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PubMed1998

A 3 year retrospective review of intrauterine insemination, using cryopreserved donor spermatozoa and cycle monitoring by urinary or serum luteinizing hormone measurements.

Insemination with donor spermatozoa is an integral part of infertility treatment. For the last 3 years in our unit, intrauterine insemination with donor spermatozoa (IUID) has been used in preference to vaginal insemination. In this retrospective study, patients were offered an initial course of five single intrauterine inseminations with cryopreserved donor spermatozoa and treatment was then reviewed. A total of 389 patients received 1465 inseminations. In all, 1119 cycles were monitored using luteinizing hormone serum analyses and 346 cycles using the urine home test kits. The clinical pregnancy rate per insemination for the cycles monitored by the serum assay was 18.0% (202/1119) compared with the urine cycles (13.7%, 46/346) (P <05). The pregnancy loss rate was not significantly different (14.4%, 29/202 and 21.7%, 10/46) (serum and urine cycles respectively). The viable clinical pregnancy rate was significantly higher (P <03) for the serum cycles than for the cycles using the urinary monitoring (15.5%, 173/1119 and 10.4%, 36/346 respectively). The cycles monitored by serum assay had a significantly higher cumulative viable clinical pregnancy rate (P <0001) of 70.2% after nine inseminations compared with the urine monitored cycles of 54.8%. The majority of patients opted for the serum cycles, with a minority self-selecting the urine cycles mainly for travelling convenience. The explanation for the significant differences between the viable clinical pregnancy rates per insemination and the cumulative viable clinical pregnancy rates may be due to the sensitivity of the urine home test kit or the patients' interpretation of the result.

Cryopreservation↗
PubMed1994

Methods to increase the success rate of artificial insemination with donor semen.

Donor insemination was performed in two fertility clinics using cryopreserved semen from the same sperm bank. Donors were selected in agreement with American Fertility Society recommendations. In the first clinic, cup insemination was combined with intra-uterine insemination in 321 cycles. Follicular development was closely monitored with vaginal echography and serum hormonal measurements. In the second clinic, 1287 insemination cycles were performed using intra-cervical insemination, timed only on basal body temperature. In the first clinic, a total of 53 pregnancies were obtained, of which seven were in 55 unstimulated cycles (12.5%), 21 in 159 cycles with clomiphene citrate stimulation (13.1%, P > 0.1), and 25 in 107 cycles stimulated with clomiphene plus human menopausal gonadotrophin (HMG) (23.9%, P < 0.03). No multiple pregnancies were observed in the latter group. In the second clinic, 159 pregnancies occurred during 1287 insemination cycles (12.4%). It is concluded that neither intra-uterine insemination, nor hormonal and echographic cycle monitoring, nor clomiphene citrate enhances the success rate of artificial insemination with donor semen, but HMG treatment probably exerts a favourable effect.

Adult↗
PubMed1983

Fertilizing ability of cock spermatozoa from the testis epididymis and vas deferens following intramagnal insemination.

A reexamination of the fertilizing ability of cock spermatozoa from the testis, epididymis and vas deferens was accomplished through the use of intramagnal insemination. Intramagnal insemination of spermatozoa taken from the testes, epididymides and vas deferentia resulted in fertility levels of 85-90% during the first week and levels of 67-90% the second week after a single insemination. In contrast, vaginal insemination of testicular spermatozoa resulted in a total absence of fertile eggs. Vaginal and intramagnal insemination of ejaculated spermatozoa resulted in fertility levels of 70 and 71%, respectively, during the first week and levels of 42 and 53%, respectively, the second week after a single insemination. There were no significant differences in hatchability of fertile eggs from hens inseminated with semen from different regions of the male tract or by different routes of insemination.

Animals↗
PubMed2006

Intrauterine insemination versus timed intercourse for cervical hostility in subfertile couples.

The postcoital test has poor diagnostic and prognostic characteristics. Nevertheless, some physicians believe it can identify scanty or abnormal mucus that might impair fertility. One way to avoid "hostile" cervical mucus is intrauterine insemination. With this technique, the physician injects sperm directly into the uterine cavity through a small catheter passed through the cervix; the theory is to bypass the "hostile" cervical mucus. Although most gynecologic societies do not endorse use of intrauterine insemination for hostile cervical mucus, some physicians consider it an effective treatment for women with infertility thought the result of cervical mucus problems. The aim of this review was to determine the effectiveness of intrauterine insemination with or without ovarian stimulation in women with cervical hostility who failed to conceive.We searched Cochrane Central Register of Controlled Trials (CENTRAL) on The Cochrane Library Issue 2, 2005, MEDLINE (1966 to June 2005), EMBASE (1980 to June 2005), POPLINE (to June 2005), and LILACS (to June 2005). In addition, we contacted experts and searched the reference list of relevant articles and book chapters. We included randomized and quasirandomized, controlled trials comparing intrauterine insemination with intercourse timed at the presumed fertile period. Participants were women with cervical hostility who failed to conceive for at least 1 year. We assessed the titles and abstracts of 386 publications and 2 reviewers independently abstracted data on methods and results from 5 studies identified for inclusion. The main outcome is pregnancy rate per couple. We did not pool the outcomes of the included 5 studies in a meta-analysis resulting from the methodological quality of the trials and variations in the patient characteristics and interventions. Narrative summaries of the outcomes are provided. Each study was too small for a clinically relevant conclusion. None of the studies provided information on important outcomes such as spontaneous abortion, multiple pregnancies, and ovarian hyperstimulation syndrome. There is no evidence from the published studies that intrauterine insemination is an effective treatment for cervical hostility. Given the poor diagnostic and prognostic properties of the postcoital test and the observation that the test has no benefit on pregnancy rates, intrauterine insemination (with or without ovarian stimulation) is unlikely to be a useful treatment for putative problems identified by postcoital testing. TARGET AUDIENCE: Obstetricians & Gynecologists, Family Physicians. LEARNING OBJECTIVES: After completion of this article, the reader should be able to recall that there is a lack of adequate studies that support that intrauterine insemination (IUI) is an effective treatment of cervical hostility, explain that the postcoital test has poor diagnostic and prognostic properties, and state that the use of both tests has no benefit on pregnancy rates. EDITOR'S NOTE: Although many assisted reproductive technology (ART) programs no longer perform postcoital tests, many perform intrauterine insemination (IUI), often with gonadotropins or clomiphene citrate, in their subfertile patients. Therefore, this review article will be of value to our readers who treat subfertile patients with IUI, whether or not they perform postcoital tests. For additional explanations of the statistical tests employed in this review, see D. Grimes, KF Schulz, Obstetrical and Gynecologic Survey, 57; Supplement 3: S35, September 2002; and D. Grimes, KF Schulz, Obstetrical and Gynecologic Survey, Supplement 2, S53-S69, September 2005.-RBJ.

Cervix Mucus↗
PubMed1990

Fertility of mares after postovulatory insemination.

In a first experiment, 11 Finnhorse mares were examined every six hours during late oestrus by rectal palpation and ultrasonography to determine the time of ovulation. The mares were inseminated over one to three subsequent cycles, 6-12 (n = 5), 12-18 (n = 5), 18-24 (n = 5) and 24-30 (n = 5) hours after ovulation. Pregnancies were terminated by prostaglandin injection 21 days after insemination. All mares inseminated within 18 hours of ovulation conceived but no mare inseminated 24 hours or more after ovulation conceived. In a second experiment, 14 mares were examined every day at about the same time and inseminated after ovulation had been detected, within 0-27 hours of ovulation. Pregnancies were terminated by prostaglandin injection 25 days after insemination and the animals inseminated again. Forty-six per cent of the mares (13 out of 28) were pregnant 16 days after insemination but there was early embryonic death in five mares, i.e. only 29% of the mares became and remained pregnant. The equine ovum seems to be capable of being fertilized for at least 18 hours after ovulation. However, the high incidence of early embryonic death in the second experiment suggests that the viability of the embryo may have decreased.

Animals↗
PubMed1979

Fertility in buffaloes after oestrus synchronisation with cloprostenol and fixed time insemination.

Fifty-seven cycling buffalo cows of the river type were treated with two doses of 0.5 mg cloprostenol intramuscularly given 11 days apart. Each animal was inseminated twice at 72 and 96 hours after the second injection of cloprostenol. The first service conception rate diagnosed by rectal palpation at 90 days was 38.6 per cent. At the time of insemination the cervix was easily penetrable on both days in only 39 (68.4 per cent) of the animals. They were inseminated at or beyond the internal cervical os, while the others were inseminated in the cervical canal. There was a marked difference in conception rate between those receiving deep inseminations (48.7 per cent) and the others (16.7 per cent). In relation to the interval from calving to insemination the conception rates for those which had calved 60 to 90, 90 to 120 and 120 to 150 days earlier were 16.6, 36.4 and 55.5 per cent respectively. The use of cloprostenol treatment and fixed-time insemination is a useful method of overcoming the problem of oestrus detection in buffaloes. Acceptable levels of fertility can be obtained in those animals which have a sufficiently relaxed cervix to permit semen deposition at the internal os, provided the interval from calving to insemination is more than 90 days.

Animals↗
PubMed2001

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

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

Animals↗
PubMed1981

Use of spermatozoa for artificial insemination. I. Fertilizing capacity of fresh and frozen spermatozoa in sows on 36 farms.

A field trial was conducted on 36 farms in the Netherlands to compare the fertilizing capacity of fresh and frozen-thawed boar spermatozoa. Four-hundred and fifty-one sows were artificially inseminated with semen than that had been frozen and thawed according to the Beltsville Method or diluted in Kiev extender and inseminated on the day of collection. Twelve boars of the Dutch Landrace and Dutch Large White breeds were used. Farrowing rates, total number of pigs per litter and number of live pigs per litter were higher (P less than .0001) for sows inseminated with fresh semen than for sows inseminated with frozen-thawed semen (79.1%, 10.6 and 9.9 vs 47.0%, 7.4 and 7.1, respectively). Farrowing rates for sows inseminated with frozen-thawed semen were higher when semen from Dutch Large White boars was used than when semen from Dutch Landrace boars was used (58.6 vs 40.9%); the pattern reversed for insemination with fresh semen (76.5 vs 81%). Boar differences based on farrowing rate ranged from 62 to 92% for fresh semen and from 29 to 72% from frozen semen. There was no inseminator effect or farm effect on farrowing rate. On the basis of these results, frozen semen used for artificial insemination under practical circumstances can be expected to result in a farrowing rate about 30 percentage points lower and a litter size about three pigs smaller than does fresh semen.

Animals↗
PubMed1987

Influence of cornual insemination on endometrial damage and microbial flora in the bovine uterus.

The objectives were to determine effects of cornual insemination on endometrial characteristics and uterine bacterial flora. Forty cows were assigned randomly (10/group) to each of the following treatments: 1) control--no uterine manipulation; 2) uterine body insemination--deposition of the inseminate at the internal cervical os; 3) cornual insemination--one-half of inseminate deposited into each uterine horn anterior to the internal bifurcation and 4) cornual insemination plus endometrial biopsy--insemination into each uterine horn and trauma induced by endometrial biopsy. Animals were slaughtered and reproductive tracts were removed 5 d after treatment. Bacterial populations of the uterine lumen were evaluated by both flushings and swabbings of each horn. Treatment did not influence the presence of luminal bacteria as determined by flushing or swab samples. Gross endometrial characteristics were quantitated in all tracts. Characteristics considered were total endometrial surface area, discolored regions that appeared to be distinctly darker than the remaining portion of the endometrium and obvious surface damage. Discolored regions were evaluated as both total areas and percentage of endometrium. Treatment did not influence total or percent discolored areas. Microscopic evaluation of these tissues revealed increased edema when compared with nondiscolored regions but no disruption of the luminal epithelium was found. Surface damage was found only in the biopsied treatment group. Observation of the endometrium revealed that extensive regeneration occurred by 5 d after treatment. The data suggest that cornual insemination does not result in uterine trauma or bacterial presence 5 d after breeding, and the endometrium is capable of regeneration after trauma during estrus.

Animals↗
PubMed1984

Stage of estrous cycle, time of insemination, and seasonal effects on estrus and fertility of Holstein heifers after prostaglandin F2 alpha.

Stage of estrous cycle, time of insemination, and season of the year were examined for their influence on estrus and fertility of 223 Holstein heifers after prostaglandin F2 alpha (treatment). Heifers treated during early stages (days 5 to 8) of the estrous cycle had shorter (by 11 h) and less variable intervals to estrus compared with treatment of heifers during late stages (days 14 to 16) of the estrous cycle. A greater proportion of heifers in the early cycle treatment (79/81, 97%) were in synchronous estrus (20-h period) after treatment compared with the late cycle treatment (71/86, 83%). Conception rates were lower when early cycle heifers were inseminated at 80 h after prostaglandin F2 alpha than when inseminated according to estrous detection and also lower as compared with late cycle heifers inseminated at 80 h. No differences in fertility were observed for late cycle heifers inseminated at 80 h compared with those inseminated according to estrous detection. Season of the year had no influence on intervals to estrus or on proportion of heifers expressing estrus after prostaglandin F2 alpha, regardless of stage of estrous cycle. Conception rate during winter, however, was higher in early but not late cycle heifers inseminated after prostaglandin F2 alpha, as compared with fall or spring. Variability of interval to estrus and of fertility after inseminations by appointment at 80 h appears to be due to stage of estrous cycle at time of prostaglandin F2 alpha treatment rather than season of the year.

Animals↗
PubMed1985

Changes of evaluation for natural-service sampled bulls brought into artificial insemination.

United States Department of Agriculture Sire Summary files were used to select bulls with a published Modified Contemporary Comparison sire evaluation prior to entry into artificial insemination. Canadian bulls were not included. Of the Brown Swiss, Guernsey, Holstein, and Jersey bulls that entered artificial insemination since 1974, 28 Brown Swiss, 19 Guernseys, 298 Holsteins, and 45 Jerseys (4 to 12%) had natural service evaluations. Of these bulls, 10 Guernseys, 154 Holsteins, and 28 Jerseys had an increase of Repeatability of 30% or more after entering artificial insemination. Evaluations for bulls just prior to their entering artificial insemination were compared with their most recent evaluations through July 1983. Average Repeatabilities for evaluations of bulls just prior to their entering artificial insemination were 32% for Guernseys, 32% for Holsteins, and 31% for Jerseys and 88, 90, and 87% for their most recent evaluations. Average Predicted Differences prior to entering artificial insemination were 305 kg for Guernseys, 394 kg for Holsteins, and 452 kg for Jerseys for milk and 11, 10, and 16 kg for fat. Most recent average Predicted Differences were 268, 380, and 532 kg for milk and 7, 10, and 18 kg for fat. Predicted Differences of natural service bulls were not overevaluated regardless of number of herds for sampling or year of entry into artificial insemination. Artificial insemination organizations can continue to acquire bulls with natural service evaluations calculated with the Modified Contemporary Comparison and be confident that these Predicted Differences are not overestimated.

Animals↗
PubMed1998

Effect of time of artificial insemination on pregnancy rates, calving rates, pregnancy loss, and gender ratio after synchronization of ovulation in lactating dairy cows.

In order to assess the optimal time of artificial insemination (AI) in relation to ovulation, lactating dairy cows (n = 732) from herds with rolling herd averages of 9980 to 11,800 kg from three milkings per day were randomly assigned to five groups by stage of lactation and parity. Ovulation was synchronized by administration of GnRH followed 7 d later with PGF2 alpha followed 2 d later with a second treatment with GnRH. Cows were inseminated at 0, 8, 16, 24, or 32 h after the second injection of GnRH (ovulation occurs between 24 and 32 h after GnRH). Pregnancy diagnoses were performed by ultrasound at 25 to 35 d post-AI. Pregnancy rates per AI were similar for the groups inseminated at 0, 8, 16, and 24 h and lower for the group inseminated at 32 h. A significant quadratic effect of treatment suggests that the middle time periods (8, 16, and 24 h) may produce the greatest pregnancy rate per AI. However, the group inseminated at 0 h had lowest pregnancy loss, and the group inseminated at 32 h tended to have the greatest pregnancy loss compared with that of the other groups. The calving rate was similar between the groups inseminated at 0, 8, 16, and 24 h and lower in the group inseminated at 32 h. The time of AI also appeared to affect gender of calf: cows bred at 0 and 32 h having a higher percentage of female offspring. In conclusion, there appears to be substantial flexibility in the time of AI after the second injection of GnRH, and lower reproductive rates were observed only when AI was after the time of ovulation.

Abortion, Veterinary↗
PubMed1980

Influence of dietary protein during the pre-breeder period on subsequent reproductive performance of large white turkeys. 3. The effects of semen volume and frequency of insemination on fertility and hatchability.

Large White turkey breeders of a commercial variety were used to determine the effects of pre-breeder dietary protein, frequency of insemination, and semen volume on subsequent reproductive performance. Treatments included female dietary protein levels of 10, 12, 14, and 17% fed from 12 to 32 weeks of age and 10, 12, an 14% protein from 20 to 32 weeks of age; male dietary protein levels of 12 and 17% fed from 12 to 56 weeks of age; and artificial insemination (AI) treatments of a) .025 ml of semen at weekly intervals, b) .025 ml of semen at biweekly intervals, and c) .05 ml of semen at biweekly intervals in a factorial arrangement of treatments. Male dietary treatment had no significant effect on fertility or hatchability of fertile eggs. Female pre-breeder protein levels also had no significant effect on fertility but resulted in lower hatchability of fertile eggs during the latter part of the production period when females were fed either the 10 or 12% protein pre-breeder diets. Weekly inseminations with .025 ml of semen resulted in the highest average level of fertility during the production year (90%), followed by biweekly insemination with .05 ml (87%) and .025 ml (85%) of semen, respectively. Hatchability of fertile eggs was significantly higher for hens receiving .05 ml of semen biweekly than for the other two AI treatments during the latter half of the production year only. However, weekly inseminations caused a significant decline (6.7 eggs/hen) in egg production when compared to hens inseminated at biweekly intervals. The average number of fertile eggs was greatest for females inseminated with .05 ml semen biweekly (54.3) compared to those inseminated with .025 ml of semen biweekly (53.0) or .025 ml of semen weekly (50.2).

Animal Nutritional Physiological Phenomena↗
PubMed1982

Fertility of the turkey hen as affected by initial insemination and onset of egg production.

A comparison between initial inseminations of Large White turkey hens prior to or after onset of egg production was undertaken to determine the effect on fertility. Semen from Bronze toms was utilized for the initial inseminations whereas all subsequent inseminations utilized White sires. After 10 weeks there were no significant differences between treatments for percent egg production or hatchability. Inseminating prior to the onset of egg production resulted in a significantly different (P less than or equal to .05) 8-week average of 97.5% fertility in the early insemination (EI) group as compared to an average of 90.4% in the late insemination (LI) group. Differences between the EI and the LI groups were greatest during the last 2 weeks of the experiment during which the EI hens maintained higher levels of fertility. Bronze poults were observed in the EI progeny following three subsequent inseminations with semen from White sires, whereas no Bronze poults were obtained from the LI hens following the third subsequent insemination with White semen.

Animals↗
PubMed1982

Late evening artificial insemination of turkey hens.

Turkey hens were artificially inseminated at three times (0800, 1100, or 2200 hr) under conditions where high or low fertility would be expected. Four trials were conducted and the same two persons collected semen and inseminated the hens in all trials. Each hen was inseminated with .025 cc undiluted semen. There was no significant difference in fertility when hens were inseminated at different times of the day in the first three trials. In a fourth trial, where high fertility was expected, hens inseminated at 0800 hr had lower fertility than those inseminated at 2200 hr. There was no significant difference between inseminating at 0800 or 1100 hr and 1100 or 2200 hr. The results of this study indicate that late evening insemination is not necessary for high fertility.

Animals↗
PubMed1986

Influence of spermatozoa numbers and insemination frequency on fertility in dwarf broiler breeder hens.

The effects of hen age (28 to 31 vs. 49 to 52 weeks of age), sperm concentration (dose used for artificial insemination), and frequency of insemination on fertility and embryonic survival of dwarf broiler breeder hens were examined. Hens in Groups 1 and 2 were inseminated weekly with single doses of either 250 million (Group 1) or 125 million (Group 2) sperm during the 4 weeks of each period. Hens in Groups 3 and 4 were inseminated every other week with duplicate doses on 2 consecutive days, with 250 million sperm/dose in Group 3 and 125 million/dose in Group 4. Hens in Groups 5 and 6 were inseminated weekly with either 250 million (Group 5) or 125 million (Group 6) sperm dose, except the 1st week of each period when they received duplicate doses as in Groups 3 and 4. In Groups 1 and 2, insemination with weekly single doses of semen (250 or 125 million sperm) had no significant effect on fertility of young or old hens. Percent fertility during the 2nd week after artificial insemination was lower in Group 4 than in Group 3 (73.0 vs. 82.9 in young hens and 70.4 vs. 80.7 in old hens). There were no significant differences in fertility between semen doses or age periods in Groups 5 and 6. In these two groups, overall fertility ranged from 94.3 to 95.9%. Complementary studies on individual fertility and embryonic survival showed the beneficial effects of duplicate followed by single inseminations of moderate doses (125 million sperm) practiced at weekly intervals in old hens. This method should be of practical application in commercial practice.

Animals↗
PubMed1989

Fertility in dogs in relation to semen quality and the time and site of insemination with fresh and frozen semen.

In this study 470 bitches were inseminated; 405 with fresh semen into the cranial vagina and 65 with frozen semen transcervically into the uterus. The pregnancy rate was 65.7% with fresh semen and 41.5% with frozen. When corrected for stage of oestrus at the time of insemination and for semen quality the pregnancy rate was 83.8% with fresh semen and 69.3% with frozen semen. The pregnancy rate improved with an increase in the number of inseminations. Inseminations with fresh semen before the time of ovulation (less than 17.3 nmol progesterone/l) were often successful. With frozen semen the peripheral plasma level of progesterone at the time of insemination was greater than 30 nmol/l in all but 1 of the bitches that became pregnant. This difference is assumed to be attributable to a longer survival time of several days for fresh semen than for frozen-thawed semen. Cytological scoring was a satisfactory method for determining the stage of oestrus when using fresh semen, but more precise methods are needed when using frozen semen. Semen quality was difficult to correlate with fertility. Pregnancies were obtained with fresh semen of inferior quality, although the litter size was smaller. With frozen semen no pregnancies resulted when the semen quality was poor. Litter size was estimated to be 21.5% smaller in bitches inseminated with fresh semen compared with naturally mated bitches. Litter size in bitches inseminated with frozen semen was 23.3% smaller than in bitches inseminated with fresh semen. Puppy deaths occurred in 35.5% of the litters in this study. The overall puppy death rate during the first 3 weeks of life was 11.9%. Although not statistically significant, there was a tendency for bitches treated with antibiotics at the time of mating or during early pregnancy to have a higher pregnancy rate and a larger litter size. There was also a tendency for breed differences in pregnancy rate, although not significant.

Animals↗
PubMed1987

Practicalities of insemination of mares with deep-frozen semen.

From 341 stallions examined for sperm quality, 61% of warm-blooded stallions and 47% of cold-blooded stallions fulfilled the pre-existing criteria for their occasional use in insemination. From these stallions 51-71% of acceptable ejaculates were obtained. Altogether 959 mares were inseminated in an average of 1.36 oestrous cycles. For the insemination of one mare in one oestrous cycle on the average 2.2 insemination doses were used. These inseminations were carried out by 41 cattle insemination technicians trained in mare insemination. A pregnancy rate of 56% and a foaling rate of 48% were achieved. Differences were found between the fertility of individual stallions (29-62%), and the pregnancy rate of mares after insemination carried out by individual technicians (0-79%).

Animals↗