Sheep Ovine carcasses are classified as lamb, yearling mutton, or mutton depending on their age as evidenced by their muscles and bones For the purpose of this fact sheet we will be discussing lamb The flavor of lamb is milder than mutton Lamb is produced from younger animals, typically less than a year old, and mutton is produced from older animals Most lambs are brought to market at about 6 to 8 months old A lamb weighs about 140 pounds and yields approximately 46 to 49 pounds of edible lean retail lamb cuts, semi-boneless If the phrase "Spring Lamb" is on a meat label, it means the lamb was slaughtered between March and October The term comes from olden times when lambs born in harsh winter weather would have little cha