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Reproduction | Frozen Semen

Frozen Semen

We recommend, that before reading this discussion, readers should first understand the principles and reasons for using Artificial Insemination (AI).

Frozen semen has become extremely popular in Australia in the last few years. 

We have been freezing horse semen and breeding to mares with frozen semen since 1984 (probably longer than anyone in Australia).

For a list of Quarter Horse stallions whose semen is current held frozen at GVEH, including "Smooth as A Cat", click here.

Follow the hyperlinks around these few pages and see if we can help you.

Breeding your mare with frozen semen

Freezing semen from your stallion at the Goulburn Valley Equine Hospital.

Detailed information on freezing semen.

Why breed with frozen semen?

It would be a huge mistake to dismiss the benefits of breeding with frozen semen, however, there are some difficulties that everyone should be aware of. We probably breed as many or more mares than anyone else in Australia to frozen semen but still do not get all mares pregnant. The real 'cold hard' truth is that there are some stallions who do not survive the freezing and thawing process very well. Unlike the cattle industry who have culled bulls that didn't freeze well, we do not have any (or much) selection pressure for freezability. In the future that may come. Already we have frozen semen from stallions who were themselves products of frozen semen. We think that this will result in a population of stallions that can have good results from frozen semen.

What can we expect from frozen semen?
In well managed breeding programs with natural service or Artificial Insemination (AI) we routinely expect around 70%+ of mares in foal per cycle. Pregnancy rate per cycle is the only accurate indicator of fertility. If you don't count the cycles and just add up the number of mares pregnant at the end of the breeding season you can end up with impressive figures such as 95%+ of mares in foal for the season. Clearly this is not accurate and may only really reflect how many cycles mares have been bred over rather than the real fertility. With frozen semen very few stallions can achieve 70%+pregnant per cycle. Only about 30% of stallions freeze well at our clinic, a further 40% freeze marginally and the other 30% are discarded after looking at their post freeze/thaw motility. To further complicate the issue, the only accurate estimate of frozen semen fertility is the number of pregnancies compared to the number of breedings. Fertility is not guaranteed even if motility looks great. This all adds up to increased expense to determine if the semen from an individual stallion is still good after being frozen and thawed.

As a potential client that is thinking of using frozen semen, stand back first and have a look at the probabilities of obtaining a foal.
In most natural or AI breeding programs the service fee is paid after a 45 day pregnancy test. 70%+ of mares are pregnant per cycle and at the end of the breeding season 95%+ are in foal (we have previously published these figures). When using frozen semen it is common to purchase 3 breeding doses of semen for a set price. If more than one pregnancy results then that is your good luck (it does happen) and if none of the breedings result in a pregnancy then there are almost always no refunds. In some instances you are required to return the left over semen once the first pregnancy has been achieved. We expect on average the fertility from frozen semen to be approximately half of that achieved with fresh. In other words around 35%-40% of mares are expected to get pregnant each cycle. Some stallions will do better than this and we have bred with one stallion who routinely achieved a pregnancy rate per cycle of 75% with frozen semen. However there are other stallions that do not even reach 20% per cycle.

Only by knowing previous breeding results can you be comfortable with your decision to breed with frozen semen.

So, what are the advantages (in addition to those advantages of using AI)?

  • Semen can be obtained from internationally based horses.
  • A stallions breeding may continue while he is performing or even while recovering from an injury or illness.
  • Semen from valuable stallions can be stored indefinitely or even in the hope that breed regulations change to allow them to use frozen semen.

Some of the disadvantages are:

  • The primary disadvantage is that many stallions techniques used for processing, packaging, freezing, thawing and insemination of their frozen semen do not result in satisfactory pregnancy rates. Currently pregnancy rates from frozen semen average approximately 50% of the same stallions pregnancy rates with fresh semen. However some stallions freeze quite well and some do not. In the future selection for those stallions that freeze well may be expected to improve the number of stallions with semen suitable for freezing and thus the per cycle pregnancy rate.
  • Costs. Veterinary charges for freezing of spermatozoa are quite high. At the GVEH our current charges are somewhere between $20-100 per insemination dose This depends on a number of factors such as sperm numbers and quality or if the semen is being frozen for export.
  • Pregnancy rates from lay freezers (non trained people) are poor and have helped create industry mis-conceptions about the difficulty of working with frozen equine semen. Based on the results of frozen semen in cattle, many countries were quick to learn that semen frozen by most mobile units was inferior to those samples frozen in major bull studs. A disadvantage of freezing at centres is loss of control of the stallion to the handling of other people. We have even had people send a handler in to manage the stallion (exercise etc) while the semen is being frozen.

Common breeder misconceptions

  • Success rates are high. This tends to increase the number of dissatisfied clients (usually those that have not been adequately informed prior to beginning the freezing of semen).
  • That anybody can freeze semen. Lots of shipments of frozen semen are arriving in Australia and occasionally the semen has been frozen by inexperienced personnel. These people often have had only a small amount of experience in sterile technique, laboratory procedures etc. Some of the samples are good, however most are inferior. Once again this leads to client dissatisfaction. We even have one person in Australia who categorically states that when dealing with their group, the semen is always frozen well and the problem must be with the lack of suitable veterinarians at the other end. Unfortunately most people in this category are very good communicators and very poor technicians.
  • Errors in identity. Many breeders are concerned that their mare may be bred with the wrong semen. Obviously well marked straws and DNA fingerprinting will eliminate these misconceptions.


What to do?

Use frozen semen if you can find a reputable dealer. Preferably get them to agree to a fee when the mare is declared pregnant at 45 days.

Contact the This e-mail address is being protected from spambots. You need JavaScript enabled to view it (AEVA) to find  a list of veterinarians that are certified to use frozen semen. Do not use anyone else to perform this exacting and difficult task.

Consider that the pregnancy rates for frozen semen are ~ 50% of the pregnancy rates of fresh semen.

Ask your veterinarian if he or she has any information on the fertility (using frozen semen) of the stallion that you are using.

Currently we are compiling a list of the fertility achieved (per cycle) from all the stallions whose semen has been used by veterinarians that are AEVA certified. These veterinarians will have access to a continually updated web-site and can use this to help you formulate your breeding plan if that particular stallion has been used in this country before.