|J. Chin. Soc. Anim. Sci. 33(Suppl.)|
李世昌(1) 吳明哲(1) 賴永裕(1) 王旭昌(2) 謝明學(2) 宋永義(3) 張秀鑾(4)
種母豬群年繁殖效率之高低主要決定於出生時活仔數與胎距長短。登錄母豬於1992至2003年間的分娩資料，杜洛克有51,184胎，平均每胎出生活仔數為8.63 頭；藍瑞斯有83,932胎，平均每胎出生活仔數為9.45頭；約克夏27,636胎，平均每胎出生活仔數為8.92 頭。近12 年來，杜洛克由8.18+2.65頭(平均+標準偏差)增為9.32+2.42頭；藍瑞斯由8.91+2.76頭增為10.20+2.50頭；約克夏由8.77+2.85頭增為8.99+2.59頭。分娩胎數在1997年因口蹄疫事件而減少20~30%，但平均每胎出生活仔數卻增加，此乃因種豬場藉機進行精實方案，保留多產母豬。每年每品種的出生活仔數最大值界於15~22頭，杜洛克生最多的一胎是21頭活仔豬(2001年)，藍瑞斯生最多的一胎是21頭活仔豬(1994年)，約克夏生最多的一胎是22頭活仔豬(1997年)。登錄母豬的每胎出生活仔數資料是種豬場的經營管理系統中，可供評估該場豬群年繁殖效率用。台灣地處亞熱帶，月平均濕度的範圍在79.2%到85.2%，年平均濕度為82.7%，故全年均處於潮濕狀況，平均每日最低溫高於年平均溫度(23.2℃)的六、七、八月份為高溫多濕的季節。每年四月份至十一月份間，南部地區每日最高溫常在29℃以上，母豬群長期處於此環境下，其胚胎存活率、分娩率、出生時活仔數亦受到配種月份及配種後環境溫差的影響。
LITTER SIZE BORN ALIVE IN PEDIGREE REGISTERED SOWS
S. C. Lee(1), M. C. WU(1), Y. Y. Lai(1), H. C. Wang(2), M. S. Hsih(2), Y. Y. Sung(3), and H. L. Chang(4)
(1)Livestock Research Institute, Council of Agriculture,
Executive Yuan (2)National Animal Industry Foundation
(3)National Taiwan University (4)National Pingtung University of Science and Technology
Sow productivity depends on litter size born alive and gestation interval. Sows with pedigree registered were recorded for their birth data from 1992 to 2003. A total of 51,184 litters was used from Duroc sows and the average of litter size born alive was 8.63 head. There was 9.45 head of litter size born alive from Landrace sows of 83,932 litters. Yorkshire sows had 8.92 head born alive per litter from 27,636 litters in average. For the past 12 years, Duroc had 8.18+2.65 (Mean+SD) head born alive per litter and increased to 9.32+2.42 head; from 8.91+2.76 head up to 10.20+2.50 head in Landrace sows; from 8.77+2.85 head to 8.99+2.59 head in Yorkshire sows, respectively. Due to FMD outbreak in 1997, there was a decrease of 20~30% on number of litters registered resulting from sow culling. However, the average litter size born alive increased after keeping most of prolific sows in a nuclear herd. The largest number in a litter ranged from 15 to 22 of alive piglets in recording data. The largest one was 21 alive piglets in Duroc dated on 2001; 21 in Landrace dated on 1994 and 22 piglets in Yorkshire dated on 1997. Data of litter performance in a breeding herd is able to evaluate reproductive efficiency of a sow herd. Housing environment for sows in relation to temperature and relative humidity, like 79.2~85.2% of RH varied in month with a mean of 82.7% and along with hot weather during June to August above the 23.2℃ of annual mean temperature in Taiwan. Therefore, sows raised in the southern region of Taiwan during the period of April to November would cause fetal loss, low farrowing rate and small litter size born alive which associated with her mating month and pregnant months.
Key Words: Litter size born alive, Pedigree registered, Breeding pigs.