A.I. guide

 Guide to Artificial Insemination at Pool House Equine Clinic 

What Is Artificial Insemination (AI)? 

AI is now a very common and viable alternative to natural breeding.  It is a technique which is carried out by trained Vets or AI Technicians, using fresh, chilled or frozen semen.  There are extensive benefits, including: –

  • Massive increase in range of stallions available, increasing the gene pool.
  • Eliminates the cost and stress of transporting mare and foal to stud.
  • Reduction of possible injury to stallion or mare.
  • Stallions may continue to be used for breeding whilst performing or recovering from injury.
  • Semen can be transported internationally and stored indefinitely (frozen only).
  • Reduction of possible disease transmission.
  • Can assist with breeding the “problem breeder” mare.


What Are The Disadvantages Of Using AI?


Fresh semen remains viable in the uterus for 3 to 5 days, whereas chilled semen remains viable for up to 36 hours and frozen only lasts up to 12 hours (or some less than 6 hours).  Timing of insemination is therefore critical and pregnancy rate is highly dependant on the ability to freeze and thaw semen from individual stallions without compromising its fertility.  For this reason some stallions will not be suitable for producing frozen or chilled semen.

Other disadvantages include: –

  • Added cost of collecting, chilling/freezing, transportation and insemination.
  • Skilled and experienced centres mandatory to optimise pregnancy rates.
  • High veterinary input required.
  • More than one cycle may be necessary for mare to become pregnant, resulting in owner frustration.


 Is My Mare Suitable For Breeding/AI?

  • Optimal age between 3-12 years, although it is possible to breed from very mature 2 year olds, and although fertility rates may be reduced, it is possible to breed from much older mares too.
  • Reproductive conformation; poor conformation will decrease conception rates.
  • Temperament is very important as it is a highly heritable trait.
  • It is important to let us know of any breeding history available about the mare as this will help with increasing the conception rate.

Choice of stallion and decision between frozen and chilled semen can be discussed with our vet team.  We also have a dedicated stud receptionist, who can answer many of your questions on 01283 799700.  We are here to make the experience as easy for you as possible.

Success will depend greatly on communication between you, your stud vet and the semen supplier.

It is your responsibility to make arrangements with the semen supplier regarding stud fee and transport costs of semen.  The semen is only ordered by the stud vet at the correct time, so the details of the stallion and the semen supplier must be made clear to us on admission to the clinic.  It is best for the semen to be sent to our clinic at Crown Inn Farm.

Individual arrangements can be arranged for those mares that are unable to travel to the clinic, although additional travel costs will apply, and it is unavailable for use of frozen semen.

Despite every effort you should be aware that some mares do not go in foal.


Horse Breeding for Beginners

All owners view their own horse as a potential champion but when deciding to put a mare in foal you must be realistic. Does your mare have really good conformation, clean tendons, strong feet and sufficient quality to breed a top class foal? Try to be honest or better still get an independent appraisal of your horse’s conformation from a vet.

Ask yourself, ‘Why do I want a foal?’ Will there be a market for it? Have I the facilities to care for a foal or can I afford to pay someone else to look after it for me? Am I prepared for and understand all the risks involved to the mare in having a foal?

Putting a mare in foal to a high quality Stallion can be expensive and a live foal in eleven months time is far from guaranteed. For the best chances of success you need to get the mare into the correct body condition. Fat mares are very difficult to get in foal so ideally we should aim for her to be a little thin (Body Score 2.5) at the beginning of the season so that she can put on some weight in the early summer. It is vital to get your mare checked out by an equine stud vet early in the year at least three weeks before you intend having her ‘covered’. The vet will check the mare’s reproductive tract with an ultrasound scan and ensure everything is healthy. Usually swabs are taken to be tested in a laboratory for diseases such as Contagious Equine Metritis (CEM) and a blood test for Equine Viral Arteritis (EVA).

Think carefully about the stallion you are going to use. Don’t be influenced by fashion. Will the stallion’s conformation enhance your mare’s? The old adage ‘no foot no horse’ is truer than ever today. So when you are selecting a stallion look at his feet first. This is especially true when breeding thoroughbreds and is frequently overlooked.

You can choose natural service or artificial insemination. Traditionally mares go to the stud and stay until they are confirmed in foal – this is ideal for the novice breeder but can be expensive as not only covering fees but livery has to be paid. Many studs will accept ‘walking in mares’. When ‘walking in’ the mare is prepared at home and taken to the stud on the correct day for covering. She will need regular scanning by an experienced vet to get the timings right. It is important to agree the terms on which your mare is to be covered before sending it to stud. There may be a no foal no fee arrangement or you may have to pay on ‘1st of October terms’ i.e. the stud fee is due if the mare is in foal on that date. Make sure you know exactly what is covered by the stud fee and what is not.

These days (except in the thoroughbred world) artificial insemination (AI) is very common and many veterinary practices offer an AI service. But do not think of AI as a cheap alternative to sending your mare to a stud. Preparing the mare and ensuring she is covered on the right day is time consuming and requires a great deal of work by your vet. Most stud vets offer an AI package so you can get this done at a predetermined price.

Advantages of AI.

  • No risk of injury to the mare at covering and a decreased risk of venereal disease.
  • Can use frozen semen so it is possible to cover the mare with a stallion from anywhere in the world (or even a stallion that is dead!)
  • Most equine veterinary practices offer an AI service at BEVA approved clinics – usually offering a ‘package deal’.
  • Minimises travelling.
  • Good fertility rates with both ‘fresh chilled’ and ‘frozen’ semen.

The mare is a seasonally polyoestrus animal which means it ovulates about once every 21 days in the spring and summer months. As the day length decreases in the Autumn many mares stop cycling this is known as anoestrus.

During the 21 day cycle the mare will only stand for covering on around 5 days. In the ideal world the mare should be covered around 12 hours before ovulation (or for AI immediately afterwards). Vets scan the ovaries to determine the precise time when the mare will be fertile.

After covering your vet will need to pregnancy check the mare at regular intervals starting at 14 days. It is important to ensure that there is only one pregnancy as mares cannot carry twins successfully. At 24 days the foetal ‘heart beat’ can be detected and this confirms a live pregnancy.

Gestation lasts 11 months and is extremely variable in the mare so we will add more information about preparing to have a foal.



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