Nitrogenous constituents in the urine of cattle, sheep and goats

Bristow, A. W.; Whitehead, David; Cockburn, J. E.

doi:10.1002/jsfa.2740590316

Cited by 209 publications

(141 citation statements)

References 26 publications

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Section: Urea In Urinementioning

confidence: 99%

“…In contrast to purines, pyrimidines undergo ring cleavage and the major end products of catabolism are b-AAs, NH 3 and CO 2 . NH 3 is present in urine in small amounts only and actually may arise from hydrolysis of urea during storage pending analyses (Bristow et al, 1992).The creatinine-N and creatine-N concentrations in urine vary between 0.08 and 0.65 g/l and between 0.12 and 0.51 g/l, respectively. Creatine is synthesized from arginine, glycine and methionine primarily in the kidney and liver, and after uptake by muscle is reversibly phosphorylated into creatine-phosphate.…”

mentioning

confidence: 99%

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Diet effects on urine composition of cattle and N2O emissions

Dijkstra

Oenema

Groenigen

et al. 2013

Animal

312

215

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Ruminant production contributes to emissions of nitrogen (N) to the environment, principally ammonia (NH 3 ), nitrous oxide (N 2 O) and di-nitrogen (N 2 ) to air, nitrate (NO 3 2 ) to groundwater and particulate N to surface waters. Variation in dietary N intake will particularly affect excretion of urinary N, which is much more vulnerable to losses than is faecal N. Our objective is to review dietary effects on the level and form of N excreted in cattle urine, as well as its consequences for emissions of N 2 O. The quantity of N excreted in urine varies widely. Urinary N excretion, in particular that of urea N, is decreased upon reduction of dietary N intake or an increase in the supply of energy to the rumen microorganisms and to the host animal itself. Most of the N in urine (from 50% to well over 90%) is present in the form of urea. Other nitrogenous components include purine derivatives (PD), hippuric acid, creatine and creatinine. Excretion of PD is related to rumen microbial protein synthesis, and that of hippuric acid to dietary concentration of degradable phenolic acids. The N concentration of cattle urine ranges from 3 to 20 g/l. High-dietary mineral levels increase urine volume and lead to reduced urinary N concentration as well as reduced urea concentration in plasma and milk. In lactating dairy cattle, variation in urine volume affects the relationship between milk urea and urinary N excretion, which hampers the use of milk urea as an accurate indicator of urinary N excretion. Following its deposition in pastures or in animal houses, ubiquitous microorganisms in soil and waters transform urinary N components into ammonium (NH 4 1 ), and thereafter into NO 3 2 and ultimately in N 2 accompanied with the release of N 2 O. Urinary hippuric acid, creatine and creatinine decompose more slowly than urea. Hippuric acid may act as a natural inhibitor of N 2 O emissions, but inhibition conditions have not been defined properly yet. Environmental and soil conditions at the site of urine deposition or manure application strongly influence N 2 O release. Major dietary strategies to mitigating N 2 O emission from cattle operations include reducing dietary N content or increasing energy content, and increasing dietary mineral content to increase urine volume. For further reduction of N 2 O emission, an integrated animal nutrition and excreta management approach is required.Keywords: nitrogen, urine, cattle, nitrous oxide, mitigation ImplicationsCattle contribute to global warming through emission of nitrous oxide (N 2 O) from urine and faeces. Urinary nitrogen (N) is much more susceptible to gaseous losses than faecal N. To reduce urinary N excretion and N 2 O emission and improve N efficiency of cattle, dietary levels of N should be decreased and an optimal balance between N and energy substrates in the diet should be aimed at. Increasing urine volume by increased dietary mineral contents appears a promising N 2 O mitigation strategy, particularly in pasture. Further reduction of effective mitigation strategies...

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Section: Urea In Urinementioning

confidence: 99%

mentioning

confidence: 99%

Diet effects on urine composition of cattle and N2O emissions

Dijkstra

Oenema

Groenigen

et al. 2013

Animal

312

215

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“…In this study, urea-N accounted for only 32% of the total N excretion in urine, and at low levels of dietary N intake, excretion of N-containing metabolites other than urea will affect the overall N efficiency of the cow more than at high N intake. Urine from cattle contains, in addition to urea-N, variable amounts of N in purine derivatives, hippuric acid (glycine conjugate of benzoic acid), creatine/creatinine, free amino acids and ammonia (Bristow et al, 1992). Factors such as benzoic acid intake, ruminal bypass protein and intestinal absorption of purines will therefore be of importance to further increase the N efficiency of dairy cows following reduction in intake of rumen degradable protein.…”

Section: Hourmentioning

confidence: 99%

Urea and short-chain fatty acids metabolism in Holstein cows fed a low-nitrogen grass-based diet

Røjen

Lund

Kristensen

2008

Animal

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Three ruminally cannulated and multicatheterised lactating dairy cows were used to investigate the effect of different supplement strategies to fresh clover grass on urea and short-chain fatty acid (SCFA) metabolism in a zero-grazing experiment with 24-h blood and ruminal samplings. Fresh clover grass was cut every morning and offered from 0800 to 1500 h. Maize silage was fed at 1530 h. The three treatments, arranged in a Latin square, differed by timing of feeding rolled barley and soya-bean hulls relative to fresh clover grass. All diets had the same overall composition. Treatments were soya-bean hulls fed at 0700 h and barley fed at 1530 h (SAM), barley fed at 0700 h and soya-bean hulls fed at 1530 h (BAM), and both soya-bean hulls and barley fed at 1530 h (SBPM). The grass had an unexpectedly low content of crude protein (12.7%) and the cows were severely undersupplied with rumen degradable protein. The treatment effects were numerically small; greater arterial ammonia concentration, net portal flux of ammonia and net hepatic flux of urea during part of the day were observed when no supplementary carbohydrate was fed before grass feeding. A marked diurnal variation in ruminal fermentation was observed and grass feeding increased ruminal concentrations of propionate and butyrate. The net portal fluxes of propionate, butyrate, isovalerate and valerate as well as the net hepatic uptake of propionate, butyrate, valerate and caproate increased after feeding at 0700 h. The hepatic extraction of butyrate showed a relatively large depression with grass feeding with nadir at 1200 to 1330 h. The increased net portal absorption and the decreased hepatic extraction resulted in an approximately six-fold increase in the arterial blood concentration of butyrate. The gut entry rate of urea accounted for 70 6 10% of the net hepatic production of urea. Saliva contributed to 14% of the total amount of urea recycled to the gut. Urea recycling to the gut was equivalent to 58% of the dietary nitrogen intake. Despite the severe undersupply of rumen degradable protein, the portaldrained viscera did not extract more than 4.3% of the urea supplied with arterial blood. This value is in line with the literature values for cows fed diets only moderately deficient in rumen degradable protein and indicates that cows maximise urea transfer across gut epithelia even when the diet is moderately deficient in rumen degradable protein.

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“…The concentration of N excreted in urine is a function of the amount of surplus metabolised N to be excreted, the volume of urine produced and the frequency of urine events (Hoogendoorn et al 2010) and can range from 1 to 18 g N/L (Bristow et al 1992;Oenema et al 1997;Hoogendoorn et al 2010). Urine volume is mainly influenced by water intake and the mineral load ingested by the animal (Selbie et al 2015), and can be high when the moisture content of the diet is high, or when the herbage leaves are wet with rain water or dew (Doak 1952).…”

Section: Introductionmentioning

confidence: 99%

Disentangling the effect of sheep urine patch size and nitrogen loading rate on cumulative N2O emissions

2016

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Abstract. Ruminant urine nitrogen (N) concentration and volume are important parameters influencing the size and N loading rate of urine patches deposited to soil. Such parameters can influence N cycling and emissions of the greenhouse gas, nitrous oxide (N 2 O) from grazed grassland, yet, there is limited information on the effect of these parameters within typical ranges reported for sheep. We used an automated, high-frequency gas monitoring system to investigate N 2 O emissions from varying urine N application rates and patch sizes under field conditions. Using artificial sheep urine, we manipulated urine N concentration to provide two urine N application rates (4 and 16 g N/L; equivalent to 200 and 800 kg N/ha). We investigated the effect of urine patch size with equal N application rates (4 · 125 cm 2 vs 500 cm 2 , at 200 and 800 kg N/ha) and the effect of patch size with unequal N application rates, but the same total amount of N applied (62.5 mL over 125 cm 2 at 800 kg N/ha and 250 mL over 500 cm 2 at 200 kg N/ha). Cumulative emissions of N 2 O generally increased with N loading rate, whether applied as one large urine patch or four smaller ones. Cumulative N 2 O emissions increased when the N was applied in four smaller urine patches compared with one large patch; this difference was significant at 800 kg N/ha, but not at 200 kg N/ha. When the total amount of N applied was held constant (1 g of N), the amount of N 2 O released was similar when urine was applied as a high N concentration small patch (800 kg N/ha) compared with a low N concentration large patch (200 kg N/ha). Urine N 2 O emission factors in this study were, on average, 10 times lower than the IPCC default of 1% for sheep excreta. This research clearly demonstrates that the chemical and physical nature of the urine patch influences N 2 O emissions, yet further research is required to gather more data on typical sheep urine volumes (individual and daily), urination frequency, urine N concentrations and the typical volumes of soil influenced by urine deposition, to provide more accurate estimates of emissions from sheep grazed pastures.

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Nitrogenous constituents in the urine of cattle, sheep and goats

Cited by 209 publications

References 26 publications

Diet effects on urine composition of cattle and N2O emissions

Diet effects on urine composition of cattle and N2O emissions

Urea and short-chain fatty acids metabolism in Holstein cows fed a low-nitrogen grass-based diet

Disentangling the effect of sheep urine patch size and nitrogen loading rate on cumulative N2O emissions

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