in order to investigate the effects of different levels of nitrogen rate on yield and seed yield components of wheat cultivars, an experiment was conducted on araghi mahalleh (gorogan) research farm in 2008. treatments, nitrogen in the form of urea (0, 90, 180 and 270 kg/ha) and cultivars (tajan, falat and n81-18) were arranged as factorial based on randomized complete block design with four re...

In dairy cows, dietary crude protein (CP) that can is not captured as milk protein is largely excreted as N in manure. Of course, some protein-N is retained for growth in first and second lactation animals and in the calf and fetal tissues during pregnancy; however, these amounts are small relative to the proportion of absorbed N going into milk. Cows and other mammals convert N from absorbed a...

protein nutritional status of dairy cows. Milk urea nitrogen reflects the amount of urea found in milk and these values are closely correlated with the concentration of urea found in the blood. MUN values should not be used by themselves when evaluation a herd’s feeding program but can be used in conjunction with evaluating milk production records, feeding management practices, and dry matter, ...

Urea rebound refers to an early postdialysis phenomenon in which urea returns to the systemic circulation, raising the blood level to a near plateau over a period of 0.5 to 1 hour [1]. The urea involved is believed to have come from either the intracellular compartment by means of diffusion resulting from the dialysis-induced concentration gradient [2,3], or tissues poorly perfused as a result ...

Isoenergetic maize silage diets, fed at maintenance to 24 suckling cows (Exp. 1) and to 3 (Exp. 2) or 4 (Exp. 3) rumen fistulated sheep, were compared with a urea and controlled release NPN diet (Exps. 1 and 2) and with a protein-N supplemented diet (Exp. 3). Supplementation increased blood urea concentrations (44.7 +/- 22.3 vs. 97.6 +/- 23.7 mg urea-N x L(-1)) (Exp. 1) and renal urea excretion...

Ammonia detoxification, which takes place via the hepatic urea cycle, is essential for nitrogen homeostasis and physiological well-being. It has been reported that a reduction in dietary protein reduces urea nitrogen. MicroRNAs (miRNAs) are major regulatory non-coding RNAs that have significant effects on several metabolic pathways; however, little is known on whether miRNAs regulate hepatic ur...

A simple method is described for directly determining serum urea nitrogen, wtihout deproteinization. The urea in 20 Ml of serum or plasma is reacted with diacetylmonoxime in the presence of thiosemicarbazide and cadmium ion under acid conditions. The absorbance of the resulting rose-purple solution is measured at 540 nm. Results agreed excellently with those obtained by a reference method that ...