Algae in Horse Water Troughs: Is It Safe?

Our nutrition expert offers tips for keeping algal blooms to a minimum in your horse’s water trough this summer.

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Algae in Horse Water Troughs: Is It Safe?
Algae in troughs is a common problem once temperatures start to rise.| Photo: iStock
Q: For most of the year my horses live out full time on pasture. In the summer their water trough grows a lot of algae. Is it okay for them to drink from the trough when it has algae, and what can I do to stop it growing?

A: Algae in troughs is a common problem once temperatures start to rise. To grow, algae need water, sunlight, and a nutrient source. Nutrients can come from organic material that has blown into the trough, manure, or even your horse’s saliva.

While most algae don’t pose a direct health concern, certain types of blue-green algae release toxins that can lead to colic and diarrhea. Additionally, a lot of algae might make the water less desirable to your horse and lead to reduced water intake. Keeping algal blooms to a minimum in your troughs is therefore a smart idea. Here are some solutions:

1. Shade

Placing a shade structure over troughs can help reduce sun exposure, slowing algae growth. However, this obviously incurs a cost and might not work in all trough locations

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Written by:

Clair Thunes, PhD, is an equine nutritionist who owns Clarity Equine Nutrition, based in Gilbert, Arizona. She works as a consultant with owners/trainers and veterinarians across the United States and globally to take the guesswork out of feeding horses and provides services to select companies. As a nutritionist she works with all equids, from WEG competitors to Miniature donkeys and everything in between. Born in England, she earned her undergraduate degree at Edinburgh University, in Scotland, and her master’s and doctorate in nutrition at the University of California, Davis. Growing up, she competed in a wide array of disciplines and was an active member of the U.K. Pony Club. Today, she serves as the district commissioner for the Salt River Pony Club.

7 Responses

  1. Hi Cindy, will this work without the oregano? Approximately how much is a generous amount and how often do you add to water trough? I top off almost every day to help keep the water fresh.

  2. I make a tincture by stuffing a couple handfuls of fresh oregano I grow myself, into a gallon jug of vinegar, and add a generous splash to my horses’ 50 gallon water trough when I fill or top it off. my horses have learned to love the taste of vinegar because I also add organic raw cider vinegar to their supplements as a probiotic. the vinegar makes the water in the trough acidic enough to prevent most algae growth. also discourages ravens & other wild critters from drinking out of the trough. I’ve been doing this for years & my horses are very healthy, no colic ever.

  3. Hi Maureen, I was wondering would the pool tabs work on a cement horse trough as well?

  4. What can I do to get rid of the algae in my horses cement trough permanently? I heard that baking soda sprinkled in the water will kill it and I also heard that baking soda willl clean it and after it’s cleaned to add a little bit more baking soda to keep the water fresh clean and clear of algae. Is this true?

  5. I use swimming pool chlorine tabs to control the algae in my horse troughs. They release chlorine slowly and can be broken down into smaller pieces for smaller tubs. Be sure to get quality tabs, not like the ones Walmart or similar stores sell. I get mine from the people who service my pool. I use them year-round so the horses always have the same tasting water. A 70 pound pail of 3″ tabs lasts me a year or more and I have one big trough for my Belgian mare and 3 small tubs for my minis. I have been doing this for probably 20 years or more with no ill effects. Now if we could find something that would dissolve the dust in the water.LOL.
    Maureen Arnold

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