A farmer was worried that none of his pigs were getting pregnant.  He
called a vet and asked what he should do if he wanted more pigs. The vet
told him he should try artificial insemination.

The farmer, not wanting to appear stupid, answered "okay" and hung up the
phone. Unclear on what the vet meant by artificial insemination, the farmer
decided it must mean he had to impregnate the pigs himself, so he loaded all
the pigs in his pickup and drove down to the woods and shagged them all.

The next day he called the vet again, and asked how would he know if the
pigs were pregnant. The vet told him they would be lying down  rolling in the
mud, but when he looked out the window not even one was lying down. So, he
loaded them up in his pickup again and drove them to the woods and shagged
them all again.

To his dismay they were all standing the next morning. So, again he  loads
the pigs in his truck, drives them to the woods and shags them for the third
time.

By the next morning the farmer is beat, so he asks his wife to hop out
of bed and look out the window to see what the pigs are doing. She says
"hmmm - that's weird, they are all in the truck and one of them  is blowing
the horn".