Definition of "yearling"

Tom Fettig and his wife, Kim, were there with 60 yearlings, about half of a herd they were helping their son raise on the outskirts of Bismarck.

2021 August 25, Henry Fountain, Benjamin Rasmussen, “‘The Worst Thing I Can Ever Remember’: How Drought Is Crushing Ranchers”, in The New York Times‎

"But is a plebe forbidden to stroll here?""If a plebe did have the brass to try it," replied Anstey slowly, "I reckon he would have to fight the whole yearling class in turn."

1910, H. Irving Hancock, Dick Prescott's Second Year at West Point, page 84