petMD is the largest global source of pet health information in the world today. Part of a global network of veterinary professionals, petMD’s content was created by veterinarians for consumers and veterinarians.
Consider the following five criteria:
1. Accuracy - Is the information correct?
2. Authority - What are the author's credentials?
3. Coverage - Is the content covered comprehensively?
4. Currency - Is the information current?
5. Purpose - Is the content biased?
If you're not certain, ask a librarian!
Also find and use websites for particular breeds such as the Cavalier King Charles Spaniel Club - USA.