Effects of cryotherapy on the palmar and plantar digital nerves in the horse

The duration of anesthetic effect and the histopathologic changes resulting from a controlled freeze of the palmar and plantar digital nerves in the horse were evaluated. Two techniques were compared: (i) nerves were frozen by direct application of the cryoprobe after surgical exposure and (ii) nerves were frozen by percutaneous application of the cryoprobe to the overlying skin. Return of skin sensation and ability to detect a stimulus were used to determine return of nerve function. The duration of anesthetic effect was significantly (P less than 0.005) longer for nerves frozen after surgical exposure than for those frozen by the percutaneous technique (mean 156 days vs 47.5 days). At the termination of the study, horses were euthanatized and all nerves were examined histologically. Neuromas-in-continuity were observed in 10 of 28 frozen nerves. Classification was based on the involvement of the supporting fibrous connective tissues of the nerve, endoneurium, perineurium, and epineurium. The direct technique of freezing the nerve after surgical exposure was repeatable and could be used to provide temporary neurectomy in the horse. The percutaneous technique caused a temporary loss of pain perception, but could not be relied on to interrupt nerve function for longer than a few weeks.     

Ileal impaction in the horse

Twelve cases of ileal impaction in the horse were reviewed. Clinical features of the disease included evidence of mild abdominal pain, reduced or absent intestinal sounds, rectally palpable distended small intestine, gastric reflux, and in the early stages, normal peritoneal fluid. Surgical correction of the impaction was accomplished in 10 horses. Of 8 horses discharged from the hospital, 7 returned to full function. It was concluded that the shorter the duration of colic before surgical intervention, the better the prognosis.     

Fusion of the distal intertarsal and tarsometatarsal joints in the horse using intraarticular sodium monoiodoacetate

Six normal horses received 3 intra-articular injections of sodium monoiodoacetate (MIA) in the distal intertarsal (DIT) and tarsometatarsal (TMT) joints of one hindlimb. Injections were at three week intervals, and post injection pain was controlled with routine administration of phenylbutazone for five days following each injection. All horses underwent a gradually increasing exercise programme consisting of walking and trotting beginning one week after the first injection and continuing for 24 weeks. All treated joints showed increasingly severe radiographic evidence of degenerative joint disease with time. Clinical signs were mild or absent during exercise. All treated joints showed radiographic and histological evidence of fusion 24 weeks after the first injection. Amount of radiographic fusion ranged from 54.49 per cent to 88.64 per cent of the joint space. Histologically, the joint space that appeared radiographically fused was filled mainly with woven and lamellar bone. Fibrocartilage and fibrous tissue was seen frequently in the transition between fused and unfused areas. Articular cartilage in unfused areas was thin, fibrillated, hypocellular and histochemically showed diminished proteoglycan content. Existing joint space was filled with fibrin and necrotic, acellular chondroid matrix. We conclude that MIA will produce fusion of the DIT and TMT joints of normal horses in 24 weeks, and may offer a relatively easy, inexpensive and non-invasive treatment for distal tarsal osteoarthritis in the horse.     

A study in animal ethics in New Brunswick

Society uses animals in ever-increasing numbers and ways, providing ethical challenges. Decisions about animal use are guided by the social consensus ethic towards animals. Because there is no clear social consensus ethic, these decisions are difficult. Society's ethic is changing and a "new ethic" towards animals is emerging. This study addressed the need to better understand society's ethics towards animals. Qualitative research methodology (focus groups) was used to study 7 different animal-interest groups. Qualitative data analysis was computer-aided. The group ethical position towards animals of its own group interest was determined for each group. The animal welfare, companion animal, and veterinary groups took Rollin's Position, a position based on both the Utilitarian and the Rights Principles; the farmer and trapper groups the Utilitarian/Land Ethic position, a dual position based on actions producing the greatest amount of pleasure and the least amount of pain for the greatest number, and preserving the integrity, stability, and beauty of the biotic community; the hunter group the Utilitarian/Judeo-Christian position, a dual position based on actions producing the greatest amount of pleasure and the least amount of pain for the greatest number, and having dominion over animals; and the naturalist group took Rollin's Position/Land Ethic. All these groups perceived medium to extreme ethical responsibility towards animals of their own group's interest that are used by others. The study showed that the predicted "new ethic" towards animals is in New Brunswick society and it is Rollin's Position.