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PubMed1990

Effectiveness of stimulated menstrual cycles and Percoll sperm preparation in intrauterine insemination.

To examine the usefulness of intrauterine insemination in women with various fertility factors, we retrospectively analyzed data from women treated during 1986 and 1987. Ninety-three patients underwent 1-11 cycles of single or double procedures, for a total of 423 inseminations in 263 treatment cycles. Twenty-six patients (28%) conceived, for a 10% total pregnancy rate per cycle, with 58% of the pregnancies resulting from double inseminations per cycle. An average of two treatment cycles was required to achieve pregnancy. Eight pregnancies (31%) occurred in spontaneous cycles, while 18 (69%) occurred in stimulated cycles. While clomiphene citrate therapy was useful in anovulatory patients, it was of no benefit in ovulatory patients being treated with intrauterine insemination. Human menopausal gonadotropin therapy was of benefit in both ovulatory and anovulatory patients when combined with intrauterine insemination. The live birth rate was higher (75%) in spontaneous cycles than in stimulated cycles (44%). Semen preparation was accomplished by sperm washing in 61% of the pregnancies and by Percoll preparation in 39%. The effectiveness of the discontinuous Percoll gradient for semen preparation for insemination was suggested by a pregnancy rate of 9% per cycle. While the mean sperm count in the pregnant group was 44 million, successful pregnancy was accomplished with a double insemination of 880,000 and 1.16 million rapidly progressive sperm in the first and second inseminate, respectively. The data confirm the important role of intrauterine insemination for the treatment of infertility.

Adult↗
PubMed1992

Therapeutic donor insemination: a prospective randomized trial of fresh versus frozen sperm.

OBJECTIVE: We evaluated the efficacy of fresh versus frozen sperm in therapeutic donor insemination. STUDY DESIGN: Fifty-seven women underwent 72 courses of treatment (a maximum of six therapeutic donor insemination cycles--three fresh and three frozen) totaling 198 cycles. Each woman served as her own control and was prospectively randomized to receive a single, timed insemination of either fresh or frozen sperm. RESULTS: Fecundity was 20.6% for fresh sperm cycles and 9.4% for frozen (p less than 0.03, by chi 2 analysis). Fresh cervical cap insemination fecundity was 20.3%; frozen was 7.8% (p less than 0.03, by chi 2 analysis). Fresh intrauterine insemination fecundity was 21.2%; frozen was 15.8% (p = 0.63, by chi 2 analysis). Fresh 3-month life-table pregnancy rates were 48% +/- 10%; frozen rates were 22% +/- 8% (p = 0.05 by Breslow analysis). Survival analysis with fixed covariates showed a positive association with the use of fresh sperm (p = 0.04). CONCLUSION: Cycle fecundity was significantly greater with fresh sperm in women undergoing cervical cap insemination or intrauterine insemination and in women undergoing only cervical cap insemination. These results have important implications for contemporary management of patients undergoing therapeutic donor insemination with frozen sperm.

Adult↗
PubMed2004

Low dose insemination in the mare: an update.

The generally recommended minimum number of spermatozoa required for conventional artificial insemination in the mare is in excess of 200 x 10(6) progressively motile spermatozoa. Recent developments in different insemination techniques such as deep uterine, hysteroscopic and oviductal insemination, which have been designed to use significantly fewer spermatozoa, are reviewed in this paper. A number of studies have demonstrated that ultrasound guided deep uterine insemination of 5 x 10(6) fresh spermatozoa can produce satisfactory pregnancy rates. The use of hysteroscopic insemination enables the insemination dose to be successfully reduced to 1 x 10(6) fresh or 3 x 10(6) frozen-thawed spermatozoa. Further reduction of the insemination dose is possible and satisfactory pregnancy rates can also be achieved by surgical oviductal insemination of mares with as few as 2 x 10(5) fresh spermatozoa. The refinement of these insemination techniques will allow us to maximise the use of frozen-thawed semen, use new technology such as sex-preselection of spermatozoa and to conserve and utilise epididymal spermatozoa at the time of castration or death of a stallion.

Animals↗
PubMed1993

Comparison of the methods of artificial insemination on the incidence of conception in single unmarried women.

OBJECTIVE: To compare pregnancy rates after intrauterine insemination (IUI) versus pericervical insemination in absolute male factor infertility using each patient as her own control. DESIGN: Ovulatory women with patent fallopian tubes without male partners were alternately inseminated with cryopreserved donor semen using either IUI or pericervical insemination techniques. A total of 81 cycles, which included up to 4 cycles per patient were performed. In this manner a comparison between the efficacy of each method could be evaluated. SETTING: The donor insemination program at the Center For Assisted Reproduction at Northwestern University Medical School. PATIENTS: Twenty-six single, healthy, unmarried women with patent fallopian tubes and < 40 years of age without male partners (absolute male factor infertility). MAIN OUTCOME MEASURES: Positive quantitative serum subunit of human chorionic gonadotropin followed by the presence of an intrauterine gestational sac seen by transvaginal ultrasonography. RESULTS: Fourteen (54%) of 26 patients conceived including two (14%) miscarriages within four insemination cycles. Seven (17.5%) patients after IUI, and 7 (17.1%) patients after pericervical insemination conceived. The pregnancy rates were similar regardless of the order of insemination method. CONCLUSION: These findings reveal that there is no statistical difference in the pregnancy outcome between these two methods of insemination in absolute male factor infertility.

Adult↗
PubMed1999

Effect of timing of artificial insemination on gender ratio in beef cattle.

It was recently reported that cows inseminated at approximately 10 or 20 h before an expected ovulation deliver predominately a bull or heifer calf, respectively. The objective of this study was to further investigate the effect of timing of insemination on the gender of offspring in cattle. Angus heifers (n = 41) and cows (n = 98) were used in the study. Heifers were synchronized with a 16-d treatment of melengestrol acetate followed 17 d later with an injection of PGF2alpha. Cows were synchronized with GnRH followed 7 d later with PGF2alpha. A HeatWatch electronic estrus detection system was used to determine the onset of estrus. Based on previous studies, it was assumed that ovulation occurs approximately 32 h after the onset of estrus. Therefore, animals were artificially inseminated at either 8 to 10 h (early; > or = 20 h before expected ovulation) or 20 to 25 h (late; < or = 10 h before expected ovulation) after the onset of estrus. Sixty to 80 d after insemination, ultrasonography was used to confirm pregnancy status and to determine the gender of fetuses. Gender of calves was subsequently confirmed at calving. Data were analyzed for effects of time of insemination and sire or semen batch on gender ratio, as well as any effect of length and/or intensity of estrus on conception rate and gender ratio. Twenty-nine of 41 heifers and 69 of 98 cows were detected in estrus after synchronization and were inseminated; 20 of 29 heifers and 48 of 69 cows were subsequently confirmed pregnant. Neither the length of estrus nor its intensity (number of mounts) had an effect on pregnancy rate or gender ratio (P > or = 0.418). Timing of insemination (early versus late) had no effect on gender ratio (P = 0.887). Semen from 13 sires representing 17 lots was used to inseminate the cows and heifers. No differences (P = 0.494) were detected in the gender ratios resulting from different sires or semen batches. In contrast to previous findings, our results indicate that inseminating beef cattle at approximately 20 or 10 h before an expected ovulation does not alter the gender ratio of the resultant calves.

Animals↗
PubMed2001

Equine sperm-oocyte interaction: results after intraoviductal and intrauterine inseminations of recipients for oocyte transfer.

Insemination of recipients for oocyte transfer and gamete intrafallopian transfer (GIFT) in five experiments were reviewed, and factors that affected pregnancy rates were ascertained. Oocytes were transferred into recipients that were (1) cyclic and ovulated at the approximate time of oocyte transfer, (2) cyclic with aspiration of the preovulatory follicle, and (3) noncyclic and treated with hormones. Recipients were inseminated before, after, or before and after transfer. Intrauterine and intraoviductal inseminations were done. Pregnancy rates were not different between cyclic and noncyclic recipients (8/15, 53% and 37/93, 39%). The highest numerical pregnancy rates resulted when recipients were inseminated with fresh semen from fertile stallions before oocyte transfer or inseminated with cooled transported semen before and after oocyte transfer. Oxytocin was administered to recipients before oocyte transfer when fluid was imaged within the uterus. Administration of oxytocin to recipients at the time of oocyte transfer resulted in significantly higher pregnancy rates than when oxytocin was not administered (17/26, 65% and 28/86, 33%). Intraoviductal and intrauterine inseminations of recipients during oocyte transfer resulted in similar embryo development rates when fresh semen was used (12/22, 55% and 14/26, 55%). However, embryo development rates significantly reduced when frozen (1/21, 5%) versus fresh sperm were inseminated into the oviduct. Results suggest that insemination of a recipient before and after transfer could be beneficial when semen quality is not optimal; however, a single insemination before transfer was adequate when fresh semen from fertile stallions was used. Absence of a preovulatory follicle did not appear to affect pregnancy rates in the present experiments. The transfer of sperm and oocytes (GIFT) into the oviduct was successful and repeatable as an assisted reproductive technique in the equine.

Animals↗
PubMed1993

Fertility of superovulated ewes after intrauterine or oviducal insemination with low numbers of fresh or frozen-thawed spermatozoa.

Two experiments investigated the effects of number of spermatozoa inseminated and time and site of insemination of fresh and frozen-thawed semen on fertility in Merino ewes treated with intravaginal progestagen pessaries and a combination of pregnant mare serum gonadotrophin and follicle stimulating hormone. In Experiment 1, ewes were inseminated in the uterus or oviducts with totals of 10(4), 10(5), 10(6) or 10(7) fresh spermatozoa 44 or 68 h after pessary removal. Ova recovered 48 h later were classified as fertilized if they had cleaved. Proportion of fertile ewes (ewes with fertilized ova per ewes inseminated) and fertilization rate of ova (ova fertilized per ova recovered) were higher for inseminations 44 h (63% and 45%) than 68 h (38% and 19%) after pessary removal (P < 0.001). More ewes were fertile after oviducal (61%) than after intrauterine insemination (39%; P < 0.05), and with high (10(6) and 10(7)) than with low (10(4) and 10(5)) doses of spermatozoa for intrauterine (54% v. 24%; P < 0.05) but not for oviducal inseminations (63% v. 59%). Fertilization of ova was better after oviducal than after intrauterine inseminations (44% v. 22%; P < 0.001), and with high than with low doses of spermatozoa (45% v. 21%; P < 0.001). In Experiment 2, ewes were inseminated with 10(5), 5 x 10(5) or 10(6) total fresh or frozen-thawed spermatozoa in the uterus or oviducts, 44 h after pessary removal.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2004

Birth of pouch young after artificial insemination in the tammar wallaby (Macropus eugenii).

Timing of artificial insemination (AI) in marsupials is critical because fertilization must occur before mucin coats the oocyte during passage through the oviduct. In this study, timing and the site of insemination were examined to develop AI in the tammar wallaby (Macropus eugenii). Birth and postpartum (p.p.) estrus was synchronized in 46 females. Epididymal spermatozoa (n=4) or semen collected by electroejaculation (n=42) were inseminated early (4-21 h p.p.) into the urogenital sinus (n=7), the anterior vaginal culs de sac (n=7), the uterus by transcervical catheter (n=5), or the uterus by injection (intrauterine artificial insemination, IUAI) (n=5). A further 16 females were inseminated late (19-48 h p.p.) by IUAI. All females were monitored for birth. A third group of six females was inseminated late (21-54 h p.p.) by IUAI and 0.4-6.6 h later, sperm had reached the oviduct in all animals. In total, an oocyte to which spermatozoa were attached was recovered and two young were born after IUAI using epididymal (n=1) or electroejaculated (n=2) spermatozoa, but no young resulted from insemination at other sites. Two females were successfully inseminated at 43 and 47 h p.p., later than most other animals, and the third was inseminated much earlier (18 h p.p.) but with highly motile spermatozoa. These young represent the first macropodids born by AI and the first marsupials conceived using epididymal spermatozoa.

Animals↗
PubMed1976

Artificial insemination of beef cattle.

A system for the artificial insemination fo beef cattle was described. The system involved preparation of the cattle and facilities, visual oestrous detection twice a day, drafting each morning and insemination of oestrous cows twice a day. The AI program was evaluated during the course of the program and at pregnancy test 35 to 90 days after the end of the insemination period. The insemination period was from 25 to 60 days depending on efficiency, with programs from 25 to 35 days being favoured. Results for 12218 first inseminations (65.9%) and 2222 second inseminations (57.8%) in 56 AI programs compared favourably with results in dairy AI. Pregnancy rates in lactating cows (70.5%) were significantly higher than in nonlactating cows and heifers (66.1%). Overall efficiency of well-managed AI programs were represented by 63% of cows put into a program becoming pregnant in a 29-day insemination period. Seventy-two per cent of the cows put into the program were inseminated yielding an 88% pregnancy rate. The efficiency of visual oestrous detection was 95% but this estimate did not include false positives. Efficiency of AI programs were effected by management, nutrition, infection, inseminators, facilities and the origin and type of cattle put into a program. Environmental factors such as handling, stress and thunderstorms did not effect efficiency except via a nutritional effect.

Animal Husbandry↗
PubMedDate not supplied

Accuracy of bovine pregnancy detection using transrectal ultrasonography at 28 to 35 days after insemination.

OBJECTIVE: To estimate the accuracy of real-time ultrasonography to detect pregnancy in dairy cows at 28 to 35 days after insemination. METHODS: Cows that did not return to oestrus between 18 and 24 days after a first insemination (n = 526) were examined by transrectal ultrasonography from 28 to 35 days after insemination. Pregnancy was confirmed by the observation of a foetus, but fluid in the uterine horn and the presence of embryonic membranes were also noted. When pregnancy was not confirmed by the observation of a foetus, a second examination 7 days later, confirmed these remaining cows as pregnant or not pregnant to the first insemination. Detection of pregnancy at this early examination was compared with manual transrectal pregnancy examination performed 10 to 13 weeks after insemination (13-week examination). RESULTS: There were 44% of cows that were pregnant to the first service, 34% that had returned for a second service 18 to 24 days after the first insemination, and 20% of cows that were not pregnant, and had not returned normally for a second service (non-pregnant, non-return) within 24 days of their initial insemination. The presence of a foetus at 28 to 35 days after insemination was accurately predicted by a simplified method where uterine fluid accumulation and embryonic membranes were observed. Foetal loss between the early detection and the 13-week examination (9% of pregnancies) indicated that 28 to 35 days post insemination was too early to reliably detect pregnancy. CONCLUSION: Early examination of pregnancy with transrectal ultrasonography is an accurate method to identify non-pregnant, non-return cows. The examination can be simplified by the observation of uterine fluid accumulation and embryonic membranes, as opposed to the more involved process of observing the foetus.

Animals↗
PubMed1990

Effects of time of insemination relative to ovulation on pregnancy rate and embryonic-loss rate in mares.

The effects of pre-ovulatory and post ovulatory insemination on pregnancy rate and embryonic-loss rate were studied in 268 mares in two experiments. Within each experiment mares were randomised within replicates as follows: to be inseminated on the day the pre-ovulatory follicle reached 35 mm (pre-ovulatory group), to be inseminated on the day of ovulation (Day 0 group), and to be inseminated on the day after ovulation (Day 1 group). Ultrasonic pregnancy diagnoses were performed on Days 11, 12, 13 and 14 (Experiment 1) and Days 11, 12, 13, 14, 15, 20 and 40 (Experiment 2). Combined for the two experiments, pregnancy rates were different (P less than 0.01) among the three groups. For Experiment 2, pregnancy rate within the pre-ovulatory group was lower (P less than 0.05) for insemination 4 days or more before ovulation than for up to 3 days before ovulation. Pregnancy rate was lower (P less than 0.05) for the Day 0 group than for the pre-ovulatory group inseminated up to 3 days before ovulation. In Experiment 2, ovulation was detected by examinations every 6 h; pregnancy rate was greater (P less than 0.05) for mares inseminated 0 to 6 h after ovulation than for mares inseminated at 18 to 24 h. No pregnancies occurred when mares were inseminated 30 h or more after ovulation. The mean day of first detection of the embryonic vesicle was different (P less than 0.0001) among the three groups. Diameter of embryonic vesicle averaged over Days 11 to 15 also differed (P less than 0.0001) among groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2002

Factors influencing sperm transfer and insemination in cat fleas (Siphonaptera: Pulicidae) fed on an artificial membrane system.

Sperm transfer through the epididymis, a prerequisite for insemination of cat fleas, Ctenocephalides felis (Bouché) was stimulated by exposure of unfed male fleas to juvenile hormone III residues for 3 d at 25 degrees C or exposure of unfed fleas to 37 degrees C for 6 d. Sperm transfer was completed at least three times faster in unfed males held at 37 degrees C than in those held at 25 degrees C. Although percentage sperm transfer in fleas fed water or 0.15 M saline at 37 degrees C was not significantly increased over that of unfed fleas, a significantly greater percentage of blood-fed males completed sperm transfer at 2, 3, and 6 d. At least two factors influenced insemination: exposure of fleas to host body temperature and amount of food consumption. When blood-fed males and females were paired and fed 0.15 M saline, 0% were inseminated at 25 degrees C versus 35% at 37 degrees C. Because percentage insemination did not increase in blood-fed males and females that were paired and fed 0.15 M saline at 37 degrees C for an additional 48 h, continuous bloodfeeding appeared to be required for maximal rates of mating and insemination. Furthermore, no females were inseminated when blood-fed males and females were paired at 37 degrees C and starved. Treatment of unfed fleas with juvenile hormone III did not substitute for bloodfeeding in stimulating mating and insemination; when blood-fed males were paired with JH III-treated females and vice versa and fed 0.15 M saline at 37 degrees C, 0% were inseminated. However, when fleas were fed 0.15 M saline and exposed to 1,250 ppm juvenile hormone III or fed whole blood and exposed to 12.5, 125, or 1,250 ppm juvenile hormone III, percent insemination was significantly increased in comparison to the controls. Therefore, juvenile hormone secretion in blood-fed fleas may regulate mating success indirectly by stimulating sperm transfer.

Animals↗
PubMedDate not supplied

A comparative study using prepared and unprepared frozen semen for donor insemination.

The aim of this study was to compare the efficacy of pericervical insemination with unprepared semen With that of intrauterine insemination with prepared donor semen in a prospective, randomized, crossover clinical trial. Fifty-four subsequent patients who qualified for therapeutic donor insemination were randomized to receive alternately either an intrauterine insemination with thawed frozen donor semen, prepared by double wash and swim-up, or pericervical insemination with unprepared thawed frozen donor semen in subsequent treatment cycles, with each patient serving as her own control. Eleven pregnancies ensued from 54 cycles of intrauterine insemination (20.4% per cycle), and 2 pregnancies ensued from 58 cycles of pericervical insemination (3.4% per cycle, p = .005). Five pregnancies ensued during the first treatment cycle (13.2%), 4 during the second treatment cycle (17.4%), 2 during the third (13.2%), 1 during the fourth (7.1%), and 1 after the fourth treatment cycle (4.8%). The significantly better pregnancy rate from intrauterine insemination with prepared semen supports this treatment option. The decrease in pregnancy rate after the fourth treatment cycle confirms the need for alternative therapy after 4 failed cycles of therapeutic donor insemination.

Adolescent↗
PubMed2000

Use of bovine somatotropin in lactating dairy cows receiving timed artificial insemination.

Objectives of the research were to examine the effect of bovine somatotropin (bST) on pregnancy rates to a timed artificial insemination protocol and to test a resynchronization system with two consecutive synchronized services. Lactating Holstein cows (n = 403) were assigned to the following treatments: bST treatment (500 mg) was initiated at 63 +/- 3 d postpartum concomitantly with initiation of the timed artificial insemination protocol or bST treatment was initiated at 105 +/- 3 d postpartum. At 63 +/- 3 d postpartum, all cows received GnRH (100 microg), an injection of PGF2alpha (25 mg) 7 d later, and a GnRH injection at 48 h after PGF2alpha and were inseminated 16 to 20 h later. Cows were reinseminated at detected estrus or resynchronized with a GnRH injection at 20 d after insemination. At 27 d after insemination, cows were examined for pregnancy. Resynchronized cows diagnosed nonpregnant received an injection of PGF2alpha and were inseminated at detected estrus or received an injection of GnRH at 48 h after PGF2alpha and inseminated 16 to 20 h later. Cows pregnant at d 27 were reexamined for pregnancy at 45 d after insemination. First-service pregnancy rates at d 45 were increased in cows not resynchronized that initiated bST treatment at 63 +/- 3 d postpartum, compared with cows initiating bST treatment at 105 +/- 3 d postpartum (37.7 +/- 5.8% and 22.1 +/- 4.2%, respectively), but the effect of bST treatment was not observed when cows were resynchronized (25.6 +/- 4.3% and 25.8 +/- 5.5%, respectively). Thus, bST increased pregnancy rates to a timed artificial insemination protocol.

Analysis of Variance↗
PubMed2001

Determination of the role of cervical closure in fertility regulation after mating or artificial insemination in beagle bitches.

In the present study, the pregnancy rate after one insemination with fresh semen performed at the optimum period of fertilization (control) was compared with the pregnancy rate after insemination by either vaginal deposition of semen or transcervical uterine insemination at 24, 48 or 72 h after closure of the cervix (n = 5 bitches per time period and group). In the group of bitches inseminated into the uterus, 2 ml of a fresh pool of semen from four male dogs was deposited transcervically or by laparoscopy into the uterus, whereas in the vaginally inseminated animals, 2 ml fresh semen was extended with 4 ml prostatic fluid. The study was performed over 5 years; some bitches were used twice during two consecutive oestrous cycles. Closure of the cervix was determined once a day by retrograde vaginogram using a radiopaque contrast dye. Closure of the cervix occurred 6.9 +/- 1.1 days (mean +/- SD) after the LH peak and 1.5 +/- 0.9 days before the first day of cytological metoestrus. The hormone values at the time of closure were 81.2 +/- 12.3 nmol progesterone l-1 and 28.4 +/- 23.2 pmol oestradiol l-1; there were no differences between groups. Of the bitches inseminated before closure of the cervix, five and four bitches became pregnant after uterine and vaginal insemination, respectively. Of the bitches inseminated into the vagina 24, 48 or 72 h after cervical closure, none became pregnant, whereas three, three and one bitches became pregnant after insemination directly into the uterus at 24, 48 or 72 h after cervical closure, respectively. The mean litter size was 3.9 +/- 1.4 pups among all pregnant animals and there were no significant differences between groups. The results of the present study indicate that mature canine oocytes may remain fertile for > 200 h after ovulation, rather than for 48-60 h as was previously believed, and that cervical closure may be a limiting factor for reproductive success after natural mating.

Animals↗
PubMed1994

Insemination results with slow-cooled stallion semen stored for approximately 40 hours.

Semen from 3 stallions was extended using 2 methods (Kenney extender and a modified Kenney extender), slowly cooled, and stored for 41 +/- 6 (s.d.) h before insemination. An insemination dose (40 ml) contained 1.5-2 billion spermatozoa. In the experiment, 26 mares were inseminated in 30 cycles. The pregnancy rate per cycle obtained with sperm stored in the Kenney extender was 87% (n = 15). When the semen was extended with the modified extender, centrifuged and stored, the pregnancy rate was 60% (n = 15). Inseminations were done every other day until ovulation was detected. If a mare ovulated more than 24 h after the last insemination, she was inseminated also after ovulation. The single-cycle pregnancy rate was 58% when the mares were inseminated only before ovulation (n = 19) but the rate was 100% when the inseminations were done both before and after ovulation (n = 9) or only after ovulation (n = 2). The difference in pregnancy rates was significant (p < 0.05), indicating that postovulatory inseminations probably serve to ensure the pregnancies. The extending and handling methods used in this study resulted in a combined pregnancy rate of 73%, and appear thus to be useful for storing stallion semen for approximately 2 days.

Animals↗
PubMed1980

Artificial insemination of subtropical commercial beef cattle following synchronization with cloprostenol (ICI 80996): II. Estrous response.

Data collected from two controlled breeding field trials involving 561 Bos indicusxBos taurus cows and heifers were analyzed for estrous and fertility response following a cloprostenol ICI-80, 996 (CLP) synchronization regime. Fertility data were discussed in a companion paper (1). In Trial 1, 128 animals were assigned to four treatments: 1) controls which were inseminated at the naturally occurring estrus; 2) Animals artificially inseminated at approximately 72 hr and 96 hr following a second CLP; 3) Animals artificially inseminated at approximately 72 hr following a second CLP; and 4) Animals artificially inseminated approximately 12 hr after detection of estrus post-second CLP. Trial II included 391 heifers distributed among six treatments: 1) Artificially inseminated between 70 and 90 hr post-second CLP; 2) Sham inseminated between 70 and 90 hr post-second CLP; 3) Processed with no manipulation of the genital tract between 70 and 90 hr post-second CLP; 4) Artificially inseminated approximately 12 hr after the detection of estrus following a second CLP; 5) Artificially inseminated at the naturally occurring estrus and 6) Non-treated heifers exposed to fertile bulls. Cloprostenol ICI-80996 was effective (P<.01) in synchronizing estrus in comparisons of treated vs non-treated controls in Trials I and II (82 vs 29%; 57 vs 19%, respectively). However, a significant reduction in the expression of estrus was observed following Timed AI when compared to heifers bred 12 hr after detection of CLP-induced estrus in Trial II (37 vs 54%, P<.05). The authors conclude that a single timed insemination of Brahman crossbred heifers suppresses the behavioral expression of estrus. Other evidence (1) indicates that the fertility during this period is similarly reduced.

Journal Article↗
PubMed1991

The effect of timing of laparoscopic insemination in superovulated ewes, with or without sedation, on the recovery of embryos, their stage of development and subsequent viability.

Twenty ewes were used as donors in a 2 x 2 factorial design experiment to investigate the effects of two different insemination times (48 vs 60 h after pessary withdrawal), with or without sedation, on the ovum recovery rate 5 d after insemination, the proportion of transferable embryos recovered, and the subsequent survival rate of embryos transferred to recipients. The ovum recovery rate following intrauterine insemination at 48 h after progestagen pessary withdrawal was 63.8 and 53.4% for sedated and nonsedated control ewes, respectively. Following intrauterine insemination at 60 h the corresponding values for sedated and control ewes were 72.6 and 73.9%, respectively. The proportion of transferable quality embryos recovered was not affected by sedation but was improved by insemination at 48 h rather than 60 h after pessary withdrawal (100 vs 35.4%). Embryo survival following laparoscopic transfer to recipients from donor ewes inseminated at 48 h, with or without sedation was 38.8% (7/18) and 50% (7/14), respectively. Following intrauterine insemination of the donors at 60 h, the survival rate in recipients was reduced for embryos transferred from both the sedated and control ewes to 6.25% (1/16) and 36.3% (4/11). It is concluded that delaying the timing of intrauterine insemination relative to pessary withdrawal and the use of acepromazine maleate as a sedative at the time of insemination are deleterious to embryo development and subsequent viability.

Journal Article↗