A study was conducted to improve the reproductive performance of Korean native goats. The length of estrous cycle and plasma progesterone concentrations during each cycles were determined by both radioimmunoassay and estrus behaviours, and the results were used in the early pregnancy diagnosis.
The estrous cycles were classified into the short(l8 days or shorter, average 16.7 days), normal(19 to 22 days, average 20.9 days) and long(23 days and longer, average 23.8 days)cycle. The average length of the 19 estrous cycles was 20.8 days.
Plasma progesterone concentrations in 12 normal cycles were the lowest(0.10 ng/㎖) at estrus, remained high from 6 to 16 days(range : 4.43∼7.93ng/㎖) and drastically decreased thereafter to reach minimal concentrations at the next estrus.
Plasma progesterone concentrations were measured for early pregnancy diagnosis at 0, 10 and 20 days after mating in the 12 Korean native goats. Plasma progesterone concentrations in the pregnant goats at 20 days after mating were significantly hiF;her than in the non-pregnant goats(p<0.001).
Of the 12 goats, 10 were confirmed pregnancy by both progesterone concentrations and kidding. The accuracy of the pregnancy diagnosis based on plasma progesterone concentrations was 100% for positive as well as for negative.
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