Kaeoket K
Faculty of Veterinary Science, Mahidol University, Phutthamonthol 4 Road, Salaya, Phutthamonthol, Nakorn-pathom, Thailand.
Reprod Domest Anim. 2008 Feb;43(1):127-9. doi: 10.1111/j.1439-0531.2007.00901.x. Epub 2007 Dec 7.
The aim of this study was to further investigate the effect of using progestin altrenogest and hCG to synchronize the oestrous cycle and its effect on follicular development, ovulation time and subsequent reproductive performance. Thirty crossbred gilts were divided into three groups. Group A (control) received a 5 ml of normal saline for 18 consecutive days by individually top-dressing. Groups B and C gilts received 20 mg (5 ml) of progestin altrenogest for 18 consecutive days by individually top-dressing. On day 3 (72 h) after withdrawal of progestin altrenogest, Group C gilts received hCG (500 IU, im). The follicular development and ovulation time were examined by transabdominal ultrasonography. Subsequent reproductive performances, i.e. number of total born per litter (NTB), number of live born per litter (NBA), number of stillbirth per litter (NSB), average piglet birth weight (ABW), lactation length (LL) and weaning to oestrous interval (WOI), were recorded. None of the gilts in Group A showed oestrus within 10 days after withdrawal of normal saline. Groups B (eight of 10) and C gilts (four of 10) came into oestrus at 5.6 +/- 0.5 and 6.5 +/- 0.6 days after withdrawal of progestin altrenogest, respectively. The ovulation time of Groups B and C gilts took placed at 25.0 +/- 4.7 and 25.0 +/- 5.0 h after standing oestrus, respectively. The pre-ovulatory follicular size (diameter) of Groups B and C gilts was 8.0 +/- 2.0 and 11.0 +/- 3.0 mm, respectively. A tendency of larger litter size (NTB) in Group B gilts was found when compared with Group A gilts. To conclude, using progestin altrenogest alone can be used to synchronize the oestrous cycle in gilts without unenthusiastic effect on the follicular development, ovulation time and subsequent reproductive performances. However, treatment of gilts with hCG at day 3 (72 h) after withdrawal of altrenogest had unenthusiastic effect on oestrus synchronization.
本研究的目的是进一步探究使用孕激素烯丙孕素和人绒毛膜促性腺激素（hCG）同步发情周期的效果及其对卵泡发育、排卵时间和后续繁殖性能的影响。30头杂交后备母猪被分为三组。A组（对照组）连续18天每天单独灌服5毫升生理盐水。B组和C组后备母猪连续18天每天单独灌服20毫克（5毫升）孕激素烯丙孕素。在停用烯丙孕素后的第3天（72小时），C组后备母猪注射hCG（500国际单位，肌肉注射）。通过经腹超声检查卵泡发育和排卵时间。记录后续繁殖性能，即每窝总产仔数（NTB）、每窝活产仔数（NBA）、每窝死胎数（NSB）、仔猪平均出生体重（ABW）、哺乳期长度（LL）和断奶至发情间隔（WOI）。A组后备母猪在停用生理盐水后的10天内均未发情。B组（10头中有8头）和C组后备母猪（10头中有4头）在停用烯丙孕素后的5.6±0.5天和6.5±0.6天发情。B组和C组后备母猪的排卵时间分别在静立发情后的25.0±4.7小时和25.0±5.0小时。B组和C组后备母猪排卵前卵泡大小（直径）分别为8.0±2.0毫米和11.0±3.0毫米。与A组后备母猪相比，发现B组后备母猪有产仔数（NTB）更多的趋势。总之，单独使用孕激素烯丙孕素可用于同步后备母猪的发情周期，且对卵泡发育、排卵时间和后续繁殖性能没有不利影响。然而，在停用烯丙孕素后的第3天（72小时）用hCG处理后备母猪对发情同步有不利影响。
