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PubMed2003

Single versus double intrauterine insemination (IUI) in stimulated cycles for subfertile couples.

BACKGROUND: Intra uterine insemination (IUI), with or without controlled ovarian hyperstimulation (COH), is one of the treatment modalities offered to couples who have tried to conceive for at least one year (subfertile couples). It has been suggested that increasing the number of inseminations from one per cycle to two might increase the probability of conception. OBJECTIVES: To determine if there is a difference in live birth or pregnancy rates for subfertile couples using single or double intrauterine insemination in stimulated cycles. SEARCH STRATEGY: We searched the Cochrane Menstrual Disorders and Subfertility group trials register (searched 8 July 2002), the Cochrane Controlled Trials Register (Cochrane Library Issue 1, 2002), MEDLINE (January 1966 to July 2002), EMBASE (January 1988 to July 2002), SCIENCE Direct Database (January 1966 to July 2002), Confsci (January 1973 to 15 July 2002), Pascal (January 1984 to July 2002) and reference lists of articles. We also contacted researchers in the field. SELECTION CRITERIA: Randomised controlled, parallel trials of single versus double intrauterine inseminations in simulated cycles in subfertile couples. DATA COLLECTION AND ANALYSIS: Two reviewers independently assessed trial quality and extracted data. Study authors were contacted for additional information. MAIN RESULTS: Three studies involving 386 women were included. There was no data for the main outcome measure of live birth per couple or ongoing pregnancy rates, and none presented comparative data for adverse events. The results of two studies that reported pregnancy rate per couple did not show a significant effect of using double insemination (Peto OR 1.45, 95% CI 0.78-2.70). REVIEWER'S CONCLUSIONS: Based on the results of pregnancy rate per couple of two trials, double intrauterine insemination showed no significant benefit over single intrauterine insemination in the treatment of subfertile couples with husband semen. There are no meaningful data to offer advice regarding clinical practice on the basis of this review.

Female↗
PubMed2001

Paternal influence on the time of first embryonic cleavage post insemination and the implications for subsequent bovine embryo development in vitro and fertility in vivo.

The objectives of this study were: (1) to evaluate the effect of sire on the time from insemination to first cleavage following insemination in vitro and the relationship of this parameter to field fertility and (2) to establish the relationship between the kinetics of cleavage in vitro and oocyte developmental competence for bulls of known field fertility. Frozen semen from six bulls with 150-day non-return rates ranging from 57-78% was used. In experiment 1, after insemination with semen from one of the six bulls, presumptive zygotes were transferred to IVC in droplets of synthetic oviduct fluid. Droplets were examined at 24, 27, 30, 33, 36, 42, and 48 hr after insemination and the number of cleaved oocytes was recorded. Blastocyst yield was recorded on Days 6-, 7-, and 8-post insemination. In experiment 2, culture droplets were examined at 30, 36, and 48 hr after insemination. At each time point, the number of cleaved embryos was recorded and these embryos were transferred into new droplets and were cultured separately for the duration of the experiment. The proportion of embryos developing to the blastocyst stage was recorded for each of the groups for each bull. The best predictor of field fertility was a model containing 33-hpi-cleavage percentage only (r = 0.689, P < 0.0001). There was also a significant correlation between blastocyst yield and non-return rate, with Day 7 blastocyst yield having the highest correlation (r = 0.356), although this was relatively low in comparison. In experiment 2, irrespective of sire, a significantly higher proportion of those early-cleaving oocytes (before 30 hpi) developed to blastocysts than those cleaving later. In most cases, a higher proportion of blastocysts derived from early-cleaving oocytes hatched from the zona pellucida suggesting that such blastocysts are of superior quality to those derived from late-cleaving oocytes. In conclusion these data confirm our earlier observations that earliest cleaving zygotes are more competent in terms of development to the blastocyst stage than those that cleave later. This phenomenon is independent of the sire used. However, we have demonstrated that the kinetics of early embryonic development as measured by the timing of the first cleavage division post insemination vary between different bulls and that these differences can be used to discriminate between bulls of high and low bull field fertility.

Animals↗
PubMed1991

Fresh versus frozen thawed semen for initial and late insemination in IVF cycles.

Frozen thawed semen has been associated with reduced semen quality and as a result diminished pregnancy rates. In vitro fertilization (IVF) can supply the true measure of the functional fertilizing capacity of fresh versus frozen-thawed semen. One hundred and six patients in an IVF program who underwent donor insemination were divided into two groups. Group I included 51 women in whom initial insemination with donor fresh or frozen semen was performed. They were compared to 65 group II women in whom late insemination with donor fresh or frozen semen was performed after initial insemination with husband semen had failed to fertilize the eggs. There was no statistically significant difference between groups I and II on initial insemination; however, statistically significant difference in fertilization (P less than 0.006) and pregnancy rates (P less than 0.001) between the two groups were achieved when late insemination was carried out. Consequently, we prefer initial insemination with frozen-thawed donor semen in cases indicated.

Adult↗
PubMed1990

Timing of insemination is correlated with the secondary sex ratio of Norway rats.

Timing of insemination in a seminatural environment had a significant, curvilinear relationship with the secondary sex ratio of litters conceived during cycling estrus. When fifth inseminations were received prior to 2.75 h after dark onset, there was a steady decline in the sex ratio as time between dark onset and fifth insemination increased. Fifth inseminations received after 2.75 h resulted in a moderate rise in the sex ratio. This curvilinear relationship was also found with artificial insemination, indicating that neither copulatory behavior nor the vaginal environment were necessary for the association. For postpartum litters there was a linear decline in sex ratio as the interval between dark onset and fifth insemination increased; however, there was no subsequent rise in sex ratio with late inseminations. Season of conception and parity of the dam were associated with sex ratio; litter size and estrous condition were not. Feasibility of the rat as an animal model for sex determination in humans is discussed.

Animals↗
PubMed2005

Hysteroscopic or rectally guided, deep-uterine insemination of mares with spermatozoa stored 18 h at either 5 degrees C or 15 degrees C prior to flow-cytometric sorting.

Practical application of sex-selected spermatozoa in the horse industry would be greatly improved by the ability to develop simplified methods for shipping, storing, and inseminating sex-selected spermatozoa. Acceptable pregnancy rates have been achieved using fresh sex-sorted stallion sperm, however many stallion owners are reluctant to send their stallions to the sorter location for collection during the breeding season. Furthermore, the technology would be more applicable if the hysteroscopic insemination technique was not necessary for adequate pregnancy rates. Hysteroscopic insemination requires expensive equipment and specially trained personnel. In the present study, stallion sperm were sex-sorted after being stored at either 5 degrees C or 15 degrees C for 18 h. Twenty million sex-sorted sperm were then inseminated using one of two insemination techniques: the hysteroscopic method or the rectally guided, deep-uterine technique. Results were determined based on 16-day pregnancy status. A first-cycle pregnancy rate of 72% (18/25) was achieved when sperm were shipped at 15 degrees C, sex-sorted, and then inseminated using the hysteroscopic method. With these results, it can be concluded that stallions are not necessary at the sorter location to achieve acceptable fertility with sex-sorted sperm. There was a tendency for more mares to become pregnant when sperm were shipped at 15 degrees C prior to sorting, when compared to shipment at 5 degrees C. Similarly, there was a tendency for more mares to become pregnant when hysteroscopic insemination was utilized, when compared to the rectally guided, deep-uterine technique. These trends suggest that if larger group numbers were available, significant differences between the treatments may be revealed.

Animals↗
PubMed2005

Low semen dose intracornual insemination of cows at fixed time after PGF2alpha treatment or at spontaneous estrus.

The numbers of spermatozoa per insemination and the site of semen deposition in the uterine horn appear to interact to influence pregnancy rate. In two experiments, the effect of a single low dose (2 x 10(6) spermatozoa) intracornual insemination (LD-ICI) on bovine pregnancy rate was compared with that of intracornual (SD-ICI) and conventional (SD-AI) inseminations of 40 x 10(6) spermatozoa. In Experiment 1, 157 cows were treated twice with PGF(2)alpha at a 14-day interval and inseminated at a fixed time (80-82 h) after the second PGF(2)alpha injection using LD-ICI (n=44), SD-ICI (n=61) or SD-AI (n=52). In LD-ICI and SD-ICI groups, semen was deposited in the horn ipsilateral to the ovulatory follicle close to the utero-tubal junction (LD-ICI-UTJ, n=33 and SD-ICI-UTJ, n=41) or in the middle part of the horn (LD-ICI-MH, n=11 and SD-ICI-MH, n=20). Pregnancy rates after LD-ICI-UTJ, LD-ICI-MH, SD-ICI-UTJ and SD-ICI-MH were 27%, 27%, 39% and 35%, respectively (P>0.05). The total pregnancy rate after LD-ICI (27%) did not differ (P>0.05) from that after SD-ICI (37%) or SD-AI (34%). In Experiment 2 (field trial), 362 cows were allotted, at spontaneous estrus, to LD-ICI-UTJ (n=86), LD-ICI-MH (n=97) or SD-AI (n=179). Pregnancy rates after LD-ICI and SD-AI were 47% and 45%, respectively (P>0.05). After LD-ICI-UTJ, the pregnancy rate (54%) did not differ significantly (P>0.05) to that obtained after LD-ICI-MH (41%) and after SD-AI (45%). The results of the study show that the single intracornual insemination of cows with 2 x 10(6) spermatozoa at fixed time, 80-82 h after the second PGF(2)alpha injection or at spontaneous estrus resulted in similar pregnancy percentage as intracornual and conventional inseminations with 40 x 10(6) spermatozoa per semen dose. With intracornual insemination using low or standard dose of spermatozoa, the pregnancy rates were not significantly affected by the exact site of semen deposition in the uterine horn, near the utero-tubal junction or in the middle part.

Animals↗
PubMed2004

[Insemination: history and state of the art in animals].

Insemination has been used since 1950 in the bovine and since the seventies in other domestic species. The use of insemination varies between the different species in terms of activity and method. The methods depend on the anatomical and physiological characteristics of each species, which lead to different sites of semen deposition and different minimal numbers of inseminated spermatozoa to obtain efficient fertility results. The use of frozen semen influences also the methods of insemination. Intra-uterine insemination is principally used when only small quantities of semen are available and/or to reduce the number of inseminated spermatozoa. Recent results in different species indicate that the use of intra-uterine insemination could be developed in the next years.

Animals↗
PubMed2004

Production of piglets with sexed semen employing a non-surgical insemination technique.

The aim of the present study was to ascertain whether multiparous sows could successfully be inseminated with sexed semen non-surgically. Spermatozoa were stained with Hoechst 33342 and separated flowcytometrically in X- and Y-chromosome bearing sperm populations employing the Beltsville Sperm Sexing Technology (BSST). After weaning, estrus was induced in sows with PMSG and hCG. Animals were inseminated once per estrus non-surgically with a specially designed catheter into the tip of the uterine horn, employing 50x10(6) of either sexed or non-sexed spermatozoa diluted in 2 ml Androhep. Pregnant sows were allowed to go to term. Mean pregnancy rate from inseminations with unsexed spermatozoa was 54.5% whereas inseminations with sexed spermatozoa resulted in 33.3% pregnant sows. All but one piglet born after insemination with sexed semen were of the predicted sex. The sex of those piglets born after inseminations with non-sexed spermatozoa was 61.1% for male and 38.9% for female sex. It is concluded that non-surgically inseminations with flowcytometrically sexed spermatozoa can be conducted successfully.

Animals↗
PubMed2005

Low-dose insemination--why, when and how.

The typical dose for insemination into the uterine body of the mare is > 300 x 10(6) progressively motile spermatozoa (PMS) and an insemination dose of > 200 x 10(6) PMS is recommended for frozen-thawed semen. Low-dose insemination techniques allow for a drastic reduction in the numbers of spermatozoa required to achieve pregnancy. Acceptable pregnancy rates can be achieved with doses ranging from 1 to 25 x 10(6) PMS in volumes ranging from 20 to 1000 microL. Two techniques have been described: hysteroscopic insemination and transrectally guided deep horn insemination using a pipette. Similar pregnancy rates can be attained by either method when 5 x 10(6) PMS are used. Hysteroscopic insemination may provide an advantage when the dose is 1-3 x 10(6) PMS. These techniques have the potential to make more efficient use of frozen-thawed or sex-sorted semen from certain stallions. The use of low-dose insemination to improve fertility of infertile stallions warrants further investigation.

Animals↗
PubMed2005

Transcervical artificial insemination in the cat.

Many studies have reported new reproductive techniques for reproduction in endangered non-domestic felids. Artificial insemination is an important tool for developing breeding programs. This manuscript reviews recent progress in feline artificial insemination, with particular emphasis on intrauterine sperm deposition. Intrauterine insemination of felids results in higher fertilization rates than intravaginal insemination, despite insemination with fewer sperm. Although surgical insemination was utilized historically, there are some reports of catheterization of the cervix of the queen. Recently, a new technique and catheter were proposed for transcervical insemination of fresh or frozen-thawed semen.

Animals↗
PubMed2005

Effect of repeated administration of PGF2alpha in the early post partum period on the prevalence of clinical endometritis and probability of pregnancy at first insemination in lactating dairy cows.

Two experiments were performed to determine the effects of repeated administration of PGF2alpha in the immediate post partum period on the prevalence of clinical endometritis at 22 and 58 days post partum, and the probability of pregnancy at first insemination, in post partum dairy cows. In Experiment 1, 228 cows on day 7 post partum were used. Cows in Group 1 (n = 114) were treated twice with PGF2alpha (25 mg, im) 8 h apart on days 7 and 14 post partum, and only once on days 22 and 35 post partum. Cows in Group 2 (n = 114) served as untreated controls. Vaginoscopy and transrectal palpation of the genital tract were done on days 22 and 58 post partum. Cows in both groups were inseminated at estrus after a voluntary waiting period of 100 days. Pregnancy was determined by transrectal palpation between 45 and 50 days after insemination. Repeated administration of PGF2alpha in the immediate post partum period did not reduce the prevalence of clinical endometritis on days 22 or 58 post partum (65 versus 62% on day 22 and 28.3 versus 35.2% on day 58 in Groups 1 and 2, respectively). There was no significant difference in the probability of pregnancy at first insemination between cows in both groups. In Experiment 2, 418 cows on day 7 post partum were used. Cows in Group 1 (n = 209) were treated twice with PGF2alpha (25 mg, im) 8h apart on days 7 and 14 post partum, and only once on days 22 and 35 post partum. Cows in Group 2 (n = 209) served as untreated controls. Cows in both groups were subjected to the Presynch and Ovsynch protocols on days 49 and 75 post partum, respectively. Pregnancy was determined by transrectal ultrasonography between days 29 and 32 after timed insemination. There was no significant difference in the probability of pregnancy at first insemination between cows in both groups. In conclusion, repeated administration of PGF2alpha to cows in this herd had no effect on the prevalence of clinical endometritis at 22 and 58 days post partum, and that there was no effect on the probability of pregnancy after insemination at estrus among cows with a voluntary waiting period of > 100 days, or at timed AI at 85 days in milk when Presynch was employed.

Animals↗
PubMed2005

Comparison of synchronization of ovulation with timed insemination and exogenous progesterone as therapeutic strategies for ovarian cysts in lactating dairy cows.

The objective of this study was to compare the effectiveness of the Ovsynch and controlled internal drug releasing (CIDR) protocols under commercial conditions for the treatment of cystic ovarian disease in dairy cattle. A total of 401 lactating dairy cows with ovarian cysts were alternatively allocated to two treatment groups on the day of diagnosis. Cows in the Ovsynch group were treated with GnRH on Day 0, PGF2alpha on Day 7, GnRH on Day 9, with timed insemination 16-20 h later. Cows in the CIDR group were treated with a CIDR insert on Day 0 for 7 days; on Day 7, the CIDR was removed, and cows were treated with PGF2alpha. All cows in the CIDR group were observed for estrus and cows exhibiting estrus within 7 days following removal of the CIDR and PGF2alpha administration were inseminated. The outcomes of interest for this experiment were the likelihood to be inseminated, return to cyclicity (determined by a CL on Day 21), conception and pregnancy rates. Data for these variables were analyzed using logistic regression. The percentage of cows inseminated in the Ovsynch and CIDR groups were 82 and 44%, respectively. Cows in the Ovsynch group were 5.8 times more likely to be inseminated than cows in the CIDR group. Cows with a low BCS were 0.48 times less likely to be inseminated than cows with a high BCS. The percentage of cows with a CL on Day 21 for the Ovsynch and CIDR groups was 83 and 79%, respectively (P > 0.05). Cows with a low BCS were 0.49 times less likely to have CL on Day 21 than cows with a high BCS. Conception and pregnancy rates for cows in the Ovsynch group were 18.3 and 14.4%, respectively. Conception and pregnancy rates for cows in the CIDR group were 23.1 and 9.5%, respectively. There was no significant differences between conception or pregnancy rates in cows in both groups. Primiparous cows were 2.6 times more likely to conceive than multiparous cows. In conclusion, the results of this study suggested that fertility was not different between cows with ovarian cysts treated with either the Ovsynch or the CIDR protocols in this dairy herd. In addition, primiparous cows had an increased likelihood for conception compared to multiparous cows, and cows with a low BCS were less likely to be inseminated or have a CL on Day 21, regardless of treatment.

Animals↗
PubMed2006

A field investigation of intra-cervical insemination with reduced sperm numbers in gilts.

A novel insemination catheter with a smaller polyurethane tip for deeper insertion into the cervix of gilts was compared with the conventional catheter. The novel catheter could be inserted 31.4 mm deeper than the conventional catheter into the gilt cervix, but the difference diminished with parity until the sixth parity when there was no difference in penetration depth between the catheters. In Experiment 1, cyclic gilts were inseminated upon display of oestrus (back pressure test) in the presence of a boar (0 h) and 24 h later. The control group (n = 300) were inseminated with 2 x 10(9) total spermatozoa and the treatment group (n = 300) with 1 x 10(9) total spermatozoa per inseminate, in both cases utilising the novel insemination catheter. No significant differences were observed for farrowing rate and litter size, the values of which were those expected for natural mating. In Experiment 2, 66 cyclic gilts were subjected to the same heat detection and service regime as for Experiment 1 but were served with <1 x 10(9) total sperm cells per inseminate using the new device. Conception rates and embryo counts were recorded. Conception rate declined with <500 x 10(6) spermatozoa, and number of embryos (a reflection of potential litter size) was significantly reduced. Use of the new catheter for gilts with 1 x 10(9) total sperm cells per inseminate will achieve commercially acceptable fertility and fecundity levels, and offer substantial commercial benefits with more rapid genetic gains.

Animals↗
PubMed1977

The immunologic effects of husband's semen on donor spermatozoa during mixed insemination.

Artificial insemination was performed on four women with the husband's and donor's semen mixed. No pregnancies resulted after several inseminations. One woman also received artificial donor insemination without success. Seminal plasmas from the husbands were allowed to react with donor semen and were observed to produce immobilization and agglutination of the donor's spermatozoa. Two of the husbands' seminal plasmas had high levels of immunoglobulin A, and all contained complements C-3 and C-4, which suggests that the mechanism is immunologic. Artificial donor inseminations were performed, and in addition the couples were advised to refrain from sexual intercourse for 2 days prior to insemination, in order to eliminate the risk of husband's seminal plasma being on the wife's cervix. Within 1 month, three of the four women became pregnant. As a practical measure, it is proposed that the effect of husband's semen on donor spermatozoa be determined prior to performing mixed inseminations and that couples refrin from sexual intercourse for 2 days prior to donor inseminations.

Complement System Proteins↗
PubMed1994

A prospective study of donor insemination recipients: secrecy, privacy, and disclosure.

OBJECTIVES: To study prospectively the attitudes and behaviors of heterosexual couples undergoing donor insemination. DESIGN: Couples undergoing donor insemination completed psychological questionnaires before treatment regarding psychiatric symptoms, self-esteem, marital adjustment, and their attitudes about privacy or disclosure. PARTICIPANTS: Forty-one of 82 heterosexual couples participated. MEASURES: A donor insemination questionnaire, a self-esteem scale, the Brief Symptom Inventory, and the Dyadic Adjustment scale were used. RESULTS: Psychiatric symptoms, self-esteem, and marital adjustment were all in the normal range. The amount of time taken by the couple to decide to do donor insemination was not related to reported psychiatric symptoms, self-esteem, marital adjustment, or marital satisfaction. Ninety-five percent of the couples believed a psychological consultation should be a mandatory part of the donor insemination treatment. The greatest concern the couples had about the donor child was its genetic and medical background. Thirty-eight percent of the couples did tell or planned to tell others about using donor insemination to conceive, and only 27% of the couples planned to tell the child of his or her donor origin. CONCLUSIONS: The results of this study support those of others, which have indicated that the majority of donor recipients are psychologically well adjusted and have average marital adjustment. In addition, this prospective study replicated the findings of other retrospective studies, indicating that most donor insemination recipients do not plan to tell the child of his or her donor origin. Additional prospective studies are needed to determine if attitudes and behavior regarding disclosure change over time.

Adaptation, Psychological↗
PubMed2000

Effect of intrauterine treatment with prostaglandin E2 prior to insemination of mares in the uterine horn or body.

Two trials were conducted to investigate the effects of intrauterine infusion of PGE2 and uterine horn insemination on pregnancy rates in mares achieved by breeding with a suboptimal number of normal spermatozoa. Estrus was synchronized and mares were teased daily with a stallion to detect estrus. Mares in estrus were examined by transrectal palpation and ultrasonography to monitor follicular status. On the first day a 35-mm diameter follicle was present, hCG (1500 IU, iv) was administered and the mares were bred the next day. Mares (Trial 1, n = 34; Trial 2, n = 28) were inseminated with 25 million total spermatozoa from either a stallion with good semen quality (Trial 1) or poor semen quality (Trial 2). In each trial, mares were assigned to 1 of 4 treatment groups as follows: Group PGE-HI - infusion of 0.25 mg PGE2 into the proximal end of the uterine horn ipsilateral to the dominant follicle 2 h prior to insemination in the proximal end of the same uterine horn; Group PGE-BI - infusion of 0.25 mg PGE2 into the proximal end of the uterine horn ipsilateral to the dominant follicle 2 h prior to insemination in the uterine body; Group SAL-HI - infusion of 1 mL sterile saline into the proximal end of the uterine horn ipsilateral to the dominant follicle 2 h prior to insemination in the proximal end of the same uterine horn; or Group SAL-BI - infusion of 1 mL sterile saline into the proximal end of the uterine horn ipsilateral to the dominant follicle 2 h prior to insemination in the uterine body. After breeding, mares were examined daily by transrectal ultrasonography to confirm ovulation, and were re-examined 14 to 16 d after ovulation for pregnancy status. Data were analyzed by Chi-square. Overall pregnancy rates were 59% for stallion 1 and 29% for stallion 2. Group pregnancy rates did not differ for mares bred by either stallion (P > 0.10). Pregnancy rates were not altered by horn insemination for either stallion (P > 0.10). Intrauterine infusion of PGE2 improved pregnancy rate in mares bred by the stallion with good quality semen (P < 0.05), but did not alter pregnancy rate in mares bred by the stallion with poor quality semen (P > 0.10). Further research is warranted to determine if intrauterine infusion of PGE2 will enhance spermatozoal colonization of the oviduct and pregnancy rates in mares, and if PGE-treatment will improve pregnancy rates achieved by subfertile stallions.

Animals↗
PubMed2001

Effect of insemination time of frozen semen on incidence of uterine fluid in mares.

Ninety five mares were inseminated with frozen semen either within 12 h before ovulation or within 8 h after ovulation. The effect of preovulatory versus postovulatory insemination (AI) on the subsequent detection of uterine fluid was studied. The overall pregnancy rate was 43% and this was not significantly influenced by preovulatory or postovulatory insemination. When mares were first examined 12 h after AI, 18 of 52 mares (35%) had accumulated uterine fluid. However, when mares were first examined 18 to 24 h after AI, only 6 of 43 mares (14%) had uterine fluid. Presence of intrauterine fluid significantly lowered pregnancy rates. Timing of insemination did not affect incidence of uterine fluid. Serum concentrations of estrogen and progesterone at time of insemination did not influence uterine clearance or pregnancy rates, but both hormones were higher at preovulatory than at postovulatory inseminations. We concluded that there was no evidence that postovulatory inseminations would predispose mares to persistence of uterine fluid after AI.

Animals↗
PubMed2002

Fertilization efficiency of in vitro matured oocytes transferred to oviducts of inseminated goats: a model to assess in vivo fertilization performance of goat spermatozoa.

An alternative to conventional in vivo validation of sperm assays might be to assess the fertilization rate of multiple oocytes transferred to the oviducts of inseminated females. Increasing the number of oocytes increases the egg-sperm ratio in the oviduct under an unaltered endocrine milieu, setting the basis for picking up statistical differences between treatments in small populations. The study evaluated the model by transferring oocytes to females inseminated under conditions that are known to modify the fertilization rate in the field. The study then evaluated the use of cattle oocytes to replace goat oocytes for assessing sperm function under this model. In Experiment 1, 12 females were inseminated at estrus with either 100 or 300 million spermatozoa 20 h before transferring homologous oocytes into the oviduct ipsilateral to the ovulation point. In Experiment 2, 10 females were inseminated either once or twice; 10-20 h later, homologous oocytes were transferred into the oviduct ipsilateral to the ovulation point. In Experiment 3, 13 bilateral-ovulated females were inseminated and 20 h later goat and cattle oocytes were transferred to contralateral oviducts. Then, 16-20 h later, oocytes were flushed from the oviduct, cleaned of spermatozoa and stained to assess the fertilization rate. The fertilization rate was improved by increasing sperm numbers at insemination (P < 0.04) and by increasing the number of inseminations (P < 0.02). The results in Experiment 3 showed that fertilization rates were similar for goat and cattle oocyte (P > 0.05) and that fertilization values were highly correlated (r = 0.811, P < 0.001). Results suggest that the model can be used for in vivo validation of in vitro sperm assays by facilitating the expression of statistical differences in small number of animals. In addition, cattle oocytes can be used to replace goat oocytes to study in vivo sperm function in goats.

Animals↗