A farmer buys several pigs, hoping to breed them for ham, bacon,
etc.... After several weeks, he notices that none of the pigs are
getting pregnant, and calls a vet for help.  The vet tells the
farmer that he should try artificial insemination.  The farmer
doesn't have the slightest idea what this means but, not wanting
to display his ignorance, only asks the vet how he will know when
the pigs are pregnant.  The vet tells him that they will stop
standing around and will, instead, lay down and wallow in the mud
when they are pregnant.
 
The farmer hangs up and gives it some thought.  He comes to the
conclusion that artificial insemination means he has to impregnate
the pigs.  So, he loads the pigs into his truck, drives them out
into the woods, has sex with them all, brings them back and goes
to bed.
 
Next morning, he wakes and looks out at the pigs. Seeing that they
are all still standing around, he concludes that the first try didn't
take, and loads them in the truck again.  He drives them out to the
woods, bangs each pig twice for good measure, brings them back and
goes to bed.
 
Next morning, he wakes to find the pigs still just standing around.
One more try, he tells himself, and proceeds to load them up and
drive them out to the woods.  He spends all day shagging the pigs
and, upon returning home, falls listlessly into bed.
 
The next morning, he cannot even raise himself from the bed to look
at the pigs.  He asks his wife to look out and tell him if the pigs
are laying in the mud.  "No," she says, "they're all in the truck
and one of them's honking the horn."