frequently asked questions (faq's)
Over the last few years we've answered literally hundreds of questions via phone, e-mail, in person, and on forums such as Horse & Hound's online breeding forum, Saddle Up, and HorseBreedersForum... Some questions get asked over and over again, so we've compiled this FAQ section. Before reading any of the FAQs or answers, please note that nothing can replace veterinary advice and care. All of our answers are general, and may not be applicable to individual animals, and are certainly not a replacement for veterinary advice. If you are uncertain about a problem, or have a question, please consult your veterinary surgeon.
GETTING YOUR MARE PREGNANT
How much will it cost to put my mare in foal?
This depends on a number of factors, and is very difficult to put a figure on. You should always budget for 2-3 cycles of attempts, rather than just a single cycle. Even with fresh, fertile semen, on a young, fertile mare things do not always go to plan.
Expect basic costs of £280-£400 per cycle, and budget for at least 2 cycles.
Is my mare in foal?
It’s not possible for anyone to tell for certain from a photo, or even from seeing the mare in person for an external examination. A blood test and/or ultrasound scan are the only things that will confirm the mare’s pregnancy status for you.
Try not to ask friends, family or post photos on forums asking this question. It will not provide you with any useful answers and may wind you up if you are told something you were hoping not to hear!
My mare is difficult/chronically lame, should I put her in foal?
You should discuss this carefully with your vet. Difficult behaviour and chronic lameness may be due to your mare’s genetics, in which case she is probably not a good candidate for breeding.
Is my mare too old to have a foal?
This is extremely difficult to answer. Mares’ fertility declines from around 12 years old, but unlike humans, equines do not go through a “menopause” or anything similar.
Generally we do not recommend putting mares in foal past their 17th year (foaling in their 18th) although a number of people breed from their mares well into their 20s.
Get your stud vet to give your mare a thorough breeding examination and general health check, and talk through the options with them. This will give you the answers you need to make a sound decision.
Is my mare too young to have a foal?
Although many fillies are fertile from 6-8 months old, they are not normally physically or psychologically mature enough to carry and raise a foal until they are 3 years old. Some 2 year old mares may be mature enough to be bred, but it will be extremely dependant on the individual mare.
Consult your vet and ask their opinion.
Is my mare too fat/skinny to get in foal?
Mares that are underweight or overweight will be more difficult to get in foal. Fat mares are often more difficult than skinny mares, although neither condition is ideal for a broodmare. Body condition score should be maintained at around 5-6, but no more than 7.
Please consult your vet if you are worried about your mare’s weight/body condition.
My mare can only get pregnant via natural covering
This is one of the many breeding myths. Mares put into this category generally suffer from delayed uterine clearance (DUC), a condition that requires minor veterinary treatment when the mare is not being exposed to the breeding stallion.
Judicious use of an exogenous hormone called oxytocin will generally help these mares get in foal.
Why should I use artificial insemination (AI) rather than natural cover?
AI is safer. Removing one animal from the breeding operation removes 4 legs and one set of teeth. It requires fewer handlers, and generally results in a calmer and safer experience for handlers and horses alike.
AI gives you a wider range of stallions to choose from. AI allows you to use stallions from anywhere around the world without your mare having to leave home.
AI helps to prevent disease transmission. The whole process becomes cleaner and more controlled, and the semen can be treated with antibiotics before being inseminated. This reduces the chance of fertility-affecting diseases like CEM being transferred compared to natural cover scenarios.
AI is more effective. A well managed AI programme will produce higher pregnancy rates than a natural cover mating. Semen can be analysed prior to being inseminated allowing problems at the stallion’s end to be identified and managed well before they would be in a natural cover scenario.
How long will she have to stay at stud?
This will vary tremendously depending on your mare, and the fertility of semen that is being used to get her pregnant.
From time of arrival to insemination will be approximately 1-3 weeks. You can then take your mare home, or leave her at the stud for her 14 day scan onwards.
If you take your mare away from most studs, and she is not pregnant, you will have to get a new set of blood tests and swabs done before she can be readmitted. So it may be a false economy to take her away before the 14 day scan.
How often will she be scanned when she is at stud?
This will depend on the individual mare’s requirements. Normally in the first few days, your mare will be scanned every other day to establish where she is in her cycle. As she approaches ovulation she may be scanned 2 or even 3 times per day in order to inseminate at the ideal time.
For frozen semen inseminations even more regular scanning may be required, and your mare could be scanned every 4-6 hours over a 12-24+ hour period.
Should I go for fresh or chilled semen?
The vast majority of stallions have semen which chills well. As long as the stallion’s semen is being handled properly by a well trained technician practising high standards, then the difference in fertility between fresh and chilled semen from any one stallion will be minimal.
Some stallions have semen that chills poorly, and for these stallions using fresh semen is the best option. The stud should be able to give advice on the stallion’s suitability for having his semen chilled.
Just remember that fresh semen has a very short life outside of the mare – and needs to be inside the mare within 4-6 hours of being collected and extended.
What do I need to do when I get my mare back from stud?
Depending on which point you bring the mare back from stud, you may need to get some more scans done. Ultrasound scans should be performed at 14, 28 or 35, and 50-60 days from the date of ovulation. These will help to monitor the embryo’s progress and ensure that any twin pregnancies are dealt with.
Beyond scanning, consult with your vet with regards to vaccinations, worming, exercise and nutrition.
How soon will the vet be able to see the pregnancy?
Early stage pregnancy should be visible by ultrasound from 14 days onward (10-11 days with a high quality scanner and an experienced vet).
Pregnancy can be palpated by an experience vet from 18 days onward.
When should my mare be scanned?
14 days, 28 days, and 50-60 days are the normal scanning dates for pregnancy detection and twin management. If twins are detected at 14 days, then additional scans and treatment may be necessary.
When will I be able to see the foal’s heartbeat?
The heartbeat starts to become visible from 24 days onward.
Why is it so important to detect and deal with twin pregnancies?
The equine uterus is not designed to carry multiple pregnancies. If a twin pregnancy is allowed to progress then in most cases it will cause pregnancy loss. In fact, twinning is the leading cause of late-term abortion and the second biggest cause of embryonic loss in the early stages of pregnancy.
Twin pregnancies must be dealt with by day 28 after ovulation, as after that stage it is likely that both pregnancies will have to be terminated, and the mare may not cycle again until up to 100 days later which could mean missing the whole rest of the breeding season.
Does artificial insemination produce the same quality of offspring as natural covering?
The method with which semen is put into the uterus has no bearing on the quality of the foals that are produced. Which sperm reaches the egg first is a fairly random process, and is not affected (positively or negatively) by the breeding method.
Of course, AI has a number of distinct advantages over natural covering, and so you may prefer artificial insemination for these reasons.
Do I really need to get my mare scanned/ultrasounded?
Yes.
The most reliable way to detect pregnancy is via an ultrasound scan. Scanning will also allow you to detect twin pregnancies which, if not dealt with, have the potential to cause severe complications later in pregnancy.
Why do I need to get my mare EVA (Equine Viral Arteritis) tested?
EVA can cause enormous problems when transmitted to pregnant mares and stallions. All mares and stallions entering studs should be EVA negative or EVA vaccinated (annually) in order to ensure that EVA is not introduced to the resident and/or visiting population at a stud. It is a notifiable disease under UK law, and farms/studs found to have horses with EVA will be quarantined by DEFRA.
Why do I need to get my mare swabbed for CEM (Contagious Equine Metritis)?
The recent CEM outbreak in the United States shows just how difficult life can become if CEM gets into a breeding population. It can cause fertility problems and potentially abortion in mares, and can be difficult to eradicate from stallions, who become carriers of the CEM organism. It is a notifiable disease under UK law, and farms/studs found to have horses with CEM will be quarantined by DEFRA.
THE PREGNANT MARE
My mare is in season, has she aborted the pregnancy?
Not necessarily. Although mares generally do not cycle once they are pregnant, around 10% of mares will show at least one season during their pregnancy.
Additionally, some mares may appear in season when they are not actually cycling. Submissive behaviour such as squatting and urinating in the presence of other horses may be mistaken for oestrus behaviour.
The best way to tell is via an ultrasound scan. Make an appointment with your stud vet.
My mare has blood coming from her vulva, has she has aborted the pregnancy?
Blood coming from the vulva is not normally a cause for concern. In the vast majority of cases, it is caused by varicose veins in the vagina rupturing. Blood then leaks from the vulva. In some cases a lot of blood can be seen, and it may be preferable to have these varicose veins treated by your vet.
If you are concerned about your mare’s pregnancy status, please make an appointment with your stud vet.
My mare has a thick purulent discharge, has she aborted the pregnancy?
Discharge that appears purulent could be a sign of abortion, and so should be taken seriously.
If you are concerned about your mare’s pregnancy status, please make an appointment with your stud vet.
My mare is lactating prematurely/bagging up very early, has she aborted the pregnancy?
Premature lactation could be a sign of impending abortion, and so should be taken seriously.
If you are concerned about your mare’s pregnancy status, please make an appointment with your stud vet.
What vaccinations do I need to give my mare during pregnancy?
You should ensure that your mare is vaccinated against EHV at 5th, 7th, and 9th months of pregnancy to avoid EHV-related abortion, plus all the normal vaccinations. Please speak to your vet who will be able to help you ensure your pregnant mare is properly vaccinated.
My mare’s temperament has changed while she is pregnant, has she aborted the foal?
The temperament change may or may not be related to the pregnancy. It is possible that her behaviour is being affected by the discomfort of carrying the foal, or the hormones produced by the foal and placenta.
Alternatively it could be unrelated to the pregnancy.
If you are concerned about your mare’s pregnancy status, please make an appointment with your stud vet.
My mare is behaving aggressively/in a stallion-like manner, what could be wrong with her?
Aggression in the pregnant mare could be due to a number of factors, including hormonal changes or discomfort. However, the main possibility that needs to be eliminated is something called a granulosa thecal cell tumour (GTC). GTC is a steroid producing tumour, which will generally produce testosterone (the male sex hormone) and cause your mare to behave as if she were a stallion.
GTCs are relatively easy to find on an ultrasound scan, and can be confirmed with blood tests for testosterone and inhibin.
It is best to consult your stud vet, ask their advice and get them to perform an ultrasound scan if appropriate.
How long can I ride my mare for while she is pregnant?
Ideally she should not be ridden after 200-230 days of gestation.
Can my pregnant mare go out with other horses?
With other mares, yes, as long as they get on fairly well. Geldings may present a danger. Some geldings are still able to achieve an erection, and will mount (and penetrate) a mare, given the opportunity. If this were to happen with a pregnant mare, and the penis penetrates the cervix, it will almost certainly cause an abortion.
What special feed requirements do pregnant mares have?
You should ensure that your mare receives adequate food through the winter, ideally complemented with a quality stud balancer. Through the last 3-4 months of pregnancy, she should be on an increasing plain of nutrition to enable her to cope with the increased demands on the unborn foal, without allowing her to become overweight.
What wormers can I use on my pregnant mare?
Some wormers should not be used on pregnant mares. For example, Equest Pramox should not be used on a pregnant mare, and Eqvalan Duo should only be used after the first 3 months of pregnancy. Check with your vet or retailer. Additionally you can find more advice here: http://www.wormers-direct.co.uk/wormingmares.html (we are not responsible for the content of external websites).
When will my mare start to look pregnant?
This will vary from mare to mare. A mare with normal body condition will probably begin to look obviously pregnant in her third trimester of pregnancy, around 7-8 months into her pregnancy at the earliest, but it can be easily confused with a mare simply putting on weight. You may be able to see weight gain or change of shape before this point, but it is not a reliable indicator of pregnancy.
If you are unsure about whether or not your mare is pregnant, please consult your vet for an ultrasound scan and/or blood test.
STALLIONS & SEMEN
At what age can I start breeding from my colt/stallion?
Colts can become fertile from 6-12 months old, but should not be used for breeding until they are at least 2, but preferably 3 years old.
2 year old colts are generally not mentally mature enough to cope with the rigours of breeding. If over bred, 2 year olds can often lose all drive to breed, and could possibly be put off breeding for their rest of their lives. If you must breed from your 2 year old, try not to breed more than 8-10 times in the season. Any more than that, and you risk ending your stallion’s breeding career before it has even begun!
What is “motility” that my vet/AI tech refers to when looking at semen samples?
Or
We had a semen sample arrive that was only 20% progressive; does that mean my mare won’t get in foal?
Or
We had a semen sample arrive that was 80% progressive; does that mean my mare will definitely get in foal?
Motility is a subjective (estimated by eye) measure of the percentage of sperm cells in a sample that are moving. A motile sperm cell could be swimming in a straight line, swimming backwards, swimming in a circle, or gently twitching along at a very low speed. This is also referred to as total motility or overall motility and although it is a useful indicator of the ratio of living:dead sperm cells, it is not a very useful indicator of potential fertility.
The important type of motility is referred to as progressive motility. Progressively motile sperm cells are those sperm that are swimming forwards in a relatively straight line. It is these cells which are capable of fertilising the egg.
It is easy to become obsessed with the percentage of progressively motile cells in a semen sample/dose. However, the percentage is not the important factor. For fresh semen, and chilled semen at the time of insemination it is the number of progressively motile sperm cells (not the percentage) that is important. The optimum number of progressive cells is 500 million, and it is this figure that is important.
To work out how many progressive cells are in an insemination dose, you must use the following formula:
Volume of dose x Concentration x % progressive motility = total progressive cells
We want the total number of progressive cells to be 500 million or more, so:
Example one: an optimal dose
20ml x 50 million sperm/ml x 50% progressive motility = 500 million prog sperm
Example two: an optimal dose despite “only” 25% of the cells being progressive
40ml x 50 million sperm/ml x 25% progressive motility = 500 million prog sperm
Example three: a sub-optimal dose despite 75% of the cells being progressive
20ml x 25 million sperm/ml x 75% progressive motility = 375 million prog sperm
All three factors (volume, concentration, and progressive motility) all have important roles to play in establishing whether or not you have an adequate insemination dose. Don’t put too much importance on progressive motility!
What is a semen extender and why is it used?
A semen extender is a liquid solution generally based on milk products that help the sperm cells survive for extended periods outside of their usual environment (that being the stallion’s or mare’s reproductive tract). Sperm cells are not designed to be outside in a lab (or any other) environment, and so need to be fed and protected. Raw, unextended, semen will not survive for more than a couple of hours outside of the mare.
The main functions of the extender are:
Dilution & protection: The fluid part of semen (i.e. the liquid that the sperm cells are ejaculated in) is called seminal plasma. Seminal plasma is toxic to sperm cells, and so needs to be diluted to stop it killing the sperm cells before they get into the mare. Fatty molecules in the extender also protect the sperm from the seminal plasma, as well as protecting them from other stresses such as cooling that is required for shipping chilled semen.
Nutrition & buffering: In an AI programme the sperm cells are being kept alive for longer than they are designed to live for, and so require an external food source. This is provided for them in the form of sugars in the extender. One of the by products of sperm cells metabolising the sugars in the extender, is acids. These acids can build up over time and damage the sperm cells. Buffers in the extender oppose the harmful action of the acids, and prevent the liquid environment from becoming acidic and killing the sperm cells. The extender also contains salts and other ions to help the sperm cells maintain a specific fluid balance, to stop them from shrivelling up or exploding!
Antibiotic & antifungal: most semen extenders contain broad spectrum antibiotics (and some contain antifungal agents) to help control the bacterial (and fungal) content of AI dose. This helps to prevent damage to the sperm cells in transit, and also helps to prevent bacterial (and fungal) infection in the mare after she is inseminated.
FROZEN SEMEN
What is the industry standard for motility of frozen semen?
It varies between 30% and 35% depending on the centre it was frozen at. It is important to remember that motility does not guarantee fertility. No lab tests are able to guarantee fertility either. The ability to produce pregnancies is your best indicator of fertility of frozen semen.
Why are frozen semen AI packages more costly than fresh/chilled packages?
This is due to the difference in longevity between fresh/chilled and frozen semen. Once inseminated, fresh/chilled semen will remain alive and viable in the mare for 48-72 hours; and significantly more for some stallions. Frozen semen, however, has a much shorter “shelf life”, and will only remain viable inside the mare for 6-12 (or perhaps even 18) hours.
This shorter longevity means that more precision is required in terms of the timing of insemination relative to ovulation; which requires a greater number of ultrasound scans, sometimes every few hours through the night. Multiple inseminations may be required depending on the availability of the semen, and the practises that individual vets and technicians adopt.
Additionally, frozen semen is more irritating to the mare’s uterus than fresh/chilled semen, and so will often cause a more intense “reaction” which may be observed as pooled fluid inside the uterus. This requires additional treatment to deal with the irritation and subsequent fluid production.
These factors all conspire to make frozen semen packages a little more expensive than fresh/chilled packages.
Is my mare a good candidate for frozen semen?
If your mare has regularly got in foal in the last few years on the first or second attempt without fluid-related complications, is between 3 and 12 years old, and has good reproductive conformation then she is probably a good candidate for frozen semen.
Older mares (13+), those with unknown fertility (maidens), those who are subfertile, or mares who have experienced delayed uterine clearance (DUC), are less likely to be good candidates for frozen semen.
How do I know if the frozen semen I am using is fertile?
The only way to be certain if it is adequately fertile, is if mares bred to the same batch of frozen have become pregnant after 3 cycles or less.
35%+ progressive motility after thawing with good velocity is a good indicator that the semen has the potential to be fertile, as do positive results from other lab tests such as mitochondrial function, membrane integrity and chromatin assays. However, it is important to realise that, at the time of writing this, laboratory tests cannot predict the fertility of frozen semen.
The frozen semen I’m using passes minimum motility standards. Does that mean it is fertile?
35%+ progressive motility after thawing with good velocity is a good indicator that the semen has the potential to be fertile, as do positive results from other lab tests such as mitochondrial function, membrane integrity and chromatin assays. However, it is important to realise that, at the time of writing this, laboratory tests cannot predict the fertility of frozen semen.
The only way to be certain if it is adequately fertile, is if mares bred to the same batch of frozen have become pregnant after 3 cycles or less.
FOALING
When should my mare go back to stud for foaling down?
A minimum of 30 days before expected foaling dates. Most pregnancies will last from 320-370 days gestation, so around 300-310 days should be the absolute latest that you should send your mare back to the stud for foaling, or move her to her foaling box. This will allow the mare to become comfortable and relaxed in her new environment, and also allow her to build up immunity to any different pathogens in the new environment that she is not used to, so this immunity can be passed on to the foal.
30 days will also give the stud staff time to get used to the mare’s usual pattern of behaviour, which will give them a better ability to be able to predict when the mare will foal.
I’ve read that my mare’s due date will be around 340-345 days after ovulation. Is that correct?
There is no such thing as an equine “due date”. The normal gestational range is 320-370 days with some considerable range. Less than 20% of foalings take place in the “average due date” range, so you should not expect your mare to foal at any predicted due date.
Do plenty of reading about the signs of impending foaling, and watch your mare carefully.
What is the earliest a foal can be born and survive?
Realistically, foals born before 300 days of gestation have a very small chance of survival. Those born after 300-320 days will generally require extra care, but will normally have a better survival rate.
How long can gestation progress?
Some foals have been born after 400 days, but these are extreme cases. Foals that are born after 370 days may be “post-mature” where they become overdeveloped, yet undernourished. Consult your vet if you think there is a problem with your pregnant mare.
This article was written by Jamie Anderson of Equine Reproduction Ltd, UK & Pelion Stud, Berkshire