Multiple Estradiol Benzoate Treatment Enhances Milk Production on Induction of Artificial Lactation in Pseudopregnant Pigs.

This study investigated the effects of multiple treatments of estradiol benzoate (EB) prior to the induction of luteal regression on the efficiency of artificial lactation induction and milk yield in pseudopregnant sows. Pseudopregnant females induced by treatment with 30 mg estradiol dipropionate (EDP) were administered 2 mg (Group EB 2 mg, n = 5) or 3 mg (Group EB 3 mg, n = 6) EB on Days-10, -7, and -4 (Day 0 = the day of prostaglandin F_2α [PGF_2α] treatment). Six pseudopregnant sows (Group EDP) received 5 mg EDP on Day -10.5 ± 1.6. The induction efficiency of artificial lactation, collected milk volume and immunoglobulin concentrations in the milk obtained from sows after PGF_2α treatment were analysed. The dosage of EB treatment before PGF_2α administration had no significant effect on either the induction rate of artificial lactation or the milk yield during the experimental period. Harvested milk volumes from EB-treated pseudopregnant sows were higher than those in Group EDP. The immunoglobulin levels in harvested milk from artificial lactating sows did not differ between the EB-treated groups. In conclusion, multiple EB treatments prior to PGF_2α administration increased milk production in pseudopregnant sows but did not affect the efficiency of artificial lactation induction.