Effectiveness of an experimental subunit ovine respiratory vaccine in reducing pneumonia in lambs.

Background: Pneumonia is the largest cause of mortality in Canadian lambs. Currently there are no licensed ovine vaccines in Canada to reduce economic losses from this production-limiting disease.

Objective Animals And Procedure: The effectiveness of an experimental subunit leukotoxin A (LtxA) and transferrin binding protein B (TbpB) vaccine was evaluated in lambs for reduction of clinical disease in an experimental challenge study and in a controlled randomized field trial in a large commercial sheep operation.

Beef Cow-calf Vaccine Knowledge Translation and Transfer (KTT) Project: Summary report on producer, veterinarian, and working group surveys regarding vaccine usage and recommendations.

Objective: The overall aim of this project was to create educational materials to support beef veterinarians and cow-calf producers in maximizing appropriate uptake of vaccine use in western Canada. The specific objective of the surveys reported here was to document current vaccine use by producers and vaccination recommendations by veterinarians and other industry stakeholders.

Population: Cow-calf producers and veterinarians involved in the western Canadian beef cow-calf sector.

Prevalence and Risk Factors Associated With Antimicrobial Resistance in Bacteria Related to Bovine Respiratory Disease-A Broad Cross-Sectional Study of Beef Cattle at Entry Into Canadian Feedlots.

A broad, cross-sectional study of beef cattle at entry into Canadian feedlots investigated the prevalence and epidemiology of antimicrobial resistance (AMR) in , and , bacterial members of the bovine respiratory disease (BRD) complex. Upon feedlot arrival and before antimicrobials were administered at the feedlot, deep nasopharyngeal swabs were collected from 2,824 feedlot cattle in southern and central Alberta, Canada. Data on the date of feedlot arrival, cattle type (beef, dairy), sex (heifer, bull, steer), weight (kg), age class (calf, yearling), source (ranch direct, auction barn, backgrounding operations), risk of developing BRD (high, low), and weather conditions at arrival (temperature, precipitation, and estimated wind speed) were obtained.

Cattle Immunized with a Recombinant Subunit Vaccine Formulation Exhibits a Trend towards Protection against Histophilus somni Bacterial Challenge.

Histophilosis, a mucosal and septicemic infection of cattle is caused by the Gram negative pathogen Histophilus somni (H. somni). As existing vaccines against H.

Reverse vaccinology as an approach for developing Histophilus somni vaccine candidates.

Histophilosis of cattle is caused by the Gram negative bacterial pathogen Histophilus somni (H. somni) which is also associated with the bovine respiratory disease (BRD) complex. Existing vaccines for H.

Single nucleotide polymorphisms in the bovine Histophilus somni genome; a comparison of new and old isolates.

Histophilus somni, a causative agent of the bovine respiratory disease complex, can also cause a variety of systemic disorders, including bronchopneumonia, myocarditis, pericarditis, arthritis, pleuritis, and infectious thrombotic meningoencephalitis. The purpose of this study was to determine if currently circulating strains differ from those of the 1980s by identifying genomic changes. Single nucleotide polymorphisms (SNPs) and insertion and deletion (INDEL) sites were examined by whole-genome sequencing in 12 samples, 6 old and 6 new.

Drug residues recovered in feed after various feedlot mixer truck cleanout procedures.

A study was conducted to determine the effectiveness of two methods of equipment cleanout, sequencing or flushing, for reducing drug carryover in feedlot mixer trucks. Feed samples were collected from total mixed rations before and after various feed mixer equipment cleanout procedures. Medicated rations contained either 11 ppm of tylosin or 166 or 331 ppm of chlortetracycline.

Antimicrobial drug use and antimicrobial resistance in enteric bacteria among cattle from Alberta feedlots.

The purpose of this study was to determine whether antimicrobial resistance (AMR) in foodborne pathogens (Escherichia coli O157, Salmonella, and Campylobacter) and non-type-specific E. coli obtained from fecal samples of feedlot cattle was associated with antimicrobial drug (AMD) use. A secondary objective was to determine if AMR in non-type-specific E.

A comparison of florfenicol-flunixin meglumine versus tulathromycin for the treatment of undifferentiated fever in fall-placed feedlot calves.

The purpose of this study was to compare the efficacy of a new combination drug, florfenicol-flunixin meglumine, with tulathromycin for initial treatment of undifferentiated fever (UF) in fall-placed calves that received metaphylactic tilmicosin on arrival at the feedlot. No significant differences were observed in UF relapses between the two drugs. Calves treated with florfenicol-flunixin had a lower crude case fatality rate (P = .

Occurrence of foodborne bacteria in Alberta feedlots.

The occurrence of generic Escherichia coli, E. coli O157, Salmonella, and Campylobacter in cattle manure, beef carcasses, catch basin water, and soils receiving manure application was determined in 21 Alberta feedlots. In cattle manure, generic E.

Comparative efficacy of tilmicosin versus tulathromycin as a metaphylactic antimicrobial in feedlot calves at moderate risk for respiratory disease.

The purpose of this study was to compare the efficacy and cost-effectiveness of tilmicosin (MIC) versus tulathromycin (DRAX) as a metaphylactic antimicrobial in feedlot calves at moderate risk for bovine respiratory disease (BRD). Calves that received DRAX had significantly (P < or = .05) lower initial BRD treatment rates compared with calves that received MIC.

Comparison of florfenicol and tulathromycin for the treatment of undifferentiated fever in Alberta feedlot calves.

The purpose of this study was to compare the efficacy and cost-effectiveness of florfenicol versus tulathromycin for initial treatment of undifferentiated fever in fall-placed steer calves that received metaphylactic tilmicosin on arrival at the feedlot. No significant differences (P > .10) were observed in undifferentiated fever relapses or the crude case fatality rate.

Clinical efficacy of a single injection of ceftiofur crystalline free acid sterile injectable suspension versus three daily injections of ceftiofur sodium sterile powder for the treatment of footrot in feedlot cattle.

A study was conducted in a feedlot in Alberta, Canada, to compare the clinical efficacy of a single injection of ceftiofur crystalline free acid sterile injectable suspension with three daily treatments of ceftiofur sodium sterile powder for the treatment of footrot. Use of a long-acting antimicrobial to treat footrot would reduce labor costs and hospital pen space requirements during high-risk periods. Four hundred cattle clinically diagnosed with footrot were systematically randomized to one of two treatment groups.

Presence of non-O157 Shiga toxin-producing Escherichia coli in feces from feedlot cattle in Alberta and absence on corresponding beef carcasses.

The study objectives were to determine the prevalence and serotypes of non-O157 Shiga toxin-producing Escherichia coli (STEC) in pens of feedlot cattle and on corresponding beef carcasses. We collected 25 fecal samples from 84 pens in 21 Alberta feedlots and 40 carcass swabs from each preslaughter pen for analysis by culture and polymerase chain reaction (PCR). Non-O157 STEC were recovered from feces from 12 (14%) of the 84 pens and 12 (57%) of the 21 feedlots by examination of 1 E.

Prevalence of antibodies to serotypes of Bluetongue virus and Anaplasma marginale in Montana feeder cattle: 2002-2003.

In a serologic survey of Montana-source weaned calves and yearling cattle, the apparent prevalence of antibodies to Bluetongue virus was 0.68% and 1.26% in 2002 and 2003, respectively, and to Anaplasma marginale at a positive cutoff at 30% inhibition it was 1.

Escherichia coli O157:H7 vaccine field trial in 9 feedlots in Alberta and Saskatchewan.

A feedlot trial was conducted to assess the efficacy of an Escherichia coli O157:H7 vaccine in reducing fecal shedding of E. coli O157:H7 in 218 pens of feedlot cattle in 9 feedlots in Alberta and Saskatchewan. Pens of cattle were vaccinated once at arrival processing and again at reimplanting with either the E.

Characterization of a shiga toxin-, intimin-, and enterotoxin hemolysin-producing Escherichia coli ONT:H25 strain commonly isolated from healthy cattle.

Among bovine fecal and recto-anal mucosal swab samples cultured in our laboratory for Escherichia coli O157:H7, we frequently isolated E. coli organisms that were phenotypically similar to the O157:H7 serotype as non-sorbitol fermenting and negative for beta-glucuronidase activity but serotyped O nontypeable:H25 (ONT:H25). This study determined the prevalence and virulence properties of the E.

Comparison of three oxytetracycline regimes for the treatment of persistent Anaplasma marginale infections in beef cattle.

Anaplasmosis, caused by the tick-borne rickettsia, Anaplasma marginale, is an economically important disease of cattle in the United States and worldwide. Cattle that recover from acute infection become carriers in which low or microscopically undetectable A. marginale rickettsemia persists.

Prevalence of antibodies to bluetongue virus and Anaplasma marginale in Montana yearling cattle entering Alberta feedlots: Fall 2001.

A serologic survey was conducted in yearling cattle imported into Alberta feedlots from Montana during October 2001 to estimate the prevalence of antibodies to bluetongue virus (BTV) and Anaplasma marginale in Montana yearling cattle. The apparent prevalence of antibodies to BTV when the competitive enzyme-linked immunosorbent assay (cELISA) was used was 0.37% (21/5608).

Antimicrobial susceptibility of hazard analysis critical control point Escherichia coli isolates from federally inspected beef processing plants in Alberta, Saskatchewan, and Ontario.

A survey to estimate the prevalence of antimicrobial resistance in Escherichia coli was conducted in 7 Canadian federally inspected processing plants during 2001. Escherichia coli isolates were recovered during routine hazard analysis critical control point sampling from beef carcasses and trim and subsequently tested for their antimicrobial susceptibility by using susceptibility panels. Of the 2653 isolates analyzed, 68% were sensitive to all 18 antimicrobials tested.

The effect of administering long-acting oxytetracycline and tilmicosin either by dart gun or by hand on injection site lesions and drug residues in beef cattle.

Forty yearling cattle were injected intramuscularly with long-acting oxytetracycline and subcutaneously with tilmicosin by dart gun or by hand in a chute 28 days prior to slaughter. The drugs caused injection site lesions and antibiotic residues in the neck and thigh that varied by technique, dose, and site.

Monitoring injection site lesions in Canadian yearling cattle and cull cows and bulls: Spring 1998.

Injection site lesions were found in 15% top butts, 22% blades, 6% eyes of rounds, 0.4% inside rounds, and 8% outside rounds from yearling cattle, estimated to cost $7.15/head processed ($15 million annually).

Salmonella spp. shedding by alberta beef cattle and the detection of Salmonella spp. in ground beef.

Breeder cows, cattle recently arrived at feedlots, and cattle about to be shipped for slaughter were tested for Salmonella spp. No Salmonella spp. were detected in fecal samples from breeding cows.

Environmental sources and transmission of Escherichia coli O157 in feedlot cattle.

A study was conducted in 2 feedlots in southern Alberta to identify environmental sources and management factors associated with the prevalence and transmission of Escherichia coli O157:H7. Escherichia coli O157:H7 was isolated in preslaughter pens of cattle from feces (0.8%), feedbunks (1.

Identification of a mutant bovine herpesvirus-1 (BHV-1) in post-arrival outbreaks of IBR in feedlot calves and protection with conventional vaccination.

Outbreaks of infectious bovine rhinotracheitis (IBR) have recently been observed in vaccinated feedlot calves in Alberta a few months post-arrival. To investigate the cause of these outbreaks, lung and tracheal tissues were collected from calves that died of IBR during a post-arrival outbreak of disease. Bovine herpesvirus-1 (BHV-1), the causative agent of IBR, was isolated from 6 out of 15 tissues.