A HISTORY OF 30 YEARS OF INDUSTRY SERVICE – THE WEST TEXAS A&M UNIVERSITY BEEF CARCASS RESEARCH CENTER

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2022-08-01T06:00:00.000Z

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In the first analysis, the West Texas A&M University Beef Carcass Research Center (BCRC) carcass grading database (n = 1,079,880) generated from 1992 to 2021 was used to identify carcass outcomes, trends, and associations. Carcass data was collected at 44 federally inspected beef abattoirs in the United States and Canada. Outcomes included hot carcass weight (HCW), loin muscle area (LMA), adjusted 12th rib fat thickness (AFT), calculated yield grade (YG), LMA to HCW ratio (RATIO), marbling score (MARB), hair coat color and sex. Mean carcass outcomes were: YG (2.9), AFT (1.3 cm), HCW (369.7 kg), LMA (87.2 cm2), KPH (2.1%), RATIO (0.2446 cm2/kg) and MARB (Small23). Regression equations were calculated to determine change in carcass outcomes over time. Mean HCW, LMA, YG, and AFT were determined to annually (P < 0.01) increase linearly by 2.35 kg, 0.42 cm2, 0.0062 units and 0.012 cm whereas RATIO decreased (P < 0.01) in a linear manner by 0.00014 cm2/kg, whereas MARB increased (P < 0.01) in a quadratic manner by 0.22 units. Based on these annual trends, predicted means values for carcass outcomes at the year 2050 are as follows: HCW (477.0 kg), LMA (107.1 cm2), AFT (1.8 cm), MARB (Slightly Abundant78), YG (3.15), and RATIO (0.2377 cm2/kg). These data illustrate strong association (P < 0.01) between YG and carcass outcomes. As YG increased by one unit (i.e. YG 2.0 to 3.0), AFT, HCW, and MARB increased (P < 0.01) by 0.5 cm, 14.6 kg, and 3.9 units, whereas LMA and RATIO decreased (P < 0.01) by 7.2 cm2 and 0.0304 cm2/kg. Hot carcass weight was also influential (P < 0.01) upon carcass outcomes. As HCW increased by 100 kg, YG, AFT, LMA and MARB increased (P < 0.01) by 0.51 units, 0.3 cm, 12.7 cm2 and 3.01 units, whereas RATIO decreased by 0.0304 cm2/kg. Similarly, as AFT increased by 0.254 cm, YG, HCW and MARB increased (P < 0.01) by 0.33 units, 5.7 kg, and 1.6 units, whereas LMA and RATIO decreased by 0.54 cm2 and 0.0054 cm2/kg. Quality grade was also strongly associated (P < 0.01) with carcass outcomes; as quality grade increased from Select to Choice, YG (+0.38 units), AFT (+0.22 cm), and HCW (+8.6 kg) increased (P < 0.01), whereas LMA (-1.5 cm2) and RATIO (-0.0756 cm2/kg) decreased. Likewise, as quality grade increased from Choice to Premium Choice, YG (+0.27 units), AFT (+0.18 cm), and HCW (+4.1 kg) increased (P < 0.01), whereas LMA (-1.0 cm2) and RATIO (-0.0054 cm2/kg) decreased. Furthermore, as QG increased from Premium Choice to Prime, YG (+0.22), AFT (+0.16 cm), and HCW (+3.2 kg) increased (P < 0.01) and LMA (-2.9 cm2) and RATIO (-0.0105 cm2/kg) decreased. Steers exhibited greater (P < 0.01) YG (2.88 vs 2.81), and HCW (360.63 vs 334.15 kg) and less (P < 0.01) LMA (86.17 vs 86.64 cm2), AFT (1.24 vs 1.40 cm), MARB (Small22 vs Small44) and RATIO (0.2412 vs 0.2606 cm2/kg) than heifers. The effect of railout status was assessed; carcasses that had been railed off-line for enhanced trimming exhibited lesser (P < 0.01) YG (-0.19), AFT (-0.12 cm), LMA (-2.50 cm2), MARB (-2.10 units) and dramatically lighter HCW (-18.23 kg), but increased RATIO (+0.0074 cm2/kg) compared to non-railout carcasses. Black hided cattle were determined to have increased (P < 0.01) YG (3.04 vs 2.67), AFT (1.35 vs 1.15 cm), HCW (357.5 vs 350.6 kg), KPH (2.15 vs 2.09), and MARB (Small43 vs Small06) and lesser LMA (85.21 vs 87.15 cm2) and RATIO (0.2394 vs 0.2497 cm2/kg) compared to non-black hided cattle. Probability of carcasses grading Choice (CH), Premium Choice (PrCH), or Prime (P) was calculated. As HCW increased from 400 to 500 kg, the probability of grading CH, PrCH, or P increased by 12, 9, and 1.4%, respectively. Likewise, as AFT increased from 1.5 to 2.5 cm, an increase of 21.9, 23.5, and 4.1% occurred in the probability of grading CH, PrCH, and P. In contrast, as LMA increased from 90 to 100 cm2, a decrease of 3.5, 1.9, and 0.20% occurred in the probability of grading CH, PrCH, and P. These data serve as excellent indicators of the future of beef production to be used by beef producers and processors. In the second analysis, the association of liver abnormalities with carcass performance was evaluated on data from 1,542,533 carcasses housed in 2 databases at the West Texas A&M University Beef Carcass Research Center, collected between 2010 and 2021. Liver abnormalities were observed during harvest and scored as: edible liver; A- = 1 to 2 small abscesses or inactive scars; A = 1 to 2 large abscesses or multiple small abscesses; A+ = multiple large abscesses; A+AD = liver adhered to diaphragm; A+OP = open liver abscess; A+AD/OP = adhered to diaphragm with an open liver abscess; cirrhosis, flukes, and telangiectasis. Liver abnormality rates in database 1 were A- = 7.4%, A = 2.7%, A+ = 2.4%, A+AD = 3.9%, A+OP = 1.4%, A+AD/OP = 0.8%, cirrhosis = 0.2%, flukes = 3.6%, telangiectasis = 0.7%, with 77.0% of livers being edible. Liver abnormality rates in database 2 were A- = 7.3%, A = 5.3%, A+ = 4.8%, A+AD = 6.2%, A+OP = 1.7%, A+AD/OP = 1.3%, cirrhosis = 0.1%, flukes = 1.3%, and telangiectasis = 0.6%, with 67.0% of livers being edible. For carcasses with severe abscesses (A+, A+AD, A+OP, A+AD/OP) and cirrhotic livers, HCW was 13.0 kg and 42.5 kg less (P < 0.01) compared to carcasses with edible livers. Carcasses with any abnormality other than telangiectasis had reduced (P < 0.05) HCW. All liver abnormalities resulted in reduced (P < 0.05) LM area, with the exception of telangiectasis, which was determined to be similar (P = 1.0) to edible livers. Less (P < 0.05) 12th-rib subcutaneous fat was observed for carcasses with A-, A, A+, A+AD, and cirrhosis abnormalities compared to carcasses with edible livers. Estimated KPH was less (P < 0.05) for carcasses with livers identified with flukes or cirrhosis abnormalities. Calculated yield grade was less (P < 0.03) for carcasses with A+AD liver scores and cirrhosis than those with edible livers. For both database 1 and 2, geographical location had an effect (P < 0.01) on liver abscess prevalence. In database 1 and 2, the greatest liver abscess prevalence was observed at Toppenish, WA (37.12%) and Arkansas City, KS (68.33%), respectively. Furthermore, seasonality of liver abscesses by month was reported to be lowest in January (14.09 and 24.08%). For database 2, liver abnormality was affected (P < 0.01) by sex class; steers had increased rates of all abscess outcomes compared to heifers. Additionally, cattle type was also observed to have an effect (P < 0.01) on prevalence of liver abscesses. Native cattle exhibited total abscess prevalence of 23.02%, compared to 16.81, 39.24 and 50.18% for Mexican, Holstein and beef x dairy cattle. Beef x dairy cattle exhibited the highest rates for A- (14.21%), A (7.94%), A+ (8.29%), A+OP (4.00%), and A+AD/OP (3.43%) liver abscess categories. These data indicate liver abnormalities, especially severely abscessed, adhered, open and cirrhotic livers, greatly effect HCW, an important economic factor effecting carcass merchandising, and other carcass outcomes. Liver abscess rate had no detrimental effect on marbling score, which may indicate the timing to which liver abscesses are developed during the feeding period compared to deposition of intramuscular fat. These results indicate control of liver abscesses is important in order to prevent losses in carcass value. In the third analysis, the association of lung abnormalities with carcass performance was evaluated on data from 60,843 carcasses housed in the West Texas A&M University Beef Carcass Research Center database and collected from 2010 to 2021 to quantify the relationship of lung health and carcass performance. Lung outcomes were scored for severity of consolidation (N = Normal and < 5% consolidation, 1 = 5 to 15% consolidation, 2 = 15 to 50% consolidation, 3 = >50% consolidation) and presence of fibrin tags (N = None, M = Minor fibrin, E = Extensive fibrin). Lung consolidation had a strong and detrimental effect (P < 0.01) on hot carcass weight, with lung scores of 1, 2, and 3 resulting in 4.2, 13.3, and 29.9 kg less carcass weight compared to carcasses with normal lungs. Minor and extensive fibrin tags (3.5 kg and 7.1 kg, respectively), independent of consolidation, resulted in lighter carcasses (P < 0.01) compared to those with normal lungs. Lung score did not have an effect on marbling score. Both lung tissue consolidation and presence of fibrin tags affected 12th rib fat thickness; lung consolidation scores of 1, 2, and 3 (-0.09, -0.21 and -0.09 cm, respectively) and fibrin tags prevalence of minor and extensive (-0.14 and -0.19 cm) resulted in less (P < 0.01) 12th rib fat thickness compared to carcasses with normal lungs. Similarly, LM area was reduced (P < 0.01) in carcasses with lung consolidation (-1.5, -3.8, and -5.5 cm2) or presence of fibrin tags (-2.3 and -2.7 cm2) compared to carcasses with normal lungs. Additionally, severity of lung consolidation and presence of fibrin tags reduced (P < 0.01) calculated yield grade; lung consolidation and fibrin tags resulted in a 0.08 to 0.20 and 0.09 to 0.13 reduction in overall yield grade, respectively. In addition to lung outcomes, liver abscess outcomes were also collected and analyzed for synergistic effect on carcass outcomes with severity of lung scores. The greatest proportion of carcasses within lung consolidation and presence of fibrin tags (47.67 and 48.88%) exhibited edible livers with a normal lung. Whereas the lowest proportion of carcasses (1.12 and 1.89%) exhibited a 3 lung consolidation score and extensive prevalence of fibrin tags with a major abscess outcome. Severity of lung consolidation was determined to have a more dramatic effect on carcass weight than presence of fibrin tags within liver abscess categories. Within the edible, minor and major abscess category, as lung consolidation increased from normal to 3 and presence of fibrin tags increased from normal to extensive, a decrease in carcass weight (21.4, 30.9, and 50.1 kg; 5.5, 7.4, and 5.4 kg), LM area (4.7, 3.9, and 6.3 cm2; 2.0, 3.1, and 1.6 cm2), and AFT (0.02, 0.18, and 0.13 cm; 0.12, 0.30, and 0.24 cm) was observed. These data indicate that lung health is an important factor that impacts carcass performance, particularly carcass weight muscling and yield grade outcomes.

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Agriculture, Animal Culture and Nutrition

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