Some effects of water restriction on nitrogen metabolism of cattle

1969 ◽  
Vol 20 (1) ◽  
pp. 185 ◽  
Author(s):  
RF Thornton ◽  
NG Yates

Water restriction was found to decrease nitrogen retention in cattle when compared with periods of similar digestible energy intake but unrestricted water intake. The decreased nitrogen retention was associated with increases in both faecal nitrogen output and urinary urea excretion. The rise in urinary urea nitrogen excretion appeared to be mediated through increased plasma urea nitrogen concentration.

2004 ◽  
Vol 47 (1) ◽  
pp. 85-91 ◽  
Author(s):  
Ivan Moreira ◽  
Alessandro Luis Fraga ◽  
Diovani Paiano ◽  
Gisele Cristina de Oliveira ◽  
Cláudio Scapinello ◽  
...  

The effects of increasing lysine levels on nitrogen balance of pigs fed on low protein diets were evaluated. Four treatments (diets) containing lysine levels (0.8, 1.0 1.2 and 1.4%) were applied to 12 starting (20.0 ± 1.8 kg) barrow pigs. Methionine, threonine and tryptophan were kept constant to the lysine ratio in all diets. Feces and urine were collected during a 5-day period. Nitrogen output in urine (NOU), total nitrogen output (TNO), nitrogen retention (NR), net protein utilization (NPU), biological value or feed protein (BVFP), urine urea nitrogen (UUN), and plasma urea nitrogen (PUN) were determined. PUN showed high negative correlations with BVFP (-0.84), NPU (-0.76), and NR (-0.78) and a positive correlation (0.79) to NOU. Lowest nitrogen excretion and the best use of diet protein were obtained with 1.1% total lysine level. PUN is efficient to indicate amino acid for pigs.


1972 ◽  
Vol 23 (4) ◽  
pp. 727 ◽  
Author(s):  
RF Thornton ◽  
BW Wilson

The relationship between urinary urea nitrogen excretion, the filtered load of urea nitrogen, and the plasma urea nitrogen concentration were studied in cows intravenously infused with 0.5–10 g urea nitrogen per hour. These levels of infusion resulted in ranges of plasma urea nitrogen concentration of 12–63 mg/100 ml, of filtered urea nitrogen of 3–19 g/hr, and of urinary urea nitrogen excretion of 2.5–12.7 g/hr. There were linear relationships between the filtered load of urea nitrogen and the plasma urea nitrogen concentration (r = 0.91), between urinary urea nitrogen excretion and the filtered load of urea nitrogen (r = 0.92), and between urinary urea nitrogen excretion and the plasma urea nitrogen concentration (r = 0.97). It was concluded that the amount of urea excreted in the urine was regulated more by the plasma urea concentration than by renal processes such as glomerular filtration rate (GFR), the concentrating ability of the kidneys, or urine flow rate. The capacity of the bovine kidneys to excrete urea and mechanisms involved in the renal excretion of urea are discussed. The successful use of 51Cr-EDTA for the estimation of GFR in cattle is reported in an appendix. __________________ *Part II, Aust. J. Agric. Res., 21: 145 (1970).


1971 ◽  
Vol 22 (3) ◽  
pp. 429 ◽  
Author(s):  
KH McIntyre

Urea was infused into sheep both intravenously and intraruminally, and at several increasing rates. The infusions were continuous for at least 6 days for each quantity of urea infused. Three predominantly roughage rations were used. Two of these had the same roughage constituents; both had relatively low protein contents, but one contained starch. The amount of urea nitrogen retained in the body from the urea infused was greatest on the ration containing starch, when the nitrogen balance improved by as much as 4.3 g/day. The concentration of ammonia in the rumen increased linearly with the amount of urea infused by either route of administration, but was much higher in the sheep infused intraruminally. Plasma urea nitrogen concentrations increased linearly with each quantity of urea infused until they reached about 30 mg/100 ml. They increased above this concentration only in the sheep fed on the low protein roughage ration without starch. The results suggest that a renal mechanism for urea excretion may control the plasma urea nitrogen concentration at about 30 mg/100 ml under certain conditions.


1970 ◽  
Vol 21 (2) ◽  
pp. 345 ◽  
Author(s):  
RF Thornton ◽  
PR Bird ◽  
M Somers ◽  
RJ Moir

The transfer of endogenous nitrogen to the hind-gut digesta of sheep and its relationship with urinary nitrogen excretion were studied concurrently with the estimation of nitrogen balance and of dry matter digestibility in sheep fitted with a re-entrant ileal cannula. Infusion of glucose into the terminal ileum increased the excretion of faecal nitrogen by 1 g/day, while the urinary urea nitrogen excretion decreased by 1 g/day, relative to the respective control levels. Plasma urea nitrogen concentrations remained unchanged. When glucose was infused, the excretion of nitrogen in the faeces was higher than the amount of nitrogen passing the terminal ileum. It is suggested that endogenous urea nitrogen was transferred to the digesta of the hind-gut, where it was incorporated into microbial protein and subsequently excreted in the faeces. The transfer of urea from the blood to either of the fermentative areas of the gut tract is apparently the preferential pathway of urea excretion in ruminants.


1974 ◽  
Vol 82 (1) ◽  
pp. 61-69 ◽  
Author(s):  
H. Elsayed Osman ◽  
B. Fadlalla

SUMMARYFive successive trials were conducted using eight adult rams (Sudan desert sheep) to study the effect of restriction of water intake on some aspects of digestion and nitrogen metabolism. The feeds used in this study were berseem hay (Medicago sativa), lubia hay (Dolichos lablab), maize hay (Zea mais), a concentrate mixture, and dry desert grasses (hummra) (a mixture ofDactyloctenium aegyptium, Schoenefeldia gracilis, Eragrostis pilosa, Aristida funiculataandAristidaspp.).Restriction of water did not affect the digestibility coefficients of organic matter, crude protein and crude fibre significantly. The digestibility coefficient of ether extract was significantly reduced whereas that of nitrogen-free extract was slightly higher when water was restricted.The concentrations of ammonia and volatile fatty acids in the rumen and of urea in the blood were recorded before and 3 h after feeding. Increases in rumen ammonia and blood urea nitrogen concentration were reduced by water restriction except when hummra was fed.Restriction of water intake also slightly increased thein vitrorate of fermentation of rumen contents which is taken as a measure of microbial activity in the rumen, and the retention of nitrogen. These results are interpreted as indications of more efficient nitrogen utilization under conditions of water restriction.There were no significant effects of the treatments on changes in the concentration of volatile fatty acids.The significance of these findings in relation to the management of desert sheep in the arid parts of the Sudan is discussed with special reference to the effect of the level of dry-matter intake on nitrogen balance.


2013 ◽  
Vol 91 (2) ◽  
pp. 811-818 ◽  
Author(s):  
V. V. Almeida ◽  
A. J. C. Nuñez ◽  
A. P. Schinckel ◽  
C. Andrade ◽  
J. C. C. Balieiro ◽  
...  

2008 ◽  
Vol 33 (1) ◽  
pp. 7-12 ◽  
Author(s):  
J. L. Figueroa ◽  
M. Martínez ◽  
J. E. Trujillo ◽  
V. Zamora ◽  
J. L. Cordero ◽  
...  

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