Nonhuman primates are usually euthanatized by an intravenous overdose of sodium pentobarbital (100 mg/kg).
Euthanasia in a CO2 chamber is effective for birds and is safe.
Sodium pentobarbital (100 mg/kg) can be administered intravenously or intraperitoneally.
Cervical dislocation of birds is rapid and inexpensive. It can be done manually with small birds. In large fowl, like turkeys and geese, an instrument like Burdizzo forceps is needed.
Decapitation with a guillotine or shears is effective with small birds.
Small birds can also be stunned (see guidelines on stunning).
Euthanasia of amphibians, fish, and reptiles has been studied less than euthanasia of other animals, and guidelines are less available.
When euthanasia of poikilothermic animals and aquatic animals is performed, the differences in their metabolism, respiration, and tolerance of cerebral hypoxia might preclude some procedures that would be acceptable in terrestrial mammals (AVMA, 1986).
Anatomic differences should also be considered. For example, veins can be hard to find. Some animals have a carapace. For physical methods, access to the CNS can be difficult, because the brain is relatively small and hard for inexperienced persons to find.
Euthanasia of Amphibians and Reptiles (UFAW/WSPA, 1989) suggests that, when physical methods of euthanasia of poikilothermic species are used, cooling to 4°C decreases metabolism and might facilitate handling; but there is no evidence that it raises the pain threshold. That report provides line drawings of the heads of various amphibians and reptiles with recommended locations for captive-bolt or firearm penetration.
Most amphibians, fishes, and reptiles can be euthanatized by cranial concussion followed by decapitation or some other physical method.
Decapitation with a guillotine or heavy shears is effective in some species that have appropriate anatomic features. It has previously been assumed that stopping blood supply to the brain by decapitation causes immediate unconsciousness followed by rapid loss of sensation. That view has recently been questioned, because the CNS of reptiles and amphibians tolerates hypoxic and hypotensive conditions (UFAW/WSPA, 1989). Decapitation should therefore be followed by pithing.