PC Delport and LJ Fourie
ABSTRACT:
This study was done to compare the collection of cat urine, for phosphate concentration de-
termination, by catheterisation with that via a proprietary cat litter (Katkor!"). The passage
of urine through the litter or its retention in the litter for a period of 2hours did not affect the
concentration of phosphates compared with that of the original sample. Apart from a small
volume of urine trapped in the litter by capillary action, and some urine adhering to the
tunnel in which the litter was placed, the litter proved to bean excellent medium for routine
urine collection from cats, and more especially as an alternative to catheterisation when
regular collection from a particular cat is required.
Results:
Table 1: Urine phosphate levels in cat urine before and after retention in litter.
| Cat indentification |
urine phosphate concentration (mmol/l)
On collection |
urine phosphate concentration (mmol/l)
After 2 h in litter |
| F3T |
39.8 |
54.2 |
| ODT |
96.8 |
108.9 |
| B8T |
37.1 |
43.7 |
| C6T |
138.5 |
129.0 |
| 1 |
106.4 |
108.8 |
| 2 |
90.5 |
93.5 |
| 3 |
135.6 |
141.9 |
| 4 |
155.7 |
169.3 |
| 5 |
172.8 |
192.1 |
| 6 |
98.7 |
106.6 |
| Mean |
107.16 |
114.81 |
| SD |
45.16 |
46.20 |
The numbers of these cats were masked to ensure unbiased analyses.
Table 2: Urine phosphate concentrations on day of collection.
| Cat indentification |
Immediate
after catheterisation |
Through litter |
Left in litter for 2 hours |
| F3T |
39.8 |
54.2 |
54.2 |
| ODT |
96.8 |
102.0 |
108.9 |
| B8T |
37.1 |
41.5 |
43.7 |
Table 3: Urine phosphate concentrations after storage at 4 °C for 7 days.
| Cat indentification |
Immediate
(after catheterisation) |
Through litter |
Left in litter for 2 hours |
| F3T |
39.8 |
55.7 |
59.3 |
| ODT |
109.3 |
108.3 |
118.2 |
| B8T |
43.6 |
42.2 |
47.2 |
Discussion:
Urine is usually collected from cats by catheterisation under general anaesthesia.
This procedure is acceptable if a single sample is required, but not when regular
collection is necessary. The variability in urine phosphate concentrations between
samples and between samples collected on successive days necessitates repeated
collections. Not only is catheterisation invasive, but the simultaneous administration
of a general anaesthetic often results in a loss of appetite accompanied by constipation,
which further complicates the accurate determination of urine and faecal phosphate concentrations.
Urine phoshate level determination in cats is used in feeding studies and specifically
when the effects of kidney-friendly diets are studied. This communication details the use of a granular,
polypropylene cat litter (Katkor’, Reinvet Products, Utrecht, the Netherlands) as a reliable alternative to
catheterisation for the regular collection of urine from cats. Studies in the Nether-
lands indicate that the litter has no effect on pH levels, protein concentration or white or red blood cell
counts in human urine. A study on polypropylene granules, similar to these in the litter,
showed that they did net absorb or emit calcium, magnesium or phosphate.
Urine was collected from 10 cats by catheterisation under general anaesthesia
and sub-sampled. One sub-sample was immediately analysed for phosphates; a
2nd sub-sample of the urine of 4 cats was poured into wide-mouthed tunnels containing the litter,
re-collected and analysed for phosphates. Urine sub- samples of all 10 cats were separately poured into litter,
left in it for 2 hours, re-collected and phosphate levels deter- mined (Table l).
Sub-samples of the urine of 3 cats were stored at approximately 4 °C for 7 days and again sub-sampled (Table 2).
Upon reaching room temperature the 1st set of sub-samples was analysed for
phosphates, the 2nd set was poured through the litter and then analysed while the 3rd set was
left in the litter for 2 hours before analysis. Four samples spiked with specific concentrations of
phosphate were also tested as controls.
The mean increase in phosphate concentrations between the urine samples of the 10 cats that were examined after
collection and the same samples poured into and left in cat litter for 2 hours was7.65 mmol/l on an initial
reading of107.16 mmol/l. The control samples spiked with phosphate at either 7.5 mmol/l or 13.3 mmol/l gave
readings varying between 6.70 and 8.59 mmol/l (n=90) and 12.39 and 14.79 mmol/l (n=90), respectively.
These differences of up to 14.5% are larger than the 7.13% difference observed for cat urine
before and after it had been left in cat litter for 2 hours.
There was no alteration in the pH of urine passed through the Katkor litter.
The weight of 130 gr of katkor litter increased by 5.69 gr after 73 ml of cat urine had been poured through it.
The gain can be ascribed to the retention of liquid by capillary action common to any granular substance.
A further 2.14 gr of urine adhered to the surface of the funnels in which the litter was placed.
Conclusion:
Katkor litter is a suitable medium for non-invasive collection of urine from cats for phosphate analysis,
particularly when this needs to be done repeatedly or collectively.
It may also prove to be suitable for the determination of other parameters, e.g. glucose, but further
studies in this regards are required.
PC Delport
Clinvet International
PO Box 11186, Universitas, 9321 South Africa
August 2005
LJ Fourie
Department of Zoology and Entomology, University of the Free state
PO Box 339, Bloemfontein, 9300 South Africa
November: 2005.
Literature list
Pastoor FJ, van’t Klooster AT, Beynen AC
An alternative method for the quantitative collection of faeces and urine of cats
as validated by the determination of mineral balance.
Zeitung fur Versuchstierkunde 1990; 33:259-263
|
