Hello dear @gwajnberg, the important thing for bovine feeding specifically in the rumen is to have a balance between protein and carbohydrate levels, as mentioned in the article, however there are forages that do not have adequate protein levels, therefore, the use of non-protein nitrogen sources such as urea arises as an alternative, to supplement the deficiency that exist in plants.

If it is not handled carefully, it can generate a high toxicity in the animal until it causes death.

So long, have a great week.