connected to a blood oxygenator and the heart is bypassed. The defective heart valve is removed and the replacement valve, typically from bovine pericardium, is precisely sewn into place. The dog’s heart is then restarted and monitored for at least two hours after the surgery is completed. Due to the expense, this is not a common procedure. Prosthetic limbs While small dogs and cats can survive comfortably with three legs, larger dogs, horses, and farm animals require the limb to support their weight. Surgery has also been done on birds that are used for breeding purposes. Each prosthetic limb is custom-made to fit the individual needs of the specific animal. Orthopedic implants UC Davis’ equine orthopedic surgery program has developed an implant that has been successful in human surgery for a long time. The intermedullary interlocking nail is used to treat horses with a long leg bone fractures. The nails are positioned within the medullary cavity and can be secured to the proximal and distal fracture segments using transcortical screws which penetrate both cortices of the bone, as well as pass through holes in the nail. The nail is placed centrally in the axis of the bone to give full support, unlike bone plates that only give exterior support. In an attempt to aid horses with bowed tendons, research has been done using carbon fiber implants that consist of about 40,000 fibers in total each of which is 8 micrometres in diameter. These fibers induce tissue growth and result in a structure of carbon and tissue about 8 mm in diameter. See also Surgery Veterinary medicine Hip dysplasia (canine) Heart valve dysplasia American College of Veterinary Surgeons References Implants (medicine) Veterinary procedures Organ transplantation