Lipids in relation to rumen function

I959lost from the rumen as ammonia, the nitrogen economy of the animal does not suffer from that ammonia loss.If, however, insufficient nitrogen of unsuitable biological value is available to the animal as a result of this process, the portion of the feed escaping digestion by the micro-organisms in the rumen assumes greater importance.This residual food nitrogen reaching the abomasum and intestines is not necessarily that most difficult to digest, because the amount of food eaten by a high-yielding cow may not allow the feed residues to remain in the rumen as long as they might otherwise do.The better the amino-acid composition of the residual feed passing from the rumen, the better the biological value of the total feed.The most desirable type of feed protein for a ruminant is, therefore, one of reasonably low solubility in the rumen yet of high biological value for the singlestomached animal.These arguments must be taken a stage further for application to agricultural practice because, although this thesis has been supported by experimental evidence, there are two further points which need consideration: (I) is the cow normally rationed sufficiently tightly for protein for any of these theoretical improvements to become evident, and (2) may it not be more economical to give a theoretically wasteful protein source if it still supplies cheaper units of biological value?