[Studies on the bacterial causes of neonatal mortality in foals. Report on post-mortem findings (author’s transl)].

This research investigates the bacterial causes of neonatal mortality in foals over two years, finding that E. coli infection is prevalent, particularly in the first weeks of life, superseding A. equuli as the key cause. Other significant infections include Klebsiella pneumonia, Salmonella spp., C. equi and streptococcal infections, with varying pathological impacts.

Research Context and Methodology

• Over the course of two years, a study was undertaken to scrutinize the causes of neonatal mortality in foals. The primary focus of the study was to determine which bacterial infections posed the most risk.
• The total sample size of the study was 121 foals. The length of the study and the considerable sample size allowed for a comprehensive investigation into the bacterial causes of death in newborn foals.

Key Findings

• The research revealed that the primary cause of death amongst newborn foals was E. coli infection, with 56% of the deaths attributed to it. This infection is most prevalent during the first weeks of life and can lead to a variety of pathological changes depending on the progress of the disease.
• A. equuli, previously the most lethal infection, was only found to be the cause of death in 1.6% of the cases, clearly surpassed by E. coli.
• Infections running an acute course often present pathologies in the lung and lymphoid organs, whereas subacute infections often lead to polyarthritis and polyserositis.
• Klebsiella pneumonia infection, accounting for 10% of fatalities, is another key cause of death in the first weeks of life of foals. The pathological changes it causes bear a striking resemblance to the changes caused by a subacute E. coli infection.
• Infections with Salmonella spp., causing 7% of deaths, and infections with C. equi and streptococci, causing 11% of deaths, are primarily found in older foals between 1-3 months.
• In 12% of the foals, despite pathological findings indicative of septicaemia, no bacteria were discovered upon bacteriological examination. This suggests that there might be other non-bacterial factors contributing to neonatal mortality in foals.

Conclusion and Discussion

• The study presents important findings that shift our understanding of the main bacterial threats to newborn foals, with E. coli infection emerging as the most prevalent cause of neonatal mortality.
• By correlating the pathology with specific infections, this research sheds light on the impacts of these infections and also points to possible treatments and preventative measures.
• The cases where post-mortem findings suggested septicaemia but bacteriological examination was negative raise questions about possible other causes of neonatal mortality, which warrants further research.