Eliasson L
Zentralbl Veterinarmed A. 1989 Jan;36(1):46-54. doi: 10.1111/j.1439-0442.1989.tb00701.x.
The main purpose of this study was to investigate the oestrous symptoms at puberty and during the two subsequent oestrous periods in the gilt. The investigation comprised a total of 369 purebred Swedish Yorkshire gilts. The gilts were carefully checked for oestrous symptoms twice daily, from 160 to 260 days of age, and blood samples for progesterone determination were drawn from 170 days until puberty. The duration of prooestrus was longer (p less than or equal to 0.001) at the at the first oestrous period than at the two subsequent oestrous periods and decreased (p less than or equal to 0.05) with an increase in age at puberty. Most of the oestrous symptoms were significantly correlated within the first and between the first three oestrous periods. Twenty percent of the gilts did not show standing reflex and anovulatory oestrus was found in 2% of the gilts at puberty, as demonstrated by progesterone determinations. The frequency of gilts not showing standing reflex at the second and third oestrus was approximately the same as at the first oestrous period. The first oestrous cycle was longer (p less than or equal to 0.001) than the second cycle. Approximately 95% of the gilts had a cycle length within 18 to 24 days at the first and second oestrous cycle.
本研究的主要目的是调查后备母猪青春期及随后两个发情期的发情症状。该调查共涉及369头纯种瑞典约克夏后备母猪。从160日龄至260日龄，每天对后备母猪的发情症状进行两次仔细检查，从170日龄直至青春期采集血样以测定孕酮。发情前期的持续时间在第一次发情期比随后两个发情期更长（p≤0.001），且随着青春期年龄的增加而缩短（p≤0.05）。大多数发情症状在第一个发情期内以及前三个发情期之间存在显著相关性。20%的后备母猪未表现出静立反射，通过孕酮测定表明，2%的后备母猪在青春期出现无排卵发情。后备母猪在第二和第三次发情时未表现出静立反射的频率与第一次发情期大致相同。第一个发情周期比第二个周期更长（p≤0.001）。在第一和第二个发情周期，约95%的后备母猪的发情周期长度在18至24天内。
