Intra-uterine insemination with low numbers of frozen-thawed boar spermatozoa in spontaneous and induced ovulating sows under field conditions

摘要

The present study was conducted to evaluate non-return rate (NR), farrowing rate (FR), and number of total pigs born/litter (TB) of weaned sows after ultra-uterine insemination (IUI) using low numbers of frozen-thawed (FT) spermatozoa. Semen from 6 boars was cryopreserved individually in a 0.5-ml straw, at a concentration of 1 x 10(9) spermatozoa/ml. A total of 40 multiparous sows with weaning-to-estrus interval of 3 to 7 days were included The sows were detected for standing estrus twice daily and randomly assigned to two groups: I) spontaneous ovulation (n = 20) and II) induced ovulation (n = 20) which the sows were given 750 IU human chorionic gonadotrophin (hCG) i.m. immediately at estrus detection Ovulation was determined every 12 h using transrectal ultrasonography. FT semen containing 1 x 10(9) motile spermatozoa/dose was used to IUI. In group I. the sows were inseminated at 24 h after the detection of estrus and repeated every 12 h until ovulation. In group II, the sows were inseminated at 36, 42 and/or 48 h after KG treatment. The results showed that the Interval from standing estrus to ovulation (EOI) differed significantly between group 1 (40 2 h) and group 11 (35.6 h: P = 0.01) Variation of EOI among sows within each group seemed to be lower in group 11 (4.5 h SD) than in group I (5 5 h SD. P = 0.5). The number of IUI per sow was 2.9 +/- 0 6 times in group I and was 24 +/- 05 times in group II There were no significant differences (P>0.05) in the NR (80 vs 85%), FR (60 vs 65%) and the TB (8.0 +/- 2.8 vs 9 4 +/- 3 7 piglets/litter) between the groups These results indicated that multiple doses of IUI with a low number of FT boar spermatozoa provided a fairly good NR, and reasonable FR and TB both in spontaneous and induced ovulating sows. The number of inseminations required for attaining acceptable fertility tended to be lower in the weaned sows with induced ovulation. (C) 2010 Elsevier B V All rights reserved