Page 546 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

Reproductive system: 2.2 The male reproductive tr act 521

VetBooks.ir season, stress, nutrition, disease and changes in and aniridia must also be recorded. Congenitally
unilateral or bilateral cryptorchid stallions are clas-
breeding management. In stallions classified as ques-
tionable, it is common practice to repeat all or part
of the BSE after 60 days in order to assess changes sified as unsatisfactory breeding prospects under the
Society for Theriogenology (USA) guidelines due to
in semen quality. Stallions which are to be used in the hereditary nature of the condition.
cooled transported or frozen-semen programmes
require additional testing not included in the stan- Testing for infectious diseases
dard BSE in order to ensure adequate numbers of Serum samples are collected and accurately identi-
sperm remain viable after processing. fied for testing for venereally transmitted diseases
such as equine infectious anaemia (EIA) and equine
PROTOCOL FOR A BREEDING viral arteritis (EVA). When serum antibodies are
SOUNDNESS EXAMINATION found for EVA, semen samples are submitted for
viral isolation or PCR (RT-iiPCR or RT-PCR) to
Identification and history detect carrier stallions that are shedding virus in
The age, breed and occupation of the stallion are semen. Bacterial culture swabs of the penile shaft,
noted on a permanent veterinary record identify- prepuce, urethra and urethral fossa are submit-
ing the stallion using markings, tattoos, microchips ted to test for the presence of venereal pathogens
and/or photographs. Historical information on Pseudomonas aeruginosa, Klebsiella pneumoniae (capsule
general management including exercise, nutrition, types 1, 2 and 5) and Taylorella equigenitalis, the caus-
hoof care, parasite control, disease and lameness is ative agent of contagious equine metritis (CEM).
noted. The owner/trainer should be questioned as to
whether the stallion has received any medications, Evaluation of libido and
supplements or performance-modifying substances. mating ability
Specific information on breeding history includes A normal breeding stallion exposed to an oes-
the number of mares bred per season, overall sea- trus mare should show strong interest and achieve
sonal conception rate, average number of oestrous an erection within 1–5 minutes (Fig. 2.131).
cycles that mares are bred to achieve pregnancy,
non-return rates and numbers of matings or insem-
inations per oestrus. It can be useful to chart this 2.131
information on a monthly basis to uncover seasonal
trends. Additionally, obtaining a description of the
stallion’s breeding routine from the owner can pro-
vide an insight into its management.

Physical examination
The purpose of the physical examination is to ensure
that the stallion has the desire and ability to breed.
Any condition that may impact on breeding ability
should be noted. Lameness, debilitation, respiratory
impairment, neurological disease and partial blind-
ness are all important problems that can negatively
affect breeding ability. Arthritis in the hindlimbs
or spine will impair the stallion’s ability or desire to
mount and thrust during breeding. Chronic painful Fig. 2.131 A maiden stallion being introduced to
conditions often decrease semen quality, probably an oestrus mare over a padded board and encouraged
via stress-related endogenous corticosteroid secre- to tease prior to training to the phantom for semen
tion. Known heritable defects such as parrot mouth collection.