People spay their female dogs for a few reasons. Spaying prevents unwanted litters, wards off certain ailments and tends to eliminate undesirable behaviors that occur when a dog is in heat or estrus. In some cases, a spayed female may still behave like she's in heat. A number of possible explanations exist for this phenomenon.
It's Probably Ovarian Remnant Syndrome
Occasionally, after a dog has been spayed, she will appear to go back into heat, as soon as weeks later or as long as years later. She will display all the usual behavioral signs, as well as the physical ones, such as bleeding and swelling of the vulva. Assuming that your dog was genuinely spayed and there wasn't a mix-up at the surgery, the phenomenon is usually ovarian remnant syndrome. It occurs when a small amount of ovarian tissue remains inside your dog after spaying and starts to become functional.
The Syndrome Can Be Treated
While dogs with ovarian remnant syndrome can't become pregnant, they should still receive treatment. The best course of action is for your dog to have an exploratory laparotomy to find and remove the remaining ovarian tissue. If this is unsuccessful, or if your dog is now too old or too unwell to have surgery, the symptoms can be managed with medication.
Behavioral Therapy Might Be Appropriate
Female dogs in heat can display certain unwanted behaviors, such as aggression, anxiety and roaming. If your dog is acting in this way after being spayed but isn't having any physical signs of heat, she may just have behavioral issues, especially if she's like this all the time. The ideal thing to do in this case is to consult a professional dog behavior expert.
Other Issues Can Be at Root
If your dog is displaying the physical and behavioral symptoms of heat but doesn't have ovarian remnant syndrome, it is likely to be caused by another medical issue. A number of illnesses can cause these signs, including certain malignant tumors. It's essential that you take your dog to a vet right away so the cause of her symptoms can be determined and treated.