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Virginia Cooperative Extension -
 Knowledge for the CommonWealth

Virginia State Fair
Youth Market Lamb Carcass Contest Summary 1999-2000

Livestock Update, November 2000

Scott Greiner, Extension Animal Scientist, Sheep, Virginia Tech

A lamb carcass contest was initiated in conjunction with the youth market lamb show at the 1999 State Fair of Virginia. In the first two years of the program, 408 lambs have been evaluated for carcass merit. The following table summarizes the carcass information from the State Fair for 1999 and 2000.

Carcass measures in 2000 were very similar to those in 1999. The carcasses in 2000 were slightly heavier than those in 2000, although live weights were similar. Measurements of fat thickness and muscle (ribeye area and leg score) were very similar for the two years. The slight increase in weight and fat thickness in 2000 was associated with a resulting decrease in the estimated percentage of boneless, closely trimmed retail cuts (%BCTRC). The %BCTRC estimates the proportion of the carcass that is saleable retail product, and is calculated from a formula utilizing carcass weight, fat thickness, body wall thickness, and ribeye area.

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, along with a set of minimum criteria for several traits. Carcasses failing to meet one or more of the following standards were placed in the Pink group:

Minimum fat thickness of .10 in.
Maximum fat thickness of .35 in. (maximum Yield Grade of 4.0)
Minimum REA for carcass weight using formula: 1.4 + (.02 x HCW)
Minimum Quality Grade of Choice-

Carcasses meeting all of the above standards were ranked using %BCTRC and live ADG 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
PinkCarcasses failing to meet one or more of the standards

The average ADG standard was the average performance of all market lambs exhibited in the live show within year (1999 average ADG = .28, 2000 average ADG = .32).

A higher percentage of the lambs met the standard for the Purple and Blue premium categories in 2000. This would indicate that the exhibitors did a better job selecting, feeding, and managing their lambs to reach the target endpoint. The decrease in the percentage of lambs that were underfinished (< .10 fat thickness) was also significantly reduced in 2000.

However, there still is a relatively high percentage of the lambs that do not have sufficient muscling for their weight, as indicated by the number of lambs that failed to meet the minimum ribeye area requirement. This would suggest the need to select and breed lambs with more muscle. Coupled with this, the lambs is both 1999 and 2000 were relatively light compared to industry standards (a significant percentage of carcass weights below 55 lb. both years). The trend in the industry is toward heavier lambs. Higher prices will likely be received for heavier lambs, provided they have acceptable carcass composition. To maintain acceptable composition (cutability, %BCTRC) at these heavier weights, lambs that are larger framed and later maturing lambs that will stay lean are needed. These lambs will also need to have significantly more muscle.

For the sheep industry to remain viable and competitive with imports and other protein sources, emphasis needs to be placed on meeting consumer preferences. Consumers desire a lean, palatable, wholesome product that is consistent in quality. Carcass traits are the primary indicators of these attributes, and are becoming increasingly important to the industry. This carcass program serves as tool to help Virginia sheep producers meet their goal of providing a high quality, consumer acceptable product.

VIRGINIA STATE FAIR
LAMB CARCASS CONTEST SUMMARY 1999-2000

 19992000
Carcass Measurements:
No. Carcasses178230
Live Wt., lb.114.2114.9
ADG, lb./day.30. 36
HCW, lb.62.763.9
Dressing %54.655.5
Adj. Fat Thickness, in..17.18
Yield Grade2.12.2
Loin eye area, sq. in.2.872.85
Leg Score (12 = Ch , 13 = Ch+)12.512.4
% BCTRC48.848.4
Quality Grade (11 = Ch-, 12 = Ch )11.211.3
Carcass Price, $/cwt.$141.09$140.22
Live Value, $/cwt.$77.10$77.92
Carcass Contest Specifications:
<.10 in. Fat Thickness29 (16.3%)6 (2.6%)
Yield Grade 4 or higher3 (1.7%)1 (0.4%)
< minimum Ribeye Area38 (21.3%)78 (33.9%)
< Ch- Quality Grade (No Roll)0 (0.0%)1 (0.4%)
   
Gold Premium Category5 (2.8%)6 (2.6%)
Purple Premium Category26 (14.6%)35 (15.2%)
Blue Premium Category44 (24.7%)68 (29.6%)
Red Premium Category38 (21.3%)41 (17.8%)
Pink Premium Category65 (36.5%)80 (34.8%)
Carcass Distributions:
Yield Grade 186 (48.3%)88 (38.3%)
Yield Grade 273 (41.0%)109 (47.4%)
Yield Grade 316 (9.0%)32 (13.9%)
Yield Grade 43 (1.7%)1 (0.4%)
   
Prime Quality Grade10 (5.6%)2 (0.9%)
Choice Quality Grade168 (94.3%)227 (98.7%)
No Roll Quality Grade0 (0.0%)1 (0.4%)
   
HCW < 45 lb.2 (1.1%)0 (0.0%)
HCW 45-55 lb.40 (22.5%)33 (14.3%)
HCW 55-65 lb.67 (37.6%)90 (39.1%)
HCW 65-75 lb.56 (31.5%)79 (34.3%)
HCW 75-85 lb.11 (6.2%)27 (11.7%)
HCW > 85 lb.2 (1.1%)1 (0.4%)



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