James W. Lloyd

Multiple professional identities: examining differences in identification across work-related targets.

Although there is a growing literature on organizational identification, relatively little research has investigated other possible targets of identification. In a sample of veterinarians working in a wide range of organizations, the authors compared their identification with the veterinary profession, their organization, and their workgroup. The authors found different patterns of identification across these targets depending on whether the individual (a) worked in a veterinary medicine or nonveterinary medicine organization and (b) was an owner/partner or an associate. Owners of veterinary medicine organizations identified more with the organization than with either the profession or their workgroup. Associates in veterinary medicine organizations identified more with the organization and the workgroup than with the profession. Veterinarians in nonveterinary medicine organizations identified more with the profession and their workgroup than with the organization. Identification with each of the targets provided independent predictive validity of job satisfaction.

The effect of subclinical Mycobacterium paratuberculosis infection on days open in Michigan, USA, dairy cows

A prospective cohort study design was used to evaluate the impact of subclinical Mycobacterium paratuberculosis infection on days open in a sample of Michigan dairy herds with a history of cows positive for M. paratuberculosis diagnosed by fecal culture. Participating herds were tested and productivity and reproduction records were monitored for 18 months. All cows > or = 24 months old were tested for M. paratuberculosis infection using the ELISA and radiometric fecal-culture (RFC) techniques. Test-negative cows were re-tested at the conclusion of the monitoring period. Multivariable regression models were used. Using both tests in parallel, the overall sample apparent prevalence for M. paratuberculosis infection was 41.8% (223/533 animals tested). Adjusting for diagnostic sensitivity and specificity, this resulted in a calculated sample true prevalence of 59.9%. ELISA-positive cows (on average) had a 28-day increase in days open when compared to ELISA-negative cows (p=0.02). The diagnostic method used to define a case altered the apparent association between paratuberculosis test status and days open. Fecal culture was a less-effective diagnostic tool for use in herds with a high prevalence of infected animals. The increase in days open in the ELISA-positive cows was an indication that perhaps reduced estrus expression or an increased post-partum anestrous period occurred in the subclinically infected ELISA-positive animals. This might have been due to a negative energy balance associated with M. paratuberculosis infection.

Recombinant bovine somatotropin: association with reproductive performance in dairy cows.

A clinical trial was performed to determine the effect of bST on reproductive performance in dairy cows on 4 Michigan dairy farms when bST was used according to labeled directions. Holstein cows (n = 555) at 4 Michigan dairy farms were randomly assigned to receive bovine somatotropin (bST) or to serve as untreated controls. Bovine somatotropin (500 mg, s.c.) was administered every 14 d beginning at 63 to 69 d of lactation and continuing until approximately 21 d prior to the end of lactation or until the producer removed the animal from the herd. A total of 229 (42.57%) animals consisting of 112 (48.91%) controls and 117 (51.09%) bST-treated cows were not diagnosed pregnant and were considered as having reproductive failure by 150 d of lactation and 92 (17.10%) of the animals consisting of 45 (48.91%) controls and 47 (51.09%) bST-treated cows had reproductive failure at the end of their lactation. No significant difference in the incidence of reproductive failure existed between the study treatment groups during either time frame. Cows with cystic ovarian disease had more instances of reproductive failure at 150 d of lactation than cows without this disease. Cows with dystocia, twin births, metritis, displaced abomasum and cystic ovarian disease had more instances of reproductive failure by the end of lactation than cows without these diseases. The bST-treated cows developed more nonspecific off feed conditions during the study lactation and had more twin births at the calving following bST administration compared to control cows. No differences were found between the study treatment groups in calculations of reproductive parameters. Logistic regression analysis found no significant effect of bST on reproductive failure; the odds ratios for the bST treatment effect on reproductive failure at 150 d of lactation and reproductive failure at the end of lactation were 0.95 (95% CI 0.67 to 1.36) and 0.95 (95% CI 0.59 to 1.54), respectively. Overall, bST was not found to have a significant impact on reproductive performance in the herds studied.

Spatial and temporal comparison of selected cancers in dogs and humans, Michigan, USA, 1964-1994.

Our aim was to investigate the geographic and time distributions of some biologically similar neoplasms in dogs and humans living in Michigan, USA, between 1964 and 1994. Our objective was to describe and compare the patterns of cancer in the two species while assessing the strength and dependence of those patterns. In this retrospective, registry-based study, histologically confirmed incident human and canine cancer cases were mapped, and second-order (K function) spatial analysis and one-dimensional nearest neighbor temporal analysis were performed on residence addresses and dates of hospital discharge/diagnosis. Included in the study were all 528 incident cases of canine lymphosarcoma, mammary adenocarcinoma, melanoma and spindle-cell sarcomas diagnosed at a veterinary teaching hospital between 1964 and 1994 having residence addresses in Ingham, Oakland, and Wayne Counties; and a stratified random sample of 913 incident human cases of comparable cancers diagnosed during the same time period from the same counties. Results suggest that processes determining spatial aggregation of cases in dogs and humans were not independent of each other, did not act uniformly over different geographic areas, operated at spatial scales <2000 m regardless of species, and tend to act upon dogs more strongly at shorter distances than on humans. Little evidence of interspecies concurrence of temporal clustering was found.

Decision tree analysis of control strategies in Danish dairy herds with outbreaks of mucosal disease

Abstract Decision tree analysis was used to evaluate control strategies for bovine virus diarrhoea virus through calculation of the loss and expenses due to cattle being persistently infected. The study was performed in eight Danish dairy herds with outbreaks of mucosal disease. The calculations were made for three alternative control strategies referriing to different test and slaughter policies after the initial case of mucosal disease: (1) no blood testing, (2) blood testing of all animals in a risk group defined as animals that are within 3 months of age of the first mucosal disease case and (3) blood testing of all animals in the herds. Sensitivity analyses were made on test price for virological examination, loss from an animal dying, loss due to an animal being slaughtered and the probability of persistently infected cattle dying if they were not blood tested. Under the assumptions used, the blood testing of animals in the defined risk group resulted in the lowest immediate loss and expenses when calculations were made on all eight herds together. However, on an individual-farm basis the recommended control strategy showed some mild sensitivity to the incorporated variables, though testing the defined risk group was always most beneficial to the greatest number of farms.

An examination of US consumer pet-related and veterinary service expenditures, 1980–2005

OBJECTIVE To evaluate US consumer expenditures for veterinary services, pets-pet supplies, and pet-related services. DESIGN Retrospective economic analysis. SAMPLE POPULATION US consumers from 1980 through 2005. PROCEDURES Descriptive statistics and probit regressions were calculated. RESULTS From 1980 to 2005, total inflation-adjusted expenditures on pet-related and veterinary services increased, as did the percentage of households with a pet-related expenditure. The percentage of households with veterinary service expenditures was fairly constant. Among households with a pet-related expenditure, the percentage purchasing veterinary services decreased. The probability for pet-related and veterinary service expenditures increased with income, education, and family size and was higher for household heads who were white, were married, owned their residence, and lived in a rural area. CONCLUSIONS AND CLINICAL RELEVANCE Overall spending on veterinary services increased substantially, providing no indication that successful practices should change strategy. Households that spent money on veterinary services increased their spending sufficiently to exceed the loss of income for veterinarians associated with the increasing proportion of pet-owning households that did not spend anything on veterinary services. Because the probability of veterinary service expenditures was strongly related to household income, caution is suggested in planning provision of veterinary services when incomes are constrained. Among households with pet-related expenditures, the decreasing percentage of households with veterinary service expenditures suggests a growing proportion of pet owners who are not having their veterinary service needs met. Because non-white households were less likely to purchase veterinary services, the veterinary profession cannot afford to delay efforts to enhance diversity and cultural competence.

Spatial and temporal distribution of selected canine cancers in Michigan, USA, 1964-1994.

Although rates are commonly used to compare regional disease occurrence, rate-independent methods might also be useful in circumstances where geographic occurrence of a disease is known, but calculation of disease rates is not feasible. This is frequently the case for diseases in companion animals, where accurate enumeration of populations-at-risk is often arduous. This study had two objectives: to demonstrate a rate-independent method for investigating disease aggregation in companion animals; and, to assess the spatial and temporal clustering of canine cases of four cancers that are biologically similar in dogs and humans. Geographic information systems and point-pattern analysis were used to assess the spatial and temporal clustering of incident cases of four types of canine cancer in three counties in Michigan between 1964 and 1994, and to generate hypotheses concerning disease aggregation. Significant (P < or = 0.01) spatial clustering was found that varied by county and cancer type. No definitive temporal patterns could be deduced from a temporal analysis of the cases of canine cancer in this study. These results demonstrate distance-based methods for assessing clustering of disease, and suggest that processes determining the aggregation of canine cancer cases do not act in a spatially uniform manner.

A stochastic distributed-delay model of disease processes in dynamic populations

Hurd, H.S., Kaneene, J.B. and Lloyd, J.W., 1993. A stochastic distributed-delay model of disease processes in dynamic populations. Prev. Vet. Med., 16:21-29. 1A simulation model that is applicable to infectious and non-infectious disease is proposed. This paper describes a model for simulation of infectious and non-infectious disease processes in dynamic populations, and compares its behavior to a stochastic version of the Reed-Frost model for a hypothetical infectious disease. A distributed-delay model is applied. Monte-Carlo simulations of both modeling approaches produced epidemics of randomly determined sizes. Although both models demonstrated the characteristic bimodal distributions of total number of cases per epidemic, the shape of the distributions was slightly different. Separation between the two peaks was not as great with the distributed-delay model as with the Reed-Frost model. The tail was slightly more extended than the Reed-Frost, and there were more epidemics in the 50100 case range. Both models produced similar average attack rates.

Lymphocyte colony formation by aleukemic sheep infected with bovine leukemia virus

The objective of this study was to investigate the effects of bovine leukemia virus (BLV) infection in sheep. A prospective study of the serologic, hematologic, and histologic changes of sheep infected with BLV was conducted. Antibodies to BLV were detectable in the sheep 3 weeks after exposure to blood from an infected cow and persisted during a 120 week examination period, whereas all control sheep remained seronegative. There were no statistically significant differences between the leucocyte counts, lymphocyte counts, and lymphocyte percentages of the infected and control sheep during the first 120 weeks of this study. However, one sheep did develop a leukopenia and lymphopenia 95 weeks after it became infected and died of histologically-confirmed lymphosarcoma 10 days later. A lymphocyte colony assay was used to study the effects of BLV infection on colony formation by sheep lymphocytes in vitro. There was no significant difference in the number of lymphocyte colonies formed by BLV infected and control sheep. Nor was there a significant difference in the number of colonies formed by lymphocytes from the BLV infected sheep, when the autologous sheep serum was replaced with either pooled serum from the infected sheep or with pooled serum from the control sheep. BLV infection in aleukemic sheep does not appear to have an adverse affect on colony formation by lymphocytes in vitro.

A measure of and predictors for veterinarian trust developed with veterinary students in a simulated companion animal practice

OBJECTIVE To gain a better understanding of the role of interpersonal trust in veterinarian-client interactions during routine health-care visits, develop a measure of trust uniquely suited to the context of veterinary medicine, and interpret the actions, beliefs, and perceptions that capture client trust toward veterinarians. DESIGN Correlational study. SAMPLE 103 veterinary students and 19 standardized clients with pets from a college of veterinary medicine at a large public Midwestern university. PROCEDURES measure of trust specific to veterinarian-client interactions was constructed on the basis of preexisting conceptualizations of the construct and administered to veterinary students and standardized clients following interactions in 2 medical scenarios in a high-fidelity simulated animal health clinic. Exploratory and confirmatory factor analytic techniques were used to validate the measure of trust, and hierarchic linear modeling was used to explore indicators of standardized client trust perceptions in one of the scenarios. RESULTS Factor analysis revealed that the measure captured 2 perceptions indicative of trust in veterinary contexts: professionalism and technical candor. Students who had behaviors reflecting these factors as well as those who were perceived as more technically competent were seen as more trustworthy by standardized clients. CONCLUSIONS AND CLINICAL RELEVANCE The development of trustworthy relationships between clients and veterinarians is important to the continued growth and success of the profession. By identifying characteristics of veterinarian trustworthiness and developing related measurement tools, proactive approaches to monitoring veterinarian-client relations can be implemented and incorporated into veterinary training and practice programs to identify areas for improvement.