Why Milk Can Be Drawn Anytime from Goats

Why can we draw milk at any time from a goat without a letdown stimulus?

Correct Answer: Oxytocin reflex is not required in goat for letdown AND goat stores up to 80% of milk in the cisterns

Both reasons together explain why milk can be drawn from goats at any time: (1) No oxytocin reflex is required for letdown in goats, and (2) Goats store up to 80% of their milk in the cisternal fraction — which is freely available without hormonal stimulation.

Milk Storage Proportions (Cistern:Alveolus)

• Goat: 80:20 — most milk is in the cistern (freely available).
• Sheep: 50:50
• Cattle: 30:70
• Buffalo & Camel: 5:95
• Sow: 0:100 (all in alveoli)

Letdown Mechanism

• In most animals, milk ejection requires oxytocin release (triggered by suckling or milking stimulus), which causes myoepithelial cell contraction around alveoli → milk moves into cisterns and ducts.
• In goats, this reflex is largely bypassed because most milk is already stored in the cistern and can be expressed freely at any time.

Why Other Options Are Wrong

• Oxytocin reflex not required only → incomplete; the cistern storage is the primary structural reason.
• Stores 80% in alveoli → opposite of the truth; it is 80% in cisterns.
• Always-open teat canal → not a documented anatomical feature.