Roe deer diarrhoea – one step further?

Chronic diarrhoea in roe deer has increased in recent years, and despite extensive investigations in Norway and other European countries, the cause remains unknown. Since many common explanations have now been ruled out, a new project is underway to explore alternative reasons why some roe deer develop this long‑lasting condition.

Chronic diarrhoea in roe deer has become increasingly common in several parts of Norway, and despite many years of investigation both here and in other European countries, the cause remains unknown. The disease has a long-lasting course and leads to weight loss and weakening in animals of all ages. Findings from the Norwegian Veterinary Institute are consistent with studies from other countries, where no specific infectious agent has been identified. This suggests that the condition is complex and likely influenced by several factors.

Roe deer are highly selective browsers, and factors such as forage availability, environmental conditions and population density can influence the composition of microorganisms in the digestive system. These shifts may lead to digestive problems and diarrhoea. In recent years, rumen and intestinal samples from healthy and diseased roe deer in the municipalities of Moss and Råde have been collected, providing a unique basis for further investigations.

Purpose

This project aims to analyze the collected rumen and intestinal samples using modern molecular methods, including 16S rRNA sequencing and shotgun metagenomics. The goal is to investigate whether chronic diarrhoea may be linked to imbalances in the gut microbiota, changes in rumen function, or previously undetected infectious agents.

The analyses will provide new knowledge about microbial composition, potential pathogens and metabolic differences between healthy and diseased animals. The overall objective is to move a step closer to understanding why some roe deer develop chronic diarrhoea, and to build a foundation for evidence-based measures that can improve animal health and reduce the occurrence of this condition.