Reconstituting the diet of grazing domestic herbivores using metabarcoding

Identifying the type of grass ingested by grazing stock remains a bottleneck for analyzing the extent to which available grass affects the properties of end animal products. The use of metabarcoding technology, as presented in this document, offers promising perspectives in terms of better understanding the interactions between ingested grass, animals (mainly their eating habits) and end products (and their quality). This experiment was carried out in order to test this technology on the faeces of dairy cattle grazing on grassland with a diversified botanical composition. By sequencing plant DNA fragments found in tested faeces, it was possible to identify the full range of ingested taxons. Twice as many taxons were found in the faeces of cattle grazing on botanically rich grassland with a low stocking rate compared to faeces from cattle grazing on botanically poor grassland with a high stocking rate.