Page 452 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

Reproductive system: 2.1 The female reproductive tr act 427

VetBooks.ir • Order the semen and plan to have the mare semen by DUI. At 8 am–10 am on day 3 the
mare is re-examined and if ovulated, is given a
inseminated within 24 hours (48 hours
maximum) of collection.
the mare is re-examined every 6–8 hours until
• Check that appropriate paperwork accompanies second insemination. If there is no ovulation,
the semen. This may include official import/ ovulation is detected and then inseminated
export documents. with the second dose. The post-insemination
• Inseminate the mare into the uterine body treatments begin 8 hours after the second
and check motility of semen on a warmed insemination.
microscope stage. • Check the mare for pregnancy at 17–18 days post
• Inseminate using a syringe without latex. ovulation.
• Check the next day for ovulation and treat
accordingly (e.g. uterine lavage, oxytocin). Frozen semen insemination
• Check the mare for pregnancy at 17–18 days post procedure (Figs. 2.25–2.27).
ovulation. • The semen is usually supplied in 0.5–5 ml straws,
which should be stored, handled and thawed
Frozen semen strictly according to the supplier’s instructions.
• Optimum time for insemination is between Each straw or packet is individually labelled.
12 hours prior to ovulation and up to 6 hours • The straws should be thawed at the appropriate
after ovulation. temperature in a temperature-controlled water
• Ultrasound scan the mare. When in oestrus and bath or polystyrene box containing water.
with a follicle of >35 mm, uterine oedema and • Take great care to avoid semen contact with
a relaxed cervix, administer an ovulating agent disinfectants, detergents or tap water and avoid
(hCG or deslorelin). temperature fluctuations as this will compromise
• Scan the mare every 8 hours until ovulation the sperm.
is detected and inseminate the mare with a • Once thawed the semen should be inseminated
deep uterine insemination (DUI) technique. immediately in its entirety.
Check sperm motility on a slide on a warmed • Transfer the semen from the straw into
microscope stage. an insemination pipette or load into an
• Scan the mare 8 hours later and treat for insemination gun.
uterine fluid with uterine lavage and oxytocin. • The DUI technique should be used to improve
Re-examine the mare every 8 hours until no pregnancy rates. Using a sterile procedure,
uterine fluid remains. gloved hands and a non-spermicidal lubricant
• To minimise the number of veterinary (e.g. KY jelly) as required, carefully introduce
examinations, various protocols have been the pipette through the cervix, pushing it gently
developed. One example is when a mare in forward until it reaches the mid-body of the
oestrus is given deslorelin/hCG at 8 pm uterus. The hand should then be placed rectally
on day 1. On day 2 the mare is examined at and the pipette guided up the uterine horn on
4–8 pm. On day 3 the mare is examined at 8 am the side of the ovulation where the semen should
and 4 pm. In most circumstances the mare be discharged. Gradually withdraw the pipette.
will ovulate around 40 hours after deslorelin • Once thawed, the semen should never be
injection and will therefore be inseminated refrozen. Many veterinarians examine a small
at 8 am on day 3 with the post-insemination drop of inseminated semen post insemination
treatment given at 4 pm on day 3. for motility. In general, it is recommended
• Where multiple doses of frozen semen are that there is a minimum of 30% progressively
available the deslorelin can be given at 4 pm on motile sperm after thawing, and dosages of
day 1, and at 4 pm on day 2 the mare is scanned 150–350 × 10 of these motile sperm have been
6
and inseminated with the first dose of frozen reported to result in acceptable conception rates.