Question

Which hormone causes milk letdown in dairy cows?

• A. Prolactin
• B. Estrogen
• C. Oxytocin
• D. Progesterone

Hint:

Prolactin = produce milk; Oxytocin = release milk. Don’t mix these up!

Answer 1

The Correct Option is C

Milk production and milk ejection are regulated by different hormones. Prolactin stimulates the alveolar cells to produce milk. Oxytocin, secreted from the posterior pituitary gland, causes contraction of myoepithelial cells around the alveoli, pushing milk into the ducts so it can be removed during milking. Estrogen and progesterone prepare the udder during pregnancy but do not cause milk letdown. Stress inhibits oxytocin release — that’s why calm milking is essential.