Salvage of blood urea nitrogen in sheep is highly dependent on plasma urea concentration and the efficiency of capture within the digestive tract1,2

2007 ◽  
Vol 85 (4) ◽  
pp. 1006-1013 ◽  
Author(s):  
N. E. Sunny ◽  
S. L. Owens ◽  
R. L. Baldwin ◽  
S. W. El-Kadi ◽  
R. A. Kohn ◽  
...  
Keyword(s):  
Blood Urea Nitrogen ◽  
Urea Concentration ◽  
Urea Nitrogen ◽  
Plasma Urea ◽  
Plasma Urea Concentration

Factors affecting the urinary excretion of urea nitrogen in cattle. II. The plasma urea nitrogen concentration

1970 ◽  
Vol 21 (1) ◽  
pp. 145 ◽  
Author(s):  
RF Thornton
Keyword(s):  
Nitrogen Concentration ◽  
Urine Flow ◽  
Urea Concentration ◽  
Urea Clearance ◽  
Urea Nitrogen ◽  
Plasma Urea ◽  
Factors Affecting ◽  
Urea Excretion ◽  
Plasma Urea Concentration ◽  
Filtered Load

The relationships between the plasma urea concentration and clearance variables associated with urinary urea excretion were investigated in urea-supplemented cattle. The plasma urea concentration was related to the urinary urea output, and thus to the urea clearance and the fraction of filtered urea excreted. It is suggested that the urine flow rate was influenced by urinary urea excretion, which in turn was influenced by the plasma urea concentration and therefore by the filtered load of urea. The probable influence of the recycling of urea to the rumen on the excretion of urinary urea is discussed.

Factors affecting the urinary excretion of urea nitrogen in cattle. I. Sodium chloride and water loads

1970 ◽  
Vol 21 (1) ◽  
pp. 131 ◽  
Author(s):  
RF Thornton
Keyword(s):  
Sodium Chloride ◽  
Flow Rate ◽  
Free Water ◽  
Urine Flow ◽  
Urea Concentration ◽  
Urine Flow Rate ◽  
Urea Nitrogen ◽  
Plasma Urea ◽  
Urea Excretion ◽  
Plasma Urea Concentration

Urea metabolism in cattle was studied under conditions of different nitrogen, sodium chloride, and water intakes. Urea supplementation increased the concentrations of ammonia and trichloroacetic acid-insoluble nitrogen in ventral rumen fluid, raised the plasma urea concentration, and increased the excretion of faecal nitrogen and urinary urea and non-urea nitrogen. Sodium chloride loading increased the free water intake and urine flow rate, and the added sodium was quantitatively recovered in the urine. Plasma urea concentration was linearly related to urinary urea excretion but the slope of this relationship was influenced by the urine flow rate. Urea clearance and the fraction of filtered urea excreted were both related to the urine flow rate and to the urine-concentrating ability of the kidney, but not to the urinary urea output. During low nitrogen intakes, urinary urea excretion was influenced more by urine flow than by solute load.

Genome-wide association for plasma urea concentration in sheep

2021 ◽  
Vol 248 ◽  
pp. 104483
Author(s):  
Taiana Cortez de Souza ◽  
Tatiana Cortez de Souza ◽  
Gregorí Alberto Rovadoscki ◽  
Luiz Lehmann Coutinho ◽  
Gerson Barreto Mourão ◽  
...  
Keyword(s):  
Urea Concentration ◽  
Genome Wide Association ◽  
Plasma Urea ◽  
Genome Wide ◽  
Plasma Urea Concentration

Urea Excretion in the Camel

1957 ◽  
Vol 188 (3) ◽  
pp. 477-484 ◽  
Author(s):  
Bodil Schmidt-Nielsen ◽  
Knut Schmidt-Nielsen ◽  
T. R. Houpt ◽  
S. A. Jarnum
Keyword(s):  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Filtration Rate ◽  
Urea Concentration ◽  
Nitrogen Excretion ◽  
Renal Tubules ◽  
Urea Clearance ◽  
Plasma Urea ◽  
Urea Excretion ◽  
Plasma Urea Concentration

The nitrogen excretion was studied in the one-humped camel, Camelus dromedarius. When a growing camel was maintained on a low N intake (dates and hay) the amount of N excreted in the form of urea, NH3 and creatinine decreased to 2–3 gm/day. This decrease was caused by a drop in urea excretion from 13 gm to 0.2–0.5 gm/day. Urea given intravenously during low N intake was not excreted but was retained. (The camel like other ruminants can utilize urea for microbial synthesis of protein.) The renal mechanism for urea excretion was investigated by measuring urea clearance and glomerular filtration rate during a period of 7 months. During normal N intake about 40% of the urea filtered in the glomeruli were excreted in the urine while during low N intake only 1–2% were excreted. The variations in urea clearance were independent of the plasma urea concentration and of glomerular filtration rate, but were related to N intake and rate of growth. No evidence of active tubular reabsorption of urea was found since the urine urea concentration at all times remained higher than the simultaneous plasma urea concentration. The findings are not in agreement with the current concept for the mechanism of urea excretion in mammals. It is concluded that the renal tubules must either vary their permeability to urea in a highly selective manner or secrete urea actively.

Residual kidney function and plasma urea concentration in patients with chronic renal failure

1990 ◽  
Vol 22 (6) ◽  
pp. 573-579 ◽  
Author(s):  
O. Schück ◽  
J. Erben ◽  
H. Nádvorníková ◽  
V. Teplan ◽  
O. Marečková ◽  
...  
Keyword(s):  
Renal Failure ◽  
Chronic Renal Failure ◽  
Kidney Function ◽  
Urea Concentration ◽  
Plasma Urea ◽  
Residual Kidney Function ◽  
Plasma Urea Concentration

Plasma Urea Concentration in Older People

1972 ◽  
Vol 14 (1) ◽  
pp. 32-35 ◽  
Author(s):  
J.S. Milne ◽  
J. Williamson
Keyword(s):  
Older People ◽  
Urea Concentration ◽  
Plasma Urea ◽  
Plasma Urea Concentration

Age-dependent blood pressure response to increased salt intake in rats influenced by a transient renal ischaemia

1986 ◽  
Vol 70 (2) ◽  
pp. 185-189 ◽  
Author(s):  
J. Kuneš ◽  
J. Jelínek ◽  
J. Zicha
Keyword(s):  
Blood Pressure ◽  
Renal Dysfunction ◽  
Renal Mass ◽  
Urea Concentration ◽  
Ischaemic Injury ◽  
Pronounced Increase ◽  
Plasma Urea ◽  
Renal Ischaemia ◽  
Salt Hypertension ◽  
Plasma Urea Concentration

1. The influence of renal dysfunction (induced by ischaemic injury) on the development of salt hypertension was studied in rats which were exposed to 60 min of renal ischaemia when either immature or adult. Saline-drinking age-matched animals served as controls. The blood pressure, plasma urea concentration, extracellular fluid volume (ECFV) and renal mass were measured 21 and 50 days after renal ischaemia. 2. Increments of plasma urea concentration and ECFV were considered to be indicators of renal dysfunction. Increased renal mass was used as an estimate of the degree of renal injury. 3. In adult rats, both plasma urea concentration and ECFV were increased 3 weeks after renal ischaemia. This correlated with a pronounced increase of renal mass. A similar relation of renal mass to ECFV was still present 50 days after renal ischaemia. 4. In rats treated when immature the increment of plasma urea concentration was much smaller and ECFV did not differ significantly from the control volumes. 5. A mild salt hypertension developed only in those rats which were treated when immature. On the other hand, the blood pressure tended to decrease in animals treated when adult. 6. It is concluded that mild renal dysfunction facilitates the development of salt hypertension in immature rats. This is in contrast with the reversed effects of extensive renal dysfunction in adult animals. 7. It is suggested that the age of animals is more important for the induction of salt hypertension than the degree of renal dysfunction.

GROWTH-DEPENDENT CHANGES IN BLOOD UREA NITROGEN LEVELS IN LINCOLN AND SOUTHDOWN LAMBS

1969 ◽  
Vol 49 (2) ◽  
pp. 197-204 ◽  
Author(s):  
H. Mukhoty ◽  
W. Combs ◽  
T. D. D. Groves
Keyword(s):  
Body Weight ◽  
Blood Plasma ◽  
Blood Urea Nitrogen ◽  
Growth Period ◽  
Urea Nitrogen ◽  
Plasma Urea ◽  
Nitrogen Levels ◽  
Rate Of Increase

The concentration of blood plasma urea nitrogen (BUN) was measured at bi-weekly intervals in four groups of growing Lincoln and Southdown lambs which received the same ration throughout their growth period. BUN increased with age and weight in each group. Although all groups showed similar changes in BUN with age, BUN concentration increased at 0.73 × 10−2, 0.88 × 10−2, 0.91 × 10−2, and 1.23 × 10−2 mg per kg of body weight gained in the case of Lincoln males, Lincoln females, Southdown males, and Southdown females, respectively. The average rates of gain for these groups were 0.33, 0.28, 0.26 and 0.20 kg per day, respectively. It appeared from these studies that at any given weight, the more mature animals at that weight tended to have higher BUN concentrations and a higher rate of increase of BUN with weight.

Effect of rumen degradable protein and lactation on nitrogen metabolism in dairy goats

1991 ◽  
Vol 71 (4) ◽  
pp. 1111-1124 ◽  
Author(s):  
J. Brun-Bellut ◽  
J. M. Kelly ◽  
G. W. Mathison ◽  
R. J. Christopherson
Keyword(s):  
Amino Acids ◽  
Digestive Tract ◽  
Urea Concentration ◽  
Dairy Goats ◽  
Rumen Microorganisms ◽  
Plasma Urea ◽  
Available N ◽  
Lactation Stage ◽  
Plasma Urea Concentration ◽  
Degradable Protein

Nitrogen flow and exchanges in the digestive tract were measured in three goats during a dry stage and a subsequent hormonally induced lactation stage. Two diets, formulated with and without urea to contain either a high or low level of crude protein and rumen-degradable protein (RDP), were tested in a crossover experimental design within each stage. The amount of urea nitrogen (N) recycled to the ruminoreticulum was higher (P < 0.05) during lactation (3.5 g d−1) than in the dry stage (0.9 g d−1), as was plasma urea concentration. However, the mean amount of urea recycled was lower (P < 0.05) when the high-RDP diet was fed (1.4 g N d−1) than when the low-RDP diet was fed (3.0 g N d−1), even though the plasma urea concentration tended to be higher in goats fed the high-RDP diet. Of the estimated ruminally available N, 90–110% was incorporated into microbial cells. The proportion of bacterial N derived from rumen ammonia (0.77–0.89) was not influenced by protein source or lactation. Of the amino acids flowing into the duodenum, 69–75% were apparently absorbed in the small intestine, whereas total digestive tract apparent digestibility ranged from 81 to 83%. No more than 60% of the fecal N was derived from undigested bacteria from the rumen. It was concluded that the amount of urea which is recycled to the rumen is under metabolic control and that there is efficient use of ruminally available N by rumen microorganisms. Key words: Goats, lactation, rumen-degradable protein, 15N, urea recycling, amino acids

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