Browsing by Author "Nagaraja, T. G."

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Effects of Saccharomyces cerevisiae CNCM I-1077 and calcium clinoptilolite zeolite compared with tylosin phosphate and negative control on health, performance, carcass outcomes, and liver abscesses of dairy-beef cross feedlot cattle*
(2024) Theurer, Miles E.; Woerner, Dale R. (TTU); Johnson, Bradley J. (TTU); Wilson, Reese (TTU); Sarturi, Jhones O. (TTU); Amachawadi, Raghavendra G.; Nagaraja, T. G.; Simpson, Jim; Fox, J. Trent; Adams, Paige; Karges, Kip K.
Objective: Our objective was to evaluate the effects of in-feed, non-antibiotic alternatives (Saccharomyces cerevisiae CNCM I-1077 and calcium clinoptilolite zeolite) on health, growth performance, carcass characteristics, and liver abscesses in dairy-beef cross composites in a commercial feedlot. Materials and Methods: Dairy-beef, intact heifers (n = 2,088; average BW = 334.8 kg) were assigned to 1 of 3 treatment groups: (1) Negative control (no feed-grade antimicrobials for control of liver abscesses; NC); (2) Saccharomyces cerevisiae CNCM I-1077 (0.5 g/heifer per day to provide 1 × 1010 cfu/heifer per day) and calcium clinoptilolite zeolite (replacing flaked corn at 1.2% on a DM basis; LB), or (3) tylosin phosphate (targeted at a rate of 68 mg/heifer per day; TY). Heifers averaged 228 d on feed at harvest. Individual carcass outcomes and liver scores were captured at harvest. Results and Discussion: Heifers in the TY treatment had reduced DMI, increased G:F, and reduced cost of gain compared with the other treatments. Carcass characteristics were not affected by treatments. Heifers offered LB tended to have fewer total liver abscesses compared with the TY group, whereas NC was intermediate. Implications and Applications: Feedlot performance improved for dairy-beef heifers offered tylosin; however, TY had the greatest percentage of liver abscesses compared with NC. Feeding the combination of Saccharomyces cerevisiae CNCM I-1077 and calcium clinoptilolite as a non-antimicrobial alternative for the mitigation of liver abscesses in dairy-beef females seems to be promising strategy; however, growth performance outcomes may be reduced compared with tylosin.
Identification of blood-based biomarkers for detection of liver abscesses in beef × dairy heifers
(2024) Wilson, Reese A. (TTU); Johnson, Bradley J. (TTU); Sarturi, Jhones O. (TTU); Crossland, Whitney L. (TTU); Hales, Kristin E. (TTU); Rathmann, Ryan J. (TTU); Bratcher, Christy L. (TTU); Theurer, Miles E.; Amachawadi, Raghavendra G.; Nagaraja, T. G.; Speidel, Scott E.; Enns, R. Mark; Thomas, Milton G.; Foraker, Blake A.; Cleveland, Matthew A.; Woerner, Dale R. (TTU)
Objective: The objective was to determine the effects of liver abscesses on complete blood counts (CBC) and liver function and to identify blood-based biomarkers for detection of liver abscesses in feedlot cattle. Materials and Methods: Blood samples were collected on a subset of beef × dairy crossbred heifers with and without liver abscesses (n = 94; n = 113, respectively). From these blood samples, CBC and serum chemistry analytes related to liver health (alkaline phosphatase, gamma glutamyl transferase, bile acids, total bilirubin, and cholesterol) were analyzed to characterize animal health and model for liver abscesses. Abscess presence was predicted using logistic regression models and machine learning algorithms, with individual heifer serving as the experimental unit. Results and Discussion: In a binary system (abscessed or not), heifers with liver abscesses had lower concentrations of lymphocyte (LYM) and total white blood cell (WBC) concentrations but elevated platelet-to-LYM ratio. Serum chemistry measures were not affected by abscess presence or liver score (severity). In univariate, predictive modeling of CBC measures, only total WBC concentration was accurate (65.85%) at predicting liver abscess presence; however, this was not deemed an acceptable biomarker due to its poor specificity (54.79%). Using total WBC, basophils, red blood cells, and procalcitonin as variables to predict liver abscess condition, the Logit- Boost model produced the greatest accuracy (80.65%) and specificity (85.71%). An accurate blood test that allows for the detection of liver abscesses during the finishing phase may allow for therapeutic management or alternative marketing of cattle; however, the marginal accuracy demonstrated in this study combined with the impracticality and cost of analyzing a blood sample may not be feasible. Regardless, the most explanatory CBC variables in cattle with abscessed livers were suggestive of an immune response. Implications and Applications: Liver condition influenced the CBC of beef × dairy heifers but not serum chemistry. Multivariate predictive models showed potential for predicting liver abscess condition based on CBC. The results of this study warrant further investigation for biomarkers of the liver abscess condition. An antemortem indicator for liver abscesses could prove useful for making management decisions and in research applications, particularly in evaluating interventions.
Ileal epithelial tissue transcript profiles of steers with experimentally induced liver abscesses*†
(2024) Lindholm-Perry, Amanda K.; Keel, Brittney N.; Hales, Kristin E. (TTU); Wells, James E.; Kuehn, Larry A.; Keele, John W.; Crouse, Matthew S.; Nonneman, Dan J.; Nagaraja, T. G.; Lawrence, Ty E.; Amachawadi, Raghavendra G.; Carroll, Jeff A.; Burdick Sanchez, Nicole C.; Broadway, Paul R.
Objective: Liver abscesses in cattle negatively affect production and cause economic losses across the beef cat- tle industry. Recently, a nutritional model has been devel- oped to induce liver abscesses that will provide a method to evaluate the underlying mechanisms driving their de- velopment. The objective of this study was to evaluate gene expression of ileal tissue from calves challenged using the new model. Materials and Methods: In the model, calves were fed a diet to induce ruminal acidosis and were then in- traruminally inoculated with bacteria typically associated with liver abscesses. On d 21, following inoculation, calves were euthanized. Seven of the 13 calves had liver abscess- es. Ileal tissues were collected and total RNA was isolated for RNA-sequencing. Results and Discussion: A total of 26 genes were dif- ferentially expressed in the calves with liver abscesses com- pared with those without. Two genes (COX2, COX3) are components of the cytochrome c oxidase enzyme in the electron chain transport pathway, and both were downreg- ulated among the animals with liver abscesses. Other genes involved in cellular restructuring, transport of compounds across cell membranes, protection of RNA, and protection of protein products were also identified. These functions il- lustrate that there are changes in the ileal epithelium that correspond to the development of liver abscesses. Implications and Applications: We identified sev- eral genes that were differentially expressed in the ileal tissue of calves that developed liver abscesses using the combination of an acidosis-inducing diet and intraruminal inoculation of bacteria. Our results suggest that the ileum has a role in liver abscess development, and future studies to validate the involvement of the mucosal barrier of the ileum are warranted.
Injecting Fusobacterium necrophorum into the peripheral circulation or hepatic portal vein of preruminant Holstein calves failed to induce liver abscesses*
(2024) Cox, Hannah E. (TTU); Menta, Paulo R. (TTU); Nagaraja, T. G.; Crossland, Whitney L. (TTU); Hales, Kristin E. (TTU); Henry, Darren D. (TTU); Strieder-Barboza, Clarissa (TTU); Broadway, Paul R.; Carroll, Jeffery A.; Ballou, Michael A. (TTU); Machado, Vinicius S. (TTU)
Objective: Our goal was to determine whether admin- istration of Fusobacterium necrophorum ssp. necrophorum into the jugular or portal vein will induce liver abscesses in preruminant calves. Materials and Methods: The study was performed as 2 experiments according to the inoculation site: jugu- lar vein or hepatic portal circulation. Experiment 1 was performed in 18 calves randomly assigned to receive intra- jugular infusion of saline (CONIV), or 107 (FUSOIV7), 109 (FUSOIV9), and 1011 (FUSOIV11) of F. necrophorum. In experiment 2, 20 calves were assigned to receive intrapor- tal infusion of saline or 106 (FUSOPV6), 108 (FUSOPV8), and 1010 (FUSOPV10) of F. necrophorum. Blood samples were collected on d 0, 1, 3, 5, 7, and 14 for hematology. Calves were slaughtered 14 d after inoculation and exam- ined for liver gross pathology. Results and Discussion: Neither model produced liver abscesses. However, in experiment 1, inoculation increased monocyte counts in FUSOIV11 calves versus CONIV, FUSOIV7, and FUSOIV9 on d 3 and 5 postchal- lenge. The neutrophil-to-lymphocyte ratio was greater for FUSOIV11 than CONIV and FUSOIV9 on d 7 postchallenge. In experiment 2, inoculation increased monocyte and neutrophils counts in the FUSOPV8 group compared with calves in other groups. Implications and Applications: Contrary to previ- ous reports, intraportal and intrajugular inoculation with F. necrophorum did not produce liver abscesses in preru- minant calves. Further research is necessary to explore alternative methodologies to use preruminant calves in experimental disease models for liver abscesses in cattle.
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.
Validation of an experimental model to induce liver abscesses in Holstein steers using an acidotic diet challenge and intraruminal bacterial inoculation*†
(2024) McDaniel, Zach S. (TTU); Hales, Kristin E. (TTU); Nagaraja, T. G.; Lawrence, Ty E.; Tennant, Travis C.; Amachawadi, Raghavendra G.; Carroll, Jeff A.; Burdick Sanchez, Nicole C.; Galyean, Michael L. (TTU); Davis, Emily (TTU); Kohl, Kesley (TTU); Line, Dalton J. (TTU); Dornbach, Colten W. (TTU); Abbasi, Mina; Deters, Alyssa; Shi, Xiaorong; Ballou, Michael A. (TTU); Machado, Vinicius S. (TTU); Smock, Taylor M. (TTU); Broadway, Paul R.
Objective: Our objectives were to develop and evaluate a model to induce liver abscesses (LA) in cattle and assess roles of Fusobacterium and Salmonella on LA formation and severity. Materials and Methods: Holstein steers (n = 40; initial BW = 110 ± 12.0 kg) were assigned randomly to treatments (n = 10 per treatment): (1) control diet (CON); (2) acidotic diet (AD); (3) AD plus inoculation of Fusobacterium necrophorum ssp. necrophorum (8.81 × 1010 cfu/steer; ADFn); or (4) AD and intraruminal inoculation of F. necrophorum (8.81 × 1010 cfu/steer) and Salmonella enterica Lubbock (1.52 × 1011 cfu/steer; ADFS). On d 0, steers were subjected to 4 acidotic cycles where they were fed the acidotic diet for 3 d and then the control diet for 2 d. Intraruminal bacterial inoculation was on d 20. From d 21, AD, ADFn, and ADFS steers remained on the acidotic diet until d 38. Euthanasia occurred on d 38, and gross pathology of the lung, rumen, liver, and colon were recorded. Results and Discussion: Liver abscess prevalence was 40% in ADFn and 50% in ADFS versus 0% in CON and AD. No pathological differences were noted in lung nor colon among treatments; however, ruminal damage was more severe in ADFn and ADFS than in CON and AD steers. Implications and Applications: Acidotic diet alone caused mild ruminal acidosis but no LA. Acidotic diet with intraruminal bacterial inoculation increased rumenitis severity and resulted in LA, thus validating the nutritional model to induce LA. Therefore, acidotic diet with intraruminal bacterial inoculation is a viable model to study the formation of LA.