To investigate the age at puberty and the seasonal breeding in Korean native goats, progesterone concentrations were measured in blood. Blood samples were collected from 8 goats at 10 day intervals from 2 months of age until the first estrus after birth, and then every 5 days for a further estrous cycle and the seasonal breeding.
The mean age and weight at puberty were 195±57 days(mean±S.D., range : 107∼260 days) and ll.l±0.9㎏(range:9.8∼12.0㎏), respectively. The mean age at first pregnancy after birth was 241±109 days(range:107∼273 days).
The estrus was observed 47.6% from October to December, and was highest in fall(38.1%) and lowest in spring and summer(14.3%). However, the estrus was observed every season.
About 67% of total conception occurred form October to January. The parturition occurred 41.7% in spring, 25.0% in summer and winter, and 8.3% in fall, respectively.
These results suggest that Korean native goats do not have a breeding season, but the reproductive activity is influenced by the season.
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