Estrogen, progesterone, prolactin and glucocorticoids work synergistically at the onset of lactogenesis. Estrogen stimulates mammary ductal growth, and the combination of estrogen and progesterone regulates lobular-alveolar development of the mammary gland. This development does not occur in infertile animal or animals suffering from reproductive disorders due to relative absence of sex steroid hormones. Artificial induction of lactation can be induced in such animals by the combination of steroid hormones estrogen and progesterone. Additionally reserpine (tranquilizer- increases prolactin level) and dexamethasone (a synthetic glucocorticoid) can be used in induction protocols to increase the success rate.
Artificial induction reduces the involuntary culling rate as well as the genetic losses. To save such genetically superior bovines, induction of lactation is the most appropriate technology used under Indian conditions. The treatment is more effective in well-fed animals with good body condition score and having normal teat and udder. Hormonal induction of lactation should be practice only in infertile animals; it should not be followed as a routine practice, as an alternate to normal lactation. Estrogen and progesterone in 1:2.5 ratios is effective in exotic and cross bred while 1:1 ratio is effective in indigenous cows and buffaloes for artificial induction because of short luteal phase. These methods of artificial induction of lactation yield 60 to 70% milk of previous lactation.