Yesterday, I took my 9 week old puppy to be vaccinated. She had a great day, very mellow. She has always been a bit nippy, but we have had success with teaching her certain commands, stopping play and ignoring her when she bites, diverting her attention, etc. Yesterday, she had the best day yet and did very well at the vet's office. Everyone loved her, and she had no major biting sessions. Today, however, almost from the moment she got up, she has been biting and lunging at me and other family members, biting harder and in different places than normal. I have had to place her in the crate three times to calm her. Up until today, I have always managed to avoid crating her for biting. I could always get her to calm down after a moment or two. Now, not only is she attacking constantly, she is super sensitive to noises and seems to have a ravenous appetite (even for a lab). Has anyone had experience with sudden changes in behavior following vaccination or a different idea about what this might be?
I would hazard a guess the difference is more in your head than anything real. Based on my 6.5 weeks experience with our lab puppy they can have really good days where they hardly bite followed by what seems like really bad ones.
When Johnny had his first set of shots, he slept for 24 hours, then right as rain and no reactions to vaccines over the years. Maybe the pup is responding to the immune system working to do what's intended. If a behavior change persists for a week, then check back with the vet