Chronic fluoride poisoning in domestic equines, horses (Equus caballus) and donkeys (Equus asinus

Repeated chronic fluoride (F) exposure for prolonged duration through water, air, and food causes F poisoning in the form of fluorosis in both humans and domestic and wild animals. However, among domestic equine animals, horses (Equus caballus) and donkeys (Equus asinus), chronic F poisoning caused by industrial fluoride pollution and fluoridated drinking water has been well studied. But these studies in these animals are still very limited. On the other hand, the sample size of these animals in these studies is also very small. Nevertheless, these studies are important from the point of view of veterinary medicine and toxicology. In these animals, F-induced diverse toxic effects or pathognomonic signs such as dental mottling or light to deep brownish staining on enamel surface of teeth, lameness, stiffness, skeletal abnormalities, crooked legs, hoof deformities, pain in joints, weight loss, unthriftiness, poor health, standing with an arched back, difficulty eating, rough hair coats, allergy or urticaria, anaemia, colic, diarrhoea, constipation, retention of urine, repeated abortions, and sterility have been reported. At the mean F concentration, in the range of 1.4 to 3.3 ppm in the drinking water, the prevalence of osteo-dental fluorosis in horses and donkeys has been found to be 78.7% and 100%, respectively. In present communication, chronic F poisoning in domesticated equine animals, horses and donkeys and its prevention in these animals have been focused. Simultaneously, research gaps have also been highlighted for researchers and veterinary scientists to do some advanced research works on these animals.