How Can Light Increase Milk Production?
Melatonin is a hormone produced in the cow’s pineal gland. When light hits a cow’s eye, it signals the cow’s body to produce less melatonin. When it is dark, melatonin is produced. Cows have an internal clock that is set by melatonin production. This internal clock affects the production of other hormones that impact milk production. Long-day lighting increases the production of IGF-I (insulin-like growth factor – I). IGF-I is the same hormone that is increased by bovine somatotropin (bST). More IGF-I production in the cow boosts milk production.
