You may request a copy of the videotape, IF there was one and IF Petco has not overtaped or destroyed it. However, you cannot compel production absent a lawsuit.
Whether that is worthwhile is a function of how badly your dog was hurt. You have said nothing about that.
The foregoing is for general information purposes and does not establish an attorney-client relationship.
I agree with the previous answer and the liability will be contested , but if the store wants to avoid liability you should put them on notice to preserve the evidence, if any.
Please be sure to indicate the best answer. If this answer was helpful, please mark as helpful below. Only. If and until you and I sign an Agreement for Legal Services, I am not your attorney. These answers are provided for informational and/or novelty purposes