Stage-Specific Associations Between Respiratory Pathogens and Mortality in Sheep: A Multivariate Analysis.
4 affiliations
- 1Animal Health Research Group: Diagnosis and Control of Diseases (SANDYC), Unidad de Investigación Competitiva (UIC) Zoonosis y Enfermedades Emergentes ENZOEM, Department of Animal Health, International Excellence Agrifood Campus 'CeiA3', University of Córdoba, 14071 Córdoba, Córdoba, Spain.
- 2Department of I+D+I, Centro Tecnológico de Investigación Agroalimentaria (CICAP), 14400 Pozoblanco, Córdoba, Spain.
- 3Department of Genetics, International Excellence Agrifood Campus 'CeiA3', University of Córdoba, 14071 Córdoba, Córdoba, Spain.
- 4International Doctoral School in Agri-Food (eidA3), Rabanales University Campus, University of Cordoba, 14071 Córdoba, Córdoba, Spain.
Abstract
Ovine Respiratory Complex (ORC) is a major cause of lamb mortality in intensive and semi-intensive sheep production systems. Its multifactorial etiology, involving bacterial and viral pathogens together with host and environmental factors, complicates disease control and limits the effectiveness of conventional preventive measures. Although respiratory pathogens are commonly detected in healthy lambs, their contribution to mortality at different production stages remains poorly understood. This study evaluated the relationships between respiratory pathogens and lamb mortality using canonical multivariate analysis. A total of 200 bronchoalveolar lavage samples were collected from apparently healthy lambs aged 50-60 days during winter (n = 80) and summer (n = 120) on 10 commercial sheep farms in southwestern Spain. Samples were analyzed by real-time PCR for the detection of major bacterial and viral respiratory pathogens, and mortality records from farms and feedlots during 2022-2023 were incorporated into the analysis. A high herd-level prevalence was detected for Pasteurella multocida, Mannheimia haemolytica, Bibersteinia trehalosi, and Mesomycoplasma ovipneumoniae, whereas Histophilus somni, Orf virus, and parainfluenza virus type 3 showed intermediate prevalence. No significant seasonal differences were observed in pathogen prevalence. ORC-associated pathogens accounted for approximately 20% of the variance in mortality, suggesting that non-infectious factors also play an important role in lamb losses. Canonical analysis identified stage-specific multivariate patterns, with M. ovipneumoniae and P. multocida contributing most strongly to the canonical dimension characterized by on-farm mortality, whereas M. haemolytica, together with P. multocida and parainfluenza virus type 3 (PIV3), contributed most strongly to the dimension characterized by feedlot mortality.These findings improve our understanding of the epidemiology of ORC and support the development of targeted surveillance, prevention, effective vaccination of ewes against the serotypes circulating within farms, and management strategies to reduce lamb mortality, improve animal welfare, and enhance the sustainability of sheep production.
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BibTeX
@article{romerosalmoral2026stagespecific,
title = {{Stage-Specific Associations Between Respiratory Pathogens and Mortality in Sheep: A Multivariate Analysis.}},
author = {Antonio Romero-Salmoral and Manuela Hernández-García and Francisco Javier Navas González and Carmen Tarradas Iglesias and Belen Huerta Lorenzo and Inmaculada Luque Moreno and Eva Boyer-Bustamante and Francisco Jurado-Martos},
journal = {Animals : an open access journal from MDPI},
year = {2026},
month = sep,
doi = {10.3390/ani16193028},
url = {https://europepmc.org/article/MED/42882998},
note = {CC BY},
}
RIS
TY - JOUR
TI - Stage-Specific Associations Between Respiratory Pathogens and Mortality in Sheep: A Multivariate Analysis.
AU - Antonio Romero-Salmoral
AU - Manuela Hernández-García
AU - Francisco Javier Navas González
AU - Carmen Tarradas Iglesias
AU - Belen Huerta Lorenzo
AU - Inmaculada Luque Moreno
AU - Eva Boyer-Bustamante
AU - Francisco Jurado-Martos
PY - 2026
DA - 2026/09/26
JO - Animals : an open access journal from MDPI
DO - 10.3390/ani16193028
UR - https://europepmc.org/article/MED/42882998
AB - Ovine Respiratory Complex (ORC) is a major cause of lamb mortality in intensive and semi-intensive sheep production systems. Its multifactorial etiology, involving bacterial and viral pathogens together with host and environmental factors, complicates disease control and limits the effectiveness of conventional preventive measures. Although respiratory pathogens are commonly detected in healthy lambs, their contribution to mortality at different production stages remains poorly understood. This study evaluated the relationships between respiratory pathogens and lamb mortality using canonical multivariate analysis. A total of 200 bronchoalveolar lavage samples were collected from apparently healthy lambs aged 50-60 days during winter (n = 80) and summer (n = 120) on 10 commercial sheep farms in southwestern Spain. Samples were analyzed by real-time PCR for the detection of major bacterial and viral respiratory pathogens, and mortality records from farms and feedlots during 2022-2023 were incorporated into the analysis. A high herd-level prevalence was detected for Pasteurella multocida, Mannheimia haemolytica, Bibersteinia trehalosi, and Mesomycoplasma ovipneumoniae, whereas Histophilus somni, Orf virus, and parainfluenza virus type 3 showed intermediate prevalence. No significant seasonal differences were observed in pathogen prevalence. ORC-associated pathogens accounted for approximately 20% of the variance in mortality, suggesting that non-infectious factors also play an important role in lamb losses. Canonical analysis identified stage-specific multivariate patterns, with M. ovipneumoniae and P. multocida contributing most strongly to the canonical dimension characterized by on-farm mortality, whereas M. haemolytica, together with P. multocida and parainfluenza virus type 3 (PIV3), contributed most strongly to the dimension characterized by feedlot mortality.These findings improve our understanding of the epidemiology of ORC and support the development of targeted surveillance, prevention, effective vaccination of ewes against the serotypes circulating within farms, and management strategies to reduce lamb mortality, improve animal welfare, and enhance the sustainability of sheep production.
SN - 2076-2615
ER -