Clinical Examination of Farm Animals - CYF MEDICAL DISTRIBUTION

CHAPTER 11
urethral rupture occurring near the scrotal neck,
urine may leak into the scrotum. As a result, damage
to scrotal tissues, especially the skin, may occur. In
animals which have been vasectomised, vertical
scars are seen on the skin of the scrotal neck, usually
on its anterior surface.
Testes These should be mobile within the scrotum.
Enclosed by the tunica vaginalis, their movement is
aided by the lubricating action of small amounts of
peritoneal fluid. The greatest testicular movement is
within the dorsoventral plane. Lateral movements
are restricted by the scrotal septum formed by layers
of the tunica dartos. The testes are most effectively
examined by gently moving them ventrally in the
scrotum using pressure from the clinician’s fingers
and thumbs (Fig. 11.2). The surface of the testes
should be smooth and firm, and their consistency
that of a ripe tomato. Occasionally, defects in the
tunica albuginea which covers each testis may be
palpated. The testicular contents may bulge through
such defects in the form of a spermatocoele or sperm
granuloma. Such lesions may develop as a result of
obstruction of semen outflow following vasectomy
or injury.
The two testes should be approximately the same
size and consistency. In the uncommon condition of
testicular hypoplasia both testes are much smaller and
softer than usual. In this hereditary condition sperm
output is absent or severely decreased. Testicular
degeneration can also result in a reduction of testicular
size and is often caused by an earlier infection. Sperm
output is again reduced and large numbers of abnormal
sperm may also be seen. Cryptorchid animals
have only one scrotal testis and should not be used
for breeding. The other organ may be retained within
the abdomen, be partially descended or palpable
near the external inguinal ring.
Disparity in testicular size may be seen in cases of
orchitis affecting one testis. The affected organ may
be enlarged, giving the scrotum an asymmetrical appearance.
The affected testis may be painful to the
touch, firmer than the normal testis and also less
mobile within the scrotum.
Overall testicular size and volume are approximate
measures of sperm output and can be equated
with the scrotal circumference measured with a tapemeasure
at its largest point (Fig. 11.3). Scrotal circumference
increases with age and is normally within the
range 28 to 35 cm.
The testes can be evaluated by ultrasound either
directly or using a stand-off technique. Both testes
normally have a similar echodensity and have
a number of horizontal bands of greater echodensity.
In cases of chronic inflammatory disease the
affected testis may have scattered areas of increased
echodensity.
A testicular biopsy may be collected by direct removal
of a small portion of testis or using a needle
biopsy technique. The biopsy can provide useful his-
Figure 11.2 Palpation of the testes – see text for details.
Figure 11.3 Measurement of the scrotal circumference.
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