Monash Veterinary Clinic

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Please note, we are closed from Sunday 24th December, we will reopen on Wednesday 27th December at 8:30am.

Frozen-Thawed Semen

The use of Frozen-Thawed Canine Semen

The use of frozen semen in dogs is both and emotional and expensive process. We feel that it is important for both the recipient and the supplier of frozen semen have a clear understanding of the procedures and recommendations. Monash Veterinary Clinic is one of the few facilities still performing both Transcervical (TCI, non-surgical) and Surgical Insemination of frozen semen. The final decision of how the semen is inseminated is determined by you, the client after careful counselling on the pro’s and con’s of each procedure.

Straws versus Pellets

There are beliefs that straws are superior in success than pellets and vice versa. There is no published information to support this. There is also no good published data to suggest that one particular extender within which the sperm is frozen is superior to other extenders. Do not be concerned how your semen is packaged; it is more important to be confident that the semen was frozen and assessed well at the time of collection and freezing. If there was one method for extending and freezing canine semen that was remarkably better than others available, everybody would use the same one. It is however important to ensure that the semen is frozen in an extender proven to work with canine semen, i.e. not cattle or horse semen extenders.

The most important factor affecting the viability of frozen semen is the age and health status of the dog when the semen is collected and frozen. The best pregnancy rates are obtained when the semen is collected and frozen from dogs between 2 and 5 years of age. Whilst semen frozen from dogs outside of this range may appear good, this semen may have a lower chance of getting a bitch pregnant.

Semen Assessment 

It is important to ensure that the semen has been assessed well at the time of freezing. Anecdotally it is recommended to use a minimum of 100 million live normal sperm for one insemination. After collection the semen is counted, then the structure of the sperm are analysed to work out how many of the sperm collected are ‘normal’ and able to fertilise. The sample is then frozen and a portion of the frozen sample is thawed to assess what percentage of the frozen sperm are moving forward (i.e. the motility of the sample). The ejaculate is then usually split up into multiple doses of a minimum of 100 million normal motile post thaw sperm.

There has been shown to be up to 20% variation between technicians counting semen, so we recommend to ensure there is well over 100 million sperm in the sample. The fertility of the semen reduces when there are more than 20% abnormal sperm in an ejaculate.

How Much Semen to Use

The more semen that is inseminated into the bitch, the greater the chance of pregnancy and the larger the litter size. Dr Catharina Linde Forseberg of Uppsala Sweden is well renown for being a leader in the field of canine semen freezing. She has the best published success rate of frozen semen inseminations; her success rate was 70%, so out of every 10 bitches inseminated 7 would be pregnant and 3 would be empty. This result comes from the analysis of over 4000 intrauterine inseminations submitted to the Swedish Kennel Club.

We recommend that if the recipient is to pay both a stud fee and the fee for the collection, freeze and assessment of the semen, then the recipient should receive the whole ejaculate, not just a proportion.

Method of Insemination

Frozen thawed semen should always be inseminated into the uterus. In Australia there are two commonly used methods of insemination, Transcervical Insemination (TCI) and Surgical Insemination.

Transcervical Insemination is a superior method of insemination to surgical insemination. With TCI there is no need for the bitch to undergo an anaesthetic, there is no surgery. With TCI the bitch stands on the table and we use an endoscope and specially designed catheter to deposit the semen into the uterus of the bitch. Unlike with surgical insemination wherein the bitch is asleep and there is no tone to the uterus, during a TCI, the catheter in the uterus stimulates contractions of the uterus to draw the semen up to the fallopian tubes where the eggs are waiting to be fertilised. Because the animal is asleep during a surgical insemination there is nothing to hold the semen in the uterus. Additionally TCI has the benefit of allowing us to do multiple inseminations with frozen thawed semen. 

There are no studies done on the effects of wound healing from surgical inseminations on fertilisation. 2012 marked the first publication on the success rate of Surgical Insemination of Frozen-Thawed canine semen, this report revealed a success rate 10% below that of Catharina’s whilst using an average of over 100 million more sperm than that used by Catharina Linde Forseberg (all of Catharina’s publications are based on insemination of semen inseminated transcervically in awake bitches). In some countries, namely Sweden and Norway, it has been illegal to do surgical inseminations on bitches for over 30 years; in the United Kingdom it has been illegal for over 10 years. Unpublished data from our clinic shows a greater success rate by more than 20% with the use of transcervical insemination of frozen thawed semen compared to surgical insemination. Dr Stuart Mason and Monash Veterinary Clinic have over 15 years of experience in transcervical insemination.

PDF on Transcervical vs. Surgical Insemination

TCI is the superior method of intrauterine insemination when compared to surgical insemination. TCI is as close as we can get to a natural mating artificially.

We understand that it may not always be possible to achieve all of the recommendations we make for obtaining enough semen for insemination of your bitch, however we feel that it should be clear to the recipient of the semen what the facts are for the use of frozen semen in bitches and the associated success rates which can be realistically obtained.

Publications on frozen semen insemination

In 2014 Dr Stuart Mason and Dr Nicole Rous published an article comparing their pregnancy rates with frozen semen by TCI versus surgical AI.  The results of the study showed a 20% greater pregnancy rate with TCI than surgical AI.  To view the article on TCI versus surgical AI click here to read.

As a follow up to the 2014 article, Dr Stuart Mason presented data from over 350 frozen semen TCI's at the ISCFR conference in Paris in 2016 showing Monash's frozen semen TCI results being consistent with the first article which contained fewer inseminations.  To view this article click here to read.