A dairy owner finds 10% of his heifers dead after they ingested Furadan F. What should he administer immediately?

In cases of organophosphate poisoning, such as with Furadan F, atropine is the specific antidote to counteract the effects of poisoning. Organophosphates inhibit an enzyme called acetylcholinesterase, leading to an accumulation of acetylcholine at nerve synapses. This results in overstimulation of the nervous system, causing various clinical signs including salivation, vomiting, diarrhea, and respiratory distress.

Atropine works by blocking the action of acetylcholine at muscarinic receptors, thereby alleviating some of the symptoms caused by this overstimulation. Administering atropine can be crucial in managing the potentially life-threatening effects of organophosphate poisoning immediately after it is suspected or confirmed.

While activated charcoal could help in absorbing the poison if administered soon after ingestion, it is not as immediately effective in reversing the toxic effects as atropine. Neostigmine, on the other hand, is contraindicated in this situation because it would worsen the poisoning by further inhibiting acetylcholinesterase. Fluid therapy might be important in supportive care, but it does not address the specific toxicity of the poison directly.

Thus, administering atropine is the most appropriate immediate action in this scenario.