|
|
| (9 intermediate revisions by 3 users not shown) |
| Line 1: |
Line 1: |
| '''Dressed Carcass Yield'''
| | [[Category:Carcass Traits]] |
|
| |
|
| Dressed carcass yield or dressing percentage is calculated by dividing hot carcass weight by live weight and multiplying by 100. It is impacted by the amount of fill, muscle, fat, breed-type, pregnancy status, etc. For example, an 828 lb. carcass divided by 1300 lb. live weight times 100 equals 63.7 dressing percentage. | | Dressed carcass yield or dressing percentage is calculated by dividing hot carcass weight by live weight and multiplying by 100. It is impacted by the amount of fill, muscle, fat, breed-type, pregnancy status, etc. For example, an 828 lb. carcass divided by 1300 lb. live weight times 100 equals 63.7 dressing percentage. |
| Line 5: |
Line 5: |
| More gastrointestinal tract content at harvest will result in a lower dressing percentage. Likewise, less gastrointestinal tract content at harvest produces a higher dressing percentage. | | More gastrointestinal tract content at harvest will result in a lower dressing percentage. Likewise, less gastrointestinal tract content at harvest produces a higher dressing percentage. |
|
| |
|
| Light muscled cattle at harvest have a lower dressing percentage. In contrast, heavier muscled cattle at harvest have a higher dressing percentage. | | Light-muscled cattle at harvest have a lower dressing percentage. In contrast, heavier-muscled cattle at harvest have a higher dressing percentage. |
|
| |
|
| Heavier hided cattle (Bos Indicus type) at harvest would be expected to have a lower dressing percentage. Light hided cattle (dairy type) at harvest have a higher dressing percentage. Mud or manure on cattle hides will reduce dressing percentage. | | Heavier-hided cattle (Bos Indicus type) at harvest would be expected to have a lower dressing percentage. Light-hided cattle (dairy type) at harvest have a higher dressing percentage. Mud or manure on cattle hides will reduce dressing percentage. |
|
| |
|
| Extremely fat cattle at harvest have a higher dressing percentage than extremely lean cattle. | | Extremely fat cattle at harvest have a higher dressing percentage than extremely lean cattle. |
|
| |
|
| The normal range for dressing percentages is 55 to 70% with the current national average being 63.24%. | | The normal range for dressing percentages is 55 to 70% with the current national average being 63.24%. |
|
| |
|
| |
| '''Quality Grade'''
| |
|
| |
| Quality refers to the overall appearance and expected palatability of the edible portion of the carcass. In 1996, quality grades were changed so that “B” maturity carcasses with Slight or Small marbling would grade Standard. Therefore, USDA Quality Grades for young beef (“A” and “B” maturity) — Prime, Choice, Select, and Standard — are recommended as the basis for quality evaluation. Marbling and carcass maturity are factors evaluated for grading beef for quality. Generally, marbling found at the 12-13th rib juncture is the main factor determining quality grade of young cattle. Maturity includes a subjective evaluation of the extent of ossification (conversion of cartilage to bone) of the vertebral column, texture and color of lean, and firmness of lean. In December 2018, USDA included dentition as a part of the quality grading rules. Cattle with two (2) or fewer permanent incisors would be approved for age verification under 30 months of age and qualify for “A” maturity and grade Prime, Choice, Select and Standard.
| |
|
| |
| '''Maturity''', an estimation of the physiological age of the carcass, is determined by evaluating the size, shape, and ossification of the bones and cartilage and the color and texture of the lean. Physiological age may not be the same as the actual age of the animal in months and years; however, in most cases, they are roughly the same. There are five degrees of maturity — A, B, C, D, and E. Approximate chronological age groupings for “A” and “B” maturity carcasses and recommended numerical scores are shown in the following table:
| |
|
| |
| {| class="wikitable" style="margin: auto;"
| |
| !colspan="6"|'''Numerical Scores and Maturity/Age Groupings'''
| |
| |-
| |
| |'''Maturity'''
| |
| |'''Score'''
| |
| |'''Age'''
| |
| |-
| |
| |A
| |
| |1.0 – 1.9
| |
| |9 – 30 months
| |
| |-
| |
| |B
| |
| |2.0 – 2.9
| |
| |30 – 42 months
| |
| |}
| |
|
| |
| A numerical score of 1.5 would suggest that the carcass was in the middle of “A” maturity, while a score of 1.9 would be appropriate for a carcass at the upper end of “A” maturity but not quite into “B” maturity. Initial maturity score is determined by the skeletal characteristics with adjustments made according to characteristics of the lean tissue. However, lean characteristics cannot be used to adjust final maturity of the carcass more than one full maturity group.
| |
|
| |
| '''Marbling''', the flecks of fat in the lean (intramuscular), is the primary factor determining quality grade after maturity has been determined. Marbling is evaluated visually in the ribeye muscle, which is exposed between the 12th and 13th ribs. Marbling contributes to meat tenderness and is also associated with the palatability traits of juiciness and flavor. There are nine degrees of marbling, ranging from Practically Devoid to Abundant. It is recommended that marbling be given a decimalized numerical score corresponding to the relative development within that degree. For example, a Small-20 equates to a numerical score of 5.2 or 520 (5.2 × 100), shown in the table below.
| |
|
| |
| Quality grades vary in the number of degrees of marbling within a grade. Although marbling is the primary determinant of quality grade, and numerical scores for grade can be determined from the following marbling table, final quality grade can be lowered for carcasses of “B” maturity, ‘dark cutters’, calloused lean, or those with very soft or very coarse textured lean.
| |
|
| |
| Recommended descriptive and numerical marbling scores for quality grades of “A” maturity carcasses are given below.
| |
|
| |
| {| class="wikitable" style="margin: auto;"
| |
| !colspan="6"|'''Numerical Scores'''
| |
| |-
| |
| |'''Quality Grade'''
| |
| |'''Marbling'''
| |
| |'''Score'''
| |
| |-
| |
| |Prime
| |
| |Abundant
| |
| |10.0 – 10.9
| |
| |-
| |
| |Prime
| |
| |Moderately Abundant
| |
| |9.0 – 9.9
| |
| |-
| |
| |Prime
| |
| |Slightly Abundant
| |
| |8.0 – 8.9
| |
| |-
| |
| |Choice
| |
| |Moderate
| |
| |7.0 – 7.9
| |
| |-
| |
| |Choice
| |
| |Modest
| |
| |6.0 – 6.9
| |
| |-
| |
| |Choice
| |
| |Small
| |
| |5.0 – 5.9
| |
| |-
| |
| |Select
| |
| |Slight
| |
| |4.0 – 4.9
| |
| |-
| |
| |Standard
| |
| |Traces
| |
| |3.0 – 3.9
| |
| |-
| |
| |Standard
| |
| |Practically devoid
| |
| |2.0 – 2.9
| |
| |}
| |
|
| |
| Relationships between marbling scores and intramuscular fat percentages are shown below:
| |
|
| |
| {| class="wikitable" style="margin: auto;"
| |
| !colspan="6"|'''Marbling and Intramuscular Fat'''
| |
| |-
| |
| |'''Marbling Score'''
| |
| |'''Intramuscular Fat, %'''
| |
| |-
| |
| |Slightly Abundant
| |
| |10.13
| |
| |-
| |
| |Moderate
| |
| |7.25
| |
| |-
| |
| |Modest
| |
| |6.72
| |
| |-
| |
| |Small
| |
| |5.04
| |
| |-
| |
| |Slight
| |
| |3.83
| |
| |-
| |
| |Traces
| |
| |2.76
| |
| |}
| |
|
| |
| It is recommended that a representative of the USDA Agriculture Marketing Service or a highly trained person be used to assess quality grade factors when collecting carcass data.
| |
|
| |
| Color of the ribeye is used as an indicator of maturity or physiological age. The eye appeal of beef at the retail counter is highly dependent on desirable color. Dark cutters are carcasses that produce lean tissue that is dark red to almost black and often result from cattle that have been stressed prior to slaughter. Meat from dark cutting carcasses is safe to eat, and its palatability is not seriously affected. However, the color reduces consumer acceptability and lowers carcass value dramatically.
| |
|
| |
| Firmness of lean refers to the relative firmness or softness of the ribeye.
| |
|
| |
| Texture of lean refers to the apparent fineness or coarseness of muscle bundles within the ribeye.
| |
|
| |
| Recommended numerical scores and descriptions for color, firmness, and texture of lean are as follows:
| |
|
| |
| {| class="wikitable" style="margin: auto;"
| |
| !colspan="6"|'''Numerical Scores and Maturity/Age Groupings'''
| |
| |-
| |
| |'''Score'''
| |
| |'''Color'''
| |
| |'''Firmness'''
| |
| |'''Texture'''
| |
| |-
| |
| |7
| |
| |Light cherry red
| |
| |Very firm
| |
| |Very fine
| |
| |-
| |
| |6
| |
| |Cherry red
| |
| |Firm
| |
| |Fine
| |
| |-
| |
| |5
| |
| |Slightly dark red
| |
| |Moderately firm
| |
| |Moderately fine
| |
| |-
| |
| |4
| |
| |Moderately dark red
| |
| |Slightly soft
| |
| |Slightly fine
| |
| |-
| |
| |3
| |
| |Dark red
| |
| |Soft
| |
| |Slightly coarse
| |
| |-
| |
| |2
| |
| |Very dark red
| |
| |Very soft
| |
| |Coarse
| |
| |-
| |
| |1
| |
| |Black
| |
| |Extremely soft
| |
| |Very coarse
| |
| |}
| |
|
| |
| More direct measures of palatability than quality grade include Warner-Bratzler shear tests for tenderness assessment, and trained sensory panel evaluation for tenderness, flavor, and juiciness. However, cost and availability will restrict usage of these methods.
| |
|
| |
| '''Yield Grade'''
| |
|
| |
| Quantity of retail product is the amount of salable meat the carcass will yield. Two alternatives are suggested for evaluating differences in yield of salable meat:
| |
|
| |
| • USDA Yield Grade (an estimate of the relative proportion of closely trimmed, boneless retail cuts from the round, loin, rib, and chuck), or
| |
| • Total percentage of retail product based on closely trimmed (no more than 0.25 in. surface fat), mostly boneless cuts, and a standardized fat content (perhaps 20 %) for ground beef.
| |
|
| |
| '''USDA Yield Grade'''
| |
|
| |
| Yield grade is an indication of retail product yield from the carcass which is expressed in whole numbers from one to five or in tenths of a grade. Expressing yield grade in tenths of a grade is desirable in making comparisons, although in retail marketing, decimals are dropped. Yield grades are calculated by the following formula:
| |
|
| |
| Yield Grade = 2.50 + (2.5 × Adj. fat thickness, in.)
| |
|
| |
| + (0.2 × Kidney, pelvic, and heart fat, %)
| |
|
| |
| + (0.0038 × Hot carcass wt., lb.)
| |
|
| |
| – (0.32 × Ribeye area, sq. in.)
| |
|
| |
| Adjusted fat thickness is an estimate of external fat, which is the most important factor in determining retail yield. It is measured at the 12th rib, perpendicular to the outside fat at a point three-fourths of the length of the ribeye muscle from the backbone. This measurement often is adjusted to reflect unusual fat distribution of the carcass. As external fat increases, the percentage of retail product decreases.
| |
|
| |
| Estimated percentage of kidney, pelvic, and heart fat (KPH) estimates fat in the kidney knob, pelvic, and heart areas as a percentage of carcass weight. As KPH fat increases, the percentage of retail product from the carcass decreases.
| |
|
| |
| Ribeye area is an indicator of muscling. The longissimus or ribeye muscle is measured at the 12th rib by using a grid or a ribeye tracing that is measured with a compensating polar planimeter or image analysis system. As ribeye area increases, retail product yield increases.
| |
|
| |
| Hot carcass weight is recorded as the carcass leaves the slaughter floor. Generally, as animals increase in weight, the percentage of retail product decreases because of increased fat deposition.
| |
|
| |
|
| |
| '''Total Percentage of Retail Product'''
| |
| <math>
| |
| Dikeman et al. (1998, J. Anim. Sci. 76:1604-1612) developed an equation that uses traits in the USDA Yield Grade system to predict percentage of total retail product trimmed to zero (0.0) in. of surface fat, as follows (predictive model {R}^{2} = 0.54):
| |
|
| |
| % Total Retail Product = 65.59 – (9.93 × Adj. fat thickness, in.)
| |
| – (1.29 × Kidney knob, %)
| |
| + (1.23 × Ribeye area, sq. in.)
| |
| – (0.013 × Hot carcass wt., lb.)
| |
|
| |
| If cattle are slaughtered at a plant that uses hot fat trimming, the following equation by Apple et al. (1991, J. Anim. Sci. 69:4845-4857) can be used (predictive model {R}^{2} = 0.75):
| |
|
| |
| % Total Retail Product = 78.95 – (0.005 × Hot carcass wt., lb.)
| |
| – (1.56 × Hot fat trim, %)
| |
| + (0.516 × Ribeye area, sq. in.)
| |
| – (1.14 × Marbling score: 4.0 to 4.9 = slight, etc.)
| |
| </math>
| |
Dressed carcass yield or dressing percentage is calculated by dividing hot carcass weight by live weight and multiplying by 100. It is impacted by the amount of fill, muscle, fat, breed-type, pregnancy status, etc. For example, an 828 lb. carcass divided by 1300 lb. live weight times 100 equals 63.7 dressing percentage.
More gastrointestinal tract content at harvest will result in a lower dressing percentage. Likewise, less gastrointestinal tract content at harvest produces a higher dressing percentage.
Light-muscled cattle at harvest have a lower dressing percentage. In contrast, heavier-muscled cattle at harvest have a higher dressing percentage.
Heavier-hided cattle (Bos Indicus type) at harvest would be expected to have a lower dressing percentage. Light-hided cattle (dairy type) at harvest have a higher dressing percentage. Mud or manure on cattle hides will reduce dressing percentage.
Extremely fat cattle at harvest have a higher dressing percentage than extremely lean cattle.
The normal range for dressing percentages is 55 to 70% with the current national average being 63.24%.
