Final answer:
The cow that should not be rebred is the one that received treatment for parasites in the past.
Step-by-step explanation:
In this scenario, the cow that should not be rebred is the one that received treatment for parasites in the past. When a cow is treated for parasites, it indicates that she had a parasitic infection. This can affect her overall health and reproductive ability, making it advisable not to rebreed her.
Learn more about Reproduction of cows