Hi thukt. VERY interesting question!
Do you have Thoroughbred race horses that are registered with a Jockey Club? If so - the Jockey Club says that all TB's born have to be conceived via Live Cover - mare to stallion mating - otherwise the foal cannot get registration papers and run at Jockey Club ruled race tracks.
Is that how it is is Viet Nam? Or do you race at race tracks that are not under Jockey Club rules?
Next problem ...
Each country has different rules as to how a stallion must be quarantined in order to collect and freeze semen from him. The rules for Europe are different than those in Australia, and Australia is different from New Zealand which is different from South Africa just to give you some examples. So - someone would need to find out what the rules are for Viet Nam in order to quarantine their stallion to follow the Viet Nam rules.
I have frozen semen here for my TB stallion - Guaranteed Gold - but it has only been frozen to North American standards so I cannot ship it anywhere else in the world. And to be honest, I cannot think of one single stallion of any breed, anywhere in the world, that would have been frozen specifically for Viet Nam rules so someone (like you) would need to determine WHAT stallion or breeds you want for your mares, contact those stallion owners and see what can be done to satisfy and comply with your rules
Would importing specific mares and stallion work better for you instead, so you could offer THOSE stallions to other mare owners as well to breed to?
Let us know if we can help further ...
And if you need to contact me - my email address is: firstname.lastname@example.org