during hot summer days, they are in danger of dehydration. Hydrating might require a bit of creativity if you have a horse who is a bit more finicky.
Make them a cocktail: Horses are sugar fiends. In the same way we’re tempted by a Pepsi when we know we should be drinking plain H2O, horses will actually choose sweetened water over the more healthy (boring) alternative. While not ideal, drinking sugar water is better than not drinking at all. Before you leave on your next trip, play bartender with your horse. Do they prefer Kool-Aid, Gatorade or apple juice? You can even add a splash of peppermint oil to the water. Perhaps a sprig of fresh mint, and a slice of cucumber for garnish. Please note that a diluted amount of flavour should do the trick, and that I was (mostly) joking about the garnish.
Be cool: Horses are just like humans in that many prefer chilled water when the temperature rises. Running the hose longer, until the coldest water comes out, could encourage them to drink more. If you want to get fancy, the same insulators that keep water buckets warm in the winter can keep them cool in the summer. This can work perfectly if you’re hauling around a covered bucket of “home water” in the trailer with you.
Play hard to get: I remember being a kid, and wheedling desperately to get horses to drink by vocally pleading and cupping my hands full of water right under their nose – it seemed to backfire. Eventually, I just started standing still, staring into the water bucket I held and ignoring the horse in question. Either they would get curious, or just be glad to drink in peace. This method was definitely more effective.
Get some wind in their mane: There’s making a horse drink, and then there’s keeping those fluids in their system instead of being sweated out. Keeping as many windows and vents open as you safely can will help them stay cool and dry. One trainer I had told me a story about driving across the country with her horse in an old stock trailer. She layered three fly masks one on top of the other to keep the bugs out of his eyes, but other than that and a light fly sheet he was exposed to the summer elements. While it’s not the modern ideal of horse travel, I bet he stayed nice and cool.
Take a chill pill: Stress can cause horses to become overheated and sweaty, and trailering itself is a sometimes stressful activity. Taking multiple short, easy local trips with a nervous horse for “practice” in the months and weeks leading up to a long haul journey could help them to grow accustomed to trailering – and therefore less likely to lose their marbles.
When all else fails, food: A horse needs to be a complete weirdo to refuse food. Fruits, veggies, fresh grass and bran mashes have high water contents, as opposed to the hay they’re snacking on in the trailer.