A Hindu person. This is not only because the cow is an incarnation of their lord Krishna but because it's their mother as it provides its nourishing milk and urine for free. The plural form of the "son of a cow" is Cow's children.
Canadian 1: Sorry look at that person! What is he doing?
Canadian 2: Sorry, he's a son of a cow, he's shitting on the street.
Canadian 1: Hahaha nice!
Barb's back was up against the wall since all her solutions to fixing her problems were failing. However, she grit her teeth and continued to problem solve, thinking to herself, "There is more than one way to skin a cow."