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Abstract

Objective—To determine the association between the existence of a calf persistently infected (PI) with bovine viral diarrhea virus (BVDV) and pen morbidity.

Animals—5,041 calves in 50 pens at a feedlot in Iowa.

Procedure—In a longitudinal study, ear notches were collected from cattle and tested for BVDV antigen. Characteristics of each pen (owner, sex, disease rate, number of groups, and source) were recorded. The association between the existence of a BVDV–PI calf and morbidity in each pen was examined.

Results—Commingling was associated with an increase in respiratory tract disease (odds ratio [OR], 3; 95% confidence interval [CI], 2.5 to 3.6). Ten BVDV–PI calves (10/5,041 [0.2%]) were identified in 8 of 50 pens. A BVDV–PI calf was associated with reduced pen-level respiratory tract disease (OR, 0.7; 95% CI, 0.5 to 0.9). Disease prevalence (mean ± SD morbidity, 7.9 ± 3.1%) was lowest in pens containing single-source cattle and a BVDV–PI calf (4 pens containing 302 cattle), compared with single-source cattle with no BVDV–PI calf (mean morbidity, 11.89 ± 9.7%; 31 pens containing 3,093 cattle), commingled cattle with no BVDV–PI calf (mean morbidity, 29.3 ± 16.22%; 11 pens containing 1,127 cattle), and commingled cattle with a BVDV–PI calf (mean morbidity, 28.6 ± 10.1%; 4 pens containing 519 cattle).

Conclusions and Clinical Relevance—Commingling was the greatest risk factor associated with morbidity in each pen. A BVDV–PI calf in a pen was not associated with increased disease prevalence in commingled groups. (Am J Vet Res 2005;66:2130–2134)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To evaluate reporting of key study design features and study outcomes in trials of antimicrobial treatment of bovine respiratory disease (BRD) in North American feedlots.

Design—Systematic review.

Sample Population—29 manuscripts (41 studies) reporting antimicrobial treatment of BRD in North American feedlot cattle.

Procedures—A search of the electronic citation databases AGRICOLA, Commonwealth Agricultural Bureau, and PubMed was conducted to identify relevant manuscripts published between 1970 and 2005. Key study design features were extracted by 2 reviewers.

Results—12 of 29 (41%) manuscripts did not disclose a funding source, and 21 (72%) had an author clearly identified as an employee of a pharmaceutical company. At the study level, 36 of 41 (88%) studies reported a random method of treatment allocation, 9 (22%) described the method of allocation sequence generation, 20 (49%) reported that study investigators were blinded to treatment, and 3 (7%) included a study size justification. No studies described the null hypothesis to be tested. Thirty-seven (90%) studies reported at least 3 outcomes; the largest number of outcomes reported was 14. It was not possible to conduct the statistical analysis as originally planned because it was not possible to discern the primary outcome for the majority of studies.

Conclusions and Clinical Relevance—Many studies did not report key study design features that would assist critical evaluation by readers. It was not clear whether the studies failed to use the design features or failed to report them. Several nondesign features, such as reporting of the null hypothesis, a primary outcome, and sample size rationale, represent relatively new standards for reporting; however, reporting these features would substantially clarify the study objective. (J Am Vet Med Assoc 2010;237:701-705)

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To identify farm characteristics and management practices associated with development of Rhodococcus equi pneumonia in foals.

Design—Prospective case-control study.

Animals—5,230 foals on 138 breeding farms with 9,136 horses.

Procedure—During 2003, participating veterinarians provided data from 1 or 2 farms with ≥ 1 foal with R equi pneumonia and unaffected farms. Data from affected and unaffected farms were compared by use of logistic regression analysis.

Results—A number of variables relating to farm size and desirable management practices were significantly associated with increased odds of farms being affected with R equi pneumonia. By use of multivariate logistic regression, affected farms were determined significantly more likely to have raised Thoroughbreds, housed ≥ 15 foals, used concrete floors in foaling stalls, and tested foals for passive transfer of immunity than unaffected farms. These results remained significant even after accounting for exposure of foals to other breeding farms during the first month of life.

Conclusions and Clinical Relevance—Breeding farms with large acreage and a large number of mares and foals have greater odds of being affected by R equi pneumonia. Clinical relevance of associations with Thoroughbred breed and concrete flooring in foaling stalls remains uncertain. Desirable management factors commonly used on farms were not effective for controlling or preventing development of R equi pneumonia. This finding indicates a need to focus on host factors that influence disease development. (J Am Vet Med Assoc 2005;226:404–413)

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine the chemoprophylactic effect of gallium maltolate on the cumulative incidence of pneumonia caused by Rhodococcus equi infection in foals.

Animals—483 foals born and raised on 12 equine breeding farms with a history of endemic R equi infections.

Procedures—Group 1 foals were treated with a placebo and group 2 foals were treated with gallium maltolate (approx 30 mg/kg, PO, q 24 h) during the first 2 weeks after birth. Foals were monitored for development of pneumonia attributable to R equi infection and for adverse effects of gallium maltolate.

Results—There were no significant differences in the cumulative incidence of R equi pneumonia among the 2 groups.

Conclusions and Clinical Relevance—Chemoprophylaxis via gallium maltolate administered orally at approximately 30 mg/kg daily for the first 2 weeks after birth failed to reduce the cumulative incidence of pneumonia attributable to R equi infection among foals on breeding farms with endemic R equi infections. Further investigation is needed to identify strategies for control of R equi infections.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To evaluate microtiter-plate format ELISAs constructed by use of different diagnostic targets derived from the Ehrlichia ewingii p28 outer membrane protein for detection of E ewingii antibodies in experimentally and naturally infected dogs.

Sample Population—Serum samples from 87 kenneled dogs, 9 dogs experimentally infected with anti-E ewingii, and 180 potentially naturally exposed dogs from Missouri.

Procedures—The capacities of the synthetic peptide and truncated recombinant protein to function as detection reagents in ELISAs were compared by use of PCR assay, western blot analysis, and a full-length recombinant protein ELISA. Diagnostic targets included an E ewingii synthetic peptide (EESP) and 2 recombinant proteins: a full-length E ewingii outer membrane protein (EEp28) and a truncated E ewingii outer membrane protein (EETp28)

Results—A subset of Ehrlichia canis-positive samples cross-reacted in the EEp28 ELISA; none were reactive in the EESP and EETp28 ELISAs. The EESP- and EETp28-based ELISAs detected E ewingii seroconversion at approximately the same time after infection as the EEp28 ELISAs. In afield population, each of the ELISAs identified the same 35 samples as reactive and 27 samples as nonreactive. Anaplasma and E can is peptides used in a commercially available ELISA platform did not detect anti-E ewingii antibodies in experimentally infected dogs.

Conclusions and Clinical Relevance—The EESP and EETp28 ELISAs were suitable for specifically detecting anti-E ewingii antibodies in experimentally and naturally infected dogs. [Am J Vet Res 2010;71:1195-1200)

Full access
in American Journal of Veterinary Research