A farmer buys several sheep, hoping to breed them for wool, chops,  etc...
After several weeks, he notices that none of the sheep are
getting pregnant and phones 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,
he only asks the vet how he will know when the sheep are
pregnant. The Vet tells him that they will stop standing
around and will, instead, lay down in the grass and roll
around when they are pregnant.

The farmer hangs up and gives it some thought. He comes
to the conclusion that artificial insemination means that
he has to impregnate the sheep. So, he loads the sheep 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 sheep. Seeing
that they  are all still standing around, he concludes that
the first try did not take and loads them into the truck
again. He drives them out to the woods, bangs each sheep
twice for good measure, brings them back and goes to
bed. Next morning, he wakes to find the sheep 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 sheep and, upon returning home, falls
listlessly into bed.

The next morning, he cannot even raise himself from
the bed to look at the sheep. He asks his wife to look
out and tell him if the sheep are laying in the grass.

"No", she says, "they're all in the truck and one of them
is honking the horn."