Could My Horse Be Selenium Deficient?


“What symptoms are seen in selenium deficient horses? I have a 30 yr. old AQHA gelding, about 2-3 months ago he went off his feed and water, seemed depressed and was moving stiffer than usual. Thats when I noticed his muscles twitching especially in his shoulder and flank areas. The twitches range from 4-5 up to 20-30 per minute in each area; with an average of 10-15 per minute. He is constantly shifting his weight on his feet when standing ( he is navicular) and does a lot of licking with his tongue. I live in the Pacific NW. He is on lush green pasture and local 2nd. cutting grass hay; beet pulp with an alfalfa cube soaked in and has a mineral salt block which I just noticed does not have selenium in it. He is on previcorx for arthritis and a probiotic (probios). He has tested negative for EPM (just lost a horse to that) PSSM and HYPP. Other than greying in his face he still has the body of a halter horse. Any help or ideas would be greatly appreciated.”

Answer by Ph.D. Equine Nutritionist, Kelsey Johnson Nonella:
Sorry to hear about your horse. It definitely sounds like he is selenium deficient. Depression, muscle stiffness, and muscle spasms are all symptoms of selenium deficiency. Interesting fact, plants have no requirement for selenium, so you can have an amazing, very nutritious hay crop with almost no selenium in it. You would be best to start him on Horse Guard right away. From his symptoms it sounds as though he is pretty deficient in selenium, so you may consider having your veterinarian check his whole blood selenium levels, and if he is low enough he may need an E-Se shot, and then a double dose of Horse Guard for 6 months, after which you could return to just 2 ounces a day. I would recommend feeding Horse Guard and putting a plain white salt block out after the mineral salt block is gone. Selenium salt blocks contain less than 10% of the selenium that your horse needs per day.

About Dr. Kelsey J. Nonella Ph.D., P.A.S.

Kelsey J. Nonella, Ph.D. is an equine nutritionist who was riding horses before she could walk. Her love for horses drives her to help educate people on what their horses’ needs in order to have happy, healthy horses. Kelsey went to Cal Poly receiving a Bachelor’s of Science in Animal Science and then onto West Texas A&M, where she got her Masters and eventually her Doctorates in Equine Science. At A&M, Dr. Nonella did extensive research on Selenium within horses. Click here to view her research. Kelsey’s colleagues have mentioned her as one of the United States equine Selenium experts.
View all posts by Dr. Kelsey J. Nonella Ph.D., P.A.S.

2 Responses to “Could My Horse Be Selenium Deficient?”

  1. Debi Elbert says:

    I was told my 19 year old Palomino Missouri Fox Trotter that I just purchased is anemic, he is also skinny and because of founder sometime in his life is prone to founder, he has a great appetite. I was told to get Trivecta but I already have him on Horse Guard Super Weight Gain. What would be best?

    • mm Dr. Kelsey J. Nonella Ph.D., P.A.S. says:


      I would recommend that you keep your Fox Trotter on Super Weight Gain until he reaches the desired weight. The extra cool energy that he is receiving, and higher levels of probiotics will help to balance his gut, and help him to starting putting weight on. Once, he is at the desired weight I would then recommend switching him to Trifecta, which will provide him joint support, in addition to a vitamin-mineral supplement, hoof supplement, and gut supplement.

      I would also look into the possibility of him having ulcers, as anemia is typically the underlying cause of another issue.

      I hope this helps. Let me know if I can answer any more questions.


      Dr. Kelsey Nonella

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