This week, Dr. David Marlin, a leading equine scientist, published an article on tongue ties: “Lack of Evidence for Tongue Ties – Time to BAN!”. Here are some of the more relevant passages. While reading, please bear in mind that Dr. Marlin is not philosophically against horseracing.
“Tongue Ties…must cause significant discomfort and pain, yet they are still widely used by racehorse trainers in some jurisdictions. The usual clinical claim is that tying the tongue forward and down with a tongue tie ‘widens the pharynx’ and ‘stops dorsal displacement of the soft palate’ (DDSP, ‘choking down’ or ‘gurgling’). The best direct evidence does not support this claim.”
Any gains performance-wise, Dr. Marlin says, is more likely the result of better control – the tie, as we all well know, prevents the horse from getting to the cruel, painful bit with his tongue, giving the jockey a more unencumbered subjugation.
His summary:
“Tongue ties are almost certainly uncomfortable and cause stress (and very likely pain) in a substantial proportion of horses. Application and wear produce clear behavioural signs of aversion: mouth gaping, head tossing/shaking, ears back, and attempts to dislodge the device. Horses that have worn them before often show stronger reactions, indicating they do not simply habituate.
“Physiological markers are consistent with a stress response: elevated salivary cortisol in resting horses and a shift toward sympathetic (fight-or-flight) activity on heart-rate variability. Physical effects include tongue discolouration from restricted blood flow, occasional bleeding or swelling, and rare reports of more serious injury. There is no good evidence they widen the airway or help most racehorses breathe or run better. The most rigorous overground endoscopy study found that pharyngeal diameter during hard exercise was actually smaller with a tongue tie, and laryngeal measures did not improve.
“Taken together, the welfare cost is well documented while any performance benefit is narrow, poorly supported for the majority of horses, and easily overstated by selection bias.”
