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Independent.ie

Thursday 21 September 2017

teasing is a crucial tool in breeding management

Wendy Conlon Teagasc Equine Specialist

Breeding

management

Teasing is an important breeding management tool. Mares which have foaled should be teased from day five or six after foaling. Maiden/barren mares in spring transitional period should be teased twice a week until they show signs and then daily until they tease out.

Once teased off from an oestrus period, begin again 14 days later to tease so that you don't miss early return to oestrus if not in foal. Continue to tease pregnant mares (less than 40 days) twice a week in case they lose the pregnancy and return to oestrus.

Maiden and barren mares generally have a lower conception rate in the first heat of the season and it is normally best to delay mating until they are in their second cycle, or indeed are cycling regularly and no longer in the transitional period.

The traditional natural breeding strategy is to cover a mare every 48 hours during her heat, beginning on the second day of showing oestrus signs. This is continued until she is no longer receptive to the stallion.

The main disadvantage with this strategy is an increased risk of developing a uterine infection and, of course, over-use of a busy stallion. Semen is not sterile and each breeding attempt introduces contamination and bacteria as well as sperm into the uterus.

A healthy mare with good perineal conformation can clear contamination within hours. However, the following mares have a much more difficult time clearing contamination:

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• Older mares which are predisposed to windsucking through poor perineal conformation

nMares predisposed to urine pooling or urine in the vagina

nMares that experience accumulation of uterine fluid; and

• Mares which have a cervix that fails to relax completely during oestrus.

Another strategy is to breed the mare before and as close to the time of ovulation as possible. This will limit the number of coverings/inseminations necessary, which is important.

nWith susceptible mares as described above

nWith stallions with large books of mares (natural service)

nWhen the number of artificial insemination breeding doses is limited; and

nWhere frozen semen is used.

The optimum time for covering a mare depends on the type of service you have chosen to use, be it natural covering or artificial insemination.

The following are the timings for each option:

• Natural covering/ fresh semen – 24-48 hours before ovulation

• Chilled semen – 12-18 hours before ovulation

• Frozen semen – six hours before to six hours after ovulation

Experienced vets can accurately predict ovulation time. It is also possible to administer an injection of Luteinising Hormone (LH) post cover/insemination to induce ovulation where a dominant follicle is present.

Veterinary intervention prior to breeding can involve the following:

• Cervical swab to identify the presence of venereally transmitted pathogens

• Speculum examination to assess the cervix

• Uterine swab when the mare is in season to check if she requires treatment/washouts prior to covering

• Possibly opening of a mare with a stitched vulva (Caslicks)

• Ultrasound scanning to monitor the development of follicles and the condition of the uterus

• Assessing the mare for the presence of uterine fluid, urine pooling, inflamed or irritated cervix and the presence of cysts. The presence and position of cysts should be noted and recorded to avoid later mistaking them for a pregnancy

• Possible administration of hormones

Post-breeding

After a mare has been covered or inseminated, daily teasing should continue and ultrasound scanning performed to confirm she has ovulated and gone out of heat.

Examination of the mare's reproductive tract by the vet within the first six to 24 hours after breeding also means that any abnormal build up of uterine fluid will be identified quickly and treated.

As the embryo does not enter the uterus for five to six days after ovulation, there is no risk to the embryo in treating the uterus during this period.

Rapid identification and treatment of mares that do not clear contamination, fluid and inflammation after breeding can help prevent persistent inflammation of the uterus lining (endometritis) and save a pregnancy.

Repeated examination and teasing of the mare after breeding helps to detect double ovulations (which can result in undesirable twin pregnancies) when they occur. It is best to follow the mare through the first 48 hours after ovulation to ensure that there are no lingering problems.

Ultrasound scanning for pregnancy should begin by day 14/15 after ovulation. Twin pregnancies identified prior to day 16 after ovulation are easier to manipulate and reduce due to the mobile nature of the embryo in the uterus up to this time.

Follow-up pregnancy examinations are recommended between days 28 and 30 for detection of a heartbeat and to monitor continued normal development of the identified embryo and tone of the uterus. Mares may be monitored again at days 40 and 60 and again at the end of September, where the covering fee is paid under first of October terms and conditions. Where foetal sexing is required, this is performed ideally from 60 to 75 days.

Problem mares

With mares that are problem breeders, a number of actions may be necessary to consider. These include:

• Uterine lavage

• Intra-uterine antibiotics

• Stitching/ Caslicks

• Oxytocin injection

Uterine lavage is also referred to as 'washing-out' or 'irrigating'. It involves putting saline fluid into the uterus, often coupled with an injection of oxytocin to ensure uterine contraction and dispelling the fluid again.

This treatment is used for removal of retained placenta ('cleanings'); and also used when administering intra- uterine fluid coupled with antibiotics.

It can be administered every eight hours (up to three times per day), but no sooner than six hours post mating.

The idea being that as the uterus contracts and expels the fluid which has been put in; it washes out the uterus in the process, removing bacteria and irritant. With some mares, the administration of intra-uterine antibiotics is necessary to target bacterial irritants in the uterus.

Stitching of the vulva is necessary for some mares with poor vulval conformation.

Exercise is especially important for mares after foaling and also for mares with a uterine infection or build up of uterine fluid.

Exercise may comprise turning the mare out in a paddock, or perhaps gentle lunging.

It has the benefits of increasing uterine muscles and tone and most importantly it helps to push unwanted fluid out of the uterus.

Irish Independent