Use of Plasma Urea Nitrogen to Vary Protein Allowances of Lambs

The optimum level of protein in the supplement for dairy cows with access to grass silage

“…In the past, the existence of the relationship between plasma urea and protein intake has been used to assess the adequacy of protein intake for sheep (Pfander et al, 1975), and while this has also been implied in the use of metabolic profiles in dairy cow nutrition, little experimental data are available on which to base optimum plasma urea levels. In the present work, equation (4) can be used to determine the blood urea level coinciding with maximum milk yield (derived from equation (1)), and this was found to be 400 mg/1.…”

Alfalfa as a supplement of dried cornstalk diets: Associative effects on intake, digestibility, nitrogen metabolisation, rumen environment and hematological parameters in sheep

“…It has been well established that the content of rumen undegradable protein in alfalfa is greater than in some forages. Given that a positive correlation exists between levels of N intake and concentration of UREAN (Pfander et al, 1975;Preston et al, 1965;Karnezos et al, 1994), metabolism levels are enhanced and blood urea nitrogen increased when large amounts of amino acids are ingested (Faulkner, 1983). The lack of variation in UREAN levels observed in our study may have resulted from the fact that NH 3 generated in the rumen met microbial protein requirement when supplemented 50-150 g alfalfa hay per day.…”

Evaluation of the use of arid-area rangelands by grazing sheep: Effect of season and supplementary feeding

“…Thus, a similar trend was observed for the plasma urea concentration, which increased during the wet season (P = 0.10) in supplemented animals. A positive correlation was reported between protein intake and blood urea concentration (Pfander et al, 1975). In addition, the forage intake level and nitrogen degradation in the rumen can influence the blood urea level (Hammond et al, 1994).…”