Yes. Freezing sperm for preservation and subsequent fertilisation of ova, in humans and animals, has been routine for some decades now. Hence the term ‘sperm bank’ for collections of frozen sperm. Fertilised embryo freezing is also routine. If I recall correctly, the first successful human embryo freezing resulting in a subsequent pregnancy was in the early 1980s.
Although I don’t know it for a fact, I would be confident that artificial insemination using frozen sperm from other parts of the world would be involved in captive breeding of endangered animals.
The technical hurdles lie in ovum freezing which has not become as reliably routine as it is for sperm and embryos. The pregnancy success rate using frozen ova is much less than that of frozen embryos.
