Illustration for article titled The Different USDA Varieties of Lamb and Mutton and What They MeanPhoto: Foxys Forest Manufacture (Shutterstock)

Lamb has something extraordinarily meaty about it. I don’t mean it has a lot of meat on its bones – although it can. I mean the experience of eating it is what eating meat should feel like. It’s often on a bone and has a strong, deep taste that is exactly the opposite of that of a sterile little chicken fillet.

Like beefNot all lambs are created equal, but the types of lamb you see in the supermarket or in the market vary less. According to, “[m]Ore as 90 percent of lamb in the US is rated USDA Prime or Choice. “However, there are three other classes – Good, Useful, and Eliminate. Similar to beef, the quality a lamb receives has a lot to do with the amount of fat present, although age and muscle thickness also affect its rating.


Meat from young lambs (between six and eight weeks old) that is “consistently muscular” with flank fat strips that range from “small” to “plentiful” is considered prime. But as the sheep get older, the need for fat increases. An older lamb needs “modest” to “abundant” stripes to be considered Prime. An annual mutton must have at least moderate fat streaks.

As soon as the sheep age in “mutton area” (older than 20 months), the meat can no longer be classified as prime, regardless of how high-fat it is. (See this graphic from USDA for a visual representation.) All prime lamb cuts are tender, either due to their youth and / or the amount of fat present, but I still happily give the meat one over at the store and choose the chops or steaks with the most marbling .


Young lamb with “trace” or “small” amounts of flank fat strips is considered an option, but the amount of fat needed to maintain this rating increases as the lamb ages. If you buy mutton from a grocery store or butcher, it is most likely Choice quality, which means it has a “modest” to “ample” level of flank fat streak. Since you can’t know exactly how old the sheep were, it’s a good idea to look for the fat and choose cuts with the most streaks or marbling.

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Good quality lamb is “consistently slightly thinly muscled” and, depending on the age of the animal, can range from “practically without” flank fat strips to a “moderate” amount. (Again, this graphic is really helpful.) You will most likely not come across whole pieces of lamb marked “good” as this meat is usually ground or made into other products.

Utility and cull

These two are, so to speak, the bottom of the sheep barrel. The utility can be “streak free” (assuming the lamb is young), and mutton with this rating can be “practically empty” or have as much as a “modest” amount of flank fat strips. “Club” refers to meat that does not meet even these meager qualifications. All utility and cull rated meat is made into other products, although I can’t tell you which type goes for which products. (I bet some are making their way into the dog food.)