Concept:Milk release after farrowing is controlled by the hormone oxytocin.Explanation:Oxytocin stimulates the let-down reflex, which releases milk from the sow's mammary glands.If the sow is not producing milk, an oxytocin injection can help eject the milk already present in the udder.Antibiotics treat infections, anthelmintic drugs remove worms, and sulphaquinoxaline treats coccidiosis.None of these drugs stimulate milk let-down in the sow.Answer:A. oxytocin