Pneumonia is the main respiratory disease in farm animals, causing substantial economic losses, due to treatment costs, reduced productivity, and mortality. The objective of this retrospective study was to evaluate cases of pneumonia submitted for necropsy, with an emphasis on morphological patterns of lesions and etiologic agents. A comprehensive analysis was conducted on necropsy reports of farm animals (horses, cattle, sheep, and goats) submitted to the Veterinary Pathology Service from 2017 to 2021. Pneumonia was diagnosed in 158 of these animals. Cattle and horses were the species most frequently affected, representing 41% (65/158) and 28% (45/158), respectively, of the cases. Pneumonia was classified based on morphological patterns of lesions. In this study, cattle were more likely to be affected with broncho or aspiration pneumonia with Klebsiella, Truperella pyogenes or Pasteurella multocida infections, whereas horses had granulomatous or interstitial pneumonia with Streptococcus equi, Klebsiella pneumoniae and Escherichia coli. We concluded that classification of the morphological pattern, based on macroscopic and microscopic descriptions and a microbiological examination, should be done for all necropsies of farm animals with respiratory system pathology, considering the substantial economic losses associated with the disease.

To Cite This Article: Souzan GGD, Moura FBCD, Contel IJ, Kastelic J, Apolonio EVP, Hataka A and Rocha NSR. 2025. Retrospective pathological insights into pneumonia in farm animals: evidence from 158 necropsies. Pak Vet J. http://dx.doi.org/10.29261/pakvetj/2025.272