Pyometra Pyometra – This word brings chills to veterinarians. Why? Because it signifies that a common surgery was not performed and a female dog of cat is now in a potentially life-threatening condition. Pyometra is an accumulation of pus in the uterine body. If a female dog or cat  is spayed, there is no way to contract this disease. Pyometras occur in middle to older aged dogs. The signs or symptoms you notice may include depression, increased drinking, vomiting, a foul-sme