Headshaking Supplement Efficacy Tested

Sure, many horse owners add feed supplements to their horses' diets to help maintain joints, hooves, and hair coats. But what about to stifle headshaking? Researchers at the University of Liverpool in England recently tested the efficacy of a feed supplement designed to alleviate this behavior in a trial involving 32 horses previously diagnosed with chronic, idiopathic (with no discernible cause) headshaking.

Study horses consumed the supplement for four weeks, followed by a placebo for four weeks, with a two-week interval between the two treatments. The researchers videotaped the horses at rest and at exercise at the outset of the study, after the first treatment, and after the second treatment. Two veterinarians assessed the headshaking recordings using a ranked scale in a blinded, randomized setup. Owners also completed a ranked questionnaire assessing their horses’ headshaking throughout the treatment course.

After reviewing the videos, the team concluded that there were no significant differences in headshaking when the horses received the supplement and when they consumed the placebo. Likewise, owners scored headshaking signs similarly whether the horse was on the supplement or on the placebo. Researchers concluded this supplement provided no benefit towards alleviating headshaking.

“There was no effect detectable in any of the horses treated with the placebo or the test material when assessed by a panel of experienced veterinarians,” noted study author Derek Knottenbelt, OBE, BVM &S, DVM, Dipl. ECEIM, MRCVS. “The findings are only significant insofar as they emphasize the importance of testing claims made by anyone in terms of treatment for any disease. The fact is that claims can be made when there is no medical implication, but the number of companies which subject themselves to this kind of trial on an open forum is extremely low.”

Interestingly, the team noted, owners reported overall improvement when their horses received either treatment—supplement or placebo—as opposed to no treatment at all. “It was clear from the results that there was a perception of improvement with either the placebo or the test material when the results were scrutinized by the owners themselves,” said Knottenbelt. “This proxy placebo effect is well-recognized.”

Chronic, idiopathic headshaking is a frustrating and potentially dangerous disorder. “This disease needs to be sorted out," Knottenbelt said. "We do not understand it at all, and yet it is a major welfare condition that affects a significant proportion of horses of all types under all conditions across the world. The reality is, however, that the human equivalent of this diseasehas attracted literally billions of pounds of research funding, and they are very little further forward than they were 25 to 30 years ago. It should not be said that there is no progress, but it is painstakingly slow and is extremely difficult because of the nature of neurologic disease.”

This study, “A randomised, blinded, crossover study to assess the efficacy of a feed supplement in alleviating the clinical signs of headshaking in 32 horses,” was published in May in the Equine Veterinary Journal

Disclaimer: Seek the advice of a qualified veterinarian before proceeding with any diagnosis, treatment, or therapy.