Cats and dogs have very different blood grouping systems. Cats inherit blood types and have an A-B blood group system where by A is dominant over B. Cat blood can be classed as Group A, B or AB. Group A which can be either A/A or A/B. Group B which is always B/B or rarely cats can be AB. | Cats and dogs have very different blood grouping systems. Cats inherit blood types and have an A-B blood group system where by A is dominant over B. Cat blood can be classed as Group A, B or AB. Group A which can be either A/A or A/B. Group B which is always B/B or rarely cats can be AB. |