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How Much is Too Much Water for New Foals?
by: Delores Kuhlwein
It’s a saying we all know too well: You can lead a horse to water, but you can’t make it drink. Linguists estimate the phrase originated back in the year 1175, so man’s ability, or lack thereof, to control a horse’s water intake has been on our minds for centuries – literally!
As we approach foaling season, a common question for many foal owners is whether a young foal should be drinking water right alongside the dam. Since having an adequate water supply is so closely linked with health, whether one is horse or human, free access seems only natural.
In fact, most available research articles advise letting a foal determine his or her needs individually, but some alarming cases of foals gorging themselves on water have popped up over the last several years. The exact causes are still uncertain, but arming yourself with knowledge regarding normal intake for a foal, and any other horse, might be the best practice yet.
What to Expect with Foals
Monitoring a foal’s water intake might not be the first thing on every foal owner’s mind, but knowing what’s common behavior serves as just another essential piece of information in a foal owner’s toolbox. According to Dr. Kathleen Crandell, Equine Nutritionist at Kentucky Equine Research, you should expect your foal’s drinking behavior to be somewhat similar to adult horses.
Crandell explained in a 2001 Kentucky Equine Research study that foals imitate their dams and other adults when learning how to drink, but instinct encourages this behavior as well. It’s the same instinct that allows orphan foals to learn to drink from a bucket.
Yet, the amount and frequency a foal drinks does vary from mature horses, and it increases with age, “Foals drink water less frequently than adults, and their drinking bouts are shorter. The duration has been measured at around a half a minute in foals, while an adult can drink as long as one minute,” states Crandell. She includes statistics for typical water consumption of a young foal: “One-month-old foals drink about 17.5 kg (39 lb.) of milk per day and about 4 kg (9 lb.) of water per day, while two-month-old foals drink about the same amount of milk but more water, about 5.5 kg (12 lb.) per day.”
The nutritionist also provides facts about typical water drinking behavior for all horses:
• Horses drink more water when it’s available to them at all times than when restricted to a couple of drinking opportunities per day.
• Outside temperature will influence water intake; intake may decrease 6-14% when there is a significant drop in temperature. Conversely, the higher the temperature, the more water the horse will consume.
• Diet influences water intake. When horses are consuming pasture grasses (which usually contain 70-80% water), the desire to drink water and the total quantity will be much less than when eating dried forages like hay.
• Temperature of the water influences intake. Intake can decrease by as much as 40% when the outside temperature is below freezing and the water temperature is low. Keeping the temperature of the water over 60°F (16° C) improves intake in cold weather.
• Salt and water consumption have a linear relationship. The more salt a horse eats, the more water it will drink. (Crandell)
Red Flags to Heed
However, it’s the departure from typical behavior that should raise red flags for the owner or breeding manager monitoring a young foal. M. Phyllis Lose, V.M.D., addresses the issue of the “water-drinking syndrome” in the classic breeding and foaling guide, Blessed are the Broodmares.
In the book, Lose warns of foals that satisfy their fluid requirements by ingesting water instead of milk, including those that stop nursing entirely. “The effect upon the foal’s gastrointestinal tract is not only undesirable but critical. Intractable, debilitating diarrhea will soon develop in foals that substitute water for milk. Unless the source of water is removed and the foal is promptly treated, the severe weakening fluid imbalance and resulting dehydration from lowered resistance will open the door to the ever-present and always-ready pathogenic bacteria,” (Lose, 113).
Lose recommends monitoring the water intake until the age of four months, but removing the water source from the foal while allowing the dam access and contacting a veterinarian if water gorging is suspected (Lose, 113). While she suggests a foal that drinks an abundance of water is rare, it’s nonetheless addressed as a topic to consider, spanning two pages of her book.
Similarly, Dr. Jimmy Merrill, D.V.M., has experienced approximately 20 cases of the water-drinking syndrome through his practice in Phoenix, Arizona at North Valley Equine. Merrill runs a comprehensive veterinary practice, but specializes in reproduction, and his exposure to young foals has resulted in an all-too familiar recognition of the syndrome. “Some foals will start drinking water excessively in the first few months of life before the normal flora of the gastrointestinal system is fully developed,” Merrill explains.
Although he says the majority of fluid intake for a foal is milk, Merrill is clear to state that water drinking is natural for a foal early in life. But he also agrees that watching the foal is an important task, and certain signs can be telling factors that there is a problem. “Monitor foals closely; they should be hanging out around the watering system. The mare’s mammary glands may become engorged due to lack of nursing, and look for diarrhea that’s not in conjunction with the mare’s heat cycle or is persistent beyond foal heat by the mare,” he says.
Uncharted Territory
Since there have been no formal studies conducted on the syndrome yet, Merrill has had to rely on his vast experience in the field for suspected causes. “I believe it is related to gastric ulcers in foals due to domestication stressors. We do know many, if not most, domesticated foals have some level of ulceration. When this becomes painful, they will do many things to alleviate this pain, such as eating dirt, shavings, excessively drinking water and many other things abnormal to natural nursing and grazing. A foal’s first set of incisors don’t come in until around six days, the second set in six weeks, and then the final incisors come in around six months. With this in mind, it will give you some idea on the progression of natural foal grazing chronology. This is important because most domestic foals don’t have access to grazing and will start developing other habits to naturally replace it, such as eating abnormal things or excessively drinking,” he clarifies.
An abstract from a two-year study of mares and foals living on pasture with free access to water published in the Journal of Animal Science also points to the relationship between grazing and drinking suggested by Merrill. “Drinking by foals was very rare. The youngest age at which a foal was observed to drink was three weeks, and 8 of 15 foals were never observed to drink before weaning,” (Crowell-Davis, Houpt, Carnevale, 1985)
The result of drinking too much water can be dangerous or even deadly, and veterinary attention is crucial. “The excessive drinking causes the normal bacteria in the gut to get disrupted, and a certain bacteria can take over, causing discomfort, gas, and diarrhea. If this isn’t corrected early, several forms of colic can occur. Anti-diarrheal medicine, probiotics, gastric protectants, and some mild painkillers may be warranted,” adds Merrill.
The bottom line? Just like anything else when it comes to horses, excessive behavior is a warning sign for possible intervention, even when it concerns a completely natural element like water. Being aware of a young foal’s water drinking habits, especially if the foal is domesticated, is key to his or her health. Adding the knowledge of what typical or atypical behavior is when it comes to water drinking can become part of every foal owner’s repertoire.
