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1. Non-Arrhenius ionic conductivities in glasses due to a distribution of activation energies

Author

Bischoff, C, Schuller, K, Beckman, S P, and Martin, S W

Subjects
Condensed Matter - Materials Science
Abstract

Previously observed non-Arrhenius behavior in fast ion conducting glasses [\textit{Phys.\ Rev.\ Lett.}\ \textbf{76}, 70 (1996)] occurs at temperatures near the glass transition temperature, $T_{g}$, and is attributed to changes in the ion mobility due to ion trapping mechanisms that diminish the conductivity and result in a decreasing conductivity with increasing temperature. It is intuitive that disorder in glass will also result in a distribution of the activation energies (DAE) for ion conduction, which should increase the conductivity with increasing temperature, yet this has not been identified in the literature. In this paper, a series of high precision ionic conductivity measurements are reported for $0.5{Na}_{2}{S}+0.5[x{GeS}_{2}+(1-x){PS}_{5/2}]$ glasses with compositions ranging from $0 \leq x \leq 1$. The impact of the cation site disorder on the activation energy is identified and explained using a DAE model. The absence of the non-Arrhenius behavior in other glasses is explained and it is predicted which glasses are expected to accentuate the DAE effect on the ionic conductivity., Comment: 2 figures

Published
2012
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2. Atascadero

Author

Martin, S. W. and Martin, S. W.

Published
2012

19. OP08 Long-term efficacy and pharmacodynamics of the anti-mucosal addressin cell adhesion molecule-1 (MAdCAM-1) monoclonal antibody SHP647 in Crohn’s disease: the OPERA II study

Author

D’Haens, G, primary, Reinisch, W, additional, Lee, S D, additional, Tarabar, D, additional, Louis, E, additional, Kłopocka, M, additional, Klaus, J, additional, Schreiber, S, additional, Park, D I, additional, Hébuterne, X, additional, Gorelick, K J, additional, Martin, S W, additional, Banerjee, A, additional, Nagy, P, additional, Wang, Y, additional, Cataldi, F, additional, and Sandborn, W J, additional

Published
2019
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24. APPLIED PHYSICS REVIEWS.

Author

Angell, C. A., Ngai, K. L., McKenna, G. B., McMillan, P. F., and Martin, S. W.

Subjects
VISCOSITY, SOLIDS
Abstract

Examines the field of viscous liquid and glassy solid dynamics by a process of posing questions that need to be answered, and then providing the best answers available as of September 15, 2000. Scope of the problem; Glassformers in internal equilibrium; Relaxing glassformers out of equilibrium; Relaxing glassformers in internal equilibrium; Glassformers below T[sub g].

Published
2000

26. Relaxation processes in glassy ionic solids

Author

Angell, C. A., Sundar, H. G. K., Kulkarni, A. R., Senapati, H., Martin, S. W., Araki, H., editor, Ehlers, J., editor, Hepp, K., editor, Kippenhahn, R., editor, Weidenmüller, H. A., editor, Wess, J., editor, Zittartz, J., editor, Beiglböck, W., editor, Dorfmüller, Thomas, editor, and Williams, Graham, editor

Published
1987
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27. A new problem in the correlation of nuclear-spin relaxation and ionic conductivity in superionic glasses.

Author

Tatsumisago, M., Angell, C. A., and Martin, S. W.

Subjects
SUPERIONIC conductors, GLASS, NUCLEAR magnetic resonance, RELAXATION phenomena
Abstract

Following the recent resolution of the longstanding problem of reconciling constant frequency nuclear-spin lattice relaxation (SLR) activation energies and d.c. conductivity activity energies in ion conducting glasses, we point out a new problem which seems not to have been discussed previously. We report conductivity data measured at a series of fixed frequencies and variable temperatures on a lithium chloroborate glass and compare them with SLR data on identically prepared samples, also using different fixed frequencies. While phenomenological similarities due to comparable departures from exponential relaxation are found in each case, pronounced differences in the most probable relaxation times themselves are observed. The conductivity relaxation at 500 K occurs on a time scale shorter by some 2 orders of magnitude than the 7Li SLR correlation, and has a significantly lower activation energy. We show from a literature review that this distinction is a common but unreported finding for highly decoupled (fast-ion conducting) systems, and that an inverse relationship is found in supercoupled salt/polymer ‘‘solid’’ electrolytes. In fast-ion conducting glasses, the slower SLR process would imply special features in the fast-ion motion which permit spin correlations to survive many more successive ion displacements than previously expected. It is conjectured that the SLR in superionic glasses depends on the existence of a class of low-lying traps infrequently visited by migrating ions. [ABSTRACT FROM AUTHOR]

Published
1992
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28. A Model-Based Longitudinal Meta-Analysis of FEV1 in Randomized COPD Trials

Author

Korell, Julia, Martin, S. W., Karlsson, Mats O., Ribbing, Jakob, Korell, Julia, Martin, S. W., Karlsson, Mats O., and Ribbing, Jakob

Abstract

A model-based, longitudinal meta-analysis of the efficacy on morning trough forced expiratory volume in 1 second (FEV1) in chronic obstructive pulmonary disease (COPD) is presented. Literature data from 142 randomized maintenance trials were included, comprising 106,422 patients who received 19 compounds. 1982 morning trough FEV1 observations were available, each representing the mean FEV1 for a study arm at a specific timepoint. The final model for absolute FEV1 included baseline, disease progression, placebo effect, and drug effect estimates for all compounds, with interstudy variability on all model components and additional interarm variability on baseline. A dose-response relationship was identifiable for 10 of the 19 compounds. Drug-drug interactions among direct bronchodilators and the effect of concomitant background COPD treatment were included. Covariates were identified on baseline. Disease progression was proportional to the baseline FEV1, and a mean baseline of <1.2 L resulted in a lower efficacy, in particular for antiinflammatory treatments.

Published
2016
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29. Methods and processes of developing the strengthening the reporting of observational studies in epidemiology:veterinary (STROBE-Vet) statement

Author

Sargeant, J. M., O'connor, A. M., Dohoo, I. R., Erb, H. N., Cevallos, M., Egger, M., Ersbøll, A. K., Martin, S. W., Nielsen, Liza Rosenbaum, Pearl, D. L., Pfeiffer, D. U., Sanchez, J., Torrence, M. E., Vigre, H., Waldner, C., Ward, M. P., Sargeant, J. M., O'connor, A. M., Dohoo, I. R., Erb, H. N., Cevallos, M., Egger, M., Ersbøll, A. K., Martin, S. W., Nielsen, Liza Rosenbaum, Pearl, D. L., Pfeiffer, D. U., Sanchez, J., Torrence, M. E., Vigre, H., Waldner, C., and Ward, M. P.

Abstract

Reporting of observational studies in veterinary research presents challenges that often are not addressed in published reporting guidelines. Our objective was to develop an extension of the STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) statement that addresses unique reporting requirements for observational studies in veterinary medicine related to health, production, welfare, and food safety. We conducted a consensus meeting with 17 experts in Mississauga, Canada. Experts completed a premeeting survey about whether items in the STROBE statement should be modified or added to address unique issues related to observational studies in animal species with health, production, welfare, or food safety outcomes. During the meeting, each STROBE item was discussed to determine whether or not rewording was recommended, and whether additions were warranted. Anonymous voting was used to determine consensus. Six items required no modifications or additions. Modifications or additions were made to the STROBE items 1 (title and abstract), 3 (objectives), 5 (setting), 6 (participants), 7 (variables), 8 (data sources and measurement), 9 (bias), 10 (study size), 12 (statistical methods), 13 (participants), 14 (descriptive data), 15 (outcome data), 16 (main results), 17 (other analyses), 19 (limitations), and 22 (funding). The methods and processes used were similar to those used for other extensions of the STROBE statement. The use of this STROBE statement extension should improve reporting of observational studies in veterinary research by recognizing unique features of observational studies involving food-producing and companion animals, products of animal origin, aquaculture, and wildlife.

Published
2016

30. Explanation and elaboration document for the STROBE-Vet statement:strengthening the reporting of observational studies in epidemiology – veterinary extension

Author

O'Connor, A. M., Sargeant, J. M., Dohoo, I. R., Erb, H. N., Cevallos, M., Egger, M., Ersbøll, A.K., Martin, S. W., Nielsen, Liza Rosenbaum, Pearl, D. L., Pfeiffer, D. U., Sanchez, J., Torrence, M. E., Vigre, H., Waldner, C., Ward, M. P., O'Connor, A. M., Sargeant, J. M., Dohoo, I. R., Erb, H. N., Cevallos, M., Egger, M., Ersbøll, A.K., Martin, S. W., Nielsen, Liza Rosenbaum, Pearl, D. L., Pfeiffer, D. U., Sanchez, J., Torrence, M. E., Vigre, H., Waldner, C., and Ward, M. P.

Abstract

The STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) statement was first published in 2007 and again in 2014. The purpose of the original STROBE was to provide guidance for authors, reviewers and editors to improve the comprehensiveness of reporting; however, STROBE has a unique focus on observational studies. Although much of the guidance provided by the original STROBE document is directly applicable, it was deemed useful to map those statements to veterinary concepts, provide veterinary examples and highlight unique aspects of reporting in veterinary observational studies. Here, we present the examples and explanations for the checklist items included in the STROBE-Vet Statement. Thus, this is a companion document to the STROBE-Vet Statement Methods and process document, which describes the checklist and how it was developed.

Published
2016

31. Methods and processes of developing the strengthening the reporting of observational studies in epidemiology - veterinary (STROBE-Vet) statement

Author

Sargeant, J M, O'Connor, A M, Dohoo, I R, Erb, H N, Cevallos, M, Egger, M, Ersbøll, A.K., Martin, S W, Nielsen, Liza Rosenbaum, Pearl, D L, Pfeiffer, D U, Sanchez, J, Torrence, M E, Vigre, H, Waldner, C, Ward, M P, Sargeant, J M, O'Connor, A M, Dohoo, I R, Erb, H N, Cevallos, M, Egger, M, Ersbøll, A.K., Martin, S W, Nielsen, Liza Rosenbaum, Pearl, D L, Pfeiffer, D U, Sanchez, J, Torrence, M E, Vigre, H, Waldner, C, and Ward, M P

Abstract

The reporting of observational studies in veterinary research presents many challenges that often are not adequately addressed in published reporting guidelines. A consensus meeting of experts was organized to develop an extension of the STROBE statement to address observational studies in veterinary medicine with respect to animal health, animal production, animal welfare and food safety outcomes. The consensus meeting was held 11-13 May 2014 in Mississauga, Ontario, Canada. Seventeen experts from North America, Europe and Australia attended the meeting. The experts were epidemiologists and biostatisticians, many of whom hold or have held editorial positions with relevant journals. Prior to the meeting, 19 experts completed a survey about whether they felt any of the 22 items of the STROBE statement should be modified and whether items should be added to address unique issues related to observational studies in animal species with health, production, welfare or food safety outcomes. At the meeting, the participants were provided with the survey responses and relevant literature concerning the reporting of veterinary observational studies. During the meeting, each STROBE item was discussed to determine whether or not re-wording was recommended, and whether additions were warranted. Anonymous voting was used to determine whether there was consensus for each item change or addition. The consensus was that six items needed no modifications or additions. Modifications or additions were made to the STROBE items numbered as follows: 1 (title and abstract), 3 (objectives), 5 (setting), 6 (participants), 7 (variables), 8 (data sources/measurement), 9 (bias), 10 (study size), 12 (statistical methods), 13 (participants), 14 (descriptive data), 15 (outcome data), 16 (main results), 17 (other analyses), 19 (limitations) and 22 (funding). Published literature was not always available to support modification to, or inclusion of, an item. The methods and processes used in the d

Published
2016

32. Explanation and elaboration document for the STROBE-Vet statement:strengthening the reporting of observational studies in epidemiology-veterinary extension

Author

O'Connor, A M, Sargeant, J M, Dohoo, I R, Erb, H N, Cevallos, M, Egger, M, Ersbøll, A K, Martin, S W, Nielsen, Liza Rosenbaum, Pearl, D L, Pfeiffer, D U, Sanchez, J, Torrence, M E, Vigre, Håkan, Waldner, C, Ward, M P, O'Connor, A M, Sargeant, J M, Dohoo, I R, Erb, H N, Cevallos, M, Egger, M, Ersbøll, A K, Martin, S W, Nielsen, Liza Rosenbaum, Pearl, D L, Pfeiffer, D U, Sanchez, J, Torrence, M E, Vigre, Håkan, Waldner, C, and Ward, M P

Abstract

The STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) statement was first published in 2007 and again in 2014. The purpose of the original STROBE was to provide guidance for authors, reviewers, and editors to improve the comprehensiveness of reporting; however, STROBE has a unique focus on observational studies. Although much of the guidance provided by the original STROBE document is directly applicable, it was deemed useful to map those statements to veterinary concepts, provide veterinary examples, and highlight unique aspects of reporting in veterinary observational studies. Here, we present the examples and explanations for the checklist items included in the STROBE-Vet statement. Thus, this is a companion document to the STROBE-Vet statement methods and process document (JVIM_14575 "Methods and Processes of Developing the Strengthening the Reporting of Observational Studies in Epidemiology-Veterinary (STROBE-Vet) Statement" undergoing proofing), which describes the checklist and how it was developed.

Published
2016

33. Methods and processes of developing the strengthening the reporting of observational studies in epidemiology - veterinary (STROBE-Vet) statement

Author

Sargeant, J. M., O'Connor, A. M., Dohoo, I. R., Erb, H. N., Cevallos, M., Egger, M., Ersboll, A.K., Martin, S. W., Nielsen, Liza Rosenbaum, Pearl, D. L., Pfeiffer, D. U., Sanchez, J., Torrence, M. E., Vigre, H., Waldner, C., Ward, M. P., Sargeant, J. M., O'Connor, A. M., Dohoo, I. R., Erb, H. N., Cevallos, M., Egger, M., Ersboll, A.K., Martin, S. W., Nielsen, Liza Rosenbaum, Pearl, D. L., Pfeiffer, D. U., Sanchez, J., Torrence, M. E., Vigre, H., Waldner, C., and Ward, M. P.

Abstract

Background: Reporting of observational studies in veterinary research presents challenges that often are not addressed in published reporting guidelines. Objective: To develop an extension of the STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) statement that addresses unique reporting requirements for observational studies in veterinary medicine related to health, production, welfare, and food safety. Design: Consensus meeting of experts. Setting: Mississauga, Canada. Participants: Seventeen experts from North America, Europe, and Australia. Methods: Experts completed a pre-meeting survey about whether items in the STROBE statement should be modified or added to address unique issues related to observational studies in animal species with health, production, welfare, or food safety outcomes. During the meeting, each STROBE item was discussed to determine whether or not rewording was recommended and whether additions were warranted. Anonymous voting was used to determine consensus. Results: Six items required no modifications or additions. Modifications or additions were made to the STROBE items 1 (title and abstract), 3 (objectives), 5 (setting), 6 (participants), 7 (variables), 8 (data sources/measurement), 9 (bias), 10 (study size), 12 (statistical methods), 13 (participants), 14 (descriptive data), 15 (outcome data), 16 (main results), 17 (other analyses), 19 (limitations), and 22 (funding). Conclusion: The methods and processes used were similar to those used for other extensions of the STROBE statement. The use of this STROBE statement extension should improve reporting of observational studies in veterinary research by recognizing unique features of observational studies involving food-producing and companion animals, products of animal origin, aquaculture, and wildlife.

Published
2016

34. Explanation and Elaboration Document for the STROBE-Vet Statement: Strengthening the Reporting of Observational Studies in Epidemiology - Veterinary Extension

Author

O'Connor, A M, Sargeant, J M, Dohoo, I R, Erb, H N, Cevallos, M, Egger, M, Ersbøll, A. K., Martin, S W, Nielsen, L. R., Pearl, D L, Pfeiffer, D U, Sanchez, J., Torrence, M E, Vigre, Håkan, Waldner, C, Ward, M P, O'Connor, A M, Sargeant, J M, Dohoo, I R, Erb, H N, Cevallos, M, Egger, M, Ersbøll, A. K., Martin, S W, Nielsen, L. R., Pearl, D L, Pfeiffer, D U, Sanchez, J., Torrence, M E, Vigre, Håkan, Waldner, C, and Ward, M P

Abstract

The STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) statement was first published in 2007 and again in 2014. The purpose of the original STROBE was to provide guidance for authors, reviewers and editors to improve the comprehensiveness of reporting; however, STROBE has a unique focus on observational studies. Although much of the guidance provided by the original STROBE document is directly applicable, it was deemed useful to map those statements to veterinary concepts, provide veterinary examples and highlight unique aspects of reporting in veterinary observational studies. Here, we present the examples and explanations for the checklist items included in the STROBE-Vet Statement. Thus, this is a companion document to the STROBE-Vet Statement Methods and process document, which describes the checklist and how it was developed.

Published
2016

35. Methods and Processes of Developing the Strengthening the Reporting of Observational Studies in Epidemiology – Veterinary (STROBE‐Vet) Statement

Author

Sargeant, J. M., primary, O'Connor, A. M., additional, Dohoo, I. R., additional, Erb, H. N., additional, Cevallos, M., additional, Egger, M., additional, Ersbøll, A. K., additional, Martin, S. W., additional, Nielsen, L. R., additional, Pearl, D. L., additional, Pfeiffer, D. U., additional, Sanchez, J., additional, Torrence, M. E., additional, Vigre, H., additional, Waldner, C., additional, and Ward, M. P., additional

Published
2016
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36. Explanation and Elaboration Document for the STROBE‐Vet Statement: Strengthening the Reporting of Observational Studies in Epidemiology – Veterinary Extension

Author

O'Connor, A. M., primary, Sargeant, J. M., additional, Dohoo, I. R., additional, Erb, H. N., additional, Cevallos, M., additional, Egger, M., additional, Ersbøll, A. K., additional, Martin, S. W., additional, Nielsen, L. R., additional, Pearl, D. L., additional, Pfeiffer, D. U., additional, Sanchez, J., additional, Torrence, M. E., additional, Vigre, H., additional, Waldner, C., additional, and Ward, M. P., additional

Published
2016
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42. Pertactin-Negative Bordetella pertussis Strains: Evidence for a Possible Selective Advantage

Author

Martin, S. W., primary, Pawloski, L., additional, Williams, M., additional, Weening, K., additional, DeBolt, C., additional, Qin, X., additional, Reynolds, L., additional, Kenyon, C., additional, Giambrone, G., additional, Kudish, K., additional, Miller, L., additional, Selvage, D., additional, Lee, A., additional, Skoff, T. H., additional, Kamiya, H., additional, Cassiday, P. K., additional, Tondella, M. L., additional, and Clark, T. A., additional

Published
2014
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43. Molecular Dynamics Modeling of the Structure and Na+-Ion Transport in Na2S + SiS2Glassy Electrolytes

Author

Dive, A., Benmore, C., Wilding, M., Martin, S. W., Beckman, S., and Banerjee, S.

Abstract

Solid-state sodium batteries, a relatively safe and potentially cost-effective energy-storage technology, have attracted increasing scientific attention recently for application in stationary grid-scale energy storage. Identifying solid electrolytes with high electrochemical stability and high Na+-ion conductivity at room temperature is critically important to enable high energy densities with enhanced rate capabilities. We evaluated sodium sulfide–silicon sulfide, xNa2S + (1–x)SiS2, glasses as potential glassy solid electrolytes (GSEs) using molecular dynamics (MD) simulations. We employed ab initio MD to determine ion conduction mechanisms, to calculate energy barriers for ion hops, and to correlate these to the local short-range structure of 0.50Na2S + 0.50SiS2glass. To simulate much larger systems for accurately calculating the ionic conductivity, we parameterized empirical Buckingham-type potential and performed classical MD simulations. After validating these calculations by comparing the structure obtained from MD to that from X-ray scattering data, we calculated the ionic conductivity of these glasses for the range of 0.33 ≤ x≤ 0.67 compositions. The calculated ionic conductivities at room temperature were in the range of ∼10–5S/cm for the x= 0.50 composition and increased significantly with sodium sulfide (x) content. These calculations provide theoretical insights into the role of Na2S content on the ionic conductivity of GSEs aiding in the selection of specific compositions to enhance the ionic conductivity.

Published
2018
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44. Assessing the Associations among Facility Design and Management Practices and Antimicrobial Drug Use in Ontario Free-Stall Dairy Herds

Author

Léger, D., Kelton, D., Lissemore, K., Reid-Smith, R., Martin, S. W., and Anderson, N.

Subjects
Drug, Lactating cattle, business.industry, Dairy herds, media_common.quotation_subject, Environmental health, Medicine, business, Antimicrobial, Management practices, Free stall, Antimicrobial drug, media_common
Abstract

This study describes drug use in lactating cattle on Ontario free-stall dairy farms and investigates factors specifically associated with antimicrobial drug use., American Association of Bovine Practitioners Proceedings of the Annual Conference, 2002

Published
2002
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45. Assessing the Associations Among Facility Design and Management Practices and Drug Use in Ontario Free-Stall Dairy Herds

Author

Léger, D., Kelton, D., Lissemore, K., and Martin, S. W.

Subjects
Drug, Sanitation, Agriculture, business.industry, media_common.quotation_subject, Environmental health, Biosecurity, Business, Animal husbandry, Food safety, Management practices, Free stall, media_common
Abstract

In recent years, issues centered on drug use in food producing animals have emerged as major food safety concerns in this agricultural sector. The dairy industry must adopt practical management strategies that minimize drug use in cattle. These strategies need to be identified and must focus on husbandry practices and facility design that minimize animal stress, and that contain specific biosecurity, sanitation and nutritional recommendations to minimize disease-and therefore drug use-in food animals., American Association of Bovine Practitioners Proceedings of the Annual Conference, 2001

Published
2001
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46. Canine heartworm testing in Canada: are we being effective?

Author

Klotins, K C, Martin, S W, Bonnett, B N, and Peregrine, A S

Subjects
Diagnosis, Differential, Canada, Dogs, Risk Factors, Dirofilaria immitis, Prevalence, Animals, Mass Screening, Dirofilariasis, Dog Diseases, Research Article
Abstract

Mass testing of dogs in Canada for the presence of Dirofilaria immitis has been ongoing since 1977. Since that time, there have also been changes in the diagnostic tests available to detect the presence of heartworm and changes in the therapy for heartworm, which necessitate a reevaluation of heartworm screening as currently practiced in Canada. The principles of evidence-based medicine were used to determine the prevalence of heartworm infection in various dog populations, and the effectiveness of screening these populations. The annual surveys of heartworm testing have shown that Canada is a low prevalence area (0.16%), with most of the test-positive dogs located in southern Ontario (0.19%), southern Manitoba (0.18%), southern Quebec (0.09%), and the southern Okanagan Valley (0.04%). Foci of higher prevalence are found within these 4 main geographic areas. Furthermore, the prevalence of heartworm infection is higher in the population of dogs not on preventative medication (0.62%), when compared to the population of dogs on preventative medication (0.04%). The evidence indicates that a heartworm diagnostic test applied to an asymptomatic dog on preventative medication contributes little information regarding the heartworm infection status of that dog. However, testing of a dog characterized as being high risk will provide clinically useful information. Recommendations regarding the testing of dogs for heartworm in Canada are derived on the basis of available evidence.

Published
2000

47. Association Between Ration Protein and Economic Efficiency of Milk Production on Ontario Dairy Farms

Author

Lissemore, K., Kelton, D., Martin, S. W., Godden, S., Vonk Noordegraaf, A., and Edge, V. L.

Subjects
Economic efficiency, Protein content, fluids and secretions, Animal science, food and beverages, Forage, Biology, Milk production, health care economics and organizations
Abstract

An investigation of the association between the protein content of the ration and the economic efficiency of milk production indicates that increasing forage protein on Ontario dairy farms increases the daily milk income minus feed costs (IMFC)., American Association of Bovine Practitioners Proceedings of the Annual Conference, 2000

Published
2000
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48. An epidemiologic study of disease in 32 registered Holstein dairy herds in British Columbia

Author

van Dorp, R T, Martin, S W, Shoukri, M M, Noordhuizen, J P, and Dekkers, J C

Subjects
British Columbia, animal diseases, Incidence, Cattle Diseases, Pregnancy, Risk Factors, Parturient Paresis, Animals, Edema, Lactation, Cattle, Female, Mastitis, Bovine, Research Article
Abstract

Data recorded in a herd health management system were obtained from 32 registered Holstein dairy herds from British Columbia. Frequencies of disease were described, and the effect of herd, age, year, season, and the interrelationships between diseases within a lactation on the occurrence of disease were evaluated. Lactational incidence rates were computed for diseases with a short period of risk (ie, udder edema, milk fever, retained placenta, metritis, displaced abomasum, and ketosis), whereas for diseases with a longer period of risk (ie, cystic ovaries, mastitis and stable footrot), incidence densities were calculated. Overall, the disease incidence was low and showed an increase in frequency by year, which we attributed to more observing and complete recording by the owner, rather than an actual increase in disease incidence. Most diseases occurred early in lactation and their frequency increased with lactation number; the exception was udder edema, which occurred mainly during the first 2 lactations. An informal path model of disease interrelationships was made conditional on herd. Based on the results we inferred 2 independent pathways: one started by udder edema, and the other by milk fever. Udder edema was directly associated with mastitis occurrence from 0 to 30 d in lactation, metritis, and cystic ovaries. Mastitis from 0-30 d in lactation increased the risk of both mastitis from 31-150 d in lactation and cystic ovaries. Both of these increased the risk of late lactation mastitis. Milk fever was directly related with displaced abomasum, which increased the risk of footrot. In general, diseases that occurred in early lactation tended to increase the risk of other diseases later in lactation.

Published
1999

49. The association of titers to bovine coronavirus with treatment for bovine respiratory disease and weight gain in feedlot calves

Author

Martin, S W, Nagy, E, Shewen, P E, and Harland, R J

Subjects
Coronavirus, Bovine, Risk Factors, Animals, Cattle Diseases, Regression Analysis, Cattle, Antibodies, Viral, Coronavirus Infections, Weight Gain, Respiratory Tract Infections, Research Article
Abstract

The association between bovine respiratory disease (BRD) and antibody titers to bovine coronavirus (BCV) was studied in 604 calves (19 different groups in 4 different feedlots from 2 provinces). Almost all calves had antibody titers on arrival in the Alberta feedlot and 82% of the calves had an antibody titer on arrival at the Ontario feedlots; titers in calves in Alberta were almost twice as high as those in calves in Ontario. The incidence of infection, in the first mo after arrival as judged by seroconversion, ranged from 61% to 100%; titer increases were much greater in calves in Ontario feedlots. Titer variables were not significantly related to BRD, except on a within-group basis (group was a confounding variable for BCV-BRD associations). Given control of group effects, calves with an antibody titer on arrival appeared to be protected against BRD for the first 28 d in the feedlot, and the association was reasonably linear over the range of titers. Each titer unit on arrival decreased the risk of BRD by about 0.8x (odds ratio). Titer change was not strongly related to the risk of BRD and the relationship was not linear over the range of titer changes. Titer change was strongly and negatively correlated with titer on arrival, and titer change was not significantly related to BRD in the presence of arrival titers. Arrival titer retained its relationship with BRD in the presence of titer data for other putative pathogens. Each higher unit of titer to BCV on arrival increased the 28-day weight gain (controlling for group, initial weight and the occurrence of BRD) by slightly more than 1 kg. Titer change was associated with decreased weight gain, when initial titer was not in the model. The lack of a linear or multivariable association between BCV titer change and BRD, and weight gain, may indicate that BCV is not a major pathogen; or, its lack of significance may merely be due to its strong correlation with arrival titer. Given the associations found in this study, particularly the interprovincial differences in arrival titers, more and different approaches to studying the possible effects of BCV on BRD are in order.

Published
1998

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