Artificial insemination in pigs today

Intrauterine insemination of sows with reduced sperm numbers: results of a commercially based field trial.

spermatozoa (46.7 and 39.1%, respectively). In contrast, the number of spermatozoa inseminated did not affect prolificacy. Laparotomy revealed that the tip of the flexible catheter reached approximately the anterior third of the uterine horn. Although deep intrauterine insemination was performed in only one uterine horn, the percentages of embryos collected from the tip of both uterine horns 2 days after deep insemination were not significantly different. The results show that in comparison with standard AI, a 20‐60-fold reduction in the number of spermatozoa inseminated and an 8‐10-fold reduction in the dose volume can be achieved without decreasing fertility when semen is deposited non-surgically into the upper first third of one uterine horn.

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Minimum number of spermatozoa required for normal fertility after deep intrauterine insemination in non-sedated sows.

This research was conducted to determine factors that influence duration of estrus, AI strategy, and reproduction results between and within commercial swine farms that use AI Data from 15,186 sows and gilts on 55 farms for a period of 61+/-42 mo per farm were used in this study The average duration of estrus was 484+/-10 h, ranging from 31 to 64 h, and was consistent from month to month within a farm (repeatability of 86%) Differences in duration of estrus between farms accounted for 23% of the total variation in duration of estrus On most farms (n = 45), gilts showed a shorter (P < 05) duration of estrus than sows (408+/-11 h vs 485+/-10 h) The duration of first estrus after weaning was longer (P < 0001) compared with that of repeat-breeder sows (502+/-10 h vs 468+/-10 h) Duration of estrus decreased (P < 05) when interval from weaning to estrus increased from 4 to 6 d (560 +/- 12 h vs 458 +/-12 h) The regression of interval from onset to estrus to first AI and interval from weaning to estrus varied between farms and ranged from -74 to +13 h/d; four farms had a positive relationship Farrowing rate decreased (P < 05) from 897+/-27% to 782+/-574 when the interval from weaning to estrus increased from 4 to 10 d The litter size decreased (P < 05) from 117 to 106 pigs when the interval from weaning to estrus increased from 4 to 7 d Compared with a single AI, double AI in sows and gilts resulted in a 43 and 70% higher (P < 05) farrowing rate, respectively When the first AI was performed after expected ovulation, reproduction results were lower than when AI was performed before or at expected ovulation in sows Duration of estrus was not related to farrowing rate or litter size in individual pigs Number of inseminations per estrus, time of AI, and duration of estrus were correlated, which made it difficult to assess which of these factors was primarily related to the farrowing rate or litter size Knowledge of average duration of estrus on farms and of factors that influence the duration of estrus on commercial farms can help to improve the efficiency of the AI strategy specific for each farm

Duration of estrus in relation to reproduction results in pigs on commercial farms.

A 100-fold reduction of the standard dose for artificial insemination in pigs (3 x 10(9) spermatozoa in 80-100 ml fluid) can be used when spermatozoa are deposited surgically next to the uterotubal junction. The present study was performed to develop a technique for non-surgical deep intrauterine insemination in pigs without sedation of the animal. In Expt 1, sows were weaned, treated to induce oestrus and used to evaluate the difficulties involved in the insertion of a flexible fibre optic endoscope through the cervix and along the uterine horn. Deep uterine catheterizations were performed on each sow at 30-40 h after hCG treatment in the crate in which the animal was housed. The endoscope was inserted through an artificial insemination spirette, moved through the cervical canal and propelled forward along one uterine horn until the entire endoscope was inserted. In 30 sows (90.9%) no or minor difficulties were observed during insertion and in these animals the procedure was completed in 4.1 +/- 0.26 min. Insertion of the endoscope through the cervical canal was not possible in only one sow (3.03%). In Expt 2, endoscopic deep intrauterine insemination at 36 h after hCG treatment was performed in 15, 18 and 13 sows with 100, 20 or 5 x 10(7) spermatozoa, respectively, resulting in farrowing rates of 86.6%, 88.9% and 92.3%, respectively; there were no significant differences among groups. Farrowing rates after deep intrauterine inseminations were also not different from those achieved after standard intracervical insemination with 3 x 10(9) spermatozoa (control group: n = 48; 87.5%). Mean litter size (9.41 +/- 0.38 to 10.02 +/- 0.25) was also similar among the different experimental and control groups. In conclusion, endoscopic non-surgical deep intrauterine inseminations can be performed quickly in sows, and normal farrowing rates and litter sizes can be obtained after insemination with a small number of spermatozoa.

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Successful non-surgical deep intrauterine insemination with small numbers of spermatozoa in sows

Semen backflow after insemination and its effect on fertilisation results in sows

This experiment was conducted to determine the effects of sperm dose at insemination on fertilization rates and accessory sperm cells attached to day 5 embryos. Multiparous sows (n = 115) were artificially inseminated once with 1 x 10(9), 3 x 10(9) or 6 x 10(9) sperm cells between 3 h and 48 h before ovulation. Transrectal ultrasonography was performed at intervals of 4 h to determine the time of ovulation and sows were killed at 120 +/- 5 h after ovulation to assess the results of fertilization. The insemination-ovulation interval had a major influence on the fertilization rate and accessory sperm count. A nonsignificant but consistent increase in fertilization rate and in number of accessory sperm cells due to the sperm dose was observed. During the insemination-ovulation interval of 12-24 h, the median fertilization rates were 95%, 100% and 100%, and the median accessory sperm counts were 11, 17 and 31 for the 1 x 10(9), 3 x 10(9) and 6 x 10(9) doses, respectively. During the insemination-ovulation interval of 24-36 h, the median fertilization rates were 88%, 95% and 97%, and the median accessory sperm counts were 6, 8 and 11 for the 1 x 10(9), 3 x 10(9) and 6 x 10(9) doses, respectively. No direct relationship was detected between embryo quality and the accessory sperm count but there was a relationship between insemination-ovulation interval and accessory sperm count. The fertilization rate was positively correlated with the breeding value for litter size of the sows. In conclusion, the effects of sperm dose on fertilization rate and on accessory sperm count in sows were small and nonsignificant, indicating only small effects of sperm dose on the functioning of the sperm reservoir in the sow.

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Influence of insemination-ovulation interval and sperm cell dose on fertilization in sows

The effects of stimulation and suppression of uterine contractility at about the time of insemination on sperm distribution and fertilization in multiparous sows are described. For assessment of fertilization, sows were inseminated about 28 h before (synchronized) ovulation and killed at day 5 after ovulation (n = 53). For assessment of sperm distribution, sows were inseminated about 20 h before expected ovulation and were killed 12 h later (n = 26). At 10 min before insemination, sows received an intrauterine infusion of one of three solutions: (i) saline (control); (ii) 0.60 mg clenbuterol hydrochloride to suppress contractility; or (iii) 1 mg cloprostenol to stimulate contractility. Both clenbuterol and cloprostenol reduced median fertilization rate (P < 0.05) and median number of accessory sperm cells (P < 0.05). Distribution of sperm cells was also affected by treatments. Clenbuterol increased, and cloprostenol decreased, the number of sperm cells (P < 0.05) in the proximal 20 cm of the uterine horn and in the uterotubal junction. In addition, clenbuterol tended to increase and cloprostenol tended to decrease the number of sperm cells in the isthmus, although these effects were not significant. However, relative to the number of sperm cells in the uterus, clenbuterol treatment reduced the number of sperm cells in the uterotubal junction and oviduct, in contrast to cloprostenol. Cloprostenol increased the reflux of semen during insemination. It is hypothesized that suppression of uterine contractility increases transuterine transport time, reducing the ability of sperm cells to enter the uterotubal junction and the oviduct. Stimulation of uterine contractility above a certain level probably increases reflux and impedes transuterine transport of sufficient numbers of sperm cells.

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E. G. Bouwman

Papers

Semen backflow after insemination and its effect on fertilisation results in sows

Influence of insemination-ovulation interval and sperm cell dose on fertilization in sows

Role of myometrial activity in sperm transport through the genital tract and in fertilization in sows

Seminal plasma does not advance ovulation in hCG-treated sows