Applied Animal Science最新文献

{"title":"Identification of blood-based biomarkers for detection of liver abscesses in beef × dairy heifers*","authors":"Reese A. Wilson ,&nbsp;Bradley J. Johnson ,&nbsp;Jhones O. Sarturi ,&nbsp;Whitney L. Crossland ,&nbsp;Kristin E. Hales ,&nbsp;Ryan J. Rathmann ,&nbsp;Christy L. Bratcher ,&nbsp;Miles E. Theurer ,&nbsp;Raghavendra G. Amachawadi ,&nbsp;T.G. Nagaraja ,&nbsp;Scott E. Speidel ,&nbsp;R. Mark Enns ,&nbsp;Milton G. Thomas ,&nbsp;Blake A. Foraker ,&nbsp;Matthew A. Cleveland ,&nbsp;Dale R. Woerner","doi":"10.15232/aas.2023-02504","DOIUrl":"10.15232/aas.2023-02504","url":null,"abstract":"<div><h3>Objective</h3><p>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.</p></div><div><h3>Materials and Methods</h3><p>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.</p></div><div><h3>Results and Discussion</h3><p>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.</p></div><div><h3>Implications and Applications</h3><p>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.</p></div>","PeriodicalId":8519,"journal":{"name":"Applied Animal Science","volume":"40 3","pages":"Pages 386-397"},"PeriodicalIF":1.5,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590286524000600/pdf?md5=2fc36d18a65db8e703f8e0f39ae8e6b1&pid=1-s2.0-S2590286524000600-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141229097","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation of virginiamycin to improve health of growing and finishing steers: I. Effects on ruminal acidosis and liver health*","authors":"Madeline E. Rivera ,&nbsp;Luiz F. Dias Batista ,&nbsp;Luis O. Tedeschi","doi":"10.15232/aas.2023-02511","DOIUrl":"10.15232/aas.2023-02511","url":null,"abstract":"<div><h3>Objective</h3><p>Our objective was to observe the effects of the interrelationship among virginiamycin (VM) inclusion (240 mg/d), ruminal pH dynamics, and hepatic plasma metabolites on rumen and animal health during a 150-d feeding trial.</p></div><div><h3>Materials and Methods</h3><p>Steers (304 ± 27 kg; n = 120) were assigned randomly to 1 of 6 dietary treatments: no VM (T₀₀₀); VM for the last 50 d (T₀₀₁); VM for the last 100 d (T₀₁₁); VM for the first 50 d (T₁₀₀); VM for the first 100 d (T₁₁₀); and VM for 150 d (T₁₁₁). All animals were orally administered 2 indwelling rumen pH and temperature recording boli on d 0 and 84. Blood samples were collected via jugular venipuncture on d −7, 28, 56, 84, 112, and 140, and plasma was analyzed for concentrations of albumin, alkaline phosphatase, direct bilirubin, total bilirubin, gamma-glutamyl transferase, and total protein using an automated blood analyzer. Concurrently, haptoglobin (HPT) was measured following a colorimetric method based on peroxidase activity. A random coefficients model with pen and animals within treatment as a random effect was used.</p></div><div><h3>Results and Discussion</h3><p>Animals that received VM for the first 100 d (T₁₁₀ and T₁₁₁) had greater mean ruminal pH during d 50 to 100 when compared with animals that did not receive VM (T₀₀₀ and T₀₀₁; 6.12 vs. 6.00, respectively). Moreover, T₁₁₁ tended to have less time under pH 5.8 (3.01 h/d) when compared with T₁₀₀ and T₀₀₁ (5.83 and 6.45 h/d, respectively). At slaughter, overall, 3.36% of cattle in the study were identified with liver abscesses (A and A−), and 24.3% had lung lesions. Plasma metabolite concentrations before slaughter did not predict the presence of liver abscesses (<em>P</em> ≥ 0.182). Based on acute phase responses, HPT was notably lower on d 84 after diet transition in VM-treated animals (46.1 vs. 68.9 mg/L). Additionally, VM inclusion boosted indicators of overall health with greater alkaline phosphatase levels and albumin-toglobulin ratios.</p></div><div><h3>Implications and Applications</h3><p>Virginiamycin has practical implications for rumen health and overall cattle health, where supplementation during the whole growing to finishing phases was more effective in capturing its full potential.</p></div>","PeriodicalId":8519,"journal":{"name":"Applied Animal Science","volume":"40 3","pages":"Pages 329-346"},"PeriodicalIF":1.5,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590286524000569/pdf?md5=1e0798e2d38cc1ac69c7e5e44f6aca17&pid=1-s2.0-S2590286524000569-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141233350","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Call for Submissions","authors":"","doi":"10.1016/S2590-2865(24)00070-3","DOIUrl":"https://doi.org/10.1016/S2590-2865(24)00070-3","url":null,"abstract":"","PeriodicalId":8519,"journal":{"name":"Applied Animal Science","volume":"40 3","pages":"Pages iv-vi"},"PeriodicalIF":1.5,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590286524000703/pdfft?md5=a0ff14106e833b26e93f2416cff6177a&pid=1-s2.0-S2590286524000703-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141244276","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Validation of an experimental model to induce liver abscesses in Holstein steers using an acidotic diet challenge and intraruminal bacterial inoculation*†","authors":"Zach S. McDaniel ,&nbsp;Kristin E. Hales ,&nbsp;T.G. Nagaraja ,&nbsp;Ty E. Lawrence ,&nbsp;Travis C. Tennant ,&nbsp;Raghavendra G. Amachawadi ,&nbsp;Jeff A. Carroll ,&nbsp;Nicole C. Burdick Sanchez ,&nbsp;Michael L. Galyean ,&nbsp;Emily Davis ,&nbsp;Kesley Kohl ,&nbsp;Dalton J. Line ,&nbsp;Colten W. Dornbach ,&nbsp;Mina Abbasi ,&nbsp;Alyssa Deters ,&nbsp;Xiaorong Shi ,&nbsp;Michael A. Ballou ,&nbsp;Vinicius S. Machado ,&nbsp;Taylor M. Smock ,&nbsp;Paul R. Broadway","doi":"10.15232/aas.2023-02485","DOIUrl":"10.15232/aas.2023-02485","url":null,"abstract":"<div><h3>Objective</h3><p>Our objectives were to develop and evaluate a model to induce liver abscesses (LA) in cattle and assess roles of <em>Fusobacterium</em> and <em>Salmonella</em> on LA formation and severity.</p></div><div><h3>Materials and Methods</h3><p>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 <em>Fusobacterium necrophorum</em> ssp. <em>necrophorum</em> (8.81 × 10¹⁰ cfu/steer; ADFn); or (4) AD and intraruminal inoculation of <em>F. necrophorum</em> (8.81 × 10¹⁰ cfu/steer) and <em>Salmonella enterica</em> 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.</p></div><div><h3>Results and Discussion</h3><p>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.</p></div><div><h3>Implications and Applications</h3><p>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.</p></div>","PeriodicalId":8519,"journal":{"name":"Applied Animal Science","volume":"40 3","pages":"Pages 398-413"},"PeriodicalIF":1.5,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590286524000612/pdf?md5=b9e548639b076fbb06c5a5abb80db95b&pid=1-s2.0-S2590286524000612-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141229947","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Relationship of liver abnormalities with carcass performance and value*","authors":"B.B. Grimes ,&nbsp;T.J. McEvers ,&nbsp;T.C. Tennant ,&nbsp;J.W. Johnson ,&nbsp;T.E. Lawrence","doi":"10.15232/aas.2023-02482","DOIUrl":"10.15232/aas.2023-02482","url":null,"abstract":"<div><h3>Objective</h3><p>We evaluated the association of liver ab- normalities with carcass characteristics and value, using 2 independent databases generated from 2010 through 2021.</p></div><div><h3>Materials and Methods</h3><p>Liver abnormalities (ab- scesses, congestive heart failure [CHF], flukes, telangiec- tasis) and associated carcass outcomes were evaluated for 371,476 carcasses housed in database 1. Liver abnormali- ties of individual carcasses (n = 1,166,056) in database 2 were captured as lot-level (n = 7,196) audits and summa- rized as frequencies across demographic categories. Data were analyzed with mixed models.</p></div><div><h3>Results and Discussion</h3><p>Livers were scored as fol- lows: edible = no abscess or abnormality, A− = 1 to 2 small abscesses or inactive scars, A = 1 or 2 large ab- scesses or multiple small abscesses, A+ = multiple large abscesses, A+adhesion (A+AD) = liver adhered to part of the gastrointestinal tract or diaphragm or both, A+open (A+OP) = open abscess, A+adhesion/open (A+AD/OP) = combination of A+AD and A+OP score. Other non- abscess liver abnormalities recorded were CHF = dark mottled blue appearance and noticeably enlarged; flukes = presence of black lymph nodes, enlarged thickened bile ducts, visible dark tracts scattered throughout the dorsal side of the liver, or presence of flukes within the liver; and telangiectasis = peppering of blue/red dots on the surface of the liver tissue. Liver abnormality rates across both da- tabases were A− = 7.3% to 7.4%, A = 2.7% to 5.3%, A+ = 2.4% to 4.8%, A+AD = 3.9% to 6.2%, A+OP = 1.4% to 1.7%, A+AD/OP = 0.8% to 1.3%, CHF = 0.1% to 0.2%, flukes = 1.3% to 3.6%, telangiectasis = 0.6% to 0.7%, with 67.0% to 77.0% of livers being edible. Carcasses with se- vere abscesses (A+, A+AD, A+OP, A+AD/OP) or CHF had less hot carcass weight (HCW; 13.0 and 42.5 kg, re- spectively) compared with carcasses with edible livers. All abnormalities except telangiectasis reduced LM area. Less 12th-rib s.c. fat was observed for carcasses with A−, A, A+, A+AD, and CHF abnormalities compared with car- casses with edible livers. As liver abscess severity increased compared with edible livers, carcass value diminished and frequency of carcasses railed off line (removed from the production line) increased, particularly for A+AD (4.2%), A+OP (9.7%), and A+AD/OP (11.9%).</p></div><div><h3>Implications and Applications</h3><p>Based on analysis of this large database, liver abnormalities, especially severely abscessed and CHF outcomes, greatly affect HCW. These results indicate control of liver abscesses, and understand- ing the development of CHF, is important to prevent loss- es in carcass value.</p></div>","PeriodicalId":8519,"journal":{"name":"Applied Animal Science","volume":"40 3","pages":"Pages 358-375"},"PeriodicalIF":1.5,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590286524000582/pdf?md5=43dcf3c03d1a18496646c60da5ef3fb9&pid=1-s2.0-S2590286524000582-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141234106","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Removing tylosin phosphate from finishing diets with increasing roughage concentrations affects growth performance, carcass characteristics, and prevalence of liver abscesses of finishing steers*","authors":"A.B. Word ,&nbsp;K.J. Karr ,&nbsp;B.P. Holland ,&nbsp;C.L. Maxwell ,&nbsp;S.K. Linneen ,&nbsp;P.J. Defoor","doi":"10.15232/aas.2023-02489","DOIUrl":"10.15232/aas.2023-02489","url":null,"abstract":"<div><h3>Objectives</h3><p>This study compared standard finishing diets with or without tylosin phosphate at an industry standard roughage concentration, as well as titrated roughage concentrations in finishing diets containing no tylosin.</p></div><div><h3>Materials and Methods</h3><p>Beef steers (initial BW = 387 ± 14.2 kg; n = 3,340) were used in a randomized complete block design with 12 pens/treatment and 65 or 70 steers per pen. Dietary treatments were (1) 7.0% corn stalks with tylosin (7TYL), (2) 7.0% corn stalks without tylosin (7NT), (3) 13.0% corn stalks without tylosin (13NT), or (4) 19.0% corn stalks without tylosin (19NT). Corn stalks replaced steam-flaked corn on a DM basis.</p></div><div><h3>Results and Discussion</h3><p>Increased corn stalks linearly increased DMI. Increased corn stalks linearly reduced final BW and ADG, and resulted in poorer G:F. Hot carcass weight was similar between 7TYL and 7NT; however, hot carcass weight (HCW) linearly decreased as corn stalk inclusion increased. Tylosin inclusion resulted in a 32% reduction in liver abscess prevalence (from 19% to 13%). Liver abscess prevalence decreased linearly with increased corn stalks; tylosin use reduced adhered livers, whereas increased corn stalks did not.</p></div><div><h3>Implications and Applications</h3><p>Replacing steamflaked corn with 13% or 19% inclusion of corn stalks in diets without tylosin phosphate could reduce liver abscess prevalence, but increased roughage may not decrease the severity of the liver abscesses. Importantly, decreased dietary energy density led to increased DMI and reduced HCW in cattle fed to the same days on feed.</p></div>","PeriodicalId":8519,"journal":{"name":"Applied Animal Science","volume":"40 3","pages":"Pages 260-268"},"PeriodicalIF":1.5,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590286524000508/pdf?md5=5fcb510b4df3a47ab4abd20f11d8b52c&pid=1-s2.0-S2590286524000508-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141231583","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"\"June\" Cover","authors":"","doi":"10.1016/S2590-2865(24)00065-X","DOIUrl":"10.1016/S2590-2865(24)00065-X","url":null,"abstract":"","PeriodicalId":8519,"journal":{"name":"Applied Animal Science","volume":"40 3","pages":"Page OFC"},"PeriodicalIF":1.5,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S259028652400065X/pdfft?md5=f53f5a845d514e5438660c9f3c2172f5&pid=1-s2.0-S259028652400065X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141231412","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"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*†","authors":"Z.S. McDaniel ,&nbsp;M.L. Galyean ,&nbsp;P.R. Broadway ,&nbsp;J.A. Carroll ,&nbsp;N.C. Burdick Sanchez ,&nbsp;A.N. Hanratty ,&nbsp;C.W. Dornbach ,&nbsp;D.J. Line ,&nbsp;T.M. Smock ,&nbsp;J.L. Manahan ,&nbsp;K.E. Hales","doi":"10.15232/aas.2023-02484","DOIUrl":"10.15232/aas.2023-02484","url":null,"abstract":"<div><h3>Objective</h3><p>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.</p></div><div><h3>Materials and Methods</h3><p>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.</p></div><div><h3>Results and Discussion</h3><p>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.</p></div><div><h3>Implications and Applications</h3><p>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.</p></div>","PeriodicalId":8519,"journal":{"name":"Applied Animal Science","volume":"40 3","pages":"Pages 269-278"},"PeriodicalIF":1.5,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S259028652400051X/pdf?md5=afa152b89eb130ae11d9f1dd57708848&pid=1-s2.0-S259028652400051X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141234688","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A real-time PCR assay for the detection and quantification of Fusobacterium necrophorum and Fusobacterium varium in ruminal contents of cattle*","authors":"Alyssa Deters ,&nbsp;Xiaorong Shi ,&nbsp;Jianfa Bai ,&nbsp;Qing Kang ,&nbsp;Jacques Mathieu ,&nbsp;T.G. Nagaraja","doi":"10.15232/aas.2023-02507","DOIUrl":"10.15232/aas.2023-02507","url":null,"abstract":"<div><h3>Objectives</h3><p>Our objectives were to develop and vali- date a quantitative PCR assay for the detection and quantification of the 2 subspecies of <em>Fusobacterium nec- rophorum</em> (ssp. <em>necrophorum</em> and ssp. <em>funduliforme</em>) and a recently recognized species, <em>Fusobacterium varium</em>, in ruminal contents of cattle collected at slaughter.</p></div><div><h3>Materials and Methods</h3><p>A quantitative PCR assay with primers and probes designed to target <em>hgdA</em>, which encodes for 2-hydroxyglutaryl dehydratase, for <em>F. necroph- orum</em> (<em>hgdA</em>-<em>n</em>) and <em>F. varium</em> (<em>hgdA-v</em>), and the leukotox- in promotor region, <em>lktA</em>-<em>n</em> and <em>lktA</em>-<em>f</em>, for the 2 subspecies of <em>F. necrophorum</em> were developed and validated. A total of 345 ruminal fluid samples were collected in an abattoir immediately after slaughter, which included 181 (52.5%) samples from cattle with apparently healthy, nonabscessed livers and 164 (47.5%) from cattle with abscessed livers. Basal media with lactate or lysine as the major energy source and each with or without josamycin, vancomycin, and norfloxacin were used to enrich ruminal samples that were below the lower limit of quantification.</p></div><div><h3>Results and Discussion</h3><p>The ssp. <em>necrophorum</em> was quantified in 22% and 29% of samples from cattle with nonabscessed and abscessed livers, respectively. The ssp. <em>funduliforme</em> and <em>F. varium</em> were prevalent in almost all ruminal samples (98% to 100%) and were not different between cattle with or without abscessed livers. The mean concentrations of the 2 subspecies and <em>F. varium</em> were 10³ to 10⁴ cfu/mL and were not different between cattle with abscessed or nonabscessed livers.</p></div><div><h3>Implications and Applications</h3><p>A major finding of the study was that only a small proportion of the ruminal contents harbored the ssp. <em>necrophorum</em>, which suggested that it is not a normal member of the ruminal microbial community. In contrast, the ssp. <em>funduliforme</em> and <em>F. vari- um</em> were prevalent in all ruminal contents tested. Because <em>F. varium</em> is a pathogen, the question whether the species contributes to the development of liver abscesses needs to be investigated.</p></div>","PeriodicalId":8519,"journal":{"name":"Applied Animal Science","volume":"40 3","pages":"Pages 250-259"},"PeriodicalIF":1.5,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590286524000491/pdf?md5=daad2811721ccb8c9c0cf322ff15762e&pid=1-s2.0-S2590286524000491-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141232387","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Use of a novel direct-fed microbial as an alternative for tylosin phosphate to control liver abscesses and decrease antimicrobial use in finishing beef steers*†","authors":"A.A. Hoffman ,&nbsp;S.C. Fernando ,&nbsp;J.E. Wells ,&nbsp;D.R. Woerner ,&nbsp;J.L. Manahan ,&nbsp;N.S. Long ,&nbsp;Z.S. McDaniel ,&nbsp;T.M. Smock ,&nbsp;J.A. Carroll ,&nbsp;N.C. Burdick Sanchez ,&nbsp;P.R. Broadway ,&nbsp;K.E. Hales","doi":"10.15232/aas.2023-02483","DOIUrl":"10.15232/aas.2023-02483","url":null,"abstract":"<div><h3>Objective</h3><p>Our goal was to evaluate the use of a novel direct-fed microbial as an alternative to antimicrobials to decrease liver abscesses in finishing beef cattle.</p></div><div><h3>Materials and Methods</h3><p>Beef steers (n = 240; initial BW = 263 ± 18.0 kg) were used in a randomized complete block design comprising 3 BW blocks and 3 pen replications per treatment during the receiving period and 3 BW blocks and 14 to 15 pen replications per treatment during the finishing phase. Experimental treatments were assigned randomly to pen within BW block and consisted of (1) negative control, dietary supplement with no tylosin phosphate; (2) positive control, dietary supplement formulated to supply 90 mg of tylosin phosphate daily (Tylan-100; Elanco Animal Health); (3) positive control with tylosin phosphate removed the last 65 d of the feeding period; and (4) novel direct-fed microbial <em>Bacillus licheniformis</em> fed daily at 1 × 10¹¹ cfu/steer.</p></div><div><h3>Results and Discussion</h3><p>From d 0 to 59, ADG, DMI, DMI as a percentage of BW, and G:F did not differ. During the finishing period, live- and carcass-adjusted final BW did not differ among treatments. Likewise, in the finishing period, there were no differences in ADG, DMI, DMI as a percentage of BW, or G:F. No differences in hot carcass weight, DP, marbling score, longissimus dorsi area, 12th-rib fat thickness, or calculated yield grade were detected among dietary treatments. Liver abscess incidence and severity were not affected by dietary treatments.</p></div><div><h3>Implications and Applications</h3><p>The use of a novel direct-fed microbial, <em>B. licheniformis</em>, in beef cattle fed in small research pens did not affect growth performance, carcass characteristics, or liver abscess prevalence or severity. <em>Bacillus licheniformis</em> is not a viable strategy to decrease liver abscesses in growing and finishing beef cattle.</p></div>","PeriodicalId":8519,"journal":{"name":"Applied Animal Science","volume":"40 3","pages":"Pages 307-316"},"PeriodicalIF":1.5,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590286524000545/pdf?md5=096f18d2c579d012b45ed106ec633881&pid=1-s2.0-S2590286524000545-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141230183","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}