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Virginia State Fair Youth Market Lamb Carcass Contest Summary 2003
Livestock Update, November 2003
Scott Greiner, Extension Animal Scientist, Sheep, VA Tech
Over the past five years, 1023 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.
Analysis of the carcass data over the past five years reveals some significant changes and improvements in the carcass merit of the lambs participating in the contest. Most significant is the steady increase in weight (both live weight and carcass weight), as well as the improvement in muscling. This improvement in muscling is reflected in larger REAs, as well as a higher percentage of the lambs meeting the minimum REA standard for their carcass weight. The proportion of carcasses above the cooperating processors' target of 55 pounds continues to improve. However, this increase in weight has been associated with a corresponding increase in fatness as shown by the decreased percentage of YG 1 and 2 carcasses compared to YG 3 and 4 carcasses. Despite this increase in fat cover, the proportion of severely overfinished lambs (YG 4 and 5) has remained low. Additionally, there have been no underfinished (less than .10 inches of fat thickness) lambs since 1999.
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.
Two types of lambs can generally categorize the Red premium group. The first are lambs that have desirable %BCTRC, but low ADG. These lambs with low performance generally were heavy at nomination. Feeding these lambs to improve ADG would potentially result in overfinished and excessively heavy lambs in many cases. In most cases, these lambs need to be lighter at nomination so they can be fed more aggressively and still have desirable carcass cutability. The second type of lamb found in the Red category are lambs that have adequate ADG, but lack a desirable combination of leanness and muscle for their weight. Many of these lambs have been fed to be 10-15 pounds heavier than their optimum weight. Finally, the Pink premium category contains lambs that are light muscled or overfinished, or a combination of both. Again, several of these lambs have been made heavier than their ideal weight from a carcass composition standpoint. To maintain acceptable composition (cutability, %BCTRC) at heavier weights, larger framed and later maturing lambs with significantly more muscling need to be selected.
Virginia State Fair
Lamb Carcass Contest Summary 1999-2003
| 2003 | 2002 | 2001 | 2000 | 1999 | |
|---|---|---|---|---|---|
| Carcass Measurements: | |||||
| No. Carcasses | 212 | 206 | 197 | 230 | 178 |
| Live Wt., lb. | 118.4 | 121.3 | 121.4 | 114.9 | 114.2 |
| ADG, lb./day | 0.37 | 0.37 | 0.35 | 0.36 | 0.30 |
| HCW, lb. | 66.3 | 66.9 | 66.2 | 63.9 | 62.7 |
| Dressing % | 55.9 | 55.0 | 54.5 | 55.5 | 54.6 |
| Adj. Fat Thickness, in. | 0.21 | 0.21 | 0.21 | 0.18 | 0.17 |
| Yield Grade | 2.5 | 2.5 | 2.5 | 2.2 | 2.1 |
| Loin eye area, sq. in. | 3.03 | 3.04 | 3.10 | 2.85 | 2.87 |
| Leg Score (12 = Ch , 13 = Ch+) | 12.7 | 12.6 | 12.6 | 12.4 | 12.5 |
| % BCTRC | 48.3 | 48.4 | 48.4 | 48.4 | 48.8 |
| Quality Grade (11 = Ch-, 12 = Ch ) | 11.4 | 11.4 | 11.4 | 11.3 | 11.2 |
| Carcass Price, $/cwt. | $140.00 | $130.00 | $96.08 | $140.22 | $141.09 |
| Live Value, $/cwt. | $78.27 | $71.53 | $52.34 | $77.92 | $77.10 |
| Carcass Contest Specifications: | |||||
| ADG standard used for premium placings | 0.37 | 0.36 | 0.33 | 0.32 | 0.29 |
| < .10 in. Fat Thickness | 0 (0.0%) | 0 (0.0%) | 0 (0.0%) | 6 (2.6%) | 29 (16.3%) |
| Yield Grade 4 or higher (> .35 in. fat) | 7 (3.3%) | 7 (3.4%) | 15 (7.7%) | 1 (0.4%) | 3 (1.7%) |
| < minimum Ribeye Area | 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%) | 1 (0.4%) | 0 (0.0%) |
| Carcass weight < 45 lb. | 0 (0.0%) | 1 (0.5%) | 0 (0.0%) | NA | NA |
| Gold Premium Category | 4 (1.9%) | 2 (0.9%) | 6 (3.0%) | 6 (2.6%) | 5 (2.8%) |
| Purple Premium Category | 47 (22.2%) | 36 (17.5%) | 37 (18.8%) | 35 (15.2%) | 26 (14.6%) |
| Blue Premium Category | 59 (27.8%) | 74 (35.9%) | 69 (35.0%) | 68 (29.6%) | 44 (24.7%) |
| Red Premium Category | 66 (31.1%) | 59 (28.6%) | 50 (25.3%) | 41 (17.8%) | 38 (21.3%) |
| Pink Premium Category | 36 (17.0%) | 35 (17.0%) | 35 (17.8%) | 80 (34.8%) | 65 (36.5%) |
| Carcass Distributions: | |||||
| Yield Grade 1 | 57 (26.9%) | 59 (28.6%) | 71 (36.4%) | 88 (38.3%) | 86 (48.3%) |
| Yield Grade 2 | 100 (47.2%) | 106 (51.5%) | 74 (37.9%) | 109 (47.4%) | 73 (41.0%) |
| Yield Grade 3 | 48 (22.6%) | 34 (16.5%) | 35 (17.9%) | 32 (13.9%) | 16 (9.0%) |
| Yield Grade 4 & higher | 7 (3.3%) | 7 (3.4%) | 15 (7.7%) | 1 (0.4%) | 3 (1.7%) |
| Prime Quality Grade | 1 (0.5%) | 1 (0.5%) | 6 (3.1%) | 2 (0.9%) | 10 (5.6%) |
| Choice Quality Grade | 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%) | 1 (0.4%) | 0 (0.0%) |
| HCW < 45 lb. | 0 (0.0%) | 1 (0.5%) | 0 (0.0%) | 0 (0.0%) | 2 (1.1%) |
| HCW 45-55 lb. | 24 (11.3%) | 33 (16.1%) | 24 (12.3%) | 33 (14.3%) | 40 (22.5%) |
| HCW 55-65 lb. | 66 (31.1%) | 49 (23.8%) | 62 (31.8%) | 90 (39.1%) | 67 (37.6%) |
| HCW 65-75 lb. | 81 (38.2%) | 74 (35.9%) | 73 (37.4%) | 79 (34.3%) | 56 (31.5%) |
| HCW 75-85 lb. | 38 (17.9%) | 39 (18.9%) | 34 (17.4%) | 27 (11.7%) | 11 (6.2%) |
| HCW > 85 lb. | 3 (1.4%) | 10 (4.9%) | 2 (1.0%) | 1 (0.4%) | 2 (1.1%) |