It's actually an outstanding problem with feeding ruminants. In pasture raised animals, they tend to forage on things that avoid giving them problems by avoidin

It's actually an outstanding problem with feeding ruminants. In pasture raised animals, they tend to forage on things that avoid giving them problems by avoiding over-grazing thru taste and foraging patterns, but in a small contained yard of constantly cut grass the toxins will build up because the plant responds as if it is over-grazing. https://doi.org/10.1016/S0167-7799(00)88995-7 https://doi.org/10.1016/S0167-7799(00)88995-7