What is "feeder cattle"

n. (context agriculture English) steers or cows that are mature enough to be placed in a feedlot in preparation for slaughter

Feeder cattle are steers (castrated males) or heifers (females) mature enough to be placed in a feedlot where they will be fattened prior to slaughter. Feeder calves are less than 1 year old; feeder yearlings are between 1 and 2 years old. Both types are often produced in a cow-calf operation.