Urine Normal Composition

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Introduction

The testing and evaluation of urine composition is an essential diagnostic indicator for many diseases. It is therefore essential to have an understanding of what is the normal composition of urine.

Normal Urine Volume

Below are the normal urine volumes for the common domestic species. The units are ml/kg/day

Species	Urine Volume
Dog	20-100
Cat	10-20
Cow	17-45
Sheep	10-40
Horse	3-18
Pig	5-30

Adapted from the Merck Veterinary Manual online reference table entitled Urine Volume and Specific Gravity

The Normal Appearance of Urine

Several pathological conditions can cause macroscopic changes to the urine. It is therefore essential to appreciate the normal appearance of urine. In many of the exotic species the urine has a very differant appearance and therefore use care when applying this to those species.

Colour

In the majority of the domestic species the urine should beyellow in colour. The colour of the urine is very dependant on the urine specific gravity so it is important to account for this. If the urine is more concentrated it will be darker in colour and vica versa as a general rule . Equine urine can become brown if left standing. Discoloured urine should be taken into consideration when carrying out tests which involve a colour change such as dipsticks. The abnormal urine colour could affect the result.

Turbidity

If the urine is not clear then this could indicate a variety of pathological states. In the horse it is normal for it to be turbid due the mucous secreted in the renal pelvis and proximal ureters.

Odour

It is normal for urine to have a slight odour from the ammonia. The odour increases with concentration and in some species such as the cat a pungent urine is normal. However a strong smelling urine could indicate a pathological state