Understanding bypass protein: when it matters and who benefits most

We often hear the term “bypass protein” thrown around in ruminant nutrition meetings, but what does it really mean — and when does it actually make money? In simple terms, bypass protein (also called rumen-undegradable protein, or RUP) is the fraction of dietary protein that escapes microbial breakdown in the rumen and reaches the small intestine intact. Once there, it’s digested by the animal’s own enzymes, providing amino acids directly to the bloodstream.