You've reached the Virginia Cooperative Extension Newsletter Archive. These files cover more than ten years of newsletters posted on our old website (through April/May 2009), and are provided for historical purposes only. As such, they may contain out-of-date references and broken links.
To see our latest newsletters and current information, visit our website at http://www.ext.vt.edu/news/.
Newsletter Archive index: http://sites.ext.vt.edu/newsletter-archive/
Standards of Performance for Livestock Projects: Market Lambs
Livestock Update, August 1998
Mark L. Wahlberg, Animal and Poultry Sciences, Virginia Tech
Background -- The sheep industry is a miniature version of what it used to be. Although there are some people who eat a lot of lamb, there are many who consume none at all. The average consumption of lamb per person in the United States is less than 2 pounds. Producers are challenged by such things as predators and imports. Packers who process lamb are small in number and located quite a distance from Virginia. Many retail outlets do not stock any lamb at all, and those that do have a limited selection. Finally, the product is often the fattest meat item in the case, and also the highest-priced. Many of the cuts, especially rib and loin chops, are small in size, so several chops are needed to make a satisfying portion.
On the plus side, lamb is viewed as a high quality and gourmet item, in some respects like lobster. It has a very good image. People that like it are willing to pay a lot for it, as long as the quality is there. Lamb is always a tender and flavorful product. Fresh American lamb is available all year around.
The Standards -- Because lamb demand is pressured by such challenges as small cut size and higher fat content, many lamb producers are increasing animal size. This allows animals to get bigger while still staying lean. However, some markets are strongly discriminating against lambs with heavier carcass weights. The weight of the ideal lamb is not yet decided.
The values shown are for a mainstream market for product that would be sold in the retail stores.
| Standards of Performance for Market Lambs | ||
|---|---|---|
| Item | Acceptable Ranges | Ideal Target |
| Live Weight | 100 to 140 pounds | 110 to 130 pounds |
| Carcass Weight | 50 to 70 pounds | 55 to 65 pounds |
| Live ADG | at least 1/2 lb per day | at least 2/3 lb per day |
| Age at Marketing | less than 10 months | less than 6 months |
| Fat Thickness | .10 to .25 inch at the last rib | .15 to .20 inch |
| Loineye Area | at least 2.5 square inches at least | 3.0 square inches |
| Yield Grade | 2.9 or less | 2.9 or less |
| Quality Grade | at least Choice - | at least Choice + |
A market lamb cannot be adequately evaluated without carcass information. Certainly some important traits can be measured in the live animal. However, measurements of backfat depth, loineye area, and Quality Grade cannot be done in the live animal without very sophisticated equipment.
The traits mentioned above are expressed as a result of both genetics and environment. Genetics is the biological plan that describes what an animal can be. Management, which includes feed, health, animal comfort, and other similar factors, must be good enough to allow an animal to express its genetic potential for a trait. As long as the lamb is healthy, fed properly, and in a comfortable environment the majority of the differences seen are due to genetics. Therefore, market lambs that hit the target are those with the right genetics that are managed in the right way.