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?

(8) Has the bull been seen to serve? Was his service behaviour normal?

Were any specific abnormalities during service noticed?

In many cases close observation of service may not have been undertaken and the owner may be unaware of important details of service behaviour.
(9) Has pregnancy diagnosis been undertaken on the animals with which the bull has been running?
What method of pregnancy diagnosis was used and was it capable of diagnosing early pregnancy (at 30 days)?
(10) Have the female animals been exposed subsequently to another bull? Has the other bull bred with them successfully?
Observation of the patient
The bull should be quietly observed to see if any obvious abnormalities which might affect his breeding ability are visible.

Few reproductive problems in the male are visible externally. 

Obvious lameness could affect his ability to serve.

Gross abnormalities in scrotal size or a disparity in testicular size may be visible, but must be confirmed and investigated during the full clinical examination.