Osteochonditis Dissecans (OCD) is a developmental condition where a flap of cartilage breaks off from the end of the bone, and lodges in the joint, triggering inflammation and pain. Osteochondrosis (OC) describes the abnormal development of cartilage which leads to OCD.
Obsessive compulsive disorders are uncommon in dogs and characterized by repetitive behaviors so intense they are difficult to interrupt and interfere with daily life.
When dogs eat garlic, onions, or other *Allium* species, red blood cell damage results. This is often called onion toxicosis, no matter what type of allium plant was consumed. **Onion toxicosis is potentially life-threatening**.
Obesity in dogs is the excessive accumulation of fat (adipose) tissue due to caloric intake exceeding caloric expenditure.
Oral resorptive lesions in dogs occur when the hard tissues of the tooth root are destroyed by cells called odontoclasts, leaving a pocket in the tooth. These lesions usually occur where the root and the crown meet, but can occur anywhere on the root.
Organophosphate and carbamate insecticides are commonly used in agricultural and gardening products as well as older generation flea and tick control products. Organophosphate (OP) and carbamate (CM) toxicosis results from exposure to a toxic dose of these chemicals.
Otitis externa is inflammation of the external ear canal and is often referred to as an ear infection. Ear infections and otitis externa are common in dogs.
Ovarian tumors in dogs are rare masses developing due to unregulated cell growth in an intact female dog’s reproductive organs.
Ovarian remnant syndrome occurs uncommonly in female dogs when part of the ovarian tissue remains in the body after an ovariohysterectomy (spay).