Objective—To develop a model to evaluate the effect
of vaccination against Tritrichomonas foetuson reproductive
efficiency in beef herds.
Sample Population—A beef herd of 300 cows and
12 bulls (8 bulls ≤ 3 years old and 4 bulls > 3 years
Procedure—The model was developed by use of
data for various risk factors and vaccine efficacy. The
reference herd was considered to be one in which T
foetus had been diagnosed and bulls were tested for
T foetus before the breeding season. Five thousand
iterations were run for each of 13 simulations, with
each simulation representing a separate combination
of risk factors.
Results—In all simulations, vaccination resulted in
significantly higher calving incidence than nonvaccination.
Shared grazing was found to be the most significant
risk factor for a decrease in calving incidence
attributable to T foetus infection, followed in importance
by lack of testing before the breeding season
and a higher proportion of old bulls. Combinations of
risk factors contributed to a loss of income of up to
22%, some of which could be blunted by vaccination.
Conclusions and Clinical Relevance—Highest calving
incidence is achieved when all bulls are tested for
T foetus before the breeding season and all bulls with
positive culture results are culled. Avoiding all risk factors
is better than vaccinating, but when this is not
feasible for a given herd, the results of this simulation
indicate that proper vaccination can decrease economic
losses attributable to abortions caused by T
foetus. (Am J Vet Res 2004;65:770–775)
Objective—To evaluate various sampling strategies for potential use in measuring prevalence of antimicrobial susceptibility in cattle.
Sample Population—500 isolates of non–type-specific Escherichia coli (NTSEC) isolated from the feces of 50 cows from 2 dairy farms (25 cows/farm and 10 isolates/cow).
Procedures—Diameters of inhibition zones for 12 antimicrobials were analyzed to estimate variation among isolates, cows, and farms and then used to determine sampling distributions for a stochastic simulation model to evaluate 4 sampling strategies. These theoretic sampling strategies used a total of 100 isolates in 4 allocations (1 isolate from 100 cows, 2 isolates from 50 cows, 3 isolates from 33 cows, or 4 isolates from 25 cows).
Results—Analysis of variance composition revealed that 74.2% of variation was attributable to isolates, 18.5% to cows, and 7.3% to farms. Analysis of results of simulations suggested that when most of the variance was attributable to differences among isolates within a cow, culturing 1 isolate from each of 100 cows underestimated overall prevalence, compared with results for culturing more isolates per cow from fewer cows. When variance was not primarily attributable to differences among isolates, all 4 sampling strategies yielded similar results.
Conclusions and Clinical Relevance—It is not always possible to predict the hierarchical level at which clustering will have its greatest impact on observed susceptibility distributions. Results suggested that sampling strategies that use testing of 3 or 4 isolates/cow from a representative sample of all animals better characterize herd prevalence of antimicrobial resistance when impacted by clustering.
Objective—To identify factors associated with interest in or choosing a career in rural veterinary practice (RVP).
Design—Cross-sectional descriptive study.
Sample Population—Veterinarians and veterinary students in the United States.
Procedures—Veterinary students and veterinarians in any area of practice were solicited to participate in an online survey through invitation letters sent to various veterinary associations. Proportions of respondents assigning high importance to various factors were analyzed for differences among gender, age, and background groups.
Results—1,216 responses were received. In general, survey respondents indicated that RVP could be characterized as the practice of veterinary medicine in any community where agriculture represented a significant part of the local economy. Responses also indicated that RVP should not be confused with large animal or food animal exclusive practice. Most respondents (38.9%) developed an interest in RVP early in life (before 8th grade), with 13.0% reportedly developing their interest in RVP during veterinary school. The most highly ranked factors with regard to influence on developing an interest in RVP were having relatives with a farm background, having a veterinarian in RVP as a mentor, and exposure to RVP during veterinary school. Gender, generational category, background (rural vs urban), and livestock experience were significantly associated with when respondents developed an interest in RVP and with factors important in developing that interest.
Conclusions and Clinical Relevance—Results of the present study suggested that various factors are associated with interest in and choosing a career in RVP. These factors should be considered when strategies for increasing interest and encouraging careers in RVP are planned.
Objective—To identify factors associated with veterinarians leaving a career in rural veterinary practice (RVP).
Design—Cross-sectional descriptive study.
Sample Population—Veterinarians from the United States who no longer worked in RVP.
Procedures—Veterinarians in any area of practice were solicited to participate in an online survey through invitation letters sent to various veterinary associations. Those who indicated that they had left RVP were asked to rank the importance of various potential factors in their decision to leave RVP.
Results—805 responses were obtained from veterinarians who had worked in RVP, of which 246 (30.6%) had left RVP. Most (231/246 [93.9%]) of those who reported leaving RVP had been in practice > 5 years, and 75.2% (185/246) had been in practice > 12 years. Eighty-three (33.7%) who left RVP pursued careers in urban areas, 72 (29.3%) entered academia, and 7 (2.8%) retired. Reasons for leaving RVP ranked by the highest proportions of respondents as being of high importance were emergency duty, time off, salary, practice atmosphere, and family concerns. Women ranked factors such as time off, mentorship, practice atmosphere, conflict with staff, and gender issues as being of high importance more often than men did.
Conclusions and Clinical Relevance—Results suggested that the perceived shortage of veterinarians in RVP may be in part influenced by a lack of retention, particularly among experienced veterinarians. Targeted efforts to tackle issues related to emergency duty, time off, salary, practice atmosphere, and family issues could help alleviate the efflux from RVP.