Applied Animal Science最新文献

{"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}

{"title":"Assessment of forage inclusion strategies as a means of reducing liver abscesses in finishing feedlot cattle*†","authors":"T.J. Paterson ,&nbsp;E. O’Hara ,&nbsp;R.J. Gruninger ,&nbsp;G.B. Penner ,&nbsp;H.A. Lardner ,&nbsp;E. Stephens ,&nbsp;W. Yang ,&nbsp;K.A. Beauchemin ,&nbsp;T.A. McAllister ,&nbsp;G.O. Ribeiro","doi":"10.15232/aas.2023-02481","DOIUrl":"10.15232/aas.2023-02481","url":null,"abstract":"<div><h3>Objective</h3><p>This study evaluated different strategies of forage inclusion in finishing beef cattle diets and their ef- fects on feed intake, ruminal fermentation and microbiota, blood serum parameters, growth performance, carcass quality, and liver abscesses.</p></div><div><h3>Materials and Methods</h3><p>Steers (n = 360, 400 ± 29 kg) were stratified by weight and randomly allocated across 24 pens, which were randomly assigned to 1 of 4 dietary treatments (15 steers/pen, 6 pens/treatment) in a completely randomized experiment. Treatments included: (1) positive control (+CTRL) fed a diet (7.5% forage on a diet DM basis) with tylosin (11 mg/kg); (2) negative control (−CTRL; control diet without tylosin); (3) a diet where forage concentration decreased (DECR) every 42 d and was static for the last 84 d (forage represented 15%, 9%, 3%, and 3% of DM, respectively) without tylosin; and (4) a diet where forage concentration increased (INCR), inverse of the DECR without tylosin.</p></div><div><h3>Results and Discussion</h3><p>The +CTRL steers had greater ADG (1.74 kg/d vs. 1.63 kg/d), shrunk total BW gain (306 vs. 287 kg), and a tendency for greater final BW (705 vs. 687 kg), than than INCR steers. As expected, a diet × period interaction was observed for DMI, but it did not differ among treatments over the full study. Yield scores and rib fat thickness were greater in –CTRL than INCR steers. The percentage of steers with minor liver abscesses tended to be less for +CTRL (51.8%) and DECR (51.8%) compared with −CTRL (62.2%) and INCR (64.3%).</p></div><div><h3>Implications and Applications</h3><p>Greater dietary con- centrations of forage earlier in the finishing phase, with a subsequent decline thereafter, has the potential to de- crease the proportion of minor liver abscesses similar to typical finishing diets including tylosin, without affecting growth performance or carcass quality.</p></div>","PeriodicalId":8519,"journal":{"name":"Applied Animal Science","volume":"40 3","pages":"Pages 279-296"},"PeriodicalIF":1.5,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590286524000521/pdf?md5=617baa5ed054874099abd1923fccb53a&pid=1-s2.0-S2590286524000521-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141230523","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":"Association of liver-abscess presence and severity with trim loss, slaughter yield, carcass grading performance, lung lesions, and value of fed-Holsteins*","authors":"R.T. Herrick ,&nbsp;C.L. Rogers ,&nbsp;T.A. Jones ,&nbsp;T.J. McEvers ,&nbsp;T.R. Brown ,&nbsp;C.L. Maxwell ,&nbsp;T.E. Lawrence","doi":"10.15232/aas.2023-02471","DOIUrl":"10.15232/aas.2023-02471","url":null,"abstract":"<div><h3>Objective</h3><p>Our objective was to evaluate the effects of liver abscesses on carcass characteristics and value of Holstein carcasses.</p></div><div><h3>Materials and Methods</h3><p>Fed-Holsteins were evalu- ated at 2 commercial processing facilities in Texas (n = 1,073) and Kansas (n = 1,070) from fall of 2016 through spring of 2017. Liver abscesses were visually assessed and scored; simultaneously, lungs were manually palpated to assess degree of consolidation and fibrin tag formation, to assess their association with liver abnormality. Finally, carcass trim was weighed from carcasses moved off line for zero tolerance trimming. Carcass and viscera values were assigned using USDA market reports and adjusted based on viscera condemnations along with premiums and dis- counts for quality and yield outcomes. Data were analyzed using the MIXED and GENMOD procedures of SAS v9.4 (SAS Institute Inc., Cary, NC) with carcass as the experi- mental unit.</p></div><div><h3>Results and Discussion</h3><p>Hot carcass weight was re- duced (−25.1 kg, −6.6%) in carcasses that had an ad- hered and open liver abscess as compared with carcasses without abscessed livers. Carcasses with adhered, open, or adhered and open liver scores had increased carcass trim (0.72, 3.92, and 3.39 kg, respectively) when compared with carcasses without abscessed livers (0.38 kg). Similarly, carcasses with adhered, open, or adhered and open liver scores returned gross carcass revenues that were 5.0% to 6.4% less (–$97.69, –$93.86, and –$121.22/carcass, re- spectively) than carcasses without abscessed livers. Liver abscesses reduced gross offal values of individual animals by 20% to 84% depending upon severity.</p></div><div><h3>Implications and Applications</h3><p>Fed-Holsteins have been a significant portion of the beef industry, even though Holsteins have increased rates of severe liver ab- scesses compared with their non-dairy-reared equivalents. Therefore, methods to control liver abscesses should be employed, to mitigate the greater financial risk that Hol- steins and dairy-reared animals incur to both cattle feeders and beef processors.</p></div>","PeriodicalId":8519,"journal":{"name":"Applied Animal Science","volume":"40 3","pages":"Pages 376-385"},"PeriodicalIF":1.5,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590286524000594/pdf?md5=d56e6e671142003aedb8bcb10255f04c&pid=1-s2.0-S2590286524000594-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141232402","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":"Supplementation of calcium magnesium carbonate, tylosin phosphate, or both on growth performance, carcass traits, liver outcomes, and rumination activity of yearling beef steers fed a finishing diet*","authors":"B.B. Grimes Francis ,&nbsp;F.L. Francis ,&nbsp;E.R. Gubbels ,&nbsp;T.C. Norman ,&nbsp;T.M. Ribeiro ,&nbsp;S.R. Hanson ,&nbsp;C.R. Ross ,&nbsp;D.M. Paulus Compart ,&nbsp;W.C. Rusche ,&nbsp;Z.K. Smith","doi":"10.15232/aas.2023-02479","DOIUrl":"10.15232/aas.2023-02479","url":null,"abstract":"<div><h3>Objective</h3><p>The objective of this study was to evaluate the effects of supplementation with calcium magnesium carbonate (CMC), tylosin phosphate (TYL), or both on rumination behavior, growth performance, liver abscess prevalence, and carcass characteristics of yearling beef steers.</p></div><div><h3>Materials and Methods</h3><p>Treatments were arranged as a 2 × 2 factorial including CMC and TYL. Beef steers (n = 156; 469 ± 18 kg) were assigned to 1 of 20 pens. Di- etary inclusion of CMC was included at 1.5% of the diet (DM basis) in replacement of dry-rolled corn, and TYL was provided at 90 mg per steer/d. Growth performance was calculated on a carcass-adjusted basis (hot carcass weight/0.625). Data were analyzed as a randomized com- plete block design with fixed effects of CMC, TYL, and their interaction; block was a random effect.</p></div><div><h3>Results and Discussion</h3><p>Dry matter intake was 4.9% less when CMC was fed and 1.6% greater when TYL was fed. Carcass weight tended to be lighter with CMC supplementation compared with CON (432 vs. 439 kg). Supplementation of TYL tended to reduce the percentage of abscessed livers by 55.7%.</p></div><div><h3>Implications and Applications</h3><p>These results indi- cate that supplementation of CMC did not result in any improvements in growth, carcass, or dietary net energy utilization, but TYL supplementation tended to reduce liver abscess prevalence.</p></div>","PeriodicalId":8519,"journal":{"name":"Applied Animal Science","volume":"40 3","pages":"Pages 297-306"},"PeriodicalIF":1.5,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590286524000533/pdf?md5=64d80c67df2eb88a0fbfba9f159854fb&pid=1-s2.0-S2590286524000533-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141233388","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":"Review: Summary of the Special Issue on liver abscesses in cattle and thoughts on future research*","authors":"K.E. Hales","doi":"10.15232/aas.2024-02553","DOIUrl":"10.15232/aas.2024-02553","url":null,"abstract":"<div><h3>Objective</h3><p>My objective was to summarize 16 original research manuscripts and 1 perspectives and commentary contribution that were submitted, peer reviewed, and ac- cepted in this Special Issue on liver abscesses in cattle.</p></div><div><h3>Materials and Methods</h3><p>A summary of key points made in the Special Issue articles is provided. Additional conclusions and thoughts about future directions of re- search to address liver abscesses (LA) in cattle are offered. <strong>Results and Discussion:</strong> This Special Issue represents the current understanding of the etiology, blood chemis- try biomarkers, dietary and management strategies, and mitigation strategies for LA in cattle used in the feedlot industry throughout the United States and Canada. Sev- enteen articles from researchers and industry professionals studying LA in cattle are included, with studies ranging from practical dietary intervention strategies to experi- ments designed to understand the mode of action and the etiology of LA development.</p></div><div><h3>Implications and Applications</h3><p>Liver abscess disease is a multifactorial, polymicrobial disease that affects mul- tiple organ systems within the body, reflecting complex interactions among the host, environment, and pathogens. The pathogenesis of this disease needs to be further exam- ined, and basic and applied research approaches should be employed to advance our understanding of liver abscesses in cattle.</p></div>","PeriodicalId":8519,"journal":{"name":"Applied Animal Science","volume":"40 3","pages":"Pages 430-436"},"PeriodicalIF":1.5,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590286524000648/pdf?md5=cc9eb5e25d05b05609b48e6fdf8365d9&pid=1-s2.0-S2590286524000648-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141235455","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":"First report of isolation of Fusobacterium varium from liver abscesses and ruminal and colonic epithelial tissues of feedlot cattle*","authors":"Alyssa Deters ,&nbsp;Xiaorong Shi ,&nbsp;Ty Lawrence ,&nbsp;T.G. Nagaraja","doi":"10.15232/aas.2023-02512","DOIUrl":"10.15232/aas.2023-02512","url":null,"abstract":"<div><h3>Objective</h3><p>Our objective was to isolate and determine prevalence of <em>Fusobacterium varium</em> in liver abscesses and the corresponding ruminal and colonic epithelial tissues and ruminal and colonic contents of feedlot cattle.</p></div><div><h3>Materials and Methods</h3><p>A total of 96 intact liver abscess samples and matched ruminal and colonic tissues and contents from cattle, originating from feedlots that did not receive in-feed tylosin, were collected at slaughter. Liver abscesses and ruminal and colonic tissue were ho- mogenized and then plated, before and after enrichment in lactate or lysine medium with selective antibiotics, onto blood agar and selective lactate or lysine agar for isolation of <em>Fusobacterium</em> and to determine prevalence and concentration. Putative colonies were tested by a quantitative PCR assay targeting the <em>hgdA</em> gene for species confirma- tion.</p></div><div><h3>Results and Discussion</h3><p>None of the liver abscess samples yielded <em>F. varium</em> by direct plating; however, <em>F. varium</em> was isolated from 3 of 96 (3.1%) following enrich- ment of the homogenate in lactate or lysine medium. In contrast to liver abscesses, <em>F. varium</em> was isolated by direct plating from 27.1% (26/96) of ruminal epithelial and 3.1% (3/96) of colonic epithelial tissue homogenates. Overall, 10.1%, 77.1%, 44.8%, 86.5%, and 70.1% of liver abscess, ruminal, and colonic epithelial tissues and ruminal and colonic contents were positive for <em>F. varium,</em> respectively.</p></div><div><h3>Implications and Applications</h3><p>The increased fre- quency of isolation and high prevalence of <em>F. varium</em> in ruminal tissue and, to a lesser extent, in the colonic tissue confirms its ability to invade tissues and possibly cause bacterial ruminitis. However, the relatively low frequency of <em>F. varium</em> isolation and low prevalence in liver abscesses suggest that it is unlikely to be an etiologic agent. Inter- estingly, there is some evidence that ruminal strains of <em>F. varium</em> were resistant to tylosin; therefore, it would be of interest to determine the prevalence in cattle receiving in-feed tylosin.</p></div>","PeriodicalId":8519,"journal":{"name":"Applied Animal Science","volume":"40 3","pages":"Pages 244-249"},"PeriodicalIF":1.5,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S259028652400048X/pdf?md5=b7bf787bb6127cde5c04de4ebe1f3353&pid=1-s2.0-S259028652400048X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141229249","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 dietary composition and feeding management regimen on liver abscess prevalence, growth performance, and carcass outcomes of feedlot steers*","authors":"K.N. Schneid,&nbsp;J.D. Young,&nbsp;T.E. Lawrence,&nbsp;J.T. Richeson,&nbsp;K.L. Samuelson","doi":"10.15232/aas.2023-02490","DOIUrl":"10.15232/aas.2023-02490","url":null,"abstract":"<div><h3>Objective</h3><p>We investigated the independent and in- teractive effects of dietary starch concentration and feed- ing management regimen on growth performance, carcass characteristics, and prevalence of liver abscesses in finish- ing beef cattle.</p></div><div><h3>Materials and Methods</h3><p>Beef steers (n = 720) were assigned to 48 pens in a randomized complete block de- sign, with treatments arranged in a 2 × 2 factorial (12 pens per treatment). Factors were finishing diets with ei- ther low (49.1%; CON) or high (64.4%; HOT) starch con- centrations and feeding management regimens designed for consistent feed delivery (REG) or randomized varia- tions (ERR) in both feed quantity (85% followed by 115% of the previous 4-d average randomly once per week) and delivery time (randomly delayed for 1, 2, 3, or 4 h twice per week).</p></div><div><h3>Results and Discussion</h3><p>No interactions between diet and feeding management regimen were detected for growth performance, carcass outcomes, or liver abscess prevalence. Steers fed HOT had greater liver abscess fre- quency (55.1% vs. 33.4%) and a greater proportion of liver scars (46.7% vs. 34.0%) compared with CON. Steers consuming HOT also had less final BW, ADG, DMI, hot carcass weight, marbling score, and calculated YG versus CON. Feeding management regimen did not affect liver abscess frequency, growth performance, or carcass merit.</p></div><div><h3>Implications and Applications</h3><p>Feeding a high- starch diet increased liver abscess prevalence and de- creased growth and affected carcass outcomes. In contrast, erratic feeding management did not affect liver or produc- tion outcomes.</p></div>","PeriodicalId":8519,"journal":{"name":"Applied Animal Science","volume":"40 3","pages":"Pages 347-357"},"PeriodicalIF":1.5,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590286524000570/pdf?md5=07392e80ae843afe55660178c2dc1f41&pid=1-s2.0-S2590286524000570-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141230900","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}