Relationships of both urine nitrogen output and plasma urea concentration with rumen protein balance in lactating goats

The updated INRA system incorporates the notion of rumen protein balance (RPB, g CP/kg DM) in an attempt to better fit feed evaluation, animal requirements and responses to diets. RPB is the difference between crude protein intake and entrance at the duodenum (excluding NH3) which is not very easy to measure in vivo. The aim of this study was to test the strength of the relationships between dietary RPB values obtained from the diet composition and criteria easier to measure, such as N urinary outputs or plasma urea concentration, both at a treatment level and at an individual level in a large dataset obtained from lactating goats fed different types of diets. RPB was a better predictor of urinary N output and plasma urea concentration than was the former French system for protein digestible in the intestine. Within experiments, RPB was highly and positively correlated with urinary nitrogen outputs and plasma urea concentration. RPB can be used to estimate the urinary N output in lactating dairy goats, but this study also showed that some of the residual variance was due to variability among animals.

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

Canadian Journal of Animal Science ◽

10.4141/cjas91-133 ◽

1991 ◽

Vol 71 (4) ◽

pp. 1111-1124 ◽

Cited By ~ 7

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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Identifying cattle with superior growth feed efficiency through their natural 15N abundance and plasma urea concentration: a meta-analysis.

10.31220/agrirxiv.2021.00107 ◽

2021 ◽

Author(s):

Gonzalo Cantalapiedra-Hijar ◽

Isabelle Morel ◽

Bernard Sepchat ◽

Céline Chantelauze ◽

Gemma A. Miller ◽

...

Keyword(s):

Feed Efficiency ◽

Laboratory Data ◽

Urea Concentration ◽

Mixed Effect ◽

Plasma Urea ◽

Individual Level ◽

The Individual ◽

Dietary Treatments ◽

Plasma Urea Concentration ◽

Animal Diet

Abstract The objective of this study was to test two candidate biomarkers of feed efficiency in growing cattle. A database was built using performance data from 13 trials conducted with growing heifers, steers and young bulls and testing 34 dietary treatments. The database included 769 individual records for animal performance and laboratory data for N isotopic discrimination measured in plasma or muscle (Δ15Nanimal-diet; n = 749) and plasma urea concentration (n = 659). Feed conversion efficiency (FCE) and residual feed intake (RFI) criteria were calculated for a duration ranging between 56 and 259 d, depending on the trial. For FCE prediction, mixed models included the random effects of study, diet within-study and pen within-study (i.e. contemporary group; CG) allowing these effects to be progressively excluded from the relationship. For RFI prediction, simple linear regressions were tested with the CG effect removed from biomarker values before analysis. Better models were obtained with Δ15Nanimal-diet compared to plasma urea concentration, irrespective of using mean or individual values and regardless of the feed efficiency criterion. Prediction error (0.027 kg/kg) from mixed-effect models using mean FCE and Δ15Nanimal-diet values would allow discrimination of 2 dietary treatments or production conditions in terms of FCE if they differ by more than 0.10 kg/kg. The Δ15Nanimal-diet values showed a negative and significant (P<0.001) relationship with FCE at the individual level and results highlighted that it is possible to significantly discriminate two animals randomly selected from the same CG if they differ by at least 0.06 kg/kg FCE. In addition, the top 20% highest and lowest animals within-CG in terms of RFI and FCE (extreme animals) showed significant (P<0.001) differences in Δ15Nanimal-diet values, while only extreme FCE animals could be discriminated when using plasma urea concentrations (P=0.002). No gain in feed efficiency prediction was observed when combining candidate biomarkers. However for FCE, when average daily gain data was combined with Δ15Nanimal-diet, the prediction at the individual level was strengthened compared to using only single predictors. Our findings confirm that Δ15Nanimal-diet may be useful to form groups of animals for precision feeding. Further studies are warranted, however, to evaluate the usefulness of this promising biomarker for genetic selection.

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Genome-wide association for plasma urea concentration in sheep

Livestock Science ◽

10.1016/j.livsci.2021.104483 ◽

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

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Urea Excretion in the Camel

American Journal of Physiology-Legacy Content ◽

10.1152/ajplegacy.1957.188.3.477 ◽

1957 ◽

Vol 188 (3) ◽

pp. 477-484 ◽

Cited By ~ 81

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.

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

International Urology and Nephrology ◽

10.1007/bf02549747 ◽

1990 ◽

Vol 22 (6) ◽

pp. 573-579 ◽

Cited By ~ 1

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

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Methionine Requirement of Weanling Large White × Landrace Pigs as Determined by Plasma Urea Concentration, Nitrogen Retention and Some Urinary Nitrogenous Components

Journal of Nutrition ◽

10.1093/jn/111.6.1025 ◽

1981 ◽

Vol 111 (6) ◽

pp. 1025-1032 ◽

Cited By ~ 6

Author(s):

Oluwafemi O. Balogun ◽

Babatunde L. Fetuga

Keyword(s):

Nitrogen Retention ◽

Urea Concentration ◽

Large White ◽

Plasma Urea ◽

Plasma Urea Concentration

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Peptide utilisation by the mammary gland of lactating goats.

Proceedings of the British Society of Animal Production (1972) ◽

10.1017/s0308229600025794 ◽

1994 ◽

Vol 1994 ◽

pp. 26-26

Author(s):

F.R.C. Backwellf ◽

B J. Bequettet ◽

J.A. Metcalf ◽

D. Wray-Cahen ◽

L. Crompton ◽

...

Keyword(s):

Mammary Gland ◽

Dairy Cows ◽

Milk Protein ◽

Dairy Goats ◽

Small Peptides ◽

Lactating Goats ◽

Uptake Studies ◽

Milk Casein ◽

Casein Synthesis

During lactation the ruminant mammary gland removes relatively large quantities of circulating amino acids (AA) to meet the requirements for milk protein synthesis but arterio-venous uptake studies in dairy cows (1) have indicated that the uptake of certain AA may be insufficient to account for their output as milk protein. The apparent deficit may be accounted for by the use of AA supplied to the gland as small peptides or proteins. A dual-labelled tracer approach involving infusion of [13C]-labelled peptides into the external pudic artery which supplies blood directly to the mammary gland demonstrated that dipeptide-bound AA can be utilised as direct precursors for milk casein synthesis in lactating dairy goats (2). However, previous studies using vascular infusion of [13C]-labelled free AA (3) have provided equivocal data on involvement of non-labelled extra-mammary derived peptides/proteinsin vivoin the biosynthesis of milk protein.

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Plasma Urea Concentration in Older People

Gerontologia Clinica ◽

10.1159/000245369 ◽

1972 ◽

Vol 14 (1) ◽

pp. 32-35 ◽

Cited By ~ 1

Author(s):

J.S. Milne ◽

J. Williamson

Keyword(s):

Older People ◽

Urea Concentration ◽

Plasma Urea ◽

Plasma Urea Concentration

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

Clinical Science ◽

10.1042/cs0700185 ◽

1986 ◽

Vol 70 (2) ◽

pp. 185-189 ◽

Cited By ~ 5

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.

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