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[Levels of thyroxine, beta carotene and vitamin A during successful and unsuccessful insemination of heifers].

We studied the concentrations of thyroxine (T4), beta-carotene and vitamin A (vit. A) on the day (zero-th day) of the first successful and unsuccessful insemination of 63 heifers that were administered feed rations balanced according to the Czechoslovak standard CSN 46,7070, housed all the year round, inseminated at uniform time (8:00-9:00 a. m.) and with blood samplings at uniform time (10:00-12:00 a. m.). In the repeat-breeder heifers during the first insemination the above parameters were determined in the same conditions on the day of their second, or third successful and also unsuccessful insemination; the changes relevant to the first insemination were evaluated. In relation to the day of the first successful insemination, we recorded a significant increase in T4 concentration (P less than 0.001; P less than 0.001) on the day of the second, or third successful inseminations. During the second insemination we recorded significantly lower T4 concentrations in the cows which had failed to be inseminated in comparison with successfully inseminated cows; these concentrations did not differ significantly from T4 concentrations in the heifers that failed to become pregnant in the first insemination. Parallelly with the rise in T4 concentration, beta-carotene concentrations also increased during the second and third inseminations (P greater than 0.05). No difference was recorded in beta-carotene concentrations after the first and second unsuccessful inseminations.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Non-surgical intrauterine artificial insemination in bitches using frozen semen.

A total of 46 bitches were inseminated directly into the uterus using non-surgical insemination procedures; the technique used in six bitches involved specially designed metal catheters and abdominal fixation of the cervix, whereas the remainder were inseminated by passing a flexible plastic catheter through the cervix using direct endoscopic visualization to facilitate the process. Twenty-seven bitches were inseminated with semen frozen at the clinic; the remainder were inseminated with imported semen. Insemination timing was based on endoscopic assessment of the vaginal mucosa, vaginal cytology and blood progesterone concentration determined using a rapid, qualitative enzyme-linked immunosorbent assay (ELISA) kit. Each bitch received between 50 x 10(6) and 200 x 10(6) total spermatozoa per insemination; post-thaw motility varied from 10 to 80%. Two inseminations were performed 48 h apart in the majority of bitches. An overall pregnancy rate of 80% (37/46) was obtained with a mean litter size of 5 +/- 3.14. Subsequent pregnancy rates were comparable for both techniques and both were considered to be effective methods of inseminating frozen semen. Considerably fewer spermatozoa were inseminated in many of these bitches than have previously been reported. In a series of seven bitches using the semen from one dog, each bitch received two inseminations of 30-35 x 10(6) live normal spermatozoa per insemination. A pregnancy rate of 85% (6/7) and a mean litter size of 7.8 was achieved. Rapid ELISA progesterone kits were used to identify the optimum time for insemination.

Animals↗

A comparison of intrauterine versus intracervical insemination in fertile single women.

OBJECTIVE: To compare the efficacy of intrauterine insemination (IUI) and intracervical insemination (ICI) when used by fertile single women in a donor insemination program. DESIGN: Prospective randomized crossover study. SETTING: Donor insemination program (not an infertility clinic). PATIENT(S): Single fertile women choosing to inseminate with frozen donor semen. INTERVENTION(S): Clients received procreative counseling and screening and were then randomly assigned to begin office insemination with ICI or IUI. If additional insemination cycles were required, the clients used the method opposite their previous method of insemination until pregnancy was achieved. MAIN OUTCOME MEASURE(S): Monthly fecundity rate was compared between the two methods of insemination. RESULT(S): Sixty-two women contributed a total of 189 cycles, 94 by IUI and 95 by ICI. The monthly fecundity rate for IUI was 15%, as compared with 9% for ICI, (P=0.14). When the analysis was confined to cycles in which only one insemination was performed (64 IUI and 65 ICI cycles), the monthly fecundity rates were 14% for IUI and 5% for ICI (P=0.04). CONCLUSION(S): Intrauterine insemination with frozen donor sperm is more effective than intracervical insemination for single women without known fertility problems.

Adult↗

Insemination of mares with low numbers of either unsexed or sexed spermatozoa.

Two experiments were conducted to determine pregnancy rates in mares inseminated 1) with 5, 25 and 500 x 10(6) progressively motile spermatozoa (pms), or 2) with 25 x 10(6) sex-sorted cells. In Experiment 1, mares were assigned to 1 of 3 treatments: Group 1 (n=20) was inseminated into the uterine body with 500 x 10(6) pms. Group 2 (n=21) and Group 3 (n=20) were inseminated into the tip of the uterine horn ipsilateral to the preovulatory follicle with 25 and 5 x 10(6) pms, respectively. Mares in all 3 groups were inseminated either 40 (n=32) or 34 h (n=29) after GnRH administration. More mares became pregnant when inseminated with 500 x 10(6) (18/20 = 90%) than with 25 x 10(6) pms (12/21 = 57%; P<0.05), but pregnancy rates were similar for mares inseminated with 25 x 10(6) vs 5 x 10(6) pms (7/20 = 35%) (P>0.1). In Experiment 2, mares were assigned to 1 of 2 treatments: Group A (n=11) was inseminated with 25 x 10(6) spermatozoa sorted into X and Y chromosome-bearing populations in a skimmilk extender. Group B (n=10) mares were inseminated similarly except that spermatozoa were sorted into the skimmilk extender + 4% egg yolk. Inseminations were performed 34 h after GnRH administration. Freshly collected semen was incubated in 224 microM Hoechst 33342 at 400 x 10(6) sperm/mL in HBGM-3 for 1 hr at 35 degrees C and then diluted to 100 x 10(6) sperm/mL for sorting. Sperm were sorted by sex using flow cytometer/cell sorters. Spermatozoa were collected at approximately 900 cells/sec into either the extender alone (Group A) or extender + 4% egg yolk (Group B), centrifuged and suspended to 25 x 10 sperm/mL and immediately inseminated. Pregnancy rates were similar (P>0.1) between the sperm treatments (extender alone = 13/10, 30% vs 4% EY + extender = 5/10, 50%). Based on ultrasonography, fetal sex at 60 to 70 d correlated perfectly with the sex of the sperm inseminated, demonstrating that foals of predetermined sex can be obtained following nonsurgical insemination with sexed spermatozoa.

Animals↗

[A.I. in pigs: breeding efficiency of one and two inseminations per heat (author's transl.)].

Breeding efficiency as expressed by the 30-60 days non-return percentage by one and two inseminations per heat was compared. Sows and gilts in a good heat (heat detection by stockmen) received only one insemination per heat, whereas females with a moderate/weal heat received two inseminations with an interval of approx. 24 hours, provided they were still in heat at the 2nd visit. The results have been set out in the tables I and II. A total of 89.1 and 90.8 percent non-returns by one and two inseminations per heat have been obtained (table I). The difference of 1.7 percentage units in favour of two inseminations is significant, (P less than 0.001). A variation within technicians of percentage of one insemination per heat from 10-97 was found, table II. 11 technicians had significant better results with two inseminations, one technician with one insemination, and by the rest of technicians no significant differences were found between one and two inseminations per heat. It is concluded that: 1) By effective heat detection, the breeding efficiency which can be obtained by one insemination per heat, is only two percentage lower than the breeding efficiency obtained by two inseminations per heat. 2) This loss in breeding efficiency is probably compensated by the economical advantage of one insemination per heat.

Animals↗

Artificial insemination with frozen semen in dogs: a retrospective study.

In a retrospective study, from 1994 to 1998, of inseminations with frozen semen in dogs, a total of 312 bitches of 70 different breeds were inseminated with imported (n = 183) or domestic (n = 129) semen. The overall whelping rate was 70% and mean (+/- SEM) litter size was 5.3 +/- 0.2 pups. The whelping rate was higher after intrauterine insemination (71%; n = 305) than after intravaginal insemination (29%; n = 7; P < 0.05). Timing of insemination was crucial; timing classified as optimal resulted in a higher whelping rate and larger litter size (P < 0.05) than did timing classified as early, late or too late. In the too late category, none of the bitches (n = 5) whelped. For optimal timing, whelping rate and mean (+/- SEM) litter size were 76% (n = 252) and 5.6 +/- 0.2, for early 33% (n = 6) and 1.5 +/- 0.5, and for late 47% (n = 19) and 2.8 +/- 0.7. Two inseminations yielded a higher whelping rate (P < 0.05) and greater mean litter size (P < 0.05) than that of one insemination, 77% and 5.6 +/- 0.3, and 60% and 4.6 +/- 0.3, respectively. However, the results obtained after one insemination were poorer partly because of an over-representation of late insemination in this group. Semen classified as of poor quality (progressive motility < 50% or percentage of abnormal spermatozoa > 20%) gave a lower whelping rate (53%) than did semen of medium (progressive motility = 50%) or good quality (progressive motility > 50% and percentage of abnormal spermatozoa < 20%), which gave whelping rates of 76 and 74%, respectively (P < 0.05). The mean litter sizes were not significantly different. Eighty-two per cent of bitches (120 of 147) inseminated twice into the uterus at a time classified as optimal with frozen semen of good or medium quality whelped. The mean (+/- SEM) litter size was 5.6 +/- 0.3 pups in this group. These results show the potential of transcervical intrauterine insemination for routine artificial insemination in dogs.

Animals↗

[Effect of cattle insemination carried out with and without assistance].

It has been studied whether help with the insemination work from a herdsman improves the result of the insemination. Totally 52,716 inseminations performed by 55 insemination technicians and veterinarians are included in the study, 18 per cent of these inseminations were performed without help. The data are analysed by a least squares procedure. The model used included lactation number of the cow (ai), insemination month (mj), the person who performed the insemination (ink), whether he had been helped with the insemination or not (hl) and interaction between ink and hl. As measure of the result of the insemination 60 days non-return percentage was used (total 60 days N.R.-% and 60 days N.R.-% corrected for short returns, zero to three days). There was found no significant effect of help at insemination on either of the 60 days N.R.-%'s studied. However, to encourage good contact between the farmers and the inseminating personnel, it is beneficial that herdsmen are present when cows are inseminated.

Animal Husbandry↗

Comparison of pregnancy rates of repeat-breeder dairy cows given gonadotropin releasing hormone at or prior to the time of insemination.

A total of 585 repeat-breeder dairy cows was used to study the effect of GnRH treatment, either at or prior to insemination, on the pregnancy rate. The cows were divided into 6 treatment groups. Cows in Group 1 (n = 142) were observed in estrus, and 11 +/- 0.42 hours (mean +/- SEM) later they were given 100 ug, i.m. gonadotropin releasing hormone (GnRH) and were inseminated. Cows in Group 2 (n = 139) were observed in estrus and were inseminated 11.4 +/- 0.43 hours later. Cows in Group 3 (n = 33) were monitored for estrus with an activated heatmount detector but were not observed in estrus; they were inseminated 1.5 +/- 0.87 hours later and were given 100 ug, i.m. GnRH. Cows in Group 4 (n = 35) were not observed in estrus, but they did activate the heatmount detector and were inseminated 2.2 +/- 0.87 hours later. Cows in Group 5 (n = 107) were observed in estrus, given 100 ug, i.m. GnRH 2.0 +/- 0.40 hours later, and were inseminated 9 +/- 0.60 hours after GnRH treatment. Cows in Group 6 (n = 129) were observed in estrus and were inseminated 10 +/- 0.50 hours later. Pregnancy rates were analyzed by Chi-square. Interactions between pregnancy rate, treatment and time of insemination were evaluated using ANOVA and LSM (P < 0.05). There was no effect on pregnancy rate when GnRH was given at or prior to insemination. Cows inseminated on the basis of observed estrus had a higher pregnancy rate (P < 0.05) than cows inseminated on the observation of an activated heatmount detector. From the results of this study, it is concluded that treatment with GnRH at or prior to insemination did not improve the pregnancy rate of repeat-breeder dairy cows.

Journal Article↗

Methods of identifying and inseminating nonpregnant beef females after synchronization of second estrus with norgestomet implants.

Beef females (547) were included in three experiments to evaluate methods of identifying and inseminating nonpregnant beef females after synchronization of second estrus with norgestomet implants. In the first experiment, heifers not pregnant to the first insemination were identified for insemination via estrus (inseminated via the a.m./p.m. rule or 48 h after implant removal). In the second experiment, females not pregnant to the first insemination were identified for insemination via estrus (inseminated via the a.m./p.m. rule) or progesterone concentrations < 1.5 ng/mL at implant removal (inseminated 48 h after implant removal). In the third experiment, heifers not pregnant to the first insemination were identified for insemination via progesterone concentrations (as in experiment 2) or anterior vagina electrical resistance values < 81 ohm resistance 48 h after implant removal (inseminated after resistance measured). All methods of identifying and inseminating nonpregnant females were equally effective (P > 0.10) and did not effect (P > 0.10) calving rates from the first and second AI.

Journal Article↗

Artificial insemination in domestic cats (Felis catus).

Artificial insemination (AI) in cats represents an important technique for increasing the contribution of genetically valuable individuals in specific populations, whether they be highly pedigreed purebred cats, medically important laboratory cats or endangered non-domestic cats. Semen is collected using electrical stimulation, with an artificial vagina or from intact or excised cauda epididymis. Sperm samples can be used for AI immediately after collection, after temporary storage above 0 degrees C or after cryopreservation. There have been three and five reports on intravaginal and intrauterine insemination, respectively, and one report on tubal insemination with fresh semen. In studies using fresh semen, it was reported that conception rates of 50% or higher were obtained by intravaginal insemination with 10-50x10(6) spermatozoa, while, in another report, the conception rate was 78% after AI with 80x10(6) spermatozoa. After intrauterine insemination, conception rates following deposition of 6.2x10(6) and 8x10(6) spermatozoa were reported to be 50 and 80%, respectively. With tubal insemination, the conception rate was 43% when 4x10(6) spermatozoa were used, showing that the number of spermatozoa required to obtain a satisfactory conception rate was similar to that of cats inseminated directly into the uterus. When frozen semen was used for intravaginal insemination the conception rate was rather low, but intrauterine insemination with 50x10(6) frozen/thawed spermatozoa resulted in a conception rate of 57%. Furthermore, in one report, conception was obtained by intrauterine insemination of frozen epididymal spermatozoa. Overall, there have been few reports on artificial insemination in cats. The results obtained to date show considerable variation, both within and among laboratories depending upon the type and number of spermatozoa used and the site of sperm deposition. Undoubtedly, future studies will identify the major factors required to consistently obtain reliable conception rates, so that AI can become a practical technique for enhancing the production of desirable genotypes, both for laboratory and conservation purposes.

Animals↗

Delayed timing of intrauterine insemination results in a significantly improved pregnancy rate in female partners of quadriplegic men.

OBJECTIVE: To review pregnancy rates obtained with three protocols used during development of a successful therapy for infertility in couples in which the male partner had spinal cord injury. DESIGN: Retrospective chart review. SETTING: Private infertility center. PATIENT(S): Eleven quadriplegic men and their spouses undergoing intrauterine insemination. INTERVENTION(S): Protocol 1: Intrauterine insemination was performed 24 hours after the LH surge was detected in unstimulated cycles. Sperm were prepared by standard sperm washing. Protocol 2: Female partners were stimulated with clomiphene citrate and hCG. Sperm were inseminated 32-34 hours after hCG injection. Sperm preparation was by serum swim-up or density gradient preparation. Protocol 3: Identical to protocol 2, except the insemination was delayed to 38-40 hours after hCG injection. MAIN OUTCOME MEASURE(S): Pregnancy rates. RESULT(S): Five patients were enrolled into protocol 1 and underwent a total of 19 inseminations with no subsequent pregnancies. They then underwent protocol 2, but no pregnancies resulted from inseminations. Four of the original couples, along with six additional couples, underwent insemination in protocol 3. A total of 19 inseminations were performed, and 6 of the 10 patients (60%) became pregnant. The success of insemination at 38-40 hours after hCG administration was significantly better than that of the initial two protocols (P<.05). No differences were observed in sperm quality between protocol 2 and protocol 3. Overall, 73% (8 of 11) of the patients became pregnant. CONCLUSION(S): Intrauterine insemination 38-40 hours after the hCG injection results in an improved chance of pregnancy. These results indicate that many couples with spinal cord injury-associated male infertility can be treated with intrauterine insemination of sperm treated by serum swim-up, with a high probability of success.

Chorionic Gonadotropin↗

Insemination time and dilution rate of cooled and chilled ram semen affects fertility.

Adult Merino ewes (n=448) were apportioned into two groups and inseminated with: extended at 30 degrees C with skim milk and stored for 6h at 15 degrees C (cooled semen) or extended with skim milk-citrate trisodium with egg yolk and stored for 24h at 5 degrees C (chilled semen). Each group was further subdivided according to the time of cervical insemination at 42, 46 and 50h after pessary (MAP-60 mg) removal and according to the dilution of the semen (120 x 10(6) spermatozoa in 0.05, 0.1 and 0.2 ml). The pregnancy rate after insemination with cooled semen was 50% better than that after chilled semen (56.7 vs. 37.5%; P<0.001). Pregnancy rate was not affected by the volume of insemination; however, there was a tendency of increased lambing rate with an insemination dose of 0.1 cc (1:2, dilution), especially when the ewes were inseminated with cooled semen. The effect of time on insemination was significant only in ewes inseminated with chilled semen at 5 degrees C (P<0.01). Insemination carried out 46 h after pessary removal resulted in higher pregnancy and lambing rate (36.5, 31.1; 52.0, 45.3; and 24.0, 20.0 at 42, 46 and 50h, respectively). Pregnancy of ewes inseminated with chilled semen at 46 h after pessary removal was similar to that obtained using cooled semen (52.0 vs. 56.7%). From this study, it is concluded that advancing the time of insemination with chilled semen at 5 degrees C improves pregnancy and that the lambing obtained under these conditions is similar to the one obtained with cooled semen.

Animals↗

Low dose insemination in synchronized gilts.

Conventional insemination techniques in pigs require 2 to 3 x 10(9) sperm/dose. When using the latest high-speed sperm-sorting technology, one can still sort only about 5 to 6 million sperm of each sex per hour. The objective of the present study was to find the minimal sperm concentration at a low-insemination volume in pigs without diminishing fertilization rate and litter size using surgical deep intra-uterine insemination (IUI). Semen from 3 boars was collected and diluted with Androhep to 5 x 10(8), 1 x 10(8), 1 x 10(7), 5 x 10(6) or 1 x 10(6) sperm/0.5 ml. In trial 1, 109 prepuberal gilts were synchronized and surgically inseminated into the tip of each uterine horn 32 h or 38 h after hCG treatment or at the time of ovulation, respectively. Pregnant gilts were allowed to go to term. Pregnancy and farrowing rates did not differ significantly except at the lowest sperm concentration if inseminated 32 h or 38 h after hCG treatment (p < 0.05). No differences were found among insemination groups for the total number of piglets, number of piglets born alive, stillborn piglets, and mummified fetuses. In trial 2, 34 gilts were inseminated as described above 32 h after hCG. Additionally, 9 gilts were inseminated once nonsurgically with 1 x 10(9) sperm as controls. Gilts were slaughtered 48 h after insemination, and embryos were recovered. Embryos were cultured in NCSU 23 (120 h), evaluated morphologically and stained with fluorescent dye (Hoechst 33342) to visualize nuclei. Recovery rates varied between 71.4% and 84.4%. Fertilization rate of the lowest sperm concentration (1 x 10(6) sperm/horn) differed significantly (p < 0.05) from all other groups. Cleavage rates at specific developmental stages did not differ. After 5 days of in vitro culture, embryos developed to morulae and blastocysts. No differences were found for these stages. In conclusion, no major differences were found between insemination groups as long as the sperm dosage was at least 10 million sperm per gilt. The low volume was sufficient for successful deep intra-uterine insemination. Embryo development was comparable to the controls.

Animals↗

Intraperitoneal insemination and retrograde sperm transport in dairy cows.

To examine the efficiency of retrograde sperm transport following intraperitoneal insemination, live and dead spermatozoa were used at different concentrations, and sperm recovery from cervical mucus (0.5 ml) 2, 6, 12 and 24 h following insemination was evaluated. Forty lactating Friesian cows, in their second to fourth lactation period, were used in this experiment. Thirty-six cows received intraperitoneally either live or dead spermatozoa. Each group of six cows received one of three total sperm numbers of 30, 45 and 90 million. Four cows were inseminated with 90 million spermatozoa into the uterus and served as a control group. All cows were inseminated towards the end of oestrus. After intrauterine insemination sperm recovery declined, but motile and/or immotile spermatozoa were recovered from all cows at any time. In cows inseminated intraperitoneally, sperm was recovered from the cervix at 6-24 h when 90 million were inseminated. A greater number of spermatozoa was recovered after dead rather than after live sperm inseminations. Only immotile, intact or broken spermatozoa and tail-less heads were recovered after intraperitioneal insemination using either live or dead spermatozoa. No sperm was recovered for 30 and 45 million inseminations. Our results show that, following intraperitoneal insemination, there is passive sperm transport from the peritoneal cavity to the genital tract close to the time of ovulation, and suggest a higher sperm retention in the genital tract when live as opposed to dead spermatozoa are used.

Animals↗

Intrauterine insemination in sows with reduced sperm number.

Usually 2-3 x 10(9) sperm per insemination are used in pigs. In other species it has been shown that changing the site of insemination allows a reduction in the amount of sperm per insemination dose. The goal of this study was to determine the minimal number of sperm that can be used, without a reduction in either the pregnancy rate or the mean litter size, using surgical deep intrauterine insemination in sows after weaning. Three different sperm concentrations (5 x 10(8), 1 x 10(8) and 1 x 10(7) sperm cells extended in 0.5 mL Androhep) were inseminated into the tip of each uterine horn. In addition two groups of control sows were inseminated once intracervically 24-32 h after the first signs ofoestrus with 1 x 10(9) and 3 x 10(9) sperm in 80 mL Androhep extender. Animals that became pregnant were allowed to farrow normally. No significant differences were observed between groups inseminated surgically with the three different sperm dosages with respect to pregnancy or farrowing rate. There was also no significant difference between the results of these groups and the results obtained from the non-surgically inseminated control groups. Neither the mean number of live-born nor stillborn piglets was significantly different between the surgically inseminated groups and the control groups. The total number of piglets born in each group was also not statistically different. The data show that the sperm number to be used for surgical insemination can be lowered without loss of the fertilization potential and may be used in the field as soon as a suitable insemination device is available.

Animals↗

Return to oestrus after first insemination in sow herds (incidence, seasonality, and association with reproductivity and some blood parameters).

As no systematic study has been done to get an accurate estimate of the incidence of return to oestrus after first insemination in sows in the Netherlands, the objectives of this investigation were: 1) to obtain an estimate of the incidence of return to oestrus after insemination at the herd level; 2) to investigate the association between incidence of return to oestrus after first insemination and reproduction characteristics in order to get an impression of the economic importance of reproductive failure. These objectives were investigated by using the reproduction results of 240 swine breeding herds in the Southern Netherlands in 1987. This information was obtained from CBK plus computerized herd management records. The average incidence rate of return to oestrus after first insemination at a herd level was 16.9 per 100 first inseminations. The occurrence of return to oestrus after first insemination was distinctly higher in the insemination months July and August compared to the rest of the year. An increased incidence, with 10 returns per 100 first inseminations corrected for confounders in a multiple linear regression model, was associated with a decrease of approximately 0.3 live born piglets/sow/year. A prospective longitudinal study was started in 1988 and 1989 in 37 sow herds. Individual sows were monitored from weaning to first insemination, to the occurrence of return to oestrus, or not, after first insemination, and to farrowing. The investigation focused in particular on the relationship between return to oestrus after first insemination and seroconversion against porcine parvovirus (PPV) and Leptospira interrogans serovar bratislava (L. bratislava).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Comparisons of intravaginal and intrauterine insemination of bitches with fresh or frozen semen.

To compare the importance of the route of insemination when using fresh or frozen semen, six groups of five bitches were inseminated either into the uterus (groups 4, 5 and 6) or the vagina (groups 1, 2 and 3) with fresh (groups 1 and 4) or frozen semen (groups 2, 3, 5 and 6). The fresh semen was collected when needed from the same dog. The frozen semen used in groups 2 and 5 was obtained from seven dogs on the same day, and pooled and processed simultaneously so that the groups were inseminated with exactly the same semen. The frozen semen used in groups 3 and 6 was obtained from different dogs and processed independently to evaluate not only the effect of the route of insemination but also the potential effect of the dog. The mean concentration of the fresh semen was 310 x 10(6) spermatozoa/ml, its motility was greater than 80 per cent and the percentage of normal live spermatozoa was 80 to 92 per cent. The mean spermatozoal concentration of the frozen semen was 200 x 10(6) spermatozoa/ml, its motility was greater than 60 per cent and the percentage of normal live spermatozoa was 80 per cent. In all the groups there were fewer than 15 per cent abnormal spermatozoa. The animals inseminated with fresh semen received significantly more spermatozoa than the others. The bitches were inseminated twice, three and five days after the estimated peak of luteinising hormone, with a total volume of 5 ml for the vaginal inseminations and 2 ml for the intrauterine inseminations. Sixty per cent of the bitches inseminated with frozen semen and 100 per cent of the bitches inseminated with fresh semen became pregnant, irrespective of the insemination technique used.

Animals↗

Unilateral intrauterine horn insemination of fresh semen in cats.

The sperm count required were investigated to obtain a conception rate of 80% by unilateral intrauterine insemination (UIUI) of fresh semen in cats. The conception rates obtained by insemination before and after ovulation were also examined. Thirty-six female cats aged 1-7 years were used in the experiments, and the number of experimental cases was 44. Seven male cats aged 2-12 years from which semen could be collected by the artificial vagina method were used. In artificial insemination, 100 iu x 2 or 250 iu of hCG was administered on days 2-4 of estrus, and sperm were introduced into the uterine horn with a greater number of ovulations (or mature follicles) 15, 20 and 30 hr after hCG administration by laparotomy. The inseminated sperm counts were 2 x 10(6) (Exp. 1). 4 x 10(6) (Exp. 2), and 8 x 10(6) (Exp. 3). As a result, ovulation was induced in 42 of 44 cases (induction rate: 95.5%) regardless of the dosage of hCG. Conception was obtained by UIUI in two of 16 animals (conception rate: 12.5%) in the Exp. 1, five of 16 animals (31.3%) in Exp. 2, and eight of 10 animals (80.0%) in Exp. 3. Regarding the relationship between the ovulation state at insemination and conception, the conception rate obtained by insemination before ovulation was clearly higher than that obtained by insemination after ovulation (p<0.05). Regarding the number of kits compared to the number of ovulations on the inseminated side, the percentages of cases in which the number of kits exceeded the number of ovulations on the inseminated side were similar in all groups inseminated with a different number of sperm. It is therefore necessary to investigate conception rates obtained by bilateral insemination to increase the fertility rate. Based on the above findings, it was shown that the sperm count required for fertilization by UIUI is 8 x 10(6).

Animals↗