An exposure pathway-describes a unique mechanism by which an. individual or population is exposed to chemical or physical agents at or originating from. a site. Each exposure pathway includes a source or release from a source, an exposure. point, and an exposure route.
Terminology: Young cattle are called calves. A young male is called a bull calf; a young female before she has calved the second time is called a heifer (pronounced heffer). A young female that has had only one calf is sometimes called a first-calf heifer..
A calf is a newborn bovine or dairy animal. A heifer is a young female that has not yet had a calf and begun to milk. A cow is a mature female bovine or dairy animal and a bull is a mature male bovine or dairy animal. Cows give milk for about ten months (or about 305 days) after having a calf. They stop milk production during a two-month dry period before giving birth and entering another ten-month milk cycle.