Page 595 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

570 CHAPTER 2

VetBooks.ir Prognosis season, all resident stallions should be thoroughly
The prognosis is poor in stallions, as infection can-
screened for venereal infections prior to use, and
the first 2–3 mares mated should have clitoral swabs
not be eliminated.
taken post mating.
CONTROL OF EQUINE Following positive isolation or clinical signs of vene-
VENEREAL DISEASES real disease, breeding operations should stop immedi-
ately. Affected animals should be isolated and screening
Many countries have Codes of Practice for hygienic for infection or carrier status should commence.
stud animal management and minimal contamina- Overuse of penile washing or disinfection techniques
tion techniques in AI (e.g. The Horserace Betting is to be avoided since this encourages overgrowth of
Levy Board in the UK, Eire and France). pathogenic species. It has been shown that the normal
Some venereal pathogens are typically not genital skin flora develop an ecological stability, which
associated with any clinical signs in the stallion can help to prevent the growth of pathogens.
(e.g. Pseudomonas aeruginosa, Klebsiella pneumoniae, AI using screened semen is an effective control
Taylorella equigenitalis) and post-mating endometritis measure for the transmission of venereal diseases
infection in the mare is the first indicator that the (in those countries where registration criteria allow
stallion is harbouring these organisms. All imported it) provided that the Codes of Practice relating to
stallions and, at the beginning of each breeding hygiene are followed precisely.

SKIN DISEASE OF THE EXTERNAL GENITALIA

BALANITIS/BALANOPOSTHITIS Clinical presentation
The stallion or gelding presents with vary-
Definition/overview ing degrees of swelling of the penile skin and/or
Balanitis is inflammation of the penis, while balano- prepuce. Crusting and discharge from the skin
posthitis is inflammation of the penis and prepuce. surface may occur in severe cases. The stallion
may be uncomfortable and resist washing of the
Aetiology/pathophysiology penis, collection with an artificial vagina or natu-
The inflammation may be the result of bacte- ral cover. Balanoposthitis alone is unusual and the
rial, viral or protozoal infections or be caused by clinician should search for underlying predisposing
chemical irritants such as fly sprays or disinfectants. causes.
Overzealous use of soaps and antibacterial solutions
can remove the normal bacterial flora, incite inflam- Differential diagnosis
mation and result in overgrowth of opportunistic Equine coital exanthema caused by EHV-3; neopla-
pathogens (Fig. 2.163). Excessive accumulations of sia of the penis; trauma to the penis.
smegma have also been implicated. Bacterial infec-
tion may accompany SCC or follow viral infection Diagnosis
with equine coital exanthema. Balanoposthitis may Swabs taken from the surface of the penis, the pre-
also occur in long-standing cases of priapism or para- puce, urethral fossa, urethra and of any surface
phimosis, due to prolonged exposure of the penis lesions should be submitted for bacterial, viral and
to adverse environmental conditions and drying of cytological examination.
the penile skin. The most common bacteria impli-
cated are Streptococcus spp., Klebsiella pneumoniae and Management
Pseudomonas aeruginosa. The parasites Trypanosoma Treatment is dependent on the cause of the con-
equiperdum (see p. 565) and Habronema (see p. 571) dition, but sexual rest is indicated until it is fully
can also cause the condition. resolved. Viral infections generally heal uneventfully