Evaluation of Conditions during Weaned Pig Transport

Transport of weaned pigs poses special challenges because of their size and thermal needs as well as the extended distances and transport times. The resultant economic impact can be substantial. Compared to transport of market pigs, weaned pigs generally encounter much farther travel distances with different adapting abilities to the environmental conditions. The objectives of this study were: 1) to characterize the environmental conditions within a typical transport trailer for weaned piglets to determine if current management practices and trailer design provides an acceptable environment as evidenced by mortality rates and environmental parameters, and 2) to analyze airflow patterns of the tranport trailer using a scale model in a wind tunnel. Data from 78 usable transport trips were collected for air temperature in each trailer compartment, ambient temperature,distance traveled, time traveled, stocking density, and mortality by compartment. The 78 trips had an average distance of 778 km (range of 264 to 1016 km), travel time of 8.51 h (range of 3.4 to 12.3 h), and mortality rate of 0.031% (range of 0 to 1.11%). There was no significant difference in mortality by compartment (p\u3e0.05). The results indicate that if pigs are transported at a higher stocking density, the compartment temperatures would be similar during cold weather (e.g., 2°C). Under mild weather condition (e.g., 16°C), significant differences could exist in compartment temperature between part of the upper deck (Upper 1) and the lower deck (Lower 4) (p\u3c0.05). In comparison, no significant differences were found at warm conditions (e.g., 29°C) (p\u3e0.05). In addition to the weather influence, in-trailer environment is affected by the side openings which may be adjusted by the driver

Association between antimicrobial drug class for treatment and retreatment of bovine respiratory disease (BRD) and frequency of resistant BRD pathogen isolation from veterinary diagnostic laboratory samples

Although 90% of BRD relapses are reported to receive retreatment with a different class of antimicrobial, studies examining the impact of antimicrobial selection (i.e. bactericidal or bacteriostatic) on retreatment outcomes and the emergence of antimicrobial resistance (AMR) are deficient in the published literature. This survey was conducted to determine the association between antimicrobial class selection for treatment and retreatment of BRD relapses on antimicrobial susceptibility of Mannheimia haemolytica, Pasteurella multocida, and Histophilus somni. Pathogens were isolated from samples submitted to the Iowa State University Veterinary Diagnostic Laboratory from January 2013 to December 2015. A total of 781 isolates with corresponding animal case histories, including treatment protocols, were included in the analysis. Original susceptibility testing of these isolates for ceftiofur, danofloxacin, enrofloxacin, florfenicol, oxytetracycline, spectinomycin, tilmicosin, and tulathromycin was performed using Clinical and Laboratory Standards Institute guidelines. Data were analyzed using a Bayesian approach to evaluate whether retreatment with antimicrobials of different mechanistic classes (bactericidal or bacteriostatic) increased the probability of resistant BRD pathogen isolation in calves. The posterior distribution we calculated suggests that an increased number of treatments is associated with a greater probability of isolates resistant to at least one antimicrobial. Furthermore, the frequency of resistant BRD bacterial isolates was greater with retreatment using antimicrobials of different mechanistic classes than retreatment with the same class. Specifically, treatment protocols using a bacteriostatic drug first followed by retreatment with a bactericidal drug were associated with a higher frequency of resistant BRD pathogen isolation. In particular, first treatment with tulathromycin (bacteriostatic) followed by ceftiofur (bactericidal) was associated with the highest probability of resistant M. haemolytica among all antimicrobial combinations. These observations suggest that consideration should be given to antimicrobial pharmacodynamics when selecting drugs for retreatment of BRD. However, prospective studies are needed to determine the clinical relevance to antimicrobial stewardship programs in livestock production systems

Bayesian contributions to the modeling of multivariate macroeconomic data

Vector autoregressions model, jointly, the dynamics of a collection of series. These models have become a popular and widely researched tool in macroeconomic forecasting. In this thesis, we propose several new ideas for these models in the context of macroeconomic forecasting using Bayesian MCMC techniques. In Chapter 2, we attempt to create a realistic data model which addresses structural mean changes, stochastic volatility, and inference concerning the unknown lag for an autoregressive process. We improve upon the estimation of multivariate stochastic volatility in Chapter 3 and propose a flexible and efficient sampling procedure. In Chapter 4, we explore various shrinkage and sparsitiy prior schemes aiming at improving forecast performance.</p

Evaluation of Conditions during Weaned Pig Transport

Transport of weaned pigs poses special challenges because of their size and thermal needs as well as the extended distances and transport times. The resultant economic impact can be substantial. Compared to transport of market pigs, weaned pigs generally encounter much farther travel distances with different adapting abilities to the environmental conditions. The objectives of this study were: 1) to characterize the environmental conditions within a typical transport trailer for weaned piglets to determine if current management practices and trailer design provides an acceptable environment as evidenced by mortality rates and environmental parameters, and 2) to analyze airflow patterns of the tranport trailer using a scale model in a wind tunnel. Data from 78 usable transport trips were collected for air temperature in each trailer compartment, ambient temperature,distance traveled, time traveled, stocking density, and mortality by compartment. The 78 trips had an average distance of 778 km (range of 264 to 1016 km), travel time of 8.51 h (range of 3.4 to 12.3 h), and mortality rate of 0.031% (range of 0 to 1.11%). There was no significant difference in mortality by compartment (p>0.05). The results indicate that if pigs are transported at a higher stocking density, the compartment temperatures would be similar during cold weather (e.g., 2°C). Under mild weather condition (e.g., 16°C), significant differences could exist in compartment temperature between part of the upper deck (Upper 1) and the lower deck (Lower 4) (p0.05). In addition to the weather influence, in-trailer environment is affected by the side openings which may be adjusted by the driver.This article is published as Harmon, J.D., S.J. Hoff, T.J. Baas, Y. Zhao, H. Xin, L.R. Follett. 2017. Evaluation of conditions during weaned pig transport. Applied Engineering in Agriculture 33(6): 901-912. DOI: 10.13031/aea.12367. Posted with permission.</p

Association between antimicrobial drug class for treatment and retreatment of bovine respiratory disease (BRD) and frequency of resistant BRD pathogen isolation from veterinary diagnostic laboratory samples

Although 90% of BRD relapses are reported to receive retreatment with a different class of antimicrobial, studies examining the impact of antimicrobial selection (i.e. bactericidal or bacteriostatic) on retreatment outcomes and the emergence of antimicrobial resistance (AMR) are deficient in the published literature. This survey was conducted to determine the association between antimicrobial class selection for treatment and retreatment of BRD relapses on antimicrobial susceptibility of Mannheimia haemolytica, Pasteurella multocida, and Histophilus somni. Pathogens were isolated from samples submitted to the Iowa State University Veterinary Diagnostic Laboratory from January 2013 to December 2015. A total of 781 isolates with corresponding animal case histories, including treatment protocols, were included in the analysis. Original susceptibility testing of these isolates for ceftiofur, danofloxacin, enrofloxacin, florfenicol, oxytetracycline, spectinomycin, tilmicosin, and tulathromycin was performed using Clinical and Laboratory Standards Institute guidelines. Data were analyzed using a Bayesian approach to evaluate whether retreatment with antimicrobials of different mechanistic classes (bactericidal or bacteriostatic) increased the probability of resistant BRD pathogen isolation in calves. The posterior distribution we calculated suggests that an increased number of treatments is associated with a greater probability of isolates resistant to at least one antimicrobial. Furthermore, the frequency of resistant BRD bacterial isolates was greater with retreatment using antimicrobials of different mechanistic classes than retreatment with the same class. Specifically, treatment protocols using a bacteriostatic drug first followed by retreatment with a bactericidal drug were associated with a higher frequency of resistant BRD pathogen isolation. In particular, first treatment with tulathromycin (bacteriostatic) followed by ceftiofur (bactericidal) was associated with the highest probability of resistant M. haemolytica among all antimicrobial combinations. These observations suggest that consideration should be given to antimicrobial pharmacodynamics when selecting drugs for retreatment of BRD. However, prospective studies are needed to determine the clinical relevance to antimicrobial stewardship programs in livestock production systems.This article is published as Coetzee JF, Magstadt DR, Sidhu PK, Follett L, Schuler AM, Krull AC, Cooper VL, Engelken TJ, Kleinhenz MD, and O'Connor AM. "Association between antimicrobial drug class for treatment and retreatment of bovine respiratory disease (BRD) and frequency of resistant BRD pathogen isolation from veterinary diagnostic laboratory samples." PLoS ONE 14, no. 12 (2019): e0219104. DOI: 10.1371/journal.pone.0219104. Posted with permission.</p

Association between antimicrobial drug class for treatment and retreatment of bovine respiratory disease (BRD) and frequency of resistant BRD pathogen isolation from veterinary diagnostic laboratory samples.

Although 90% of BRD relapses are reported to receive retreatment with a different class of antimicrobial, studies examining the impact of antimicrobial selection (i.e. bactericidal or bacteriostatic) on retreatment outcomes and the emergence of antimicrobial resistance (AMR) are deficient in the published literature. This survey was conducted to determine the association between antimicrobial class selection for treatment and retreatment of BRD relapses on antimicrobial susceptibility of Mannheimia haemolytica, Pasteurella multocida, and Histophilus somni. Pathogens were isolated from samples submitted to the Iowa State University Veterinary Diagnostic Laboratory from January 2013 to December 2015. A total of 781 isolates with corresponding animal case histories, including treatment protocols, were included in the analysis. Original susceptibility testing of these isolates for ceftiofur, danofloxacin, enrofloxacin, florfenicol, oxytetracycline, spectinomycin, tilmicosin, and tulathromycin was performed using Clinical and Laboratory Standards Institute guidelines. Data were analyzed using a Bayesian approach to evaluate whether retreatment with antimicrobials of different mechanistic classes (bactericidal or bacteriostatic) increased the probability of resistant BRD pathogen isolation in calves. The posterior distribution we calculated suggests that an increased number of treatments is associated with a greater probability of isolates resistant to at least one antimicrobial. Furthermore, the frequency of resistant BRD bacterial isolates was greater with retreatment using antimicrobials of different mechanistic classes than retreatment with the same class. Specifically, treatment protocols using a bacteriostatic drug first followed by retreatment with a bactericidal drug were associated with a higher frequency of resistant BRD pathogen isolation. In particular, first treatment with tulathromycin (bacteriostatic) followed by ceftiofur (bactericidal) was associated with the highest probability of resistant M. haemolytica among all antimicrobial combinations. These observations suggest that consideration should be given to antimicrobial pharmacodynamics when selecting drugs for retreatment of BRD. However, prospective studies are needed to determine the clinical relevance to antimicrobial stewardship programs in livestock production systems