Evaluation of a Pasteurella multocida Respiratory Disease Induction Model for Goats (Capra aegagrus hircus)

Abstract

Infectious respiratory diseases are a serious health concern worldwide. However, few models describe the experimental induction of lung infection, or the effect of experimental infection on clinical pathologic parameters in goats. Goats offer benefits compared to cattle because of size and tractability and compared to sheep with regard to specific features of their anatomy. In previous experimental models of infection in goats, coadministration of an immunosuppressive dose of a corticosteroid is common; however, protocols that use corticosteroid often note mortality as an adverse effect. We therefore investigated an infection protocol that did not use immunosuppression but instead relied on 2 intratracheal inoculations of Pasteurella multocida in healthy meat goats to induce clinical and hematologic changes associated with respiratory infection. Healthy Boer or Boer-Kiko cross goats (n = 6; age, 10 mo) were inoculated with Pasteurella multocida and were monitored over a 312-h period for clinical and hematologic parameters of infection. After induction of pneumonia, the goats had a significant 1.2 °C rise in rectal temperature and auscultatable rales for up to 96 h. Lymphocyte counts, serum amyloid A values, and respiratory scores were significantly different before and after induction of disease and were consistent with respiratory infection. No mortality was associated with this experimental infection, and minimal gross pathologic changes were noted at study termination. The clinical and pathologic findings of this study suggest a potentially reproducible method of establishing clinical respiratory infection in goats. The repeated intratracheal inoculation method of inducing caprine respiratory disease can be used to produce experimental respiratory disease in goats when the use of corticosteroid is not desirable. With the feasibility of this method established, additional research evaluating the optimal dose and frequency of P. multocida administration is needed.