Browsing by Author "Lawrence, T. E."

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Comparative effects of zilpaterol hydrochloride and ractopamine hydrochloride on live performance and carcass characteristics of calf-fed Holstein steers
(2014) Brown, T. R. (TTU); Miller, M. F. (TTU); Brooks, J. C. (TTU); Sexten, A. K.; Lawrence, T. E.; Thomas, C. L.; Yates, D. A.; Hutcheson, J. P.; Hodgen, J. M.
Holstein steers (n = 2,275) were assigned to 1 of 3 treatments: 1) a control diet containing no β-agonists, 2) a diet that contained zilpaterol hydrochloride (ZH; 8.3 mg/kg [100% DM basis]) for 20 d with a 3-d withdrawal period before harvest, and 3) a diet that contained ractopamine hydrochloride (RH; 30.1 mg/kg [100% DM basis]) for 28 d before harvest. No differences (P ≥ 0.18) were detected between treatments for initial BW, BW at d 28, or DMI. Final BW, BW gain for the last 28 d, total BW gain, ADG for the last 28 d, and overall ADG were greater (P < 0.05) for steers fed ZH or RH than for steers fed the control diet. Additionally, G:F for the last 28 d and G:F for the entire trial was increased (P < 0.02) for steers fed ZH (0.147, 0.147) or RH (0.153, 0.151) compared to steers fed the control diet (0.134, 0.143), respectively. Steers fed ZH or RH had HCW that were 15.5 and 8.2 kg heavier (P ≤ 0.01) and LM areas that were 7.1 and 2.3 cm2 larger (P < 0.01) than control cattle. Steers fed ZH also had dressed carcass yields that were 1.3% to 1.5% greater and USDA calculated yield grades that were decreased 0.16 to 0.23 units compared to RH and control steers. No differences (P ≥ 0.39) were found between treatments for marbling score, fat thickness, and percentage KPH. Steers fed ZH had an increased (P ≤ 0.04) percentage of yield grade 1 and 2 carcasses (15.1, 55.0) and a reduced (P ≤ 0.02) percentage of yield grade 3 carcasses (27.1) compared with those fed RH (10.5, 49.1, 36.1) or the control diet (9.0, 47.4, 36.4), respectively. Additionally, ZH-fed steers had a decreased (P ≤ 0.04) percentage of yield grade 4 and 5 carcasses (2.8) compared with steers fed the control diet (6.9). Steers fed ZH had an increased (P ≤ 0.01) percentage of USDA Select grading carcass (31.0%) and a decreased (P ≤ 0.01) percentage of USDA Choice grading carcasses (65.0%) compared with steers fed RH (25.8%, 70.2%) and no β-agonist (24.8%, 72.0%), respectively. Feeding either β-agonist to calf-fed Holstein steers increased live performance through increased BW, BW gain, and ADG. Furthermore, supplementing calf-fed Holstein steers with ZH provides greater improvements in HCW, LM area, and yield grade components, with a slight decrease in quality grade when compared to calf-fed Holstein steers supplemented with RH.
Effect of zilpaterol hydrochloride supplementation on cutability and subprimal yield of beef steer carcasses
(2010) Hilton, G. G.; Garmyn, A. J.; Lawrence, T. E.; Miller, M. F. (TTU); Brooks, J. C. (TTU); Montgomery, T. H.; Griffin, D. B.; van Overbeke, D. L.; Elam, N. A.; Nichols, W. T.; Streeter, M. N.; Hutcheson, J. P.; Allen, D. M.; Yates, D. A.
Beef steers (n = 11,877) from 7 studies were fed zilpaterol hydrochloride (ZH) for 0 or 20 to 40 d before slaughter to determine the effects of ZH on subprimal weight and yield. Carcasses were selected based on mean HCW of treatment groups for fabrication into boneless, closely trimmed, or denuded subprimals, lean, fat, and bone. Data from the 7 trials were pooled for statistical analysis. Feeding ZH increased (P < 0.05) weights of all major subprimals compared with steers not supplemented with ZH. Also, subprimals from the hindquarter, including valuable cuts like the tenderloin, strip loin, and top sirloin butt, increased (P < 0.05) as a percentage of cold carcass weight from steers fed ZH. The tenderloin was 0.06 percentage units greater (P < 0.05), the strip loin was 0.08 percentage units greater (P < 0.05), and the top sirloin butt was 0.11 percentage units greater (P < 0.05) in ZH-fed steers when compared with steers not fed ZH. Supplementation of ZH greatly increased (P < 0.05) total saleable carcass yield by 1.76 percentage units, whereas ZH inclusion decreased (P < 0.05) the percentage of fat trim and bone by 0.58 and 1.10 percentage units, respectively. Therefore, ZH can be utilized by the beef industry to improve red meat yield efficiency throughout the beef production chain. © 2010 American Society of Animal Science.
Effects of feeding zilpaterol hydrochloride for twenty to forty days on carcass cutability and subprimal yield of calf-fed Holstein steers
(2009) Boler, D. D.; Holmer, S. F.; McKeith, F. K.; Killefer, J.; VanOverbeke, D. L.; Hilton, G. G.; Delmore, R. J.; Beckett, J. L.; Brooks, J. C. (TTU); Miller, R. K.; Griffin, D. B.; Savell, J. W.; Lawrence, T. E.; Elam, N. A.; Streeter, M. N.; Nichols, W. T.; Hutcheson, J. P.; Yates, D. A.; Allen, D. M.
Zilpaterol hydrochloride (ZH) is designed to increase carcass leanness, chilled side weight (CSW), and percent saleable yield. The objective of this study was to evaluate the effect of a single dose of ZH on cutability and subprimal yield of calf-fed Holstein steers when fed for increasing durations. Two hundred forty steers were fed 8.3 mg/kg of ZH on a DM basis for 0, 20, 30, or 40 d, with a 3-d withdrawal before slaughter. After slaughter, steers were fabricated into 4 pieces (round, loin/flank, rib/plate, and chuck), packaged in combos, shipped to 2 locations, and further fabricated into subprimal pieces and trim. Trim was collected from each primal and separated into groups based on composition of 90, 80, and 50% lean. Zilpaterol hydrochloride increased (P = 0.01) CSW by 6.22 kg and saleable yield by 6.4 kg when included in the diet for 20 d. Furthermore, saleable yield as a percentage of CSW was increased (P = 0.03) 1.18 percentage units when included in the diet for 20 d. Steers fed ZH for 20 d had heavier strip loins (4.47 vs. 4.12 kg, P = 0.02), tenderloins (2.75 vs. 2.49 kg, P = 0.02), and ribeye rolls (5.74 vs. 5.30 kg, P = 0.01) than steers not fed ZH. These advantages are further demonstrated as a percentage of CSW. Strip loins (P = 0.06), tenderloins (P = 0.04), and ribeye rolls (P = 0.04) of ZH-fed steers had a greater percentage of CSW than controls. Zilpaterol hydrochloride also increased the percentage of CSW of the 3 primary components of the round when fed for 20 d. The knuckle was 0.10 percentage units heavier (P = 0.11), the top round was 0.24 percentage units heavier (P = 0.04), and the bottom round was 0.22 percentage units heavier (P = 0.03) in ZH-fed steers when compared with steers not fed ZH. Based on these data, it can be concluded that ZH significantly increased subprimal cutting weights, yields, and percentage saleable yield of calf-fed Holstein steers when fed for at least 20 d before slaughter. Zilpaterol hydrochloride increased percentage of CSW of subprimal cuts from Holstein steers in the round and to a lesser degree in the loin. © 2009 American Society of Animal Science.
Liver abscesses—New perspectives on a historic fed-cattle issue
(2024) Broadway, P. R.; Nagaraja, T. G.; Lawrence, T. E.; Galyean, M. L. (TTU); Hales, K. E. (TTU)
Purpose: Our purpose was to provide commentary and new perspectives related to liver abscesses, a historic problem in beef cattle, by describing and discussing docu- mented research, anecdotal observations, and opinions re- garding the causation, detection, and prevention of liver abscesses. Sources: Sources for this article include peer-reviewed, scientific literature; abstracts; proceedings; theses and dissertations; popular press articles; personal communica- tions; and unpublished research data. Synthesis: Liver abscess (LA) disease in cattle is a multifactorial, polymicrobial disease that has wide-rang- ing effects on productivity and profitability throughout all stages of the beef production cycle. The interest in and the study of LA has drastically increased in the past several years, driven largely by efforts to identify alterna- tives to the use of antibiotics for LA control. Although a primary, prevailing theory on LA formation has existed for decades, recent research has led to alternative theo- ries as well as new questions about the role of breed-type specific management, behavior, feed intake patterns, and other factors on LA causation. The inability to detect LA before slaughter complicates research evaluating mitiga- tion strategies and disease etiology. Moreover, the inability to detect LA in live cattle has hindered researcher efforts to understand timing of abscess development or whether an abscess can resolve. Conclusions and Applications: Although the prima- ry pathogens associated with LA have been identified, an effective mitigation strategy has eluded researchers. None- theless, new perspectives and research efforts are needed from both basic and applied perspectives using multidis- ciplinary, collaborative approaches to successfully combat the challenges faced by the beef industry related to LA.
The effect of zilpaterol hydrochloride on meat quality of calf-fed Holstein steers
(2009) Holmer, S. F.; Fernández-Dueñas, D. M.; Scramlin, S. M.; Souza, C. M.; Boler, D. D.; McKeith, F. K.; Killefer, J.; Delmore, R. J.; Beckett, J. L.; Lawrence, T. E.; VanOverbeke, D. L.; Hilton, G. G.; Dikeman, M. E.; Brooks, J. C. (TTU); Zinn, R. A.; Streeter, M. N.; Hutcheson, J. P.; Nichols, W. T.; Allen, D. M.; Yates, D. A.
The objective of these studies was to evaluate the effects of zilpaterol hydrochloride (ZH), fed for 0, 20, or 30 d, on meat quality attributes of calffed Holstein steers. Steers were slaughtered at a commercial facility, and carcasses were selected by HCW to represent the pen mean. Further carcass selection was based on quality grade (Choice and Select) and yield grade. Proximate composition, measures of water holding capacity, and tenderness using Warner-Bratzler shear force after 7, 14, or 21 d postmortem were evaluated on the shoulder clod (triceps brachii), top butt (gluteus medius), and strip loin (longissimus lumborum). Percentage of purge for the 3 subprimals was not different (P > 0.05) among ZH treatments. Steers fed ZH for 20 d or 30 d had decreased (P < 0.05) percentages of fat in the triceps brachii, compared with 0-d ZH. Percentage of fat was less (P < 0.05) in the gluteus medius and longissimus lumborum when steers were fed ZH for 30 d compared with those steers fed ZH for 0 d. Percentage of fat was greater in Choice triceps brachii (P < 0.05) and longissimus lumborum (P < 0.10) compared with Select. Thaw loss was not different (P >0.05) for any muscle due to ZH treatment. Only longissimus had a greater (P < 0.05) cooking loss with ZH treatment. Cooking loss was not different (P > 0.05) for the gluteus medius or longissimus lumborum due to quality grade or aging day. At each aging day, the 20-and 30-d ZH longissimus lumborum had greater (P < 0.05) shear force values than 0 d; however, 20- and 30-d ZH had a greater absolute change in shear force from 7 to 21 d than that of 0 d ZH. Triceps brachii steaks were less tender (P < 0.05) after ZH treatment, but gluteus medius steaks were not different (P > 0.05). There was no difference (P > 0.05) in shear force due to quality grade. Results illustrate the use of ZH in calffed Holstein steers will have minimal effects on purge, thaw, or cooking loss. Percentage of intramuscular fat will decrease, especially when fed for longer durations. Steaks from ZH treated steers were tougher than steaks from control animals at all aging times, but ZH steaks became more tender with postmortem aging. © 2009 American Society of Animal Science.