Intra-uterine and Deep intra-uterine Insemination using Cryopreserved Boar Semen in Spontaneously-ovulating Sows บทคั ดย่ อ การผสมเที ยมแบบสอดท่ อเข้ าตั วมดลู กและปี กมดลู กด้ วยน้ ํ าเชื ้ อพ่ อสุ กรแช่ แข็ งในแม่ สุ กรที ่ ตกไข่ ตามธรรมชาติ คคนางค์ บู

Abstract The present study was performed to investigate the in vivo fertility of frozen-thawed (FT) boar semen after intra-uterine (IUI) and deep intra-uterine insemination (DIUI) in spontaneously-ovulating sows. A total of 48 weaned sows were included. The sows were divided into three groups, i.e. natural mating (NM) (n=30), IUI (n=9) and DIUI (n=9). In the IUI and DIUI groups, the sows were inseminated twice, at 24 and 36 h after the detection of oestrous by IUI with 2x10 9 spermatozoa/dose or DIUI with 1x10 9 spermatozoa/dose. Transrectal ultrasonography was used to determine the time of ovulation after insemination. The results revealed that the conception as determined by a 24-day non-return rate of the sows was 96.6%, 88.8% and 66.6% (p=0.03) and the farrowing rate (FR) was 96.6%, 66.6% and 66.6% (p=0.01) in NM, IUI and DIUI groups, respectively. The numbers of total piglets born per litter were 9.4±2.8, 11.3±2.9 and 7.6±3.1 piglets in the NM, IUI and DIUI groups, respectively (p=0.10). These data indicate that the spontaneously-ovulating weaned sows inseminated with either IUI or DIUI using a relatively low numbers of FT spermatozoa resulted in a lower FR compared to NM. The total number of piglets born per litter after IUI was higher than DIUI. Keywords: artificial insemination, frozen-thawed spermatozoa, ovulation, so

Effect of the administration of GnRH or hCG on time of ovulation and the onset of estrus-to-ovulation interval in sows in Thailand.

Abstract The aim of the present study was to evaluate the control of ovulation by the administration of human chorionic gonadotropin (hCG) or gonadotropin-releasing hormone (GnRH) at the onset of estrus. Thirty-three multiparous sows housed under tropical conditions and showing standing estrus within 5 days after weaning were included. The sows were allocated to three groups, spontaneous ovulation (control group, n = 10), induced ovulation using 750 IU hCG (hCG group, n = 10), and induced ovulation using 50 μg GnRH (GnRH group, n = 13). The hormones were given at the onset of estrus and the occurrence of ovulation was monitored every 6 h by transrectal ultrasonography. Data for weaning-to-estrus interval, onset of estrus-to-ovulation interval (EOI), and the length of estrus were recorded. All sows in the control and hCG groups ovulated, while 3 out of 13 sows treated with GnRH developed cystic ovaries (did not ovulate). Of those sows ovulating, the EOI of the hCG (40.2 ± 1.7 h) and GnRH (37.5 ± 3.3 h) groups were shorter than that of the control group (63.6 ± 9.6 h; P < 0.05). In conclusion, the administration of either hCG or GnRH at the onset of estrus can control time of ovulation but, at the dose employed, sows receiving GnRH may develop ovarian cysts