Page 560 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

Reproductive system: 2.2 The male reproductive tr act 535

VetBooks.ir boisterous and unruly in the breeding environment, daily grooming, turn out and exercise decreases
aggressive behaviour.
and handling and management are poor. Common
inappropriate behaviours include excessive biting
and striking at the handler, wheeling around, charg- Prognosis
ing towards the mare or phantom, biting the mare With long-term retraining and consistent handling,
during breeding and kicking out after dismounting. the prognosis is good. Educating and involving all
Rarely, a well-managed stallion with good manners persons who will have contact with the stallion are
will present with a history of unpredictable savage very important. In stallions of limited breeding
behaviour towards people or horses not associated value, castration may be the most appropriate way to
with breeding. These individuals are dangerous and prevent human injury and improve the quality of life
may not be amenable to treatment. of the horse. Properly managed stallions that exhibit
unpredictable savage behaviour towards humans or
Diagnosis other horses may warrant euthanasia.
A complete history of the stallion’s management is
determined including type of housing, amount of ERECTILE DYSFUNCTION
exercise and daily and breeding routines. A detailed
description of the undesirable behaviour is obtained Definition/overview
from the stallion’s manager. The stallion’s breed- Erectile dysfunction is the inability of a stallion to
ing routine is observed, with careful attention paid obtain or maintain an erection, despite appropriate
to handling techniques and the stallion’s attitude stimulation.
and expressions. A complete physical examination,
including palpation of the external genitalia, and Aetiology/pathophysiology
lameness examination is performed. Psychological factors or physical abnormalities of
the genital or neurovascular systems can cause erec-
Management tile dysfunction. Psychological factors are discussed
Retraining of aggressive stallions should only be car- in the section on low libido (p. 532). Conditions
ried out by an experienced team in a safe facility. The preventing retraction of the penis (paraphimosis or
stallion should be handled with the least amount of priapism) frequently result in erectile dysfunction.
restraint equipment possible, usually a snug-fitting Injury during breeding is the most common cause
halter with a chain over the nose or a bridle with a of paraphimosis. Lacerations on breeding phantoms
snaffle bit, and a dressage whip or 100 cm (39 inches) with openings for mounting an artificial vagina,
length of plastic pipe. The whip or pipe is not used thermometers forgotten in artificial vaginas and
for excessive punishment, but can be used to extend kicks are common causes of trauma. Paraphimosis
the arm length of the handler so that he/she may pro- can also occur secondary to neurological disease
vide direction while standing at the horse’s shoulder. or debilitating illness. Priapism may occur after
Retraining must begin in an environment that is not administration of phenothiazine drugs and reser-
sexually stimulating and include teaching the stal- pine. Occasionally, erectile failure may occur when
lion to walk quietly in hand, halt on command, back the partially erect penis folds and becomes trapped
up and move the haunches away from the handler. within the prepuce.
Training should focus on positive reinforcement of
appropriate behaviour. The goal of the first collec- Clinical presentation
tion or breeding is improved behaviour and a calm Most stallions present with a history of traumatic
and positive experience for the stallion. Use of an injury and chronic paraphimosis. The skin of the
extremely docile, oestrus mare wearing appropriate penis and prepuce is often thickened and tough, and
protective equipment facilitates success. Behaviour sensation is impaired. Fibrosis of the CCP results
can be further shaped during subsequent training from prolonged priapism, paraphimosis and ensu-
sessions. Decreasing social isolation through intro- ing thrombosis and oedema. During sexual arousal,
duction of a suitable companion horse and through the penis fails to become sufficiently turgid for