Clinical Examination of Farm Animals - CYF MEDICAL DISTRIBUTION

CHAPTER 11
Clinical Examination of the Male
Genital System
Introduction
The majority of male cattle are castrated, and in these
animals the genital system acts chiefly as a conduit
for the passage of urine. Breeding bulls are an important
part of the herd. To be effective sires, bulls must
be in good health, have a satisfactory conformation
and be free, as far as known, from genetic defects.
They should also have a good libido, be able to
mount and achieve intromission of the erect penis
into the cow’s vagina. They must be able to ejaculate
semen of sufficient quality to fertilise the ova of
healthy cows. In order to establish that a bull has
these qualities a comprehensive and methodical
examination is necessary.
Applied anatomy
The anatomy of the male genital system is illustrated
in (Fig. 11.1). Details of the anatomy of individual
genital organs are described below under ‘Clinical
examination’.
Signalment of the case
Details of this can be useful in the diagnosis of male
breeding problems. Although puberty may be
reached at 9 months, bulls are generally not used as
sires until they are 18 months of age or over. Younger
animals may have a poorly developed libido and
poor semen quality. Excessive use of very young
animals may also compromise sperm production.
Libido may fall off in older bulls, and heavy bulls
may have physical difficulty in mounting to
serve. Some strains of Hereford bulls have a poorly
developed libido.
History of the case
The general history of the case will have been discussed
earlier in the diagnostic process. The owner
should be questioned to determine the nature of any
current fertility problem, the origin of the bull and his
past performance. The following questions should
be asked:
(1) Has the bull been recently purchased? If so are
details available of his past performance? Has
he ever sired a calf? When was he last known to
have sired a calf?
(2) Has the bull been in good general health? Has
he lost condition recently? Have there been
any signs of lameness or other orthopaedic
abnormality?
(3) Did his herd of origin have any past fertility
problems? What was its health status? Was the
herd known to be free from bovine virus diarrhoea
infection and other diseases which may
affect fertility? What is the disease status of his
present herd?
(4) Has the bull served cows presented to him individually
(in hand) or has he been running with
the herd?
(5) If serving cows individually, has he been frightened
in any way? Are the staff handling him
experienced in their work?
(6) How many female animals was he running
with? Is he still with them and if not when was
he removed from their group? Has normal
oestrus behaviour been observed in the
group? Have they been bred from successfully
before?
(7) What is the condition of the female animals? If
in poor condition for how long has this been a
problem? Has the cause of their poor condition
been investigated?
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