if the entity is not in farming business than livestock will be treated only as it's stock in trade, but if you treat it as fixed assets than accouonting will be like this-
1.) While purchasing
Live stock a/c DR.
To Cash/bank a/c Cr.
-- we can not charge depreciation on it, as life can not be estimated therefor there will be no entry for dep.
2.) Entry when livestock is dead / discarded
Cash/bank a/c DR.
(amt. recovered from sale of live stock or if its dead than amt. recovered from its residue)
To Live stock CR.
-- Diff in live stock a/c will be profit / loss from its disposal and it will be transfered to P/L account.