If the usufruct be constituted on a flock or herd of livestock, the usufructuary shall be obliged to replace with the young thereof the animals that die each year from natural causes, or are lost due to the rapacity of beasts of prey.
If the animals on which the usufruct is constituted should all perish, without the fault of the usufructuary, on account of some contagious disease or any other uncommon event, the usufructuary shall fulfill his obligation by delivering to the owner the remains which may have been saved from the misfortune.
Should the herd or flock perish in part, also by accident and without the fault of the usufructuary, the usufruct shall continue on the part saved.
Should the usufruct be on sterile animals, it shall be considered, with respect to its effects, as though constituted on fungible things. (499a)