Nitrogen-Balance Studies with Red Sokoto (Maradi) Coats for the Minimum Protein Requirements

Abstract

Elliott and Topps (1963) demonstrated with two breeds of African cattle (steers) that only 33.3 per cent of the intake of digestible crude protein advocated by Brody (1945) was necessary to keep these steers in nitrogen equilibrium. Elliot and Topps (1964) also showed with Blackhead Persian wether sheep that only 40 per cent of the intake of digestible N recommended by Brody (1945) was necessary to keep these sheep in nitrogen equilibrium, a point usually considered to be synonymous with the maintenance requirement for digestible N. They used (a) the regression equations of digestible N on N retention and (b) the regression equations of digestible N intake on urinary N. They obtained daily mean value of 2.84--17: 1.55 g digestible N for the first method and 2.10= I--0.55 g digestible N for second method. However, they pointed out that the choice of N retention as the independent variable in the equation was not a very accurate one as it was subject to considerable experimental errors on short-term trials. Deif et al.(1968) obtained linear relationship between absorbed or digestible N and N retention when rams received various levels of casein, gluten or urea. They obtained the average slopes of the regression equations which they termed as N retention index for the absorbed N or the" biological value"