Page 951 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

926 CHAPTER 7

VetBooks.ir 7.5 7.6

7.7

Figs. 7.5–7.7 Urine sediment evaluation findings.
Calcium carbonate crystals are a common component
of equine urine (7.5). Leucocytes present in the urine
(7.6). Granular casts (7.7). (Photos courtesy R Jacobs)

Urinary tract inflammation, infection, neopla-
Table 7.3 Characteristics of normal equine urine
sia, endotoxaemia or trauma may result in increased
pH 7.5–9.0 (concentrated feeds tend to numbers of erythrocytes in the urine. Pyuria (>5–8
acidify urine) white blood cells [WBCs]/high-power field (hpf)) is
Specific gravity 1.018–1.025 usually associated with urinary tract inflammation
Osmolality ~900 mOsm/kg and/or infection. Bacteria can be present in the urine
Glucose Negative sediment in urogenital tract infection. Normally,
Protein Negative* the sediment contains no or few bacteria; however,
White blood cells <5/hpf the absence of visible bacteria does not rule out
Red blood cells <5/hpf infection. Quantitative and qualitative bacterial cul-
Epithelial cells None present if voided sample ture should be performed on urine that was collected
by catheterisation or, in foals, by cystocentesis.
Casts Usually negative – hyaline casts Casts are mucoproteineous substances that are
sometimes present
Crystals Common formed within the distal renal tubules. Cast forma-
tion increases when urinary tract inflammation or/
Haemoglobin Negative and infection is/are present. Casts are rare in nor-
Myoglobin Negative mal equine urine as they usually dissolve in alkaline
Bacteria Usually negative if catheterised urine urine; therefore, the absence of casts does not rule
Mucus Present out renal disease. Casts are also present only tran-
siently and may not be detected in all cases of acute
* False-positive protein result may occur on urine dipsticks with alkaline renal disease or in every urine sample.
urine.