Contrary to conventional perceptions when it comes to freezing dog sperm, there is really no ‘black magic’ involved.  The system for freezing is in principal rather simple, the success of which is contingent in a large part to the method used, how it is handled and of course the other factor in the equation ....... the bitch it is used on.

Regardless, there are many questions that arise in a breeders mind when they are considering incorporating this technology into the longevity of their valuable bloodlines.  The following are many of the typical questions asked of breeders that may clarify some questions that you may have yourself.

How is sperm frozen without killing it ?

Sperm cells of any species are meant for one single purpose ... procreation.  For this reason, they are meant to travel from the male to the female in an uneventful manner and under ideal conditions in order to produce offspring.  Obviously, when we intervene in the process, the sperm cells will be subject to ‘stress’ that jeopardizes their survival.

Stress to the sperm cell include, temperature changes, exposure to air and light, exposure to foreign material, vibration etc.  In order to minimize or eliminate the loss of sperm, specialized procedures must be followed.  So, how do we freeze sperm without killing them .....

Minimal trauma is required during the collection from the stud, which entails gentle handling, quick and easy arousal and use of  clean equipment.  The collection requires separation of the ‘fractions’ or components of what the dog ejaculates at the time of collection as there are some components that are detrimental to the successful freezing of the sperm.

‘extend’ the sample in a medium called an extender that will buffer the sperm from the effects of temperature change and provide the cells with the energy they need during the process of chilling, freezing and eventual thawing.

chill and freeze the sperm gradually over several hours in order to minimize the trauma they will experience. The temperature changes from body temperature to refrigerator temperature to the ultimate final temperature of -197^oC for long term storage.

How long do sperm survive once frozen ?

In theory, given the nature of the components that are used for preparing the sperm for freezing and the storage temperature of - 197^oC, they should survive in this suspended state so to speak indefinitely.

In Canine Cryogenics Canada’s experience, sperm has been evaluated after having been frozen for 15 years and it looked as good as it did the day it was frozen.   

What is sperm stored in ?

The actual media in which sperm is frozen and ultimately stored in is called liquid nitrogen (LN2) which is the liquid from of the gas nitrogen.  It actually looks like slow boiling water but certainly has a different temperature ...... - 197^oC! At this temperature, tissue freezes instantaneously. 

The vessel in which the LN2 is contained is essentially a double walled aluminum tank with a vacuum seal between the two walls to provide insulation.

What are straws, pellets, goblets and canes ?

Straws and pellets are 2 methods used for the actual freezing and storage of the prepared sperm.  The straw actually looks like a drinking straw but is smaller and made of material that withstands the severe temperature of freezing.  The sperm is drawn into the straw, sealed and then frozen and stored in this way.  The volume is typically 1/2cc or 0.5ml.  Pellets are just as they appear, sperm that is frozen in drops, that take the appearance of pellets once frozen.  Once pellets have been prepared they are usually transferred to a plastic tube for storage at liquid nitrogen temperatures.

Goblets are plastic cylinders open at one end that the straws will fit into.  Once the straws are contained in a goblet, they are attached to an aluminum cane for ease of handling and identification on storage.

What is meant by chilled sperm ?

Chilled sperm is just that, sperm that is chilled to 2^oC - 6^oC. However, prior to chilling, the sperm must be prepared appropriately to handle the effects of chilling using what is commonly known as an extender.  Chilling is the procedural step required prior to the actual freezing and is done gradually starting at room temperature and eventually to refrigerator temperature over 1 - 3 hours. 

If a request is made to chill a sample for shipping to be used for insemination, this is the same material.

What is an extender ?

An extender is the material that is used to prepare sperm for chilling prior to freezing.  It is comprised of many components, the most important ones being those that provide buffering capacity against temperature shock and nutrients for required by the sperm cells to deal with these stresses.

Why would I freeze my dog’s sperm ?

Reasons for freezing a stud dog’s sperm are as individual as the breeders who use this methodology. However, consider the following scenarios and if any apply to you, then you should be considering the technology. 

• sudden or unexpected loss of an invaluable stud dog
• too many bitches requiring your stud dog’s services and not enough of him to go around
• the ‘live’ version is not available because he is in Venezuela at the World Dog Show
• he is getting old but his contribution to your line and/or breed needs to continue
• you have the bitch with the perfect bloodlines needing your stud dog’s services but the owner refuses to ship her to you for breeding
• you have a lot of important stud dogs that can contribute to your line but not the resources to keep them all
• your stud dog does not fit into your breeding program now, but will in 5 to 10 years
• you want to have your stud dog neutered for health reasons particularly in his later years

How do I know if my dog is a good candidate for freezing ?

To use an old adage .... ‘the proof is in the pudding’!

This in actuality is very applicable to at least providing some preliminary information as to whether your boy or boys are good candidates for the procedure.  What is meant by this is if you know your dog is a good producer, has a history of being a good producer and provides good quality sperm samples, the answer is yes, he is a good candidate.

Beyond this, there are other considerations that need to be addressed and they are itemized below  

• age  - this is an obvious one.  As we get older, typically most of our ‘belongings’ start to deteriorate and sperm is no different.  Younger sperm generally freezes better.  However, Canine Cryogenics Canada has frozen sperm on 10 year old stud dogs that is more than adequate for use.  So although age is a consideration it should not necessarily be a deterrent.  
• health status - similar to the age issue, healthier dogs produce healthier sperm.  So if you have a dog that is unhealthy, get him healthy prior to collecting for freezing
• breed of dog - there is a common belief that some breeds of dog produce sperm that freeze better than other breeds of dog.  Given the number of variables that play a role in the success or failure of a freeze it is hard to determine if a breed or breeds freeze better than others.  Canine Cryogenics Canada has frozen sperm on several different breeds of dogs but not enough of any one breed to say with any certainty that breed is a factor.
• quality of sperm - this is probably the most important consideration for obvious reasons.  The quality of the sperm includes the number of sperm, how many are normal vs abnormal, how well do they swim and ultimately how well do the sperm handle the freezing process.  These are all determinations that are made the day of collection unless and evaluation had been made immediately prior to Canine Cryogenics Canada for processing. 

How is an insemination done with frozen semen ?

The unfortunate thing about sperm after it has been frozen is it’s survival once it has been thawed.  Typically sperm that is ‘fresh’, meaning just ejaculated and used for insemination will survive in the reproductive tract of the bitch for 2 - 6 days!  This is great when both parties are available for a natural breeding or immediate insemination with freshly collected semen, as it allows a bigger window of opportunity for a successful fertilization.

However, when sperm has been frozen and then thawed, it’s survival time is greatly reduced to the range of hours allowing for a much narrower window of opportunity.  This necessitates the proper and precise monitoring of the recipient bitch's estrous cycle and ensuring that the sperm are where they are supposed to be when the bitch is ready.

Therefore the insemination with thawed sperm is best accomplished using one of two methods :

• surgical implant (rapid surgical procedure involving isolation of the uterus and injecting the thawed sperm directly into the uterus).
• trans-cervical implant (introduction of the sperm using a catheter or specially designed inseminating rod directly into the uterus).

Both methods allow for direct delivery of the sperm to the site of fertilization... the uterus.  There are pro’s and con’s to each method and the decision as to which method should be used is best determined by the owner of the recipient bitch, the temperament of the bitch, quality of the thawed sperm and probably most importantly the comfort level and experience of the veterinarian performing the procedure.

How successful is the use of frozen sperm in producing litters of puppies ?

There are a number of different reports as to the success of producing a litter of puppies ranging from 60 - 85%.  The critical factors that contribute to the success include freezing methodology used, appropriate monitoring of estrous cycle of recipient bitch, method of insemination, experience of veterinarian performing the insemination and the age and reproductive history of the recipient bitch.

How much does it cost ?

For the Canine Cryogenic Canada fees, go to the ‘Pricing Schedule’ page.  It should be noted that there may be some adjustment to fees depending on the individual.  For example, there is a discounted rate for breeders introducing rare and unrecognized breeds

What guarantees do I have if I use the services of Canine Cryogenics Canada ?

You have a guarantee of one of the best methods available for freezing your stud dog’s sperm.  You will know the day the sample is collected, what the post thaw motility is in addition to other parameters that are measured at this time.  Canine Cryogenics Canada will notify you at this time if the sample is adequate for storage and use in the future.   

A guarantee of producing a litter is not available.  The reason for this is again the number of variables that are involved once decision is made to use the frozen semen for insemination.  That is to say, the bitch is the other factor in the equation and if the monitoring of her estrous cycle is done correctly, the semen is of good quality with good post thaw motility and is prepared appropriately and the insemination of choice is suitable for the particular circumstance, your chances of success are very high.

As we all know, even natural breedings do not always take, so to guarantee 100% success with the use of frozen semen is impossible.