紐西蘭白兔分娩月份和窩仔數對哺乳仔兔體重之影響
李茂盛 李世昌 張秀鑾 吳明哲
台灣省畜產試驗所
本試驗以1990年1月至1997年12月的紐西蘭白兔分娩記錄5217胎，進行母兔分娩月份和窩仔數對哺乳仔兔出生重、三週齡重和存活率之影響的分析比較。母兔分娩月份為1~2月，其仔兔的出生重最重，有68.2g，顯著地較分娩月份為6~8月的仔兔出生重(57.3g)還重；而三週齡重則分別為400.6g和329.1g。在2月和7月出生的仔兔之三週齡存活率分別為89.7%和81.0%。當把窩仔數依出生時每胎活仔數歸類為小(1~3頭活仔兔)、中(4~8頭活仔兔)和大(9~17頭活仔兔)三種時，仔兔出生重、三週齡重和存活率均以窩仔數小的仔兔為最大值。窩仔數小、中和大的仔兔出生重分別為75.6、61.6和53.5g；三週齡重分別為473、344和282g；三週齡存活率分別93.3、87.0和77.0%(P<0.05)。結果顯示台灣夏季對紐西蘭白兔的出生重、三週齡重和存活率均有不利的影響，而來自窩仔數大的仔兔於哺乳期三週後之增重倍數僅有5.3倍，顯著地低於窩仔數小者(6.3倍)和中者(5.6倍)。
關鍵語：兔、季節、體重。
THE INFLUENCE OF FARROWING MONTH AND FRATERNAL
SIZE ON
BODY WEIGHT OF NURSING PUPS IN NEW ZEALAND WHITE RABBIT
M. S. Lee, S. C. Lee, H. L. Chang and M. C. Wu
Taiwan Livestock Research Institute
A total of 5217 litters of New Zealand White rabbits was recorded from January of 1990 to December of 1997. The influence of farrowing month and fraternal size on body weights of pups at birth and 3-week old and their survival rate. The birth weight of pups was the heaviest one, 68.2g, when they were born in January and February. It was significantly heavier than that of pups born in June to August (57.3g). They weighed 400.6 and 329.1g at 3-week old, respectively. Survival rates of 3-week old pups born in February and July were 89.7 and 81.0%, respectively. Three fraternal size groups: small (1~3 alive pups), medium (4~8 alive pups) and large (9~17 alive pups) were classified according to the number of born alive. Pups in the small group had a heaviest birth weight and 3-week old weight and a greatest survival rate. Birth weights of pups in the small, medium and large groups were 75.6, 61.6 and 53.5g; 3-week old weight were 473, 344 and 282g; and survival rate at 3-week old were 93.3, 87.0 and 77.0%, respectively (P<0.05). Results indicated that a summer depression on birth weight of pups and their 3-week old weight and survival rate existed in the summer of Taiwan. Nursing pups in the large fraternal size group increased only 5.3 times on body weight at 3-week old and it was significantly less than that of the small (6.3 times) and medium (5.6 times) groups.
Key Words: Rabbit, Season, Body weight.