Importation of Frozen Semen from Overseas to NZ
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Advice Before Purchasing and Importing Frozen Semen From Overseas
Incorporating overseas genetics into your breeding program can be exciting and rewarding, but it is a complex process and can be expensive. There are 3 fundamental factors that determine the success of artificial insemination with frozen semen
- Breeding management and ovulation timing
- Artificial Insemination
- Frozen semen quality and quantity
We can control and optimise points one and two, but not point three. Where we put the semen, and when we put the semen in, are things we can control to give you the best chance of a pregnancy. At GlenBred, our pregnancy rate is greater than 83% with semen collected from dogs younger than 4 years of age and frozen by GlenBred. However, when the semen has been frozen elsewhere it is out of our control and unfortunately the quality and sometimes the quantity of frozen semen allocated per AI dose that we receive is sub optimal and we cannot compensate for these deficiencies. Poorly frozen semen is the most common cause for failure to achieve pregnancy. We recently published data in a peer-reviewed reproduction journal (see publications page on this website) from an analysis of over 1200 bitches inseminated at GlenBred in the past 10 years. We found that the most significant factor affecting pregnancy rate was semen quality. Therefore, to try and maximise your chance of purchasing and importing doses of frozen canine semen containing an adequate number of sperm and ultimately of high quality, we have put together some guidelines:
Semen Freezing – the facts
Once frozen, and so long as the semen is kept in well maintained liquid nitrogen tanks designed for long term storage, it will last forever without any significant decline in quality. We have produced a number of litters of puppies from semen frozen by Dr Marion Wilson (the founder of GlenBred) 35 years ago.
Factors that affect the quality and quantity of frozen semen:
There are several methods employed around the world to freeze canine semen. There is also enormous variation between centres and individuals that freeze canine semen in regards to their skills, experience, techniques and knowledge. It is therefore very important that whoever is collecting the ejaculate from your chosen dog for freezing is experienced and reputable. Be cautious of those who freeze canine semen using proprietary or ‘secret’ extenders and methods, or those that claim superior results are achieved with semen they freeze in pellets compared to straws. There is no objective evidence to this claim, and in many species it has been scientifically proven that there is no difference in post thaw motility and fertility between pellets or straws. Furthermore, as with other species, there are also many steps involved in freezing canine semen as well as a variety of different extenders that can be used, but there is neither one single method nor one extender that is significantly superior to others. Regardless of what extender and what method is used, the main determinants of good post thaw motility, and ultimately fertility, is the skill of the person collecting and freezing the dog, the individual dog and his inherent fertility. There are many factors that affect a dog’s fertility. Some of the more important factors include his age at the time of semen freezing, health status (especially in regard to his reproductive organs such as the prostate, testicles, epididymi), how often he is used at stud and importantly his reproductive history (especially whether he is a proven sire – ideally with both natural mating and with his frozen semen). There is variation in fertility and ‘freezability’ between individual dogs as the selection pressure for fertility is low. This variation is not only related to inherent individual factors but also breed, health and how often a dog has been used at stud and most importantly, age. Semen frozen from older dogs (> 5 years) is more unpredictable and generally has poorer results in regards to fertility
Semen Assessment – getting all the information you need before deciding to purchase frozen semen from overseas.
After an ejaculate is collected, and at each step in the freezing process, including assessment after thawing, a sample of semen should be removed and assessed under the microscope for a number of basic seminal parameters including motility, concentration, morphology, and cytology. A number of operators use a “CASA” system which is a computer assisted assessment method of objectively assessing semen. These systems provide print outs of a number of seminal parameters. These findings should be provided in a semen report which you can request prior to committing to the purchase of the frozen semen. Unfortunately, what is reported is not always representative of what we see once the semen arrives in New Zealand. It is not uncommon to thaw frozen semen with significantly poorer seminal characteristics than what was reported by the person who froze the semen. This is extremely disappointing and often heart breaking for the owner of the bitch who has put in considerable time and significant expense to import the semen all the way to New Zealand. However, at least having a report gives the bitch owner and purchaser a record of what they believe was purchased, in case compensation, replacement or reimbursement of the frozen semen needs to be discussed. Be skeptical when someone reports a post thaw progressive motility of greater than 80 or 90%. This would be an unusual finding, with most frozen-thawed canine semen having an average 50-55% progressively motile sperm after thawing.
Thaw media is a simple extender, usually containing the base chemicals of the freezing extender being used for freezing but without egg yolk or glycerol. For some freezing techniques, especially those that freeze in pellets, it is just saline that the frozen semen is thawed in. It is important to understand, that in most situations thaw media is not essential for thawing semen and won’t make sub-standard semen great semen, nor does it change the fertility of the semen; there are no magical “accelerants”. However, you should check with the providers of the frozen semen if using a thaw media is essential. Thaw media can be advantageous in regards to the volume of the insemination dose. Larger volumes can facilitate sperm transport in the uterus so if a thaw media is provided we will always endeavor to import it and use it. It is also important to note that not all thaw media can automatically enter New Zealand, so we need to investigate its eligibility prior to importation.
What is in an insemination dose?
The internationally accepted minimum number of frozen-thawed canine sperm per insemination dose is 100 million progressively motile sperm. A number of operators, especially in European countries, use double this dose per heat/cycle by carrying out two inseminations i.e using an entire dose of 100 million motile frozen thawed sperm at each insemination. This can result is greater success in regards to pregnancy rate and litter size.
What we recommend when embarking on importing frozen canine semen:
If possible, import two AI doses per heat/breeding (i.e. 200 million motile frozen-thawed sperm rather than 100 million motile frozen-thawed sperm):
Purchase an ejaculate rather than a dose of semen if possible:
One ejaculate can provide between 2 and 10 AI doses depending on breed, size and age of the dog. Limiting yourself to a single AI dose of ‘100 million sperm’ when the costs involved in importing frozen semen from overseas, monitoring a bitch for ovulation timing and ultimately carrying out an intrauterine insemination are significant, is not ideal. Therefore, if you are able to negotiate the purchase of an ‘ejaculate’ rather than an AI dose this will give you much greater control over the number of sperm inseminated per bitch. Stud fees can then easily be determined after AI or after pups are born and should not be linked to a minimum sperm number per AI dose.
Discuss semen quality with us prior to committing to the purchase of frozen semen and definitely before importing semen. Quality is more important than the technique used to freeze the semen. Specifically ask the owner of the dog for a detailed semen report prior to agreeing to purchase any semen. Some operators can also provide a video of the motility after thawing of the sperm you wish to purchase.
Investigate the fertility history of the dog – has he produced puppies and what age is his last litter? Has his frozen semen produced puppies? What age was the dog when his semen was frozen? We know that pregnancy rates are higher after AI with semen that was collected and frozen when the dog was young (< 4 years old).
What is in it for us?
We want what you want – a healthy litter of puppies! We believe that having invested the time and expense, you are entitled to receive sufficient, good quality semen to impregnate your bitch and give her the best possible chance of success.