With the seemingly endless bit choices available in tack catalogs, choosing the one that best optimizes the horse’s performance and welfare can seem like a daunting task. Equitation scientists are now tackling this topic, and they’re starting with the traditional single-jointed snaffle bit.

"The traditional (snaffle) bit has hardly changed over the past 3,000 years, and it’s time to question whether it’s really appropriate for horses in the modern age," said Klaske Van der Horst, MSc, lecturer at University of Applied Sciences HAS Den Bosch in Hertogenbosch, The Netherlands. Together with her colleagues, van der Horst compared performance and welfare criteria between horses ridden with a traditional 18-mm snaffle bit and an 11-mm, two-jointed "Myler" bit with a tongue port.

What they found was that performance stays the same with either bit, but the Myler appears to cause horses less stress, van der Horst said.

Fifteen Dutch Warmblood horses were trained over a period of three weeks by their regular experienced riders, sometimes using their own snaffle bits and sometimes using a Level 2 or Level 3 Myler bit (depending on the shape of the horse’s mouth). At the end of the three-week period, each horse performed two dressage tests: one with the traditional bit, and one with the Myler bit. Van der Horst evaluated the horses’ heart rate interval variations during movement to evaluate stress levels (the greater the variation, the lower the stress), and she checked for fluctuations in neck positions and observed how much saliva they produced. She also noted the number of times they gaped open their mouths and how often they were on or off the bit