Hello I am Dr. Joey. Thanks for trusting me to help you and your pet today. I am a licensed veterinarian with over 16 years of experience. I look forward to working with you.
This is not an uncommon behavior but when to this degree it does indicate there is a problem. It is important to have your veterinarian perform an exam to evaluate for pain in the spine/tail region and evaluate her anal sacs to ensure there is no infection/pain in these locations. In some dogs this can be a seizure-type problem (so more neurological and central brain issue) and in other dogs it is more of an obsessive compulsive disorder. From a behavioral perspective tail chasing often is a response to anxiety and sometimes there are specific triggers when the behavior is new but the dog generalizes over time because the chasing is self rewarding.
The first step is for your veterinarian to do an exam to determine if there is an obvious problem. If not, then sometimes a trial with pain relief medication or anti anxiety medication can be discussed. If not working or no response, then I highly recommend you ask for a referral to see a veterinarian behaviorist (which is a board certified specialist in this area) since these can be very tough situations to work through. For you at home try to reduce any identifiable stressors, teach a relax on cue (may need to work with a trainer to achieve this). The crate could be further enhanced as a relaxation area. Provide predictability by having her settle quietly and be attentive to you for things she values. Sometimes a calming cap could be worth trying, and as mentioned before, sometimes anti-anxiety medication may be useful.
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