Oral magnesium and boron found to reduce headshaking in horses

Various treatments have been tried to help headshaking horses, including face masks, nose nets, nutritional supplements, antihistamines, corticosteroids, neuromodulation, and even surgery.
Various treatments have been tried to help headshaking horses, including face masks, nose nets, nutritional supplements, antihistamines, corticosteroids, neuromodulation, and even surgery. © UC Davis School of Veterinary Medicine

Giving magnesium and boron can benefit headshaking horses, the findings of research suggest.

Trigeminal‐mediated headshaking, which used to be called idiopathic headshaking, is caused by a low threshold of firing of the trigeminal nerve in the face.

In most cases, the condition is worse during spring and summer, and geldings are over-represented.

Various treatments have been tried, including face masks with ultraviolet light protection, nose nets, nutritional supplements, antihistamines, corticosteroids, neuromodulation, and even surgery on the nerve.

Results have been variable.

Unsuccessful management can leave horses with uncontrollable clinical signs, often leading to poor performance, wastage, and, in severe cases, euthanasia.

Owners in a survey indicated that magnesium supplementation decreased headshaking behavior in 40% of horses with an over-sensitive trigeminal nerve.

Some horses affected with trigeminal‐mediated headshaking have ionized magnesium concentrations below normal levels, and giving them an infusion of magnesium sulfate has been shown in a study to decrease headshaking by 29%.

Researchers at the University of California, Davis, set out to see whether adding magnesium and boron to the diet of affected horses would influence headshaking behavior.

Their study, reported in the Journal of Veterinary Internal Medicine, also included boron supplementation, as it is known to increase ionized magnesium concentrations in the blood.

Shara Sheldon and her colleagues hypothesized that magnesium supplementation with or without boron would decrease headshaking. They also hypothesized that boron would enhance magnesium absorption, further increasing blood concentrations of ionized magnesium and further decrease headshaking.

Their study involved six healthy geldings used as controls and six geldings diagnosed with trigeminal‐mediated headshaking.

The experiment ran over 42 days, with the horses divided into three groups to be rotated through three week-long diets.

One diet comprising hay and a pelleted feed combined with a quarter of a cup of canola oil and two tablespoons applesauce. Another comprised hay and the pelleted feed combination supplemented with magnesium. The third diet comprised hay and the pelleted feed combination supplemented with both magnesium and boron.

The magnesium was given in the form of magnesium citrate, at a rate of 24.2 milligrams per kilogram of body weight, and the boron was given as boron citrate at a rate of 2 milligrams per kilogram of body weight.

The horses had a washout period of a week between each diet, during which they received only hay.

Blood samples were taken for biochemical analysis at the start of the study, when horses had been on a hay-only diet for a week, and after each week of supplementation.

All three diets were found to increase the levels of ionized and total magnesium in blood when compared to the baseline hay diet. However, these levels were highest in the horses receiving the magnesium and magnesium-boron combination.

Horses receiving the three treatments had a significant reduction in headshaking when compared to the hay-only diet.

Magnesium in combination with boron had the greatest effect, assessed as a 64% reduction in headshaking when compared to the hay diet only. This combination reduced headshaking by 36% when compared to the diet of hay and pelleted feed.

The most severely affected horses were found to enjoy the greatest benefit of magnesium supplementation.

“Oral supplementation with magnesium or magnesium in combination with boron should be considered in horses affected with headshaking,” they said.

“The increased response to boron should be investigated further,” they added.

The researchers acknowledged that their study involved a small number of horses and only short‐term supplementation.

“A longer duration of magnesium supplementation would have been useful to investigate the long‐term effects in headshaking behavior,” they said.

“Although the overall decrease in headshaking behavior in this group of six horses might not reflect the effects on the headshaking population at large, this is a promising therapeutic option that should be investigated in a broader population of horses affected with trigeminal‐mediated headshaking.

“Although magnesium supplementation did not completely alleviate all headshaking behavior, a reduction might improve the horse’s quality of life and performance, make a horse rideable or manageable, and avoid euthanasia.”

Magnesium supplementation could be considered, especially if ionized magnesium was low, as was found in the horses with headshaking in this study, they said.

Supplementation with magnesium could be considered as an adjunct to other treatment attempts for the management of the condition, they said.

The full study team comprised  Sheldon, Monica Aleman, Lais Costa, Kalie Weich, Quinn Howey and John Madigan, all with the University of California, Davis.

Effects of magnesium with or without boron on headshaking behavior in horses with trigeminal‐mediated headshaking
Shara A. Sheldon, Monica Aleman, Lais R.R. Costa, Kalie Weich, Quinn Howey, John E. Madigan
Journal of Veterinary Internal Medicine, 16 April 2019, https://doi.org/10.1111/jvim.15499

The study, published under a Creative Commons License, can be read here


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10 thoughts on “Oral magnesium and boron found to reduce headshaking in horses

  • April 20, 2019 at 1:56 am

    My gelding was diagnosed with headshaking syndrome over three years ago. I give him Hydroxyzine HCL (CMPD-V) 500mg/scoop powder twice a day. Sometimes three times if I notice him nodding his head a lot. I would love to try the magnesium supplement also. What one is the most eatable? He is very spoiled and picky. I would appreciate any help I can get on this matter. Thank you

  • April 20, 2019 at 4:17 am

    If ionized magnesium was low, perhaps it’s not a deficiency but a regulation issue, the electrolytes not working properly. Electrolytes not working properly has already been linked to tying-up and anhidrosis.

  • April 20, 2019 at 8:25 am

    Was the boron in powder or? I have only found it in capsules for humans.

    • September 24, 2020 at 3:20 pm

      Dear Anne and others borax is available at the supermarket very cheaply, while your there buy some Epsom salts. Borax is the sodium salt of boron, and epsom salts is the magnesium salt of sulphur.
      Add a level teaspoon of borax and a soup spoon of Epsom salts to a mug of hot water to dissolve and pour over food and mix in well. Use the borax 2 or 3 times a week the magnesium daily.

      And while your at it take an eighth of a teaspoon of the borax disolved in water daily along with a magnesium tablet daily for a pain and stiffness free existence.

      Arthritis and all bone and tendon problems, joint problems, worn cartridge are all boron deficiency.
      Are you aware that proprietary animal feeds contain no boron, why you ask? Read the borax conspiracy by Walter last.

    • November 15, 2020 at 5:05 pm

      20 Mules is the common and most popular brand in the USA. Used by many people now that’s it’s being rediscovered since the FDA labelled it poison. It is less toxic than table salt.
      It costs about $5-7 for a lb box.

  • April 21, 2019 at 1:03 pm

    Hay and pelleted feed is not a specific enough description of the horses’ diets.
    Is there a more specific account of what was fed please?

  • April 22, 2019 at 5:26 am

    Do they make a powder in Boron for horses and where can I get it?

    it would be perfect if it came together with magnesium!!

  • September 3, 2019 at 9:47 am

    I have been using magE and have noticed a big improvement in my gelding head shaker. Where can I get boron from? I am in Australia

  • June 25, 2020 at 8:15 pm

    Why did the study include magnesium citrate instead of magnesium asparatate?


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