Urea and allantoin in milk of cows during and after provision of too much or too little protein. 5. Effect of an incorrect protein supply for lactating cows and its consequences

Kirchgessner, M.; Kreuzer, M.

During 3 periods of 21 days 18 cows had adequate protein supply (control) or 25% excess of protein followed by adequate amount or by 25% deficit, then control supply. All diets were equal in energy. With 11.6, 14.5 and 17.1% crude protein in diet, crude protein and allantoin values in milk did not change but urea reached 8.7, 17.7 and 29.4 mg/100 ml. Urea was affected also by nitrogen excretion in milk. Of total allantoin produced 6 to 7% was excreted in milk.