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PubMedDate not supplied

Intrauterine insemination with husband's semen as alternative to other assisted reproduction techniques.

The objectives of this study was to assess the efficacy and clarify how many intrauterine insemination cycles can justifiably be proposed, in terms of cost and benefits for the patient, as alternative to other assisted reproduction procedures. Two hundred and twenty infertile couples were referred to our centre and six intra-uterine insemination cycles in combination with controlled ovarian hyperstimulation were proposed for them. A total of 650 treatment cycles were completed. The indications of intra-uterine insemination were male factor (147 couples), cervical factor (31 couples), male and cervical factor (30 couples) and unexplained infertility (12 couples). Superovulation was induced in 92 patients with human menopausal gonadotrophins, in 90 with clomiphene citrate, in 22 with FSH HP, while in 16 patients the intra-uterine inseminations were carried out during spontaneous cycles. Considering the entire population, a mean monthly pregnancy rate equal to 8.9% was obtained and a cumulative pregnancy rate equal to 39% at the end of six intra-uterine insemination cycles. In particular, in the patients treated with HMG+hCG, a mean monthly pregnancy rate equal to 10.9% and a cumulative pregnancy rate to 46% at the end of the six cycles were obtained. In conclusion, when the indications allow, we believe it is justified to propose six cycles of intra-uterine insemination in combination with controlled ovarian hyperstimulation with HMG and hCG. The theoretical probability of success at the end of six cycles has proved comparable and advantageous in terms of cost and risks for the patient, if compared with other assisted reproduction techniques.

Adult↗
PubMed1998

Deep uterine insemination of cattle: a fruitful way forward with smaller numbers of spermatozoa.

After describing the site of fertilisation and that of the functional sperm reservoir in the female tract, proposals are made concerning a modified site of sperm deposition in cattle. By means of a deep pre-ovulatory insemination into the ipsilateral uterine horn, the chances should be raised of establishing viable spermatozoa in the isthmus where they would undergo a form of physiological encapsulation and storage. Release and activation of such spermatozoa would be prompted by imminent ovulation. Potential advantages of this approach include those of raising the overall fertility of genetically valuable bulls whose non-return rates are sub-optimal; reducing the number of spermatozoa in each insemination dose; using effectively the limited numbers of sex-selected sperm cells (X and Y chromosome bearing spermatozoa) currently available from flow cytometry. Putative disadvantages might include rectal palpation of the ovaries to locate the pre-ovulatory follicle; perforation of the uterine wall by the deep insemination catheter; risk of polyspermic fertilisation; and the inappropriateness of the technique for non-clinically qualified inseminators. Each of these reservations is responded to in a rational manner. Given a change of attitude, a modified technique of insemination would be feasible under commercial conditions and might give a welcome boost to a sagging artificial insemination industry.

Animals↗
PubMed1976

[The frequency and causes of spontaneous abortion following artifitial insemination (author's transl)].

This paper is concerned with the causes of spontaneous abortion in a sample of 200 pregnancies induced by artificial insemination. In particular it examines the importance of the following factors: existing disorders in the woman's menstrual cycle, the influence of hormone treatment during the conception cycle, the age of the woman treated, and the type of semen used. Of the 200 pregnancies in our treatment sample 27 terminated in abortions (13.5%). Clinical examination before treatment established the presence of menstrual disorders in 69 of 180 women to be treated: 23.9% exhibited corpus luteum deficiency, 12% anovular cycles, and 2% oligomenorrhea. On the basis of this preliminary examination the principal cause of abortion proved to be an existing corpus luteum deficiency, since 15 of the 27 abortions occurred in women with this type of menstrual disorder. Our observations show that it is important when performing artificial insemination to correct the patient's existing menstrual disorders by means of hormone treatment. This emerges from the following figures: In 26 cases without hormone treatment the incidence of abortion was 35%. In 174 cases that received hormone treatment during the successful cycle only 18 abortions occurred (an incidence of 10.3%). Breaking down hormone treatment into 6 basic types, we get incidences of abortion ranging from 0 to 25% in the different groups. Dividing the treatment sample into age groups reveals an 11 to 14% incidence of abortion in the 30 to 34 age group; in the 35 to 40 group age group the incidence doubles to 26%. Whereas existing menstrual disorders and adequate hormone treatment significantly influence the incidence of abortion, there is no close relationship between incidence of abortion and the type of semen used. The innocuousness of using deep-frozen semen with an admixture of glycerine has been shown by various authors reporting on laboratory and clinical investigations. For 117 pregnancies induced purely with deep-frozen semen we had an incidence of abortion of 13.7%. This figure is of the same order as the incidence of abortion in pregnancies induced by insemination with fresh semen. The results obtained permit one to conclude that incidence of abortion is not significantly dependent on the type of semen used. Our work demonstrates the importance of assessing the patient's genital constitution from both the functional and the organic points of view, not merely in order to achieve conception but also for the purposes of preventing abortion by means of the appropriate hormone treatment. If satisfactory therapeutic results are to be achieved candidates for artificial insemination must therefore be given a thorough diagnostic examination beforehand and, if necessary, adequate hormone treatment during the insemination cycle.

Abortion, Spontaneous↗
PubMed1987

Penetration of mouse eggs at various intervals after insemination as influenced by concentration of sperm and strain of male.

This study was conducted to determine the extent to which the percentage of mouse eggs that were penetrated by sperm at the end of the period of sperm penetration was due to the proportion of eggs penetrated per unit of time and to the span of time of sperm penetration. Female mice of ICR strain were inseminated 1.5 hr after ovulation with 5 X 10(6) sperm/50 microliter from males of DBA/2N, CF1 or C57BL/6N strains to determine the effect of the male. To determine the effect of concentration of sperm ICR females were inseminated with 2, 4, 6, or 8 X 10(6) sperm/50 microliter from CF1 males. Females were killed at various intervals after insemination and the eggs were recovered and examined for evidence of penetration by a sperm. The time intervals from both insemination to the onset of egg penetration and from insemination to cessation of penetration were similar for the three strains of males. Throughout the period of penetration of eggs a constant percentage of eggs was penetrated per hour for a particular strain of male. The relative percentage penetrated per hour very closely approximated the relative percentage of eggs finally penetrated for each strain of male. The percentage of eggs penetrated per hour was linearly positively related to the concentration of sperm inseminated. The final percentage of eggs penetrated depended primarily on the rate at which the eggs were penetrated during the period of sperm penetration and not on the length of the period of egg penetration which was constant.

Analysis of Variance↗
PubMed1988

Comparison of heterospermic and homospermic inseminations as measures of male fertility.

This study attempted to determine a basis for the previously observed greater sensitivity of heterospermic tests when compared to homospermic tests for detecting differences in fertility between males. In theory, the results of heterospermic tests are an indication of the proportion of eggs fertilized per unit time whereas results of homospermic inseminations measure only the cumulative or final proportion of eggs fertilized. The fertilizing ability of sperm from males of CF1 and C57BL/6N strains of mice was compared homospermically using both relatively high and low concentrations of sperm and by measuring the proportion of eggs penetrated per unit of time. The fertilizing ability of sperm from these strains was also compared using heterospermic inseminations. When females were inseminated with a high concentration of sperm, males of both strains fertilized a high and indistinguishable percentage of eggs when examined after 30 hr. When females were inseminated with either a low concentration of sperm or when the proportion of eggs penetrated was measured at 5 hr, differences between strains of mice were distinguishable. Heterospermic insemination further magnified the observed difference between strains. The results of this study confirm that measuring the percentage of eggs fertilized per unit of time can enhance the magnitude of differences between males in fertility as compared to measuring only the final percentage of eggs fertilized. Measuring the percentage of eggs fertilized per unit of time does not, however, entirely account for the large differences observed between fertility of males when they are compared using heterospermic inseminations.

Animals↗
PubMed1985

The evaluation of a laparoscopic insemination technique in ewes.

Following synchronisation of oestrus using FGA and PMSG, ewes were inseminated by either the conventional cervical (CC) method or directly into the uterus by laparoscopy (LI). The CC method was carried out either at 48 and 60 hours following progestagen withdrawal with 480 x 10(6) spermatozoa per inseminate or once only at 56 hours with 600 x 10(6) spermatozoa. The laparoscopic method was performed at 52 hr using 48 x 10(6) spermatozoa per ewe. In the first two trials eggs were recovered at laparotomy. The egg recovery rate was significantly lower (P<0.05) for those ewes which had been inseminated by the LI method (74%) compared with those inseminated by the CC method (85%); fertilization rates were not significantly different (92% and 89% respectively). In the third trial 20 ewes were bled to determine their periovulatory LH concentrations and the timing of peak LH concentrations correlated with the outcome of each insemination. Ewes inseminated using laparoscopy did not conceive when their LH surge occurred >58 hr after progestagen withdrawal. In this and in the final experiment, the combined pregnancy rates and litter sizes (assessed radiographically) were 67% (n = 51) and 2.21 (n = 34) for the CC method and 75% (n = 48) and 1.97 (n = 36) for the LI method (P>0.05).

Journal Article↗
PubMed1987

Transferable embryo recovery rates following different insemination schedules in superovulated beef cattle.

The objective of this study was to evaluate the transferable embryo recovery rates from superovulated donor cattle after different artificial insemination (AI) schedules. Sixty mixed-breed crossbred females were administered follicle stimulating hormone (FSH) and prostaglandin F(2)alpha (PGF(2)alpha) to induce a superovulatory response. At standing estrus, donor females were randomly allotted to one of five treatment groups for AI. Donors were inseminated with two units of high-quality or low-quality frozen semen at 12, 24, 36, or 48 h after the onset of estrus in treatment Groups I, II, III, and IV, respectively, or inseminated with two units at 12, 24, 36, and 48 h (eight units/donor) in control Group V. Donor females inseminated once at either 12 or 24 h after the onset of estrus did not differ from donors inseminated in Group V in overall fertilization and transferable embryo recovery rates. The highest fertilization rate (89.5%) and transferable embryo recovery rate (74.9%) per donor resulted when AI was performed with high-quality semen at 24 h after the onset of estrus. These findings indicate that repeated insemination of superovulated beef cattle is not necessary to attain optimal fertilization rates and production of transferable quality embryos in beef cattle.

Journal Article↗
PubMed1989

A method of artificial insemination in captive White-tailed deer (Odocoileus virginianus ).

Production of fawns by artificial insemination in captive White-tailed deer (Odocoileus virginianus ) has been accomplished by using frozen-thawed spermatozoa. The purpose of this study was to determine if frozen-thawed semen deposited at the posterior face of the os cervix could produce conception. Five hand-raised female White-tailed deer and one hand-raised male White-tailed deer were used over two breeding seasons 1984-1985 and 1985-1986. The vasectomized buck was ued to detect estrus in the does. The does were inseminated with frozen-thawed semen containing at least 100 million live normal cells with a 60% or higher motility. The artificial insemination catheters used in this study worked well, but due to the small size of the cervix, the catheter could only be passed up to the first cervical ring, the site at which the semen was deposited. Over two breeding seasons, nine does were inseminated with frozen-thawed spermatozoa; each doe was inseminated once each estrous cycle at one of the following times: 0, 6, 12, 18, 24 or 30 h. after detection of estrus. Of the nine does inseminated with frozen-thawed spermatozoa, six conceived and carried to term 11 healthy normal fawns, yielding an overall conception rate of 67%.

Journal Article↗
PubMed1992

The effect of sperm number on fertility in blue fox vixens (Alopex lagopus ) artificially inseminated with frozen silver fox (Vulpes vulpes ) semen.

During the breeding seasons of 1989 and 1990, a total of 617 blue fox vixens aged 1 to 6 years (mean +/- SEM, 2.6 +/- 0.1) were inseminated with frozen silver fox semen with either 150 million (n = 213, 1989 + 1990), 100 million (n=172, 1990), 75 million (n = 119, 1989) or 37.5 million (n = 113, 1989) spermatozoa per insemination. Two intrauterine inseminations, each with an insemination volume of 1.0 ml, were performed at 24-hour intervals on the first and second days after maximum vaginal electrical resistance was measured. Conception rates were 87% (186 of 213) with 150 million spermatozoa per insemination, 85% (146 of 172) with 100 million, 77% (91 of 119) with 75 million and 68% (77 of 113) with 37.5 million. The mean numbers of cubs per litter +/- SEM for the four groups were 7.6 +/- 0.2 (168 registered litters), 7.5 +/- 0.3 (115 litters), 6.4 +/- 0.4 (86 litters) and 6.4 +/- 0.4 (75 litters). A negative effect on both the conception rate and mean litter size at whelping was observed with decreasing sperm numbers (conception rate percentage: p = 0.0001, Chi-square, litter size: p = 0.02, Kruskal-Wallis Test). Only the two larger numbers of spermatozoa gave litter sizes comparable to those obtained by artificial insemination (AI) with fresh semen.

Journal Article↗
PubMed1992

Conception rates in dairy cows after timed-insemination and simultaneous treatment with gonadotrophin releasing hormone and/or prostaglandin F2 alpha.

This study was designed to determine conception rates in dairy cows after timed-insemination and simultaneous treatment with gonadotrophin releasing hormone (GnRH) and/or prostaglandin F2 alpha (PGF2alpha). A total of 2352 cows was randomly assigned to six groups. Cows in Groups 1 to 5 were palpated per rectum to determine the presence of a corpus luteum (CL) on the ovary, and blood samples were obtained for the determination of plasma progesterone (P4) concentrations. Cows with a CL and P4 concentrations >1 ng/ml were treated (Day 0) with PGF2alpha (25 mg, i.m.) and were observed for estrus. Cows in estrus prior to 72 hours after treatment (Group 5, n = 106) were bred, but were not treated. Cows not observed in estrus by 72 hours were divided into four remaining groups, were bred between 72 and 80 hours and were assigned as follows: Cows in Group 1 (n = 203) were not treated; Cows in Group 2 (n = 200) were treated with GnRH (100 ug, i.m.); Cows in Group 3 (n = 201) were treated with PGF2alpha (25 mg, i.m.); and cows in Group 4 (n = 202) were treated with both GnRH and PGF2alpha. Cows in Group 6 (n = 1440) were not treated with PGF2alpha on Day 0 and were estrual cows that were bred on days when cows in Groups 1 to 5 were time-inseminated. The percentage of cows in all groups pregnant at 45 to 50 days after one insemination was compared using analysis of variance (P<0.05). The conception rate of cows in Group 2 was significantly higher than that of cows in Groups 1 to 4. There was a significant group-by-season interaction. Cows treated with GnRH during the spring had a higher conception rate than at other times of the year. Conception rates of cows in Groups 1 to 4 that were inseminated during the summer were low and not significantly different from each other. Conception rates of cows in Groups 5 and 6 inseminated during the summer were not significantly different from each other, but were significantly higher than that of cows in Groups 1 to 4 that were inseminated during the summer.

Journal Article↗
PubMed1992

The optimum time for single artificial insemination of blue fox vixens (Alopex lagopus) with frozen-thawed semen from silver foxes (Vulpes vulpes).

During the breeding season of 1991 a total of 608 blue fox vixens aged 1 to 6 years (2.3 +/- 0.1 years, mean +/- SEM) from 2 farms were artificially inseminated intrauterine once with frozen-thawed silver fox semen (1 ml dose containing a total of 150 million spermatozoa). The vixens were allocated to 3 different groups according to the time of insemination. Vixens in Group 1 (n = 203), Group 2 (n = 198), and Group 3 (n = 207) were inseminated on the first, second or third day after the peak value of vaginal electrical resistance, respectively. An overall conception rate of 75% (456 of 608) and 6.0 +/- 0.1 (mean +/- SEM) cubs per litter was obtained. Conception rates and mean litter sizes were significantly different between groups of vixens with respect to day of insemination (P = 0.02, Chisquare, Kruskall-Wallis Test). Vixens inseminated on the second day (Group 2) had the highest conception rate (81%) and the largest mean litter size (7.0 +/- 0.2 cubs) of the three groups, while those inseminated on the third day (Group 3) had the lowest conception rate and mean litter size (70%, 5.4 +/- 0.3 cubs).

Journal Article↗
PubMed1994

Insemination results with slow-cooled stallion semen stored for 70 or 80 hours.

An insemination trial was conducted to evaluate the fertility of extended slow-cooled stallion spermatozoa stored for 70 h or 80 h at 5 to 7 degrees C before insemination. Then, 1 or 2 of the first sperm-rich fractions were collected with an open-ended vagina from 4 stallions. Semen from each stallion was diluted within 2 to 3 min after collection with a modified Kenney skim milk extender (6). The proportion of raw semen in the insemination doses was 24+/-6%. One insemination dose (25 to 50 ml) consisted of approximately 2 billion total spermatozoa. In the trial, palpation per rectum and ultrasonography of 34 mares (40 cycles) were performed every 12 h. The pregnancy rate per cycle (30-d) with semen stored for 70 h before insemination was 77% (17 cycles) and, with semen stored for 80 h, 57% (23 cycles). The difference was not statistically significant. The combined pregnancy rate per cycle was 65%. These results indicate that stallion semen can retain its fertilizing capacity for up to 80 h when collected and diluted using this procedure and when the inseminations are done less than 12 h after ovulation.

Journal Article↗
PubMed1995

Factors influencing the success of transcervical insemination in Merino ewes.

The experiments described examined the effects of a number of factors on the level of uterine insemination achieved in Merino ewes by a transcervical insemination technique (Guelph system for transcervical artificial insemination; GST-AI). Cervical penetration rate is an important limitation to the use of such methods in Merinos. Simulated insemination was performed to estimate the proportion of ewes in which a pipette could be passed through the cervix to the uterus. In Experiment 1, cervical penetration rate (n = 14 to 30) was unaffected by an increase in postpartum interval at AI from 12 to 26 wk. The results of cervical penetration for individual ewes were found to be repeatable (P < 0.05). Experiment 2 (197 ewes) revealed a clear effect of ewe parity on penetration rates in hormonally synchronized ewes during the nonbreeding season (P < 0.05). In Experiment 3, estrus synchronization using progestagen (n = 51) or prostaglandin (n = 50) did not affect penetration rate. The penetration rate was slightly higher in the naturally cycling ewes, but the difference was not significant. Comparison of ewes from Experiments 2 and 3 suggests the possibility of a major effect of stage of the breeding season on the penetration rate (P < 0.05). It is concluded that ewe selection and management techniques may be used to increase the proportion of transcervical insemination attempts resulting in uterine insemination. However, fertility testing will be required to determine whether such improvements translate into correspondingly increased pregnancy rates.

Journal Article↗
PubMed1995

Intraperitoneal insemination in repeat-breeder cows: a preliminary report.

Intraperitoneal insemination of 62 repeat-breeder dairy cows resulted in 9 pregnancies. The pregnancy rate was not different for intraperitoneal or uterine inseminations. In nonpregnant cows, reproductive variables such as the percentage of cows returning to estrus, the average interval from insemination to the next estrus, and the pregnancy rate following subsequent uterine insemination were not influenced by intraperitoneal insemination. Our results suggest that intraperitoneal insemination could be an alternative procedure to the usual deposition of semen into the uterus in repeat breeder cows.

Journal Article↗
PubMed1995

Comparisons between three different extenders for canine intrauterine insemination with frozen-thawed spermatozoa.

Ejaculates from 7 dogs were obtained on the same day and were pooled. This pooled semen was separated into 3 equal fractions and processed simultaneously, the only difference being in the extender used for freezing. The extenders were laiciphos (containing laiciphos, egg yolk, distilled water and glycerol- Group 1); Tes/Tris (containing Tes/Tris, egg yolk, distilled water and glycerol- Group 2); and biociphos (containing biociphos with glycerol in it, egg yolk and distilled water- Group 3). Spermatozoa were conditioned in 0.5ml French straws and presented normal characteristics before freezing and after thawing. The sperm concentration of the pooled was 683 x 10(6) sperm/ml; sperm motility was above 95%, the percentage of live spermatozoa was above 95% and was of good quality and mobility. Characteristics of the spermatozoa after thawing were the same for spermatozoa frozen with laiciphos and Tes/Tris. Mean sperm concentration was 201.5 +/- 4.95 x 10(6) sperm/ml, sperm motility was 65%, the percentage of live spermatozoa was 80% and the quality of motility.was good. Spermtozoa frozen with biociphos had the following post-thaw characteristics: sperm concentration was 201 x 10(6) sperm/ml, sperm motility was 50%, the percentage of live spermatozoa was 78% and the quality of mobility was medium. Abnormalities were less than 15% for all spermatozoa after thawing. Intrauterine artificial inseminations were performed by laparoscopic intrauterine insemination twice at Days 3 and 5 after the estimated LH peak in 15 normally cyclic Beagle bitches (5 per group) presenting normal hormonal profiles. There were no differences between groups. The females were inseminated with 1.0 ml of spermoatozoa (concentration of 200 x 10(6) sperm/ml) diluted with 1.0 ml of extender. A 60% pregnancy rate was obtained in bitches inseminated with frozen-thawed spermatozoa extended with laiciphos or Tes/Tris and 100% in bitches inseminated with spermatozoa extended with biociphos. Females inseminated with laiciphos, Tes/Tris and biociphos had a mean litter size of 5 +/- 2.6, 3 +/- 1 and 3.4 +/- 1.3 pups, respectively. This study demonstrated that post-thaw assessment of sperm characteristics is not the best technique for evaluating sperm fertility after freezing or for assessing different semen extenders.

Journal Article↗
PubMed1996

Synchronization of estrus in yearling beef heifers with the melengestrol acetate/prostaglandin F(2alpha) system: efficiency of timed insemination 72 hours after prostaglandin treatment.

Two experiments were conducted to determine the conception rates of heifers time-inseminated following melengestrol acetate/prostaglandin F(2alpha) (MGA/PG) estrous synchronization treatment. In Experiment 1, timed insemination of heifers at 72 h after the PG injection, without regard for behavioral estrus, tended to improve (P < 0.15) the percentage of heifers pregnant to artificial insemination (AI) compared with that of synchronized heifers bred 12 h after they were first detected in estrus. In the timed-insemination treatment, heifers exhibiting behavioral estrus 48 to 72 h after PG tended to have an increased (P < 0.15) conception rate to AI compared with heifers exhibiting estrus within 48 h of PG administration. In Experiment 2, the number of heifers conceiving to AI following the MGA/PG estrous synchronization regimen was increased by mass insemination of all heifers not exhibiting estrus by 72 h after PG. The pregnancy rate to AI was higher in heifers with serum progesterone (P(4)) concentrations higher than 1 ng/ml compared with that of heifers with concentrations lower than 1 ng/ml. Of heifers with serum P(4) greater than 1 ng/ml, the pregnancy rate to AI tended to be higher when concentrations exceeded 2 ng/ml than when concentrations were 1 to 2 ng/ml. In cyclic heifers, timed insemination can increase the percentage of heifers pregnant after being synchronized with MGA/PG.

Journal Article↗
PubMed1996

The effect of time of intrauterine insemination on the development and viability of embryos collected from superovulated ewes.

Eighteen Border Leicester x Scottish Blackface ewes, primed with 300 mg progesterone (12 d) and superovulated with decreasing doses (6, 5, 3 and 2 mg) of porcine FSH, were inseminated with fresh semen, using laparoscopic intrauterine procedures at 48 (Group E) or 60 h (Group L) after exogenous progesterone removal. Five days after insemination, embryos were collected and classified on the basis of their morphological development. During the subsequent 3 d of in vitro culture (38.5 degrees C; 5% CO2) the embryos were evaluated at 24-h intervals. After 72 h, the embryos were individually fixed (24 h) and stained with aceto-orcein and the nuclei were then counted to provide an objective index of cell proliferation and development. Mean (+/-SEM) ovulation rates for the 2 groups (9.2+/-1.5 and 7.1+/-1.2, respectively) and the corresponding percentages (53 vs 59) of embryos collected by laparoscopy were unaffected by insemination time. All donors yielded fertilized ova, but whereas all Group-E donors yielded 1 or more viable embryos (i.e., >32 cells), only 5 Group-L ewes yielded viable embryos (P<0.10). At collection, the percentages of embryos at the morula stage of development were 98 (Group E n = 44) and 39 (Group L n = 38; P<0.001). Few of the remaining ova (Group E = 0% Group L = 8%) were at the 1-cell stage of development when collected, indicating that retarded development post fertilization, not fertilization failure, was the principal consequence of delayed insemination. The percentages of embryos that continued to develop during in vitro culture were 91 and 37 for Groups E and L, respectively (P<0.001), and all of these reached the blastocyst stage. Of these blastocysts, 75 and 50% in Groups E and L hatched in vitro (P<0.10), with mean (+/-SEM) nuclei counts of 148+/-22.7 and 76+/-13.8 (P<0.02), respectively. In conclusion, while delayed intrauterine insemination did not affect the efficiency of ovum collection, it caused a major reduction in the yield of embryos that were capable of developing during in vitro culture. However, fertilization failure accounted for only 13% of the loss in viability following late insemination.

Journal Article↗
PubMed1997

A large-scale program in laparoscopic intrauterine insemination with frozen-thawed semen in Australian Merino sheep in Argentine Patagonia.

This report shows the results of a large-scale laparoscopic intrauterine insemination program on a flock of Australian Merino sheep in Argentine Patagonia. The study was carried out on a total of 1824 ewes (3-to-7-yr-old) and 480 ewe hoggets (19-20 months old) on 2 farms in the southeastern region of Santa Cruz Province, in April and May 1996. The animals, divided into 15 groups, were synchronized with vaginal sponges containing 60 mg medroxyprogesterone acetate for 14 d and injected with 200 IU PMSG upon sponge removal. Estrus was screened every 12 h by means of vasectomized marker rams. The animals were inseminated laparoscopically by the intrauterine route using 2 schemes: 1) at a fixed time (12 h) after estrus detection, or 2) at a fixed time (60 h) after sponge removal irrespective of estrus. Pregnancy was determined at 30 d by transrectal ultrasound imaging. The results showed that 1) the onset of estrus occurs most often between 24 and 48 h after sponge removal, 2) ewe hoggets undergo estrus significantly earlier than sexually mature ewes, 3) in those animals showing estrus, there appears to be no relationship between fertility (as assessed by pregnancy outcome) and time of estrus, 4) there is a significant association between the percentage of estrus occurrence and pregnancy rate, 5) fertility is significantly higher in ewes than in hoggets, 6) for practical purposes insemination at a fixed time after the onset of estrus has no advantage over that of to insemination at a fixed time after sponge removal. It is concluded that large-scale laparoscopic intrauterine insemination can be successfully applied in Australian Merino ewes and ewe hoggets in low-productivity areas such as that of Argentine Patagonia and that estrus detection is unnecessary when insemination is performed at 60 h after sponge removal.

Journal Article↗