David Smith

Dr. David Smith

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Research Focus & Metrics

Academic Career Length

15Years (2012-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 November 2012 in Veterinary Clinics of North America: Food Animal Practice
Verified
Journal Article
Closed access
DSDavid Smith
David Smith

1 September 2018 in Journal of the American Veterinary Medical Association
Verified
Journal Article
Closed access
MWMin Wang
Min Wang
LSLiesel G. Schneider
Liesel G. Schneider
KHKristina J. Hubbard
Kristina J. Hubbard
DSDavid Smith
David Smith
OBJECTIVE To develop a partial budget analysis of direct costs associated with bovine respiratory disease (BRD) in preweaned calves on US beef cow–calf operations and identify factors that strongly influence those costs. DESIGN Risk analysis model. ANIMALS US preweaned beef calf inventory from 2011 through 2015. PROCEDURES A stochastic simulation model was developed by use of a computer spreadsheet and add-in software. Input data were obtained from the USDA, peer-reviewed literature, and a survey of beef cow–calf producers. A simulation consisting of 10,000 iterations was used to account for either uncertainty or variability in model inputs. The median (90% confidence interval) was reported for each output variable. Global and local sensitivity analyses were performed to identify the most influential factors and quantitatively evaluate the effects of inputs on the estimated costs. RESULTS From 2011 through 2015, BRD in preweaned calves cost the US beef cow–calf industry approximately $165 million annually, of which costs associated with the death, treatment, and decreased weaning weight of BRD-affected calves were approximately $126, $25, and $15 million, respectively. CONCLUSIONS AND CLINICAL RELEVANCE Although BRD in preweaned calves may have a fairly small effect on the total gross income for the US beef cow–calf industry as a whole, it can have a substantial adverse effect on the net profit of BRD-affected herds. The model developed provided important information regarding the cost of BRD in preweaned calves on US beef cow–calf operations and identified factors that had an import effect on those costs.

1 February 2018 in The Bovine Practitioner
Verified
Journal Article
Open access
PDF file
CGCourtney M. Griffin
Courtney M. Griffin
JSJenna A. Scott
Jenna A. Scott
BKBrandi B. Karisch
Brandi B. Karisch
AWAmelia R. Woolums
Amelia R. Woolums
JBJohn R. Blanton
John R. Blanton
DSDavid Smith
David Smith
Our objective was to determine the effect of vaccination and deworming at arrival (d 0) on bovine respiratory disease (BRD) incidence, mortality, and growth of Stocker calves. Calves (n=80) were stratified by d -3 weight and fecal egg count (FEC) into 20 pens of 4 calves. Pens were randomly assigned to treatments in a 2x2 factorial design, testing d 0 vaccination (modified-live respiratory virus and clostridial vaccine, or not) and deworming (oral fenbendazole and levamisole, or not). Body weights were measured on days 0, 14,28,42, 56, 70, and 85, and FEC were measured on days -3, 28, 56, and 85. Incidence of BRD was greater for d 0 vaccination (RR=3.2), high fever (>104°F, >40°C) at d 0 (RR=6), and higher d -3 FEC (RR=1.2 per 100 epg). Mortality was greater for d 0 vaccination (OR=8.3) and high fever (OR=41.6). Growth was 10.3 lb (4.7 kg) lower for d 0 vaccination, 24 lb (11 kg) and 16 lb (7.3 kg) lower for moderate (103°F to 103.9°F; 39.4°C to 39.9°C) and high fever, respectively, and 17.6 lb (8 kg) lower for each additional BRD treatment a calf received. Deworming was neither beneficial nor detrimental to any health or performance factors. Health and growth performance of Stocker calves may be adversely affected by vaccination at arrival, higher arrival FEC, and fever at arrival.

1 November 2018 in Preventive Veterinary Medicine
Verified
Journal Article
Closed access
KHKristina Hubbard
Kristina Hubbard
MWMin Wang
Min Wang
DSDavid Smith
David Smith

24 October 2020 in Animals
Verified
Journal Article
Open access
PDF file
CCCassie J Cain
Cassie J Cain
KWKimberly A Woodruff
Kimberly A Woodruff
DSDavid Smith
David Smith
The objective of this study was to identify phenotypic characteristics of dogs predictive of adoption after being received into a shelter. Individual dog records for 2017 were requested from shelters in five states that received municipal funding and utilized electronic record keeping methods. Records from 17 shelters were merged into a dataset of 19,514 potentially adoptable dogs. A simple random sample of 4500 dogs was used for modelling. Variables describing coat length, estimated adult size, and skull type were imputed from breed phenotype. A Cox proportional hazard model with a random effect of shelter was developed for the outcome of adoption using manual forward variable selection. Significance for model inclusion was set at alpha = 0.05. Dogs from shelters in the North were more likely to be adopted than dogs from shelters in the South (hazard ratio (HR) = 3.13, 95% C.I. 1.27–7.67), as were dogs from Western shelters versus those from Southern shelters (HR = 3.81, 95% C.I. 1.43–10.14). The effect of estimated adult size, skull type, and age group on adoption were each modified by time in the shelter (p < 0.001). The results of this study indicate that what dogs look like is predictive of their hazard for adoption from shelters, but the effect of some characteristics on hazard for adoption depend on time in the shelter. Further, this study demonstrates that adopters prefer a certain phenotype of shelter dog including those that are puppies, small sized and not brachycephalic, when accounting for time in the sheltering environment.

1 August 2013 in Foodborne Pathogens and Disease
Verified
Journal Article
Closed access
AVAmanda R. Vogstad
Amanda R. Vogstad
Rodney MoxleyRodney Moxley
Rodney Moxley
GEGalen E. Erickson
Galen E. Erickson
TKTerry J. Klopfenstein
Terry J. Klopfenstein
DSDavid Smith
David Smith
Preharvest control of Escherichia coli O157:H7 (STEC O157) may prevent human illness by reducing the presence of STEC O157 throughout the beef production chain. Immunization of cattle with a type III secreted protein vaccine inhibits colonization of cattle with STEC O157 and reduces the probability of fecal shedding and hide contamination. Our objectives were to perform a meta-analysis to estimate efficacy of a three-dose regimen of TTSP vaccine at reducing the presence of STEC O157 in the feces of feedlot cattle and to test factors that might modify vaccine efficacy. Pen-level data (n=184 pens, 1462 cattle) from four randomized controlled vaccine trials conducted from 2002 to 2008 at the University of Nebraska–Lincoln were analyzed. Factors explaining a culture-positive fecal sample were tested in generalized estimating equations logistic regression and log-binomial models. An autoregressive correlation structure was defined to account for clustering of repeated test-periods within block. Clustering or potential confounding by study was accounted for by treating study as a fixed effect. STEC O157 was detected from 661 of 5451 postvaccination fecal samples. The probability to detect STEC O157 postvaccination was 8.4% and 15.8% in vaccinated and unvaccinated cattle, respectively. Interactions between vaccination and (1) study; (2) prevalence of control pens within each time–place cluster; and (3) days from vaccination were not significant or fit poorly with observed data. Adjusting for study, cattle in pens receiving three doses of vaccine were less likely to shed STEC O157 (odds ratio=0.46, p<0.0001). Model-adjusted vaccine efficacy was 48% (95% confidence interval: 0.37–0.57). We concluded that a three-dose regimen type III secreted protein vaccine was efficacious at reducing the probability of detecting STEC O157 in the feces of cattle and that vaccine efficacy was not modified by study or level of prevalence observed in control pens.