How do you make your bull so strong?

An elderly couple went to watch a contest for the strongest bull.
After the contest they went to the 3rd prize bull's owner, wanting to know what his secret was.

The woman asked; "How donou make your bull so strong?"
The owner said; "You have to make sure the bull makes love once a week." The woman turned to her husband and said;"See!" The old man was displeased but said nothing.

They then went to the 2nd prize bull's owner and the old woman asked the same question, to which the owner replied; "You must make sure your bull makes love 2 or 3 times a week." Again the woman turned to her husband and said; "See! See!"

The old man was annoyed but remained silent.They then went to the 1st prize bull's owner and again the old woman asked the same question. The reply was; "You must make sure your bull makes love at least once every day." The woman turned to her husband and said;"See! See! See!"

This time the old man got angry and asked the owner; "But does your bull always make love to the same cow?" The owner replied; "No, no. Many many cows." The old man quickly turned to the old woman and said; "See! See! See! See!"