Main Causes of Death in Piglets from Different Brazilian Nursery Farms Based on Clinical, Microbiological, and Pathological Aspects

Simple Summary Mortality within the nursery pig herd constitutes a pivotal factor contributing to economic losses and concurrently serves as a valuable indicator of production efficiency. The correct diagnosis is an important tool for guiding management corrections, improvements in animal performance, and decision making in herds. Thus, this study aimed to establish the main causes of death in nursery pigs from different nurseries through necropsies. Eighteen nurseries were analyzed (a total of 120,243 housed piglets), and 557 necropsies were performed. Conclusive diagnosis totaled 93.2% (519/557). Bacterial and viral diseases constituted the majority of conclusive diagnoses (72.9%) (378/519), followed by undefined causes at 14.4% (75/519) and non-infectious diseases at 12.7% (66/519). There was an increase in mortality rate in individual nurseries associated mainly with bacterial disease outbreaks. Therefore, infectious diseases constituted the largest portion of the diagnoses, offering a great opportunity for improving production rates in herds. In this sense, the aspects highlighted of the main causes of death can guide accurate diagnosis and specific decision making in nurseries.Abstract Necropsies can reveal herd problems or comorbidities that can lead to management corrections, improvements in animal performance, and better decision making. Furthermore, the pattern and causes of mortality might differ when different systems are evaluated. The present study was conducted to establish the main causes of death in nursery pigs from different systems in Brazil, as well as the clinical, microbiological, and pathological aspects of these mortalities. Eighteen nurseries were analyzed (a total of 120,243 housed piglets), and 557 necropsies were performed. Streptococcus suis infection was the most prevalent cause of death (21.2%), followed by bacterial polyserositis (16.7%), chronic atrophic enteritis (13.5%), salmonellosis (8.8%), pneumonia (8.6%), and colibacillosis (6.1%). The increase in mortality rate in individual nurseries and, consequently, in the diagnoses was commonly associated with disease outbreaks. Infectious diseases constituted the largest portion of the diagnoses, making a great opportunity for improving production rates in herds. Moreover, the extensive range of observed diagnoses highlights the importance of conducting preliminary diagnostic investigations based on necropsy to determine the causes of death. This approach allows for the direction of complementary tests, which can diagnose agents with greater specificity. As a result, this allows for the implementation of more effective prevention and control strategies.