Use of tanniferous plants against gastro-intestinal nematodes in ruminants

Summary

On organic farms, infections of gastro-intestinal nematodes (GIN) in grazing cattle, sheep and goats can have a detrimental impact on animal health, and are therefore of substantial economic importance. The aim of our interdisciplinary project is to investigate the basic conditions for the implementation of a control strategy against GIN based on the use of tanniferous plants. The project combines research on plant growth and management, animal nutrition and parasitology. The first results, especially those from Onobrychis viciifolia (sainfoin), presented here are encouraging. O. viciifolia has a consistently high concentration of condensed tannins (CT) throughout the whole growing season. Thus, the optimal time for harvest can be determined in relation to agronomic properties such as fodder quality and yield and does not have to be related to a specific time period with high tannin concentration in the herbage. Despite its high CT content, the animals accepted O. viciifolia very well. Finally, the anti-parasitic properties of fresh CT-containing O. viciifolia were largely preserved in silage and hay leading to a substantial decrease in worm egg excretion in faeces. The present findings are promising for a potential integration of the CT-approach into the complementary control strategies against GIN in sheep.