ESTIMATION OF MICROBIAL PROTEIN SUPPLY TO SHEEP AND CATTLE BASED ON URINARY EXCRETION OF PURINE DERIVATIVES - AN OVERVIEW OF THE TECHNICAL DETAILS

Abstract

Introduction 1 Principle of the method 1 Brief background of purine metabolism in ruminants 2 Limitation of the method 5 Sample collection 5 Determination of purine derivatives 6 Dilution of urine samples 6 List of published methods 8 Determination of allantoin by a colorimetric method 9 Determination of xanthine plus hypoxanthine by enzymatic method 12 Determination of uric acid by uricase method 15 Calculations 16 Daily excretion of purine derivatives 17 Calculation of microbial N supply 17 Presentation of results 18 Use of spot samples 19 Related Literature 19