Avocados grow in tropical and mediterranean climates throughout the world.
Toxicity following the ingestion of avocado has been observed in cattle, horses, goats, sheep, rabbits, guinea pigs, rats, mice, canaries, budgerigars, cockatiels, ostriches, chickens, turkeys, and fish.
The ingestion of fruit (usually immature), leaves, stems, bark, and seeds has been associated with poisoning in animals. The toxic principle identified in avocado is persin. When isolated from leaves this compound caused mastitis in lactating mice at 60 mg/kg and myocardial necrosis at 100 mg/kg. Sheep fed 2.5 g/kg body weight for 32 days developed cardiac insufficiency. Guatemalan varieties are more commonly associated with symptoms and are thought to be more toxic.
The avocado tree can grow to 66 ft in height with ellliptical to egg-shaped leaves that are 4-12 inches long. The Mexican variety typically has smaller thin-skinned fruits while the Guatemalan varieties are characterized by medium to large fruit with rough, thick, woody skins. Hass avocados, popular in the US, are Mexican-Guatemalan hybrids.
Colic and diarrhea.
NSAIDS and analgesics may improve mastitis symptoms. Symptomatic treatment of cardiac insufficiency.
Cardiomyopathy, pulmonary edema, and necrosis of myocardial tissue.
In birds, acute respiratory distress and sudden death have been observed following the consumption of avocado. Caged birds appear to be more sensitive.
Horses develop edematous swelling of the lips, mouth, tongue, eyelids, head and neck which may result in respiratory distress.
No diagnostic tests readily available.
Diagnosis is based on history of exposure to avocado and clinical signs consistent with toxicity.
Exposure of livestock and horses to abandoned avocado orchards should be avoided.