Browsing by Author "Theurer, Miles E."
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Item 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.Item Evaluation of Carcass Performance and Biomarkers Associated with Liver Abscess(2023-12) Wilson, Reese A.; Woerner, Dale R.; Johnson, Bradley J.; Sarturi, Jhones O.; Crossland, Whitney L.; Theurer, Miles E.The inestimable economic loss in carcass value and feedlot performance associated with liver abscess in feedlot cattle has become a prominent and troublesome issue due to the multifactorial, sub-clinical nature of this disease. The first objective of this study was to determine the effects of liver abscess presence and severity on beef × dairy crossbred heifers on growth performance and carcass characteristics, while the second objective of this study was to investigation potential blood-based biomarkers for live-animal detection of liver abscess. A total of 1,984 beef × dairy heifers (initial body weight [BW] = 334.8 ± 4.6 kg) were assessed in a prospective cohort study. Treatment comparisons were assorted based on liver scores at time of harvest as follows: 1) non-abscessed (0); 2) 1 to 2 small abscesses (A-); 3) multiple small abscesses or 1 to 2 large abscesses (A); 4) and multiple large abscesses, open abscess, or signs of gut pile and/or diaphragm adherence (A+). Heifers (N = 200) which fit the treatment description (0 = 110; Abscessed [A-, A, or A+] = 97) had liver weights recorded and blood samples collected at harvest for modeling of potential predictors of the liver abscess condition. The experimental design, a prospective cohort study, used animal as experimental unit and included fixed effects of liver score and random effects of sorted pen (n = 30) nested within harvest dates (n = 9). For carcass outcomes by liver score and abscess size, results indicated hindered carcass performance in heifers with severe abscess (A+ or large abscess). Heifers scored as A+ yielded an economic loss of $70.51/hd in overall carcass value (sum of by-product and carcass pricing). While the live-animal performance of these same heifers also indicated the greatest hinderance in performance was associated most with heifers with sever abscess (A+ or large abscess), where the largest majority of cattle with severe abscess gained less than 0.45 kg per day (P = 0.02). Furthermore, liver weight was affected by liver abscess, with A+ scores weighing as much as 1kg or more than healthy livers (0; P < 0.01). In a binary system (abscessed or not), heifers with liver abscess had lesser values of LYM and WBC concentration (P < 0.01) but elevated PLR (P < 0.01). Serum chemistry measures were not affected by abscess presence or liver score (severity; P ≥ 0.06). In univariate modeling of CBC measures, only WBC concentration was accurate (65.85%; P < 0.01); however, not deemed an acceptable biomarker due to its’ poor specificity (54.79%). Using machine learning algorithms for modeling abscess condition, the LogitBoost model produced the greatest accuracy (80.65%; P < 0.01) and specificity (85.71%). An accurate blood test that allows for the detection of liver abscess 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. Overall, both late live-animal performance and carcass outcomes were negatively impacted by liver abscess in beef × dairy heifers and induced economic losses as much as $70.51/hd. Minor response in serum chemistry occurs as a result of liver abscess, while immune response measures including LYM and WBC should be further explored.Item 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.Item Infrared thermography or rectal temperature as qualification for targeted metaphylaxis in newly received beef steers and the effects on growth performance, complete blood count, and serum haptoglobin during a 42-day feedlot receiving period*(2023) Smock, Taylor M. (TTU); Broadway, P. Rand; Burdick Sanchez, Nicole C.; Carroll, Jeffery A.; Hoffman, Ashley A. (TTU); Long, Nathan S. (TTU); Manahan, Jeff L. (TTU); McDaniel, Zach S. (TTU); Theurer, Miles E.; Wells, Jim E.; Hales, Kristin E. (TTU)Objective: The objective was to evaluate rectal tem- perature and infrared thermography as qualification for targeted metaphylaxis, and effects on clinical health, growth performance, complete blood count, and serum haptoglobin in newly received beef steers during a 42-d feedlot receiving period. Materials and Methods: Crossbred beef steers (n = 240; arrival BW = 258 ± 22.5 kg) were used. Experimental treatments were arranged as a generalized complete block design: sterile saline (NCON); conventional metaphylaxis administered to all steers (CONV); targeted metaphylaxis administered to steers with rectal temperature ≥39.7°C (RECT); or targeted metaphylaxis administered to steers with ocular infrared temperature ≥39.7°C (EYE). Body weight and blood samples for quantification of complete blood count and serum haptoglobin were collected on d 0, 14, and 42 relative to metaphylaxis. Results and Discussion: Metaphylaxis was adminis- tered to 0% of NCON, 100% of CONV, 48.9% of RECT, and 48.6% of EYE steers (P < 0.01). Therapeutic bovine respiratory disease (BRD) treatment rate did not differ (P = 0.16), although overall BRD treatment rate was minimal. Metaphylaxis was 62.5% of total active antimicrobial compound administered to RECT and 32.1% of total ac- tive antimicrobial compound administered to EYE. Both methods of targeted metaphylaxis decreased percentage of animals administered antimicrobials relative to CONV (P < 0.01), but total milligrams of active drug compound administered was not different (P = 0.65). Body weight, DMI, DMI as percentage of BW, and G:F did not differ at any time point (P ≥ 0.07). A tendency (P = 0.06) was observed for ADG from d 0 to 14, where CONV was greatest, RECT and EYE were intermediate, and NCON was least. Day 0 to 42 ADG was greatest in CONV and RECT, least in NCON, and intermediate in EYE (P < 0.01). Platelet count tended (P = 0.10) to be greatest in NCON and RECT, followed by EYE and CONV. No further hematologic treatment differences were observed (P ≥ 0.22). Implications and Applications: Overall BRD morbidity was unexpectedly low in the present study. Both methods of targeted metaphylaxis decreased the propor- tion of animals administered antimicrobials relative to conventional metaphylaxis; however, total milligrams of active drug compound administered was not different. The ADG of steers administered targeted metaphylaxis based on rectal temperature did not differ from those ad- ministered conventional metaphylaxis. Use of targeted metaphylaxis with measures of body temperature may decrease the proportion of animals administered metaphylaxis while maintaining optimal health and growth perfor- mance outcomes.