Artificial induction of lactation in 5 month old transgenic female calf

Abstract

The purpose of this study was premature induction of lactation in the transgenic calf to confirm the expression of human lactoferrin gene in the milk as early as possible. We performed the induction of lactation in 6 normal 1-month old calves and 3 normal and 1 transgenic 5-month old calves. In order to induction of lactation, 1-month old calf was injected with estradiol benzoate (0.2 mg/kg), 17-β estradiol cypionate (0.1 mg/kg) and progesterone (0.25-0.5 mg/kg) in every other day by 21 days. After 10 days cessation of administration, dexamethasone (0.028 mg/kg) was injected intramuscularly, however, lactation was failed. In the 5-month old calves, estradiol benzoate (0.2 mg/kg) and progesterone (0.5 mg/kg) were injected individually every other day during 21 days. After 10 days cessation of administration, dexamethasone (0.1 mg/kg) was injected intramuscularly and milk was lactated in the next day. Lactation was successfully induced in the 5-month old normal and transgenic calves and we confirmed the lactoferrin gene in the milk of transgenic calf. In conclusion, confirmation of human lactoferrin gene expressed in the milk of the transgenic calf was possible in 20 months earlier than in normal condition.