Ruminal ammonia formation in relation to the protein requirement of sheep: II. Comparison of casein and herring-meal supplements

Abstract

1. Herring-meal supplements fed to sheep on a basal diet low in protein were more effective than casein supplements in promoting nitrogen retention and growth. 2. The herring-meal supplements caused less extensive formation of ammonia in the rumen than did the casein supplements. This is considered responsible for the differences found in the value of the proteins. 3. Meat from the sheep fed herring meal was not tainted in flavour. 4. The use of formaldehyde to preserve herring before making them into meal had no deleterious effects when the meal was fed to sheep.