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Klima C.L.,Agriculture and Agri Food Canada | Klima C.L.,University of Western Ontario | Zaheer R.,Agriculture and Agri Food Canada | Cook S.R.,Agriculture and Agri Food Canada | And 4 more authors.
Journal of Clinical Microbiology | Year: 2014

In this study, we determined the prevalence of bovine respiratory disease (BRD)-associated viral and bacterial pathogens in cattle and characterized the genetic profiles, antimicrobial susceptibilities, and nature of antimicrobial resistance determinants in collected bacteria. Nasopharyngeal swab and lung tissue samples from 68 BRD mortalities in Alberta, Canada (n = 42), Texas (n = 6), and Nebraska (n = 20) were screened using PCR for bovine viral diarrhea virus (BVDV), bovine respiratory syncytial virus, bovine herpesvirus 1, parainfluenza type 3 virus, Mycoplasma bovis, Mannheimia haemolytica, Pasteurella multocida, and Histophilus somni. Excepting bovine herpesvirus 1, all agents were detected. M. haemolytica (91%) and BVDV (69%) were the most prevalent, with cooccurrence in 63% of the cattle. Isolates of M. haemolytica (n = 55), P. multocida (n = 8), and H. somni (n = 10) from lungs were also collected. Among M. haemolytica isolates, a clonal subpopulation (n = 8) was obtained from a Nebraskan feedlot. All three bacterial pathogens exhibited a high rate of antimicrobial resistance, with 45% exhibiting resistance to three or more antimicrobials. M. haemolytica (n = 18), P. multocida (n = 3), and H. somni (n = 3) from Texas and Nebraska possessed integrative conjugative elements (ICE) that conferred resistance for up to seven different antimicrobial classes. ICE were shown to be transferred via conjugation from P. multocida to Escherichia coli and from M. haemolytica and H. somni to P. multocida. ICE-mediated multidrug-resistant profiles of bacterial BRD pathogens could be a major detriment to many of the therapeutic antimicrobial strategies currently used to control BRD. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

Benedict K.M.,Colorado State University | Gow S.P.,University of Saskatchewan | Reid-Smith R.J.,Public Health Agency of Canada | Booker C.W.,Feedlot Health Management Services | Morley P.S.,Public Health Agency
Canadian Veterinary Journal | Year: 2012

Accurate antimicrobial drug use data are needed to enlighten discussions regarding the impact of antimicrobial drug use in agriculture. The primary objective of this study was to investigate the perceived accuracy and clarity of different methods for reporting antimicrobial drug use information collected regarding beef feedlots. Producers, veterinarians, industry representatives, public health officials, and other knowledgeable beef industry leaders were invited to complete a web-based survey. A total of 156 participants in 33 US states, 4 Canadian provinces, and 8 other countries completed the survey. No single metric was considered universally optimal for all use circumstances or for all audiences. To effectively communicate antimicrobial drug use data, evaluation of the target audience is critical to presenting the information. Metrics that are most accurate need to be carefully and repeatedly explained to the audience.

Brandt R.T.,Brandt Nutrition Systems LLC and Midwest PMS | Corbin M.J.,Zoetis Inc. | Quinn M.J.,Feedlot Health Management Services
Professional Animal Scientist | Year: 2016

A total of 2,576 steers allotted to 24 pens were used to evaluate 2 forms of ractopamine, Optaflexx (Elanco Animal Health, Greenfield, IN) or Actogain 45 (Zoetis, Florham Park, NJ) brands of ractopamine hydrochloride, on steer performance and carcass traits (12 pens; 1,288 steers per treatment). Both test articles were fed at a rate of 16.4 g/t (DM basis) to target a consumption of 210 mg per head for an average (range 28 to 31) of 30 d. Total gain, daily gain, and feed efficiency tended (P < 0.10) to favor Actogain 45 on a live basis. However, there were no significant differences (P ≥ 0.32) between treatments for carcass-adjusted total gain, daily gain, or feed efficiency. Furthermore, there were no differences for estimated total carcass gain or rate of carcass gain (P ≥ 0.34). Finally, there were no differences (P ≥ 0.29) in HCW or any carcass USDA YG or QG variables. There was no evidence of lameness or locomotion impairment in any steer during the course of this study or at time of slaughter. It was concluded there were no differences between Optaflexx and Actogain 45 on performance or carcass traits of steers when fed at a rate of 16.4 g/t (DM basis) for the final 30 d on feed. © 2016 American Registry of Professional Animal Scientists.

Gifford C.A.,Oklahoma State University | Holland B.P.,South Dakota State University | Mills R.L.,Oklahoma State University | Mills R.L.,Austin Peay State University | And 9 more authors.
Journal of Animal Science | Year: 2012

Inflammation caused by bovine respiratory disease (BRD) continues to be one of the greatest challenges facing beef cattle producers and feedlot managers. Inflammation decreases DMI, ADG, and G:F in feedlot calves, decreasing growth rate and increasing days on feed, which results in economic losses during the feeding period. During the past decade, marketing of feedlot animals has changed from selling cattle on a live basis to a grid-based marketing system. When cattle are marketed on a live basis, the economic effects of BRD stop at increased health cost and decreased feedlot performance, carcass weight, and death loss. However, when cattle are marketed in a grid-based system, inflammation has the potential to also affect carcass cutability and quality. The effects of inflammation on feedlot cattle in regards to performance are well understood; however, specific effects on cattle growth and ultimately carcass merit are not as well described. Recent studies in feedlot cattle have indicated that the incidence of BRD decreases both HCW and marbling; however, mechanisms are not understood. Research in other species has demonstrated that during the acute phase response, pro-inflammatory cytokines promote skeletal muscle catabolism to supply AA and energy substrates for immune tissues. Further, during this early immune response, the liver changes its metabolic priorities to the production of acute phase proteins for use in host defense. Together these dramatic shifts in systemic metabolism may explain the detrimental effects on performance and carcass traits commonly associated with BRD in feedlot calves. Moreover, recent studies relative to human health have revealed complex multilevel interactions between the metabolic and immune systems, and highlighted inflammation as being a significant contributor to major metabolic diseases. The objective of this paper is to review data to help explain the economical and physiological effects of inflammation on cattle growth and carcass merit. © American Society of Animal Science.

Klima C.L.,University of Lethbridge | Alexander T.W.,Agriculture and Agri Food Canada | Selinger L.B.,University of Lethbridge | Read R.R.,University of Calgary | And 4 more authors.
Journal of Microbiological Methods | Year: 2010

Mannheimia haemolytica is an opportunistic pathogen that can cause fibrinonecrotic pneumonia in cattle and is the main bacterial agent implicated in bovine respiratory disease-complex (BRD). Despite its economic importance to the cattle industry, few studies have characterized the genetic nature of M. haemolytica and none have genotyped isolates from feedlots. Identifying and monitoring genetic variants of M. haemolytica is important to understanding the etiology of BRD in cattle. We investigated the capacity of three genotyping techniques (BOX-PCR, (GTG)5-PCR and PFGE analysis of SalI-restricted DNA) to discriminate among 24 reference strains from the family Pasteurellaceae and 40 M. haemolytica isolates collected from feedlot cattle. From cluster analysis of the M. haemolytica isolates, PFGE was revealed as most discriminating, followed by BOX-PCR and then (GTG)5-PCR (Simpson's diversity index > 0.98, 0.82, and 0.72, respectively). Of these methods, PFGE also had the greatest mean repeatability (0.96). The PFGE and BOX-PCR assays grouped all M. haemolytica in a single cluster but only BOX-PCR and (GTG)5-PCR grouped the Mannheimia glucosida and Mannheimia ruminalis strains together. Refinement of genotyping procedures for M. haemolytica could offer new insight into the etiology of this pathogen in BRD. Crown Copyright © 2010.

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