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Purine derivatives in urine and plasma of lactating cows given different levels of feed intake

Published online by Cambridge University Press:  21 November 2017

Z. M. Daniels ,
X.B. Chen ,
D.J. Kyle ,
K. Sinclair  and
E.R. Ørskov
Z. M. Daniels
Affiliation:
Rowett Research Institute, Bucksburn, Aberdeen AB2 9SB
X.B. Chen
Affiliation:
Rowett Research Institute, Bucksburn, Aberdeen AB2 9SB
D.J. Kyle
Affiliation:
Rowett Research Institute, Bucksburn, Aberdeen AB2 9SB
K. Sinclair
Affiliation:
SAC, 581 King Street, Aberdeen AB9 IUD
E.R. Ørskov
Affiliation:
Rowett Research Institute, Bucksburn, Aberdeen AB2 9SB
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Extract

It has been demonstrated in previous work (Chen et al 1993) that the molar ratio of purine derivatives (PD) to creatinine (C) in spot urine samples can be used as an index of microbial protein supply in sheep. This study was to examine the feasibility of using this approach in cattle.

Twelve lactating beef cows were allocated into three groups and each group was fed one of the following levels of restricted feeding: (1) 13 kg fresh weight (FW)/d (high), (2) 10 kg FW/d (medium); (3) 7 kg FW/d(low), given in two equal meals. The diet was pelleted and contained (on fresh weight basis): 0.40 sodium hydroxide treated straw, 0.24 barley, 0.10 soya, 0.25 molassed sugar beet pulp and 0.01 urea. Daily urinary excretion of PD was measured for a week. Two-hourly collections of urine (regarded as ‘spot urine’) were also made over the same period for measurement of PD/C molar ratio. Plasma PD concentration was measured in three jugular blood samples taken on the last day of urine collection. Milk yield was indirectly measured by calf weights before and after suckling. The results were analysed to examine the variability of PD/C in spot samples and the relationship of the spot PD/C measurement with the daily PD output.

Type
Ruminant Nutrition and Digestion
Information
Proceedings of the British Society of Animal Production (1972) , Volume 1994 , March 1994 , pp. 105
Copyright
Copyright © The British Society of Animal Production 1994

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References

Chen, X.B. Grubic, G., Ørskov, E.R. and Osuji, P. (1992). Effect of feeding frequency on diurnal variation in plasma and urinary purine derivatives in steers. Animal Production 55: 185–191 Google Scholar
Chen, X.B., Mejia, A.T., Kyle, D.J. and Ørskov, E.R. (1993) Purine derivatives in spot urine samples and plasma of sheep: a possible index of microbial protein supply. Animal Production. 56, 420A Google Scholar