Recent trends in halter breeding have given rise to Arabian horses with extremely concave features, raising concerns that the trait is detrimental to the animal's welfare. Comparisons have been made to a similar trend with some dog breeds, where show judging awarding certain features has led to breeders seeking an ever more exaggerated form, with little concern as to the inherent function of the animal. Some veterinarians speculate that an extremely concave face is detrimental to a horse's breathing, but the issue has not been formally studied.