insect repellent sailsman

A salesman was traveling through the country side, selling insect
repellent. He came to a farmhouse and tried his pitch on the farmer.
"Sir, my bug spray is so good you will never be bitten again. I
guarantee it."

The farmer was dubious. "Young man, I'll make you a proposition.
I'll tie you out in my cornfield buck naked, covered with that bug spray.
If there is not a single bite on you come morning, I'll buy a whole case
from you. And get everyone in the county to buy a case; we'll make you
rich.

The salesman was delighted. They went to the field and he stripped.
The farmer sprayed him thoroughly with the bug spray and tied him to a
stake. Back to the house went the farmer. The next morning, the farmer and
his family trooped out to the cornfield. Sure enough, the salesman was
there, hanging in his bonds, not a single bite on him. Yet he was a total
wreck! Pale, ghastly, haggard and drawn, but not one bite on him.

The farmer was perplexed. "Son." he said,, Now you don't have a
bite on you but you look like hell! What the devil happened?"

The salesman looked at him through bloodshot eyes and asked with a
weak croaking voice "Doesn't that calf have a mother?"