Distillers’ grains for ruminants: Assessing protein quality


Alvaro Garcia

The protein the cow receives comes from 2 origins: feed protein and microbial protein. Depending on its degradability, part of the feed protein is broken down in the rumen (RDP) byspecific microorganisms which will use its nitrogen (and sometimes other elements), carbonchains, hydrogen, oxygen, and energy to produce their own protein.

The passage of digesta from the pre-stomachs to the intestine will carry this protein (MP) asconstituent of microbial cells to be digested in the intestine. The protein that is not degradable(RUP) in the rumen will pass intact to the intestine to also be digested there. There is usuallya small fraction (heat damaged protein) that cannot be digested and will go through thedigested tract intact, ending up in the manure.

Rumen undegradable protein

We need to think of protein in terms of 2 macro pools, the rumen population, and the host. Let us concentrate on the importance of the protein that escapes the rumen and is digestedin the intestine of the cow. We often call this protein bypass protein or rumen undegradableprotein (RUP).

For proteins to be degraded by microorganisms or animal enzymes they must be in aqueoussolution. It is therefore easy to understand why protein solubility is associated withdegradability.

Continue reading this article published in Dairy Global.