State Fair of Virginia Lamb Carcass Contest Summary 2007

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Over 1750 lambs have been evaluated through the Lamb Carcass Contest held in conjunction with the Virginia State Fair youth market lamb show since 1999. The program provides feedback to lamb exhibitors and breeders relative to the impact of their genetics and management on carcass performance.

Each carcass is placed into one of five premium categories (Gold, Purple, Blue, Red, and Pink), using a combination of carcass merit and live performance. Carcass not meeting one or more of the following qualification standards were placed in the Pink category:
Minimum fat thickness of .10 in.
Maximum fat thickness of .35 in. (maximum Yield Grade of 3.9)
Minimum REA for carcass weight using formula: 1.4 + (0.02 x hot carcass weight)
Minimum Quality Grade of Choice-
Minimum carcass weight of 45.0 pounds

Carcasses meeting all of the above standards were ranked using percentage boneless, closely trimmed retail cuts (%BCTRC) and live average daily gain (ADG). The formula to estimate %BCTRC uses carcass weight, fat thickness, body wall thickness, and ribeye area and represents the predicted proportion of the carcass that is saleable retail product. Average daily gain is calculated for each lamb from the time of nomination in late June to the state fair (approximately 100 days). The ADG standard was the average performance of all market lambs exhibited in the live show within year. Carcass premium categories were established as follows:

Gold	> 50 %BCTRC & > 0.45 ADG
Purple	> 50 %BCTRC & ADG < Gold Standard or > 49 %BCTRC & ADG > average
Blue	> 49 %BCTRC & ADG < average or > 47.5 %BCTRC & ADG > average
Red	> 47.5 %BCTRC & ADG < average or %BCTRC < 47.5
Pink	Carcasses failing to meet one or more of the standards

The following table summarizes the carcass information from the State Fair over the nine years the program has been conducted. Since 1999, there has been a steady increase in weight (both live weight and carcass weight). Associated with this weight increase has been a corresponding increase in ribeye area. While a portion of the increase in REA is directly related to weight, the lambs have also improved in overall muscling, as indicated by a higher percentage of the lambs meeting the minimum REA standard for their carcass weight. Despite the increases in weight over time, fat thickness and overall cutability (%BCTRC) have remained relatively constant. A very high percentage of the carcasses are YG 1 and 2, and the low percentage of undesirable YG 4 carcasses is much more favorable than industry average.

The increasing percentage of carcasses in the Gold, Purple, and Blue premium categories would suggest that exhibitors are more effectively selecting, feeding, and managing their lambs to reach a desirable target endpoint. This is confirmed by the general trend for a lower percentage of Pink premium category lambs (lambs disqualified for not meeting minimum carcass specifications).