This week we take a look at photosensitization in alfalfa-fed horses, surprising poll pressure study results, the benefits of classical music, and thought-provoking racehorse injury studies.
Getting a ‘handel’ on equine stress
The International Society for Equitation Science’s annual conference at France’s Cadre Noir academy, which showcased viewpoints on ‘Understanding horses to improve training and performance’, proposed that classical music may reduce equine stress. Researchers found that during typically stressful activities like travelling and shoeing, the playing of classical music decreased several equine stress indicators.
“It also induced a faster post-stress, equine heart recovery,” said study lead Claire Neveux, who conducted the research in conjunction with the University of Strasbourg and the University of Caen. The findings, which are likely to be of interest to sport horse trainers, were widely reported in the mainstream European press, including the UK’s Telegraph newspaper.
A bit of a surprise
British bitting manufacturer Neue Schule has issued a ‘Poll Pressure Guide’ following a study initiated by the company’s founder, Heather Hyde. The study threw up some fascinating facts, including the finding that with normal rider rein pressure, the hanging cheek or ‘baucher’ snaffle not only does not exert poll pressure, as many riders and trainers believe, but in fact exhibits a poll-relief effect.
Another finding of interest was that the much-loved loose ring snaffle can apply some poll pressure, due to a pulley action caused by the ring dragging down through the bit’s bore-hole. Unsurprisingly, nelson and balding gags feature high up on the poll pressure scale.
Racehorse studies give us food for thought
A study of racehorse injuries was recently published in the Journal of Equine Science which looked at twenty years of Asian veterinary data that measured vertical ground reaction forces on galloping equine forelimbs. The findings showed that incidences of limb fractures increased as dirt track conditions became muddier, and incidences of fractures decreased as grass track conditions became softer.
The study also found that fractures occurred ‘mostly’ at corners, and ‘more frequently’ at the time of changing the leading limb when galloping. Surfaces and weather conditions clearly affect equine traction and vertical ground reaction forces, although there are no comparable eventing studies.
Alfalfa hay can trigger photosensitization
A 2016 study published in the Veterinary Journal found that alfalfa hay can trigger primary photosensitization in horses. (Photosensitization can occur when ‘photo-toxic’ or ‘photo-active’ substances build up in the skin, and interact with sunlight.)
Skin conditions like equine dermatitis can occur as a result in un-pigmented skin, or skin areas with little hair, reported researchers including Birgit Puschner, Professor and Researcher in Molecular Biosciences at America’s University of California.
The photosensitive reactions are proposed to occur as a result of horses eating phototoxic compounds in affected alfalfa (lucerne) hay, while secondary photosensitivity can arise when a horse’s liver cannot properly excrete some compounds.
The compounds Chlorophyll A and B and Pheophorbide were suspected to play a role in alfalfa-induced primary photosensitization, however it was deemed in the study that these compounds were not responsible; the guilty plant pesticide residues have, to date, not yet been identified.
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