Providing healthy water sources


Our horses’ wild ancestors drank from a variety of water sources. It’s not surprising then that many people think it’s fine for their own horses to do the same. But this couldn’t be further from the truth, for a number of reasons.

Over the decades, we have effectively polluted most of what would have been usable drinking water, and have added chemicals such as chlorine and fluoride to the rest. To complicate matters, the modern horse’s constitution can often no longer handle some of the things it used to be able to.

Water basics

The importance of good drinking water is not lost on most people. It is as vital for us as it is for our horses. As with most animals, a lack of water to your horse is more detrimental than a lack of any other substance (beyond oxygen). Water is essential for every function, from digestion to cell repair. Dehydration can result in colic, and a host of other health and performance issues. Obvious physical signs of dehydration are not evident until around a 6% loss of body weight. In other words, your horse can be well on his way to dehydration and you won’t even know it. Performance is affected well before the 6% loss.

When a horse has constant access to good water, he will typically only drink for around 30 seconds every few hours. It’s when he doesn’t have access to water for a period of time that you’ll see him take a significant drink.

You can lead a horse to water…

There’s an old saying: “You can lead a horse to water but you cannot make him drink.” But you can increase the likelihood he will take a drink if you ensure his water source is optimally palatable. Here is a chart indicating minimum, average and maximum daily water consumption by body weight:

Working horses, pregnant and lactating mares, and horses with increased salt or protein intake will likely consume more water. Numerous other factors can affect water consumption, including seasonal and temperature changes, diet changes and/or forage quality, health issues and workload.

There’s constant debate over what water temperature is best for horses. What it largely seems to come down to is personal preference for different horses. While most have no problems with cool to lukewarm water, some dislike drinking cold water. The best thing you can do is to monitor your horse, and provide a heated water source in cold weather if necessary. In addition:

• Make sure water is easily accessible at all times.
• Check water sources regularly for debris.
• Clean water sources regularly.

• In cold weather, check water sources often to ensure they have not frozen over.
• If using water heaters, or water near electric fencing, make sure nothing produces a shock that would discourage your horse from drinking. Some are quite wary of getting close to an electric fence in order to take a drink.

Getting technical

There are two simple ways to evaluate the quality of your water source:

1. Conduct a sight and taste test, provided your water comes from a well or municipal system – I don’t suggest you drink out of a pasture pond! It is relatively easy to track water quality if you are drinking the same water as your horse (house and barn on the same system) because you will be able to pick up right away on any changes, such as extra sediment or a change in color or taste.

2. Take a sample of your water to your local testing station and have them thoroughly test it. This service is often free, and will give you a comprehensive report on any issues with your water.

What to look for

a) TDS, or total dissolved solids, is typically the main number used in determining water quality. Wikipedia defines TDS as “an expression for the combined content of all inorganic and organic substances contained in a liquid which are present in a molecular, ionized or microgranular (colloidal sol) suspended form.” High levels of TDS may render water unfit for consumption.

b) You must also consider levels of water contaminants, which may vary depending on geographic location, farm management techniques, and other environmental factors.

c) You must also take a look at any bacteria or viruses that might be in the water. The most commonly tested for bacteria are coliforms/M.P.N (i.e. E. coli). If found in the water, they can indicate that more/other types are also present in varying levels. These can include the fairly common salmonella, and the less common giardia.

Nature’s water sources

Though not ideal in these times, there is usually little reason your horse cannot drink from a naturally occurring water source in his pasture. He may do so anyway if there is one present, even if you do offer an alternate source such as a trough or automatic waterer. The same rules still apply, though – just because the water is “there” does not mean less work on your part. Monitor and test the water on a regular basis to ensure quality. Beware of manure or chemical runoff into the water source. Check regularly for debris, freezing over and so on. Blue green algae is toxic and found in many natural fresh water sources. The algae produce cyanotoxins which are dangerous to horses and humans.

Keys to good quality

The keys to good water quality are appropriate management, monitoring and testing. Any water situation can go awry. Moving water, such as in streams and rivers, is more likely to have bacterial contaminants due to runoff. Those with well water more often have to deal with high or out-of-whack mineral concentrations. And still/pond water is very prone to algae – this can include water troughs and buckets that do not get emptied or cleaned often enough. Just because a water source becomes dangerous doesn’t mean your horse won’t drink it – some toxic substances may not actually decrease the water’s palatability or your home’s intake from the contaminated source.

a) These contaminants are not toxic but at concentrations above the amount given may decrease water palatability. In contrast, many of the other contaminants listed may be toxic if water containing concentrations above those given here is the only water consumed.

b) A higher concentration may be safe for horses. A concentration of 4 ppm is probably marginally safe for horses, but water with more than 8 ppm should be avoided.

c) High nitrate concentrations occur most commonly as a result of fecal contamination.

d) Although chronic selenium toxicosis has been reported from consuming water containing 0.005 to 0.002 ppm selenium, concentrations below 0.01 ppm are not generally considered harmful.

e) Or 833 ppm sulfur. Sulfate concentrations above 300 to 400 ppm can be tasted, and above 750 ppm can have a laxative effect in people. The highest no-effect concentration in horses isn’t known but is probably similar to that for cattle and swine (below 2500 ppm).

f) High zinc concentrations may occur where galvanized pipes are connected to copper. This results in electrolysis, releasing zinc from the galvanized pipes into the water.


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