Clinical Examination of Farm Animals - CYF MEDICAL DISTRIBUTION

Clinical Examination of the Urinary System
renal failure, mercury poisoning and the recovery
(diuretic) phase of acute renal failure.
Idiopathic polydypsia – the calf drinks and urinates excessively
and gets in the habit of drinking greatly
in excess of its needs; it is able to concentrate its
urine.
Damage to tubular epithelium – this can occur in some
cases of renal disease or damage by heavy metal
poisoning; in these conditions the animal is unable
to concentrate its urine.
The water deprivation test is helpful in determining
whether polyuria is permanent or reversible (see
below).
Anuria
Anuria mostly occurs in cases of complete urethral
obstruction, e.g. urolithiasis. It may also occur in
terminal disease, complete renal failure and severe
shock.
Postrenal – pyelonephritis, cystitis, urolithiasis
(early), enzootic haematuria (bleeding bladder
tumours).
Haemoglobinuria
This is the result of rapid intravascular haemolysis of
the blood. Causes include the following:
• isoerythrolysis – rare in cattle
• babesiosis
• leptospirosis
• postparturient haemoglobinuria
• bacillary haemoglobinuria – Clostridium haemolyticum.
Myoglobinuria
Causes include severe myopathy, especially calves
with vitamin E and/or selenium deficiency, and
downer cows.
Oliguria
Oliguria may be prerenal, renal or postrenal. Causes
include the following:
Prerenal – severe dehydration, shock, chronic heart
failure
Renal – acute nephrosis, glomerulonephritis
Postrenal – ureteral or urethral obstruction.
Proteinuria
Causes include
• glomerulonephritis
• renal infarction
• nephrosis
• amyloidosis.
Haematuria
This may be renal or postrenal. Examples include the
following:
Renal – severe glomerulonephritis, sulphonamide
poisoning, renal infarction
Bile pigments
The presence of bile pigments in the urine suggests
liver dysfunction and jaundice. Ayellow froth is seen
if a urine sample containing bile pigments is shaken.
Further tests of renal function
Estimation of blood urea and creatinine are useful indicators
of the efficiency of renal function: the levels
of both substances rise in cases of renal failure. Low
levels of plasma protein are seen in a number of conditions,
including severe renal damage.
Water deprivation test
This test is a useful indication of the patient’s ability
to concentrate its urine to preserve the water content
of the body. Urine samples are collected before and
after a period of 12 hours during which the animal’s
water supply is withheld. In normal animals the specific
gravity of the urine rises to at least 1.030 after
water deprivation. In animals with renal damage the
specific gravity does not rise. The test should be used
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