British Breeder Magazine May 2020

Article - VET INSIGHT
Decision Making
…and the options available
The decision to breed a foal from a mare
is only the first step in a multifaceted
journey and the following should be
considered.
• Type and level of horse to be breed
and which stallion to use
• Timing - Ideally breed during
the peak fertility months May -
August. Futurity Equine Bridge
or commercial foal sales may
necessitate earlier breeding. To start
pre-April, an artificial lights regime
must be implemented from early
December to ensure the mare is
cycling in time.
• Competition schedules - often
determine the availability of a mare
or stallion.
• Accurately document the mare’s
previous breeding history; this can
influence breeding plans.
Depending on the requirements of the
stud or clinic being used, the mare will
need: health check, pre-breeding tests
and possibly vaccinations. A high health
status and disease control is important
to ensure all visiting mares to a Stud/
Vet Clinic are free from any contagious
or infectious disease and up to date with
Flu/Tetanus vaccinations. Mares should
also be certified free from Contagious
equine metritis (CEM) and Equine viral
arteritis (EVA) for the current year,
and have negative results for Equine
infectious anaemia (EIA) and Strangles
within 30days of arrival at the Stud or
Vet Clinic.
Natural Covering (NC) is the cheapest
method available to breeders and is
the only method permitted in certain
industries i.e. thoroughbred racehorses.
Many sport horse stallions are not
available for natural cover due to
increased risk of disease transmission
and injury. NC may not suit all mares
as there is less control over a number of
variables.
Artificial Insemination (AI) - allows
a wider Stallion choice and a more
controlled approach to breeding. Frozen
semen can be used from deceased
stallions; chilled & frozen semen can be
used from stallions located all over the
world. The process involves ultrasound
examinations of the mare’s ovaries
and uterus, ovulation induction, semen
shipping, and correct insemination
timing.
AI can allow mares to remain at home
as the semen comes to them. In best
practice mares using frozen semen or
mares that are tricky to get in foal should
visit the clinic for AI to achieve the best
possible outcome. If AI is performed at
home, it is best to invest in a simple set of
examination stocks for the safety of the
mare and attending vet.
AI allows semen to be assessed & semen
quality can be improved by trying
different extenders. The inseminating
volume can be lowered with mares that
may react badly to AI but sometimes
these factors can be out of the
inseminating vet’s control.
AI eliminates the risk of injury associated
with natural covering and also reduces
venereal disease transmission. However,
there are limiting factors, e.g. failed
semen delivery or poor shipped semen
quality.
Embryo Transfer (ET) can be useful for
competing mares, valuable mares (to
avoid the foaling risk), optimise genetics
and make it possible to have multiple
foals on the ground in one year. Mares
who struggle to retain a foetus or have
a history of early pregnancy loss are
good candidates for ET. Mares requiring
long-term medication unsuitable for use
during pregnancy or with behavioural
issues may also be good candidates. ET
is more complicated and needs careful
planning in order to ensure good results.
68 | BRITISH BREEDER