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2004 State Fair of Virginia Lamb Carcass Evaluation Summary
Livestock Update, November 2004
Scott P. Greiner, Ph.D., Extension Animal Scientist, Sheep, VA Tech
Since 1999, over 1200 lambs have been evaluated through the Lamb Carcass Contest held in conjunction with the youth market lamb show at the State Fair of Virginia. The following table summarizes the carcass information from the State Fair over that period.
Each year the carcasses were placed into five categories (Gold, Purple, Blue, Red, and Pink) to award contest premiums. The carcasses were ranked using a combination of carcass merit and live performance. Carcass merit standards were established as follows:
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 July to the state fair (approximately 70 days). Carcass premium categories were established as follows:
| Gold | > 50 %BCTRC & > .50 ADG |
| Purple | > 50 %BCTRC & ADG < .50 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 ADG standard was the average performance of all market lambs exhibited in the live show within year.
Over the six years the program has been conducted, 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 in recent years. 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 Red and Pink premium category lambs.
VIRGINIA STATE FAIR LAMB CARCASS CONTEST SUMMARY 1999-2004
| 2004 | 2003 | 2002 | 2001 | 2000 | 1999 | |
|---|---|---|---|---|---|---|
| Carcass Measurements: | ||||||
| No. Carcasses | 199 | 212 | 206 | 197 | 230 | 178 |
| Live Wt., lb. | 123.7 | 118.4 | 121.3 | 121.4 | 114.9 | 114.2 |
| ADG, lb./day | 0.35 | 0.37 | 0.37 | 0.35 | 0.36 | 0.30 |
| HCW, lb. | 69.1 | 66.3 | 66.9 | 66.2 | 63.9 | 62.7 |
| Dressing % | 55.8 | 55.9 | 55.0 | 54.5 | 55.5 | 54.6 |
| Adj. Fat Thickness, in. | 0.21 | 0.21 | 0.21 | 0.21 | 0.18 | 0.17 |
| Yield Grade | 2.5 | 2.5 | 2.5 | 2.5 | 2.2 | 2.1 |
| Loin eye area, sq. in. | 3.14 | 3.03 | 3.04 | 3.10 | 2.85 | 2.87 |
| Leg Score (12 = Ch , 13 = Ch+) | 12.7 | 12.7 | 12.6 | 12.6 | 12.4 | 12.5 |
| % BCTRC | 48.3 | 48.3 | 48.4 | 48.4 | 48.4 | 48.8 |
| Quality Grade (11 = Ch-, 12 = Ch ) | 11.3 | 11.4 | 11.4 | 11.4 | 11.3 | 11.2 |
| Carcass Price, $/cwt. | $140.00 | $140.00 | $130.00 | $96.08 | $140.22 | $141.09 |
| Live Value, $/cwt. | $78.07 | $78.27 | $71.53 | $52.34 | $77.92 | $77.10 |
| Carcass Contest Specifications: | ||||||
| ADG standard used for premium placings | 0.34 | 0.37 | 0.36 | 0.33 | 0.32 | 0.29 |
| < .10 in. Fat Thickness | 0 (0.0%) | 0 (0.0%) | 0 (0.0%) | 0 (0.0%) | 6 (2.6%) | 29 (16.3%) |
| Yield Grade 4 or higher (> 0.35 in. fat) | 9 (4.5%) | 7 (3.3%) | 7 (3.4%) | 15 (7.7%) | 1 (0.4%) | 3 (1.7%) |
| < minimum Ribeye Area | 22 (11.1%) | 30 (14.2%) | 30 (14.6%) | 19 (9.7%) | 78 (33.9%) | 38 (21.3%) |
| < Ch- Quality Grade (No Roll) | 0 (0.0%) | 0 (0.0%) | 0 (0.0%) | 0 (0.0%) | 1 (0.4%) | 0 (0.0%) |
| Carcass weight < 45.0 lb. | 0 (0.0%) | 0 (0.0%) | 1 (0.5%) | 0 (0.0%) | NA | NA |
| Gold Premium Category | 2 (1.0%) | 4 (1.9%) | 2 (0.9%) | 6 (3.0%) | 6 (2.6%) | 5 (2.8%) |
| Purple Premium Category | 38 (19.2%) | 47 (22.2%) | 36 (17.5%) | 37 (18.8%) | 35 (15.2%) | 26 (14.6%) |
| Blue Premium Category | 68 (34.3%) | 59 (27.8%) | 74 (35.9%) | 69 (35.0%) | 68 (29.6%) | 44 (24.7%) |
| Red Premium Category | 62 (31.3%) | 66 (31.1%) | 59 (28.6%) | 50 (25.3%) | 41 (17.8%) | 38 (21.3%) |
| Pink Premium Category | 28 (14.1%) | 36 (17.0%) | 35 (17.0%) | 35 (17.8%) | 80 (34.8%) | 65 (36.5%) |
| Carcass Distributions: | ||||||
| Yield Grade 1 | 38 (19.2%) | 57 (26.9%) | 59 (28.6%) | 71 (36.4%) | 88 (38.3%) | 86 (48.3%) |
| Yield Grade 2 | 116 (58.6%) | 100 (47.2%) | 106 (51.5%) | 74 (37.9%) | 109 (47.4%) | 73 (41.0%) |
| Yield Grade 3 | 35 (17.7%) | 48 (22.6%) | 34 (16.5%) | 35 (17.9%) | 32 (13.9%) | 16 (9.0%) |
| Yield Grade 4 & higher | 9 (4.5%) | 7 (3.3%) | 7 (3.4%) | 15 (7.7%) | 1 (0.4%) | 3 (1.7%) |
| Prime Quality Grade | 1 (0.5%) | 1 (0.5%) | 1 (0.5%) | 6 (3.1%) | 2 (0.9%) | 10 (5.6%) |
| Choice Quality Grade | 197 (99.5%) | 211 (99.5%) | 205 (99.5%) | 189 (96.9%) | 227 (98.7%) | 168 (94.3%) |
| No Roll Quality Grade | 0 (0.0%) | 0 (0.0%) | 0 (0.0%) | 0 (0.0%) | 1 (0.4%) | 0 (0.0%) |
| HCW < 45 lb. | 0 (0.0%) | 0 (0.0%) | 1 (0.5%) | 0 (0.0%) | 0 (0.0%) | 2 (1.1%) |
| HCW 45-55 lb. | 15 (7.6%) | 24 (11.3%) | 33 (16.1%) | 24 (12.3%) | 33 (14.3%) | 40 (22.5%) |
| HCW 55-65 lb. | 55 (27.8%) | 66 (31.1%) | 49 (23.8%) | 62 (31.8%) | 90 (39.1%) | 67 (37.6%) |
| HCW 65-75 lb. | 66 (33.3%) | 81 (38.2%) | 74 (35.9%) | 73 (37.4%) | 79 (34.3%) | 56 (31.5%) |
| HCW 75-85 lb. | 54 (27.3%) | 38 (17.9%) | 39 (18.9%) | 34 (17.4%) | 27 (11.7%) | 11 (6.2%) |
| HCW > 85 lb. | 8 (4.0%) | 3 (1.4%) | 10 (4.9%) | 2 (1.0%) | 1 (0.4%) | 2 (1.1%) |