Is it permissible to purchase dogs from an endangered breed with the intention of preserving them, along with the possibility of using them for guarding in the future?

It is impermissible to buy, sell, or raise dogs, except for hunting dogs, livestock guardian dogs, or farm guardian dogs. This is based on the hadith narrated by Abu Hurairah (may Allah be pleased with him) from the Messenger of Allah (peace and blessings be upon him), who said: "Whoever keeps a dog, other than a dog for hunting, or for guarding livestock, or for guarding land, will have two qirats deducted from his reward every day." The sale of a dog and its price are unlawful; it is neither valid nor permissible.