Are you thinking of putting your mare in foal? This blog covers the different stages when getting your mare in foal, and also the care and wellbeing of your mare once in foal. If you have any further questions or would like to know more about our Stud Packages, please contact us.
PREBREEDING HEALTH CHECKS
Before breeding, you should get her assessed to check that she is suitable for breeding. Our pre-breeding checks include:
>> Examination of external genitalia. Including assessing the conformation around the perineum, and external genitalia and mammary glands.
>> Ultrasound examination of the reproductive tract, cervix, uterus and ovaries. This is an opportunity to check whether both ovaries are present and check for follicles or the presence of a corpus leutem, which tells us which stage of the cycle the mare is in.
>> General clinical examination to check the mare is suitable for breeding.
If the mare is going to stud, the following additional health checks may be required.
>> Clitoral swab to check for Contagious Equine Metritis (CEM)
>> Taylorella equigenitalis (contagious equine metritis)
>> Pseudomonas aerguionsa
>> Klebsiella pneumonia
>> Endometrial swabs to check the uterus is free from infection
>> Bloods
>> Equine viral arteritis
>> Equine infectious anaemia
>> +/- strangles
CHOOSING A STALLION
When choosing a stallion for your mare, it is important to consider what sort of offspring you want to produce. Critically look at your mare and assess her strengths and weaknesses and try to choose a stallion that compliments her.
Consider;
>> Athletic ability – are you looking to breed a performance horse?
>> Temperament – what sort of temperament is your mare, and what would compliment her? What temperament of offspring are you looking for?
>> Conformation – look for good conformation that will complement the mare.
>> Bloodlines – check the stallion’s sire and dam lines.
>> Fertility – try and enquire about his fertility. You can ask about his proven fertility. Ask specific questions about his semen quality, for example, the density of semen, motility score and percentage of alive/normal semen.
>> Health checks – most stallions from reputable studs will come with health papers showing they are free from disease – it is worth checking these are available with the stud. Appropriate health certificates MUST accompany imported semen, and veterinary confirmation of freedom from disease must accompany UK semen. N.b. Following Brexit, semen being imported from NI must be accompanied by the appropriate international health certificate (as semen importation is currently following the same rules as the EU).
>> Progeny – what are the offspring of the stallion like – temperament, performance, conformation.
WHEN IS MY MARE IN OESTRUS?
During the breeding season (spring and summer), the mare has a recurring oestrus cycle. A mare is described as being in oestrus when she is in season and receptive to the stallion.
The oestrus cycle of the mare averages 21-22days with 4-7 days of oestrus. Ovulation (when the egg is released from the ovary) occurs approximately 1-2 days before oestrus ends.
The mare is monitored for her natural cycle, or oestrus is induced with prostaglandin E. Prostaglandin E short cycles the mare and brings her into season within 3-5 days of injection.
Once the mare has come into season, she is monitored closely for signs of ovulation. Oestrus lasts between 4-7 days, and the mare will likely ovulate 2 days before the end of that. The mare is regularly scanned to assess for signs of imminent ovulation.
>> The uterus; when a mare is in season she will develop oedema within her uterus. The level of oedema helps to predict when ovulation will take place.
>> The ovaries; for the presence of a dominant follicle. Each follicle contains an oocyte (an egg). The follicle grows in size – typically to between 4-5cm before ovulation when the egg is released into the uterus.
>> The cervix; visually assess and digitally palpate (feel) the cervix. A mare in season that is due to ovulate will have a soft, fleshy, pink cervix that is approximately 2 fingers dilated.
OVULATION AND INDUCTION OF OVULATION
The next step is to induce ovulation. Typically, an ovulation agent is administered to encourage the mare to ovulate within approximately 40 hours.
HOW IS THE SEMEN SUPPLIED?
How the semen is supplied will affect how you go about breeding your mare, so it is important you understand the difference between natural cover, fresh, chilled and frozen semen.
1. Natural cover; this is when a mare is covered naturally. Typically, the mare will be frequently scanned until she is ready to be covered. She will then be covered in hand.
Occasionally mares at stud will be covered multiple times, for example, on alternate days during her oestrus cycle.
2. Fresh; fresh semen comes in two forms; either fresh or fresh chilled. Fresh is when the stallion is collected from, and the semen is placed directly into the mare. This only really works if the mare is on the same site and can be inseminated immediately after collection. It’s a technique less commonly used compared with natural cover or fresh chilled.
3. Fresh chilled; the semen is collected, processed and chilled ready for transport. Once collected, the semen can live for between 48-72 hours. Chilling allows the semen to be shipped across the country or internationally before being inseminated into a mare in season.
4. Frozen semen; is collected, processed and small straws are frozen in liquid nitrogen. Once frozen, the semen can last for many years, extending the availability of that semen long after the stallion has passed on. When the mare comes into season, her ovulation can be timed, and the semen defrosted and inseminated as close to ovulation as possible. Frozen insemination needs to be carried out in our clinic. Initial scanning is still performed at your yard, with your mare brought into the clinic when she’s approaching ovulation.
INSEMINATION PROCESS
The mare is either covered naturally or inseminated with fresh or frozen semen.
MANAGEMENT POST INSEMINATION
Post insemination, usually the following day, the mare is scanned again to check for post insemination fluid and to check the ovulation. If fluid has accumulated within the uterus, this reduces the chance of a pregnancy “holding”. Oxytocin, a drug that causes the uterus to contract and squeeze out the fluid, is used. The uterus can also be flushed with sterile saline. The semen, at this point, is safely up by the ovaries so, there is no risk of flushing it out. Antimicrobials, if required, may be put into the uterus if there is concern about post-breeding endometritis.
PREGNANCY SCANNING
Pregnancy scans are performed on day 14-16 post ovulation. A second scan on day 28 is recommended. At this point in a healthy pregnancy, we will see a heartbeat.
GESTATION PERIOD
The average gestation of a horse is 335-342 days. Foals born before 320 days are typically premature and not viable.
PREVENTATIVE HEALTH FOR YOUR MARE
VACCINATIONS
Vaccinating the pregnant mare serves two purposes; to protect the mare and unborn foal from disease during pregnancy and eventually to protect the newborn foal. If the mare is vaccinated during pregnancy, she will not only protect the foal during pregnancy, but the colostrum will also contain important antibodies that the foal can absorb to protect the newborn from disease.
INFLUENZA AND TETANUS
>> Continue to vaccinate your mare annually.
>> Give a booster vaccination 4 weeks before the due date; this boosts the mares immune system, which increases the number of antibodies in the colostrum which will protect the newborn foal.
>> If the mare has not had this booster vaccination or the foal has had insufficient colostrum, we would recommend the foal receives a tetanus antitoxin injection in the first few days of life
EQUINE HERPES VIRUS
Consider vaccinating against equine herpes virus at month 5, 7 and 9 of gestation.
>> Equine Herpes Virus 1 is associated with abortion in mares and is highly recommended for broodmares at large studs.
>> It is often associated with “abortion storms” (large numbers of abortions) at studs where the disease can easily and quickly spread through the herd. Private small yards with individual pregnant mares are at lower risk of contracting the disease, but this risk is increased if there are multiple competing horses on the same yard as the broodmares
ROTAVIRUS
Rotavirus vaccines can protect foals from diarrhoea and is recommended for broodmares at large studs. This vaccine needs to be given at months 8, 9 and 10 of gestation.
PARASITE MANAGEMENT
Individual mares should have a tailored worming plan. Regular worm egg counts throughout pregnancy (every 3 months) are recommended to monitor the parasite burden. The importance of good pasture management shouldn’t be underestimated. Owners and yard managers should think about the number of horses on the pasture, pasture rotation, and poo picking.
Administration of ivermectin to the broodmare within the last 4 weeks of pregnancy is common practice to minimise the parasitic load of Strongyloides westeri. This parasite’s infective larvae are transmitted to the foal via nursing beginning around 4 days after birth.
NUTRITION
Nutritional management of the broodmare is important, and you should look to achieve a body condition score between 2.5-3 out of 5. Mares should be fed ad-lib forage at all times during pregnancy, with the exception of overweight mares, which should be restricted to reduce risk to both mare and foal.
For the first 8 months of pregnancy, mares can be maintained on good quality forage and grass. Consider supplementing the mare with hard feed in the last 3 months of pregnancy, with food higher in energy and protein levels and is supplemented with vitamins and minerals.
OTHER MANAGEMENT CONSIDERATIONS INCLUDE
Dental care
Routine farriery
Contact our Equine Repro Team if you would like more information about putting a mare in foal and our available stud packages.
