早熟母豬的女兒豬為早熟母豬的機率
張秀鑾(1) 吳明哲(1) 李世昌(1) 黃鈺嘉(1) 王旭昌(2) 陳保恒(2) 宋永義(2)
(1)行政院農業委員會畜產試驗所 (2)台灣區種豬發展基金會
在一歲齡前能產下女兒豬的母豬視為早熟母豬。本研究應用種豬登錄資料庫的種母豬資料，並設定母豬的出生年是在1994年以前者方納入本研究範圍。首先估算母豬產下女兒豬的年齡，並依該母豬分娩女兒豬時的年齡區分其所產女兒豬為'大女兒豬'或'小女兒豬'；意即該母豬在一歲齡以前產下的女兒豬為'大女兒豬'，而在四歲齡以後產下的女兒豬則為'小女兒豬'。隨後追蹤'大女兒豬'和'小女兒豬'產下第一頭孫女豬的年齡，依前述早熟母豬之定義，在一歲齡以前產下'大孫女豬'之女兒豬即視為早熟母豬。本研究計有12,160頭登錄為種母豬之孫女豬，其初產日齡最早者在藍瑞斯、約克夏和杜洛克品種分別為266、296和283天。分析結果發現三個品種中，早熟母豬的'大女兒豬'也是早熟母豬的機率，在藍瑞斯、約克夏和杜洛克種分別為7.38、4.41和9.19﹪；而'小女兒豬'是早熟母豬的機率則顯著地較低，分別為2.57、1.91和1.84﹪。不分品種比較時，'大女兒豬'和'小女兒豬'為早熟母豬的機率則分別為7.45和2.29﹪，顯示早熟母豬所產下的'大女兒豬'也是早熟母豬的機率為同母'小女兒豬'的三倍以上。因此，建議選留初產的女兒豬為種畜，應可縮短世代間距，加速選拔。
關鍵語：世代間距、品種、母性效應。
PROBABILITY OF EARLY MATURE DAUGHTER FROM EARLY
MATURE DAM IN PIGS
H. L. Chang(1), M. C. Wu(1), S. C. Lee(1), H. C. Huang(1)
H. C. Wang(2), B. H. Chen(2) and. Y. Y. Song(2)
(1)Taiwan Livestock Research Institute, Council of Agriculture
(2) Swine Improvement Foundation of Taiwan
Sows with 1st daughter by one year of age were defined as early mature sows in this study. Data of registered sows born by 1994 was used for analysis. Ages of sow at daughters born were calculated and used to identify the groups of daughters. Gilt was classified in 'eldest daughter' group if age of corresponding dam was by one year of old when gilt was born. Again, gilt was classified in 'younger daughter' group if age of corresponding dam was above 4 years of old when gilt was born. The same definition was applied in identification of granddaughter groups. In total, there were 12,160 registered granddaughter sows with minimum ages at first littering being 266, 296 and 283 days of old in Landrace (L), Yorkshire (Y) and Duroc (D) breeds, respectively included in the study. Results showed that probabilities of 'eldest daughter' from early mature dam being early mature sow were 7.38, 4.41 and 9.19﹪in L, Y and D breeds, respectively. Nevertheless, the corresponding probabilities of 'younger daughter' from early mature sow were 2.57, 191 and 1.84﹪in L, Y and D breeds, respectively which were significantly lower than those observed in 'eldest daughter'. Furthermore, probabilities of the 'eldest' and 'younger' daughters from early mature sows being early mature ones were 7.45和2.29﹪, respectively which indicated that the probability of the 'eldest daughter' being early mature one was three times that observed in the corresponding maternal 'younger ' female sibs when comparison was made in pooled data with breed effects negligence. In conclusion, it is suggested to select gilts from primiparous sows for replacement in order to shorten generation interval and thus to accelerate the genetic improvement in pig selection program.
Key Words: Generation interval, Breed, Maternal effect.