Uterine effusion in dogs is pyometra, which requires surgery to remove the diseased uterus in the hospital. If it is not removed, it may cause the dog's uterus to become enlarged, lack of energy, loss of appetite, fever, etc., which is harmful to the dog's health. bigger. Generally, pyometra is more likely to occur in older female dogs, especially female dogs that have never given birth. Therefore, if you do not plan to let your dog have children, it is best to sterilize your dog.