Casuistic evaluation of tongue tie use in standardbred and thoroughbred racehorses in Germany-A questionnaire study

Abstract

Tongue Ties (TTs) are devices used to fixate the tongue to the mandible and hold it in this position during exercise with the goal of facilitating control of the horse and as a conservative treatment for dorsal displacement of the soft palote (DDSP). They have been used in racehorses for over 100 years. The conflicting evidence of its efficacy at preventing DDSf? combined with public concerns of potential welfare implications, have led to the banning of TTs by the Federation Equestre Internationale (FEI) in 2004. However, TTs are still approved for use in racing in many countries. Their use is documented during racing by their racing authorities, but not in Thoroughbred (Direktorium fur Vollblutzucht und Rennen, DVR) and Standardbred (Hauptverband fur Trabereucht, HVT) racehorses in Germany. The prevalence of TT use is about 5% in racehorses in Great Britain, increasing to up to 89% of horses with a diagnosis of DDSP. Therefore, they are used very commonly and often in combination with other equipment. The objective of this study was to collect casuistic data on their use during training and racing in Germany. Data of 499 Thoroughbred racehorses were collected by sending questionnaires to 153 Thoroughbred trainers registered ot the German racing authority (DVR). In addition, data of 82 Standardbreds were collected from 9 trainers. Of these 581 horses, 133 participated in international racing, while the others were trained for national races. Trainers were asked for their reasons to use TTs in training and racing, expected and seen changes by their use, material and fixation time of the tongue strap, the occurrence, frequency and characteristics of negative side effects. Overall, 17.2% of all horses were trained and 19.3% were storied using TTs. Young 3- A nd 4 year old Standardbreds were trained more often using TTs than Thoroughbreds, while more Thoroughbreds than Standardbreds 5 years and older wore TT during training and racing. The most common fixation time of the tongue was 20 minutes. Most trainers used elastic nylons (22/35), while leather straps (7/35), cotton (2/35) and elastic (14/35) were less common. Positive effects most commonly reported by trainers were inhibition of tongue displacement over the bit (37/41) and reduction of respiratory noise (24/41). The majority also reported improved exercise performance in training (63%) and racing (76%). A slight majority of 22/41 trainers reported no adverse effects associated with the use of TT, while the others described negative effects in up to 10% of applications (14/41) or even more than 12 % (5/41). The most common adverse reactions here were discoloration of the tongue under fixation (n= 16) followed by bleeding (n = 4) and paralysis (n = 1). In conclusion, despite common use and positive effects reported by Thoroughbred and Standardbred trainers, the application of a TT seems to impair animal welfare in a number of racehorses. The use of TTs was outlawed in Thoroughbred racing in June 2018 in Germany, but is still allowed for Standardbreds by the racing authorities. The results of our study might provide objective evidence for future decisions by the racing authorities in Germany.