Browsing by Author "Galyean, M. L. (TTU)"

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Effects of increasing the concentration of neutral detergent fiber in roughage and bulk density of steam-flaked corn on growth performance, carcass characteristics, and liver abscesses of finishing beef steers fed diets without tylosin phosphate*†
(2024) McDaniel, Z. S. (TTU); Galyean, M. L. (TTU); Broadway, P. R.; Carroll, J. A.; Sanchez, N. C.Burdick; Hanratty, A. N. (TTU); Dornbach, C. W. (TTU); Line, D. J. (TTU); Smock, T. M. (TTU); Manahan, J. L. (TTU); Hales, K. E. (TTU)
Objective: We evaluated the effects of dietary NDF concentration from alfalfa hay and bulk density of steam- flaked corn (SFC) on growth performance, carcass characteristics, and liver abscesses in finishing beef steers. Materials and Methods: Crossbred beef steers (n = 214; 60 pens; initial BW = 417 ± 11.9 kg) were blocked by BW and assigned randomly to treatments and fed an average of 112 d. The treatments were arranged as a 2 × 3 factorial with 10 pens per treatment and consisted of 3 NDF concentrations from alfalfa hay (3%, 4.5%, or 6%) and 309 g/L (24 lb/bu) or 412 g/L (32 lb/bu) SFC (69% or 33% starch availability, respectively). Growth performance and carcass data were analyzed with PROC MIXED of SAS with pen as the experimental unit. Quality grades and liver scores were analyzed as binomial proportions using PROC GLIMMIX. Contrast statements were used to separate linear and quadratic effects of increasing roughage NDF. Results and Discussion: Dry matter intake responded quadratically from d 0 to 35 as roughage NDF increased from 3% to 6%, and DMI increased linearly as roughage NDF increased on d 70 to 105 and d 0 to final. Otherwise, no differences in growth performance were noted. Marbling score responded quadratically to roughage level and was greater for steers fed 3% than for those fed 4.5% or 6% roughage NDF. Steers fed 309 g/L SFC tended to have a larger LM area than those fed 412 g/L SFC. The total percentage of abscessed livers at slaughter decreased linearly as roughage NDF was increased from 3% to 6% of DM as did the presence of A+ abscesses. In addition, total liver abscesses were 13.9 percentage points less in steers fed 412 versus 309 g/L SFC. Implications and Applications: Results suggest that increasing roughage NDF and bulk density of SFC are dietary strategies that can decrease the presence of liver abscesses at slaughter without negatively affecting growth performance.
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.
Random metaphylaxis effects on health outcomes, complete blood count, antimicrobial use, and growth performance of high-risk beef steers
(2023) Hanratty, A. N. (TTU); Sanchez, N. C.Burdick; Broadway, P. R.; Carroll, J. A.; Hoffman, A. A. (TTU); Manahan, J. L. (TTU); McDaniel, Z. S. (TTU); Smock, T. M. (TTU); Dornbach, C. W. (TTU); Line, D. J. (TTU); Theurer, M. E.; Galyean, M. L. (TTU); Hales, K. E. (TTU)
Objective: Our objectives were to evaluate the effects of random metaphylaxis administered at feedlot arrival to 0, 33, 66, or 100% of high-risk beef cattle on clinical health, growth performance, complete blood cell counts, and antimicrobial use during a 35-d receiving period. Materials and Methods: Crossbred beef steers (n = 216; arrival BW = 197 ± 6.4 kg) were used in a general- ized complete block design consisting of 2 source blocks, each with 4 BW blocks, and 4 treatments. Experimen- tal treatments and steers were randomly assigned to pen within source block: (1) negative control, s.c. injection with sterile saline (0M); (2) 33% of steers per pen giv- en metaphylaxis at random with tildipirosin (33M); (3) 66% of steers per pen given metaphylaxis at random with tildipirosin (66M); and (4) positive control; conventional metaphylaxis given to 100% of steers with tildipirosin (100M). Body weight and blood samples for quantification of complete blood count were collected on d 0, 14, and 35. Metaphylactic treatment was included in the model as a fixed effect, and BW block within source block was included as a random effect. Results and Discussion: The percentage of steers treated with an antimicrobial for bovine respiratory dis- ease once was greater (P < 0.01) for 0M and 33M than for 66M and 100M. Neither BW on d 35 nor ADG from d 0 to 35 differed among treatments (P ≥ 0.65), but DMI and DMI as a percentage of BW from d 0 to 35 was greater (P ≤ 0.03) for 66M and 100M than for 0M and 33M. No dif- ferences in hematological variables were detected among treatments (P ≥ 0.19), whereas most complete blood count variables were affected by day (P < 0.01). Most notably, the neutrophil:lymphocyte ratio was greater (P < 0.01) on d 0 than on d 14 and 35. Implications and Applications: These data suggest that arrival metaphylaxis can be randomly administered to 66% of cattle without increasing bovine respiratory dis- ease morbidity, while simultaneously increasing DMI simi- lar to conventional metaphylaxis. Random metaphylaxis to 66% of steers at arrival decreased antimicrobial use for metaphylaxis while simultaneously maintaining health outcomes and growth performance of high-risk beef cattle.