Feed intake and urinary excretion of nitrogen and purine derivatives in pregnant suckler cows fed alternative roughage-based diets

Microbial Characteristics, Microbial Nitrogen Flow, and Urinary Purine Derivative Excretion in Steers Fed at Two Levels of Feed Intake

The Urinary Excretion of Purine Derivatives in Sheep Offered Nitrogen and Phosphorus Deficient Diets

Urinary allantoin excretion as a measure of microbial protein production, has been shown to be responsive to ruminal nitrogen (N) supply (Balcells et al. 1993). Dietary phosphorus (P) deficiency has also been observed to reduce microbial protein flow (Gunn and Ternouth 1994). The aim of this experiment was to examine the effects of P and N deficiencies upon microbial protein formation, as deter...

Urinary Nitrogen Excretion of Sheep Fed Nitrogen-free Diets

The urinary nitrogen excretion of sheep offered a low nitrogen diet was lower than when the sheep were fed a nitrogen-free mixture post-ruminally. This result is discussed in terms of Folin’s (1905) definition of endogenous nitrogen, and the nitrogen recycling and utilization which can occur in the rumen/reticulum of sheep. Reasons are given why post-ruminal feeding should give an endogenous ni...

Urinary excretion of purine derivatives as an index of microbial-nitrogen intake in growing rabbits.

Three experiments were carried out to establish a response model between intake and urinary excretion of purine compounds. In Expt 1 the relationship between the intake of purine bases (PB) and the excretion of total purine derivatives (PD) was determined in seven growing rabbits with a mean initial live weight (LW) of 2.03 (SE 0.185) kg, aged 70 d, each fitted with a wooden neck collar to prev...

Urinary excretion of purine derivatives, microbial protein synthesis, nitrogen use, and ruminal fermentation in sheep and goats fed diets of different quality.

The objective of this study was to compare N balance, microbial N flow (MNF) estimated from purine derivatives (PD) urinary excretion, and its variation when estimated using purine bases:N ratios in liquid associated bacteria (LAB) from models reported in the literature (MNF - response models) or measured ratios in liquid and solid-associated bacterial (SAB) pellets (MNF-LAB+SAB), diet digestib...