“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.