Changes of plasma progesterone concentrations during the gestation and peripatum period, and return to estrus after parturition in Korean native goats

한국재래산양(韓國在來山羊)의 임신(姙娠) 및 분만전후(分娩前後)의 혈장(血漿) progesterone 농도변화(濃度變化)와 분만후(分娩後) 발정재귀시기(發情再歸時期)

The purpose of present study was to investigate the progesterone concentrations throughout gestation and peripartum period, and the return to the first estrus postpartum for improvement of reproductive efficiency in Korean native goats. The average length of gestation was 148 days(range : 144~154 days) and the average number of live births was 2 kids(range : 1~5 kids) in 12 Korean native goats. Progesterone concentrations were measured in blood samples taken from 12 goats every 5 days during gestation period. Plasma progesterone concentrations were 0.10 ng/ml at Day 0 of pregnancy and increased gradually until Day 20(6.58 ng/ml). Then they decreased slightly from Day 30 to 40(range : 4.32~4.82 ng/ml), increased again after Day 40 and remained thereafter until Day 140(range : 4.32~10.36 ng/ml). The progesterone levels declined sharply to basal levels at parturitum. Plasma progesterone concentrations during the pestpartum were 6.98 ng/ml at 10 days, 4.86 ng/ml at 6 days 3.18 ng/ml at 2 days before parturition, and 0.10 ng/ml at parturition, respectively. The basal levels were maintained until the first estrus postpartum. The mean intervals from parturition to the first estrus postpartum on the basis of progesterone determination and estrus detection were $100{\pm}64(mean{\pm}S.D.)$ days in 7 Korean native goats.