Respiratory and systemic health parameters in pigs raised in a conventional farm or in isolation

Rika Jolie DVM, MSc, PhD; Lennart Backstrom DVM, PhD; Linda Olson DVM; Chris Chase DVM, PhD

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Objective: To examine the longterm effects of the farm environment--including exposure to airborne contaminants and disease agents--on animal health by raising pigs from the same farm in the conventional farm environment or in an isolated facility.

Methods: The farm was selected for the high prevalence of pneumonia and active porcine reproductive and respiratory syndrome virus (PRRSV). One-week-old pigs were raised on the farm (Farm), or were weaned at 2 weeks of age and raised in an isolated research facility (ISO). Bronchoalveolar lavage fluid (BALF) was collected at 5, 7.5, 10, 15, and 20 weeks of age for cell differentials, superoxide anion (SO), and phagocytosis activity. Blood samples were analyzed for cell type and numbers, and respiratory disease antibodies. At 20 weeks of age, pigs were slaughtered and respiratory tracts were examined. The airborne environment of farm and isolated housing was sampled for dust, endotoxin, peptidoglycan, ammonia, and carbon dioxide.

Results: Farm pigs seroconverted to PRRSV and Mycoplasma hyopneumoniae after 10 weeks of age, which resulted in increased BALF cell infiltration, increased SO, and lower phagocytosis activity compared to ISO pigs. ISO pigs also had activated BALF cells, as suggested by the increased SO and phagocytosis activity. Macroscopic pneumonia lesions, indicative of M. hyopneumoniae, were only observed in the Farm pigs. Airborne contamination was greater in the farm environment than in the isolated environment.

Implications: Housing pigs in a clean, isolated, disease-free, and low-stress environment positively influences health of pigs. Minimal airborne contamination is sufficient to induce cellular changes in BALF and infectious agents, such as PRRSV, could further alter the BALF cellular composition and cell activity.

Keywords: environment, dust, endotoxin, respiratory disease, bonchioalveolar lavage

RIS citationCite as: Jolie R, Backstrom L, Olson L, et al. Respiratory and systemic health parameters in pigs raised in a conventional farm or in isolation. J Swine Health Prod 1999;7(6):269-275.

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