Penobscot Veterinary Hospital can perform radiology exams, which can be used for OFA certification. An OFA hip certification should be done on dogs being bred that are susceptible to hip dysplasia, such as Labradors. The X-rays for an OFA hip certification are performed at age two or older, although a preliminary OFA can be done around one year of age. OFA rates passing hips as Excellent, Good, and Fair. These ratings are spelled out on each certificate and an OFA number is assigned. When purchasing a dog, you should request to see an OFA certification which most reputable breeders will have readily available.