日本ザ-ネン種と沖縄肉用山羊の分娩季節と産子数

概要

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This study was made to determine the breeding season and litter size in the Okinawa meat goat and two populations of goats of the Japanese Saanen breed. The delivery rate for the Japanese Saanen breed in Japan proper was high (79%) in March and April. The percentage of females delivered in March and April was also high (57%) for the same breed in Okinawa prefecture. In the females of the Japanese Saanen breed in Okinawa prefecture, the delivery rates in other months were always higher compared with those in Japan proper. In the Okinawa meat goat, the highest percentage (34%) of delivery was observed in February and March.After March, the delivery rates decreased, falling to 3-6% during June and August, but from November, they increased again, indicating that Okinawa meat goats can reproduce throughout the year. Average litter sizes of the Japanese Saanen breed in Nagano and Okinawa prefectures were 1.9±0.7 and 1.7±0.7, respectively. Litter size at each parity in the populations of those two prefectures increased until the 4th parity. Although they decreased at the 8th parity in Nagano prefecture and at the 7th parity in Okinawa prefecture, no decrease of litter size until the 8th parity was observed in the Okinawa meat goat (average litter size, 1.7±0.6).
社団法人日本畜産学会の論文