Date of Award
Master of Science
Veterinary Diagnostic and Production Animal Medicine
H. Scott Hurd
A safe food supply is essential to public health. Changes in management practices affecting animal health could significantly impact public health. While animals with clinical illness will not pass ante-mortem inspection, animals with subclinical illness could be harvested. These animals could have peelouts, or pleural/peritoneal lesions that do not allow for complete viscera removal, requiring extra trimming. Swine are commonly asymptomatic carriers of Salmonella<\italic> infection. If animals are also infected with respiratory pathogens, it is possible that peelouts could lead to carcass contamination.
This study has three objectives: to obtain a peelout prevalence estimate, determine if common swine respiratory pathogens are associated with peelouts (Streptococcus suis, Pasteurella multocida, Bordetella bronchiseptica, Haemophilus parasuis, Actinobacillus suis, Actinobacillus pleuropneumoniae<\italic> ), and determine if carcasses with peelouts are more likely to have Salmonella contamination.
Six abattoirs from different geographical locations in the United States were chosen, and two different sampling periods were run. Samples were taken from 50 lesioned carcasses and 50 non-lesioned carcasses. Two sets of samples were taken: a lung sample immediately after evisceration and a pleural swab from the corresponding carcass after trimming and before the final carcass rinse. The pleural swabs were tested for Salmonella<\italic> and the lung samples tested for respiratory pathogens using a standard bacteriological isolation and culture protocol. Data was analyzed using logistic regression.
The prevalence of peelouts by abattoir visit ranged from 2.64% to 28.39%, with a national prevalence estimate of 9.77% (95% CI 5.31% to 14.22%). Salmonella<\italic> contamination rates ranged from 0% to 23.53% for lesioned and 0% to 16% for non-lesioned carcasses. Respiratory pathogen contamination rates for lesioned and non-lesioned carcasses ranged as following: Streptococcus suis<\italic> , 5.45% to 50%, 2.04% to 56.76%, Pasteurella multocida<\italic> , 0% to 33.33%, 0% to 42%, and Bordetella bronchiseptica<\italic> , 0% to 6.12%, 0% to 2.22%. No significant association was found between peelouts and respiratory pathogens. There was no strong association between Salmonella<\italic> contamination and peelouts, except in abattoirs with significant Salmonella<\italic> contamination (22.77% lesioned carcasses, 8% non-lesioned carcasses). Therefore, we cannot ignore the role that pig health could have on public health, especially in herds with higher amounts of bacterial contamination.
Amber Jo DeClercq
DeClercq, Amber Jo, "The impact of pig health on public health: quantitative data for risk assessments" (2014). Graduate Theses and Dissertations. 13841.