Investigation on the "Club Foot" disorder in Arabian Pureblood horses reared in Italy

Horses used in equestrian disciplines are subjected to intense exertion, making the athlete’s physical integrity a vital point, in order to optimize performance as well as to limit the onset of traumatic disorders. Several parameters are involved in choosing a subject for sport activities, one of the most decisive being the absence of any disorder or malformation of the limbs. The aim of this research was to detect the incidence of the disorder commonly referred to as "Club Foot” or “Mismatched Foot” in Arabian Pureblood horses, attempting to understand its causes. In this breed the pathology is widespread because in their environment of origin, the rocky desert, a hard and almost goat's hoof is not invaleable so selection against this disorder has never been done. The Club Foot is defined as a acquired or congenital flexural deformity of the distal interphalangeal joint, caused by a shortening of the musculotendinous unit of the deep digital flexor tendon (DDFT). The hoof capsule is distorted and the palmar angle of the third phalanx increases to 60° or more, and the horse is forced to walk on his toes. Most commonly, this condition affects the forelimbs, one or both. In the congenital forms, the newborn is unable to extend the joint of the distal limb, it cannot place the foot on the ground and subsequently tries to walk on the toe. These deformities are believed to result from mal-positioning of the fetus in the uterus, errors in the nutritional management during gestation, exposure to influenza virus or, in some circumstances, a genetic link. Traits were taken from 141 adult Arabian Pureblood horses (51 males and 90 females) belonging to 8 Italian different farms during the period 1982-2017. For each horse we observed the presence or not of the disorder following these criteria: alignment of the front hooves, recognition of pathological signs through analysis of hoof axis, presence of dishing on the anterior hoof wall from the coronary band to the toe, hoof width, heel height, frog atrophy, presence of laminitis symptoms. Moreover we considered the enviromental condition of each farm: box stalls, paddocks, nutrition, orientation and other observations. 24.11% of the examined horses (20 females and 14 males) displayed the disorder but no differences between males and females or between shod and unshod were observed. Enviromental conditions do not influence the rate of pathology in the different farms. Future works may include a larger number of animals.