Category: Canine

Mast cell tumor
Mast cell tumor, histiocytic mastocytoma, mast cell sarcoma

Affected Animals:
Mast cell tumors are very common in dogs. Dog breeds more commonly affected include boxers, Boston terriers, bullmastiffs, English setters, and golden retrievers. Older dogs are more commonly affected, but MCT can occur in any age or sex.

Overview:
Mast cell tumors, or MCTs, are among the most common tumors in dogs, with the skin being the most common primary site for MCTs in this species. Mast cell tumors can occur anywhere in the body. The systemic form of mast cell tumors, with visceral, lymphatic or bone marrow involvement is referred to as mastocytosis. Despite the sometimes "benign" appearance, mast cell tumors tend to exhibit a very unpredictable biological behavior. Therefore many veterinary oncologists consider all mast cell tumors malignant until proven otherwise.

The mean age of dogs with mast cell tumors is nine years. Predisposition to mast cell tumors appears to occur in Boxers, Boston terriers, beagles, bulldogs, and Schnauzers. Although Boxers appear to be at a higher risk for development of MCTs, most tumors in this breed tend to be well differentiated.

When feasible, treatment involves addressing the tumor locally, with surgery and/or radiation treatment. In some cases, systemic treatment may be necessary, but is often not successful due to the extent of the disease.

Category: Canine

Chronic degenerative atrioventricular valvular disease, endocardiosis, chronic valvular fibrosis
Mitral valve disease, mitral valve degeneration, mitral valve insufficiency

Affected Animals:
Dogs. The disease is extremely rare in cats. Mitral valve disease more commonly affects middle-aged and older small-to-medium sized breeds. Breeds with a high prevalence of this disease include the cavalier King Charles spaniel, the Chihuahua, the miniature poodle, the miniature pinscher, fox terriers, Boston terriers, and miniature schnauzers. Males are 50 percent more likely than females to be affected. Cavalier King Charles spaniels may have symptoms at an earlier age than other breeds.

Overview:
Mitral valve disease is a serious heart condition caused by the abnormal function of the valve that separates the upper and lower chamber of the left side of the heart. Dogs with mitral valve disease typically have difficulty exercising and a cough that increases in frequency as the disease progresses towards congestive heart failure and pulmonary edema.

The heart is made up of four chambers: the left and the right atria and left and right ventricles. Each upper chamber, or atrium, is separated from a lower chamber, or ventricle, by an atrioventricular valve. The valve on the left side of the heart is called the mitral valve, and the valve on the right side is called the tricuspid valve. In a normal dog, the leaflets of each valve open to allow blood to move from the atria into the ventricles and then close completely when the heart pumps the blood out of the ventricles and into the blood vessels.

1.      Right Atrium

2.      Right Atrioventricular Valve (Tricuspid Valve)

3.      Right Ventricle

4.      Left Atrium

5.      Left Atrioventricular Valve (Mitral Valve)

6.      Left Ventricle

7.      Papillary Muscle

8.      Chordae Tendinae

9.      Diseased Mitral Valve Leaflets

Mitral valve disease is caused by the accumulation of the plaque within the heart valve, although the cause of this plaque is unknown. The plaque results in the deformation of the valve leaflets and regurgitation of blood back into the atrium. This leakage in turn causes a decrease in blood flow from the heart. A valve that fails to close completely will allow blood to leak back into the atrium, resulting in a heart murmur.

In order to compensate for this deficiency, the heart dilates and the volume of blood pumped increases. This compensation allows a dog to remain free of symptoms for some time, but simultaneously worsens the disease, the eventual result of which is congestive heart failure.

Mitral valve disease is more common in middle-aged and older small-to-medium breeds. While the prognosis for dogs with mitral valve disease is poor, some dogs may be managed with medications for a period that varies from case to case. Dogs may live for years after manifesting symptoms of mitral valve disease.

Category: Canine

Orchidectomy
Neutering, castration,

Affected Animals:
Young dogs may tolerate the surgery better than older dogs, but dogs of any age can have this procedure performed safely if the appropriate precautions are taken.

Overview:
Orchidectomy, or neutering, is a procedure that is performed on many male dogs. There are ethical reasons, as well as behavioral and medical conditions, that warrant this surgery. Although an orchidectomy requires general anesthesia, it is a short and simple procedure. Most dogs will return to their normal behavior by the following day. Nevertheless, they will need to have their activity levels reduced for the week following surgery; a rest period will allow the incision to heal properly.

Most veterinarians will discuss the benefits of neutering during one of the initial puppy visits. Because of incorrect "old wives’ tales" about neutering circulating in the public, many new owners feel hesitant about this surgery. However, the veterinarian can dispel many of these myths and discuss any other specific concerns.

Category: Feline

Orchidectomy
Neutering, castration,

Affected Animals:
An orchidectomy should be considered for any unneutered male cat, in order to prevent unwanted reproduction and undesirable behaviors such as spraying and roaming. Many medical conditions also require neutering as part of treatment, including testicular neoplasia, severe testicular or scrotal trauma, and perineal urethrostomy, a surgery for male cats that have recurrent urethral obstructions. This surgery may be performed on cats of any age, though younger cats will have an easier recovery.

Overview:
Orchidectomy, or neutering, is a procedure commonly performed on male cats for ethical, behavioral, and medical purposes. The surgery requires general anesthesia, but is a short and simple procedure. Most cats behave normally following surgery, but should be kept quiet and indoors for a week afterwards, in order to facilitate the healing of incisions and prevent complications. An orchidectomy will not affect a cat’s personality, and it will prevent certain potentially serious problems, including unwanted reproduction and undesirable behaviors such as spraying and roaming.

Most veterinarians will discuss neutering and its benefits with an owner when their pet is still a kitten. Some owners are hesitant when it comes to having their pet neutered, but a veterinarian should be able to counter any of the prevailing popular myths. Talking to owners of neutered cats is the best way for a cat owner to become more comfortable with the procedure.

Category: Canine

Noise phobia
Fear of thunderstorms, thunderstorm phobia, fear of loud noises

Affected Animals:
Any breed of dog of either sex may be affected. In one report, the age at which dogs were presented for this problem ranged from one to 11 years. However, 78 percent of the cases presented were between the ages of one and five years.

Overview:
A very common problem in dogs, noise phobia is an excessive fear of a sound that results in the dog attempting to avoid or escape from the sound. As a result of its phobia, a dog may injure itself and damage or destroy property. Sounds that noise-phobic dogs commonly fear are thunder, firecrackers and gunshots.

Category: Canine

Osteochondrosis, osteochondritis dissecans (OCD)
OCD, osteochondrosis, osteochondritis dissecans, shoulder/elbow/stifle dysplasia, joint mice

Affected Animals:
Dogs, humans, pigs, horses, cattle, chickens, and turkeys.

Overview:
Osteochondrosis is a disease that affects cartilage formation; the cartilage, due to an abnormal thickening, is unable to receive a normal supply of nutrients from the joint fluid, causing it to become weaker and more susceptible to damage. Cartilage provides a protective gliding layer between the bones in a joint, and when it is injured and lesions form, the dog will experience pain, lameness, and arthritis. Lesions may occur on one or both sides of the body.

1. Scapula
2. Humerus
3. Humeral Head
4. Floating Cartilage and Bone
5. Detachment Site

In all animals, osteochondrosis can affect many different joints, but in the dog, the most common sites of disease are the shoulder, elbow, stifle or knee joint, and tarsus or hock. Generally, osteochondrosis occurs in young, large to giant breeds, although it is also seen in mixed breeds. The most commonly affected breeds include the German shepherd, golden and Labrador retriever, rottweiler, Great Dane, Bernese mountain dog, and Saint Bernard.