Theage at puberty and the breeding season in Korean native goats

Kang, Byong-kyu; Choi, Han-sun; Park, Young-jun; Park, Bum-jun; Son, Chang-ho

Korean Journal of Veterinary Research 1992;32(2):275-280.

Byong-kyu Kang, Han-sun Choi, Young-jun Park, Bum-jun Park, Chang-ho Son

College of Veterinary Medicine, Chonnam National University

한국재래산양(韓國在來山羊)의 성성숙일령(性成熟日齡) 및 계절번식성(季節繁殖性)

강병규, 최한선, 박영준, 박범준, 손창호

전남대학교 수의과대학

Abstract

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 $195{pm}57$ days($mean{pm}S.D.$, range : 107~260 days) and $11.1{pm}0.9kg$(range : 9.8~12.0kg), respectively. The mean age at first pregnancy after birth was $241{pm}109$ 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.

Key Words: progesterone, puberty, seasonal breeding, Korean native goat