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Intrauterine inseminations with washed human spermatozoa.

The success of intrauterine inseminations with washed human spermatozoa was evaluated in four groups of patients. The first two groups were couples in whom either the man or the woman had detectable circulating sperm-agglutinating antibodies. The third group included couples where the woman exhibited hostile or absent cervical mucus, whereas the fourth group represented couples with oligozoospermic males. The couples underwent 3.7 +/- 2.1 insemination cycles, with a 30% overall pregnancy rate for all four groups. Intrauterine inseminations of women with hostile cervical mucus yielded a 68% conception rate. Couples with either male or female serum sperm-agglutinating antibodies showed 25% and 40% pregnancy rates, respectively. However, none of the couples with oligozoospermic males achieved pregnancy. Intrauterine inseminations with washed human spermatozoa thus represent a satisfactory method of achieving pregnancy in women with hostile cervical mucus and in couples with circulating sperm agglutinating antibodies. Couples in whom oligozoospermia has been identified as the principal cause of infertility do not seem to benefit from this therapy.

Adult↗

Ram sperm selection by a dextran/swim-up procedure increases fertilization rates following intrauterine insemination in superovulated ewes.

The objective of this study was to compare the efficacy of 2 dextran/swim-up media to increase the sperm quality parameters and the maintenance of these parameters at 15 degrees C and 30 degrees C over 6 hours. Additionally, this study examined whether differences in sperm quality reflect different reproductive efficiencies following intrauterine insemination in superovulated ewes. The study involved 2 selected samples (SS) obtained by dextran/swim-up, performed either with (SS+) or without (SS-) capacitating compounds, and a control sample consisting of raw semen diluted in the same medium. The efficacies of the swim-up sperm selection procedures were similar in both media, and no significant differences were found among the evaluated parameters. Conversely, we found important differences between selected and control samples. Sperm motility, viability (as assessed by carboxifluorescein diacetate/propidium iodide [PI] staining), and mitochondrial activity (as assessed by rhodamine 123/PI) were significantly higher in the selected samples than in the control. Additionally, following incubation at 15 degrees C, the preservation of sperm quality was significantly better in the selected samples than in the control samples. After 6 hours of incubation at 15 degrees C, selected samples had a motility value of 46%, which was significantly (P < .001) higher than the value observed in control samples (27%). The percentage of viable cells observed after 6 hours of incubation at 15 degrees C was significantly (P < .0001) higher in selected samples than in the control samples. Furthermore, after 2 hours of incubation at 30 degrees C, swim-up samples had viability values that were significantly (P < .0001) higher than those of the control samples. SS+ and SS- samples did not differ significantly in spermatozoa yield, sperm quality, or survival. Differences between selected samples and controls were reflected in the fertilization rate obtained following intrauterine insemination in superovulated ewes that experienced a 52-hour interval between progestagen removal and artificial insemination. A restricted criterion for fertilization rate evaluation was established, and only the percentage of embryos recovered from the uterine horns 6 days after insemination was considered with respect to the total number of corpora lutea counted in the ovaries. The fertilization rate of SS- samples (50%) was significantly higher (P > .001) than those of the SS+ (2%) and control samples (5%).

Animals↗

Sperm concentration dependency in the fertilization and zonae sperm binding properties of mouse eggs inseminated in vitro.

Sperm penetration of zonae and fertilization of mouse eggs in vitro was studied as a function of sperm concentration over the range 10(3)-10(6) cells/ml. Maximal fertilization was obtained at 10(5) sperm/ml with markedly reduced levels seen at lower concentrations. Eggs inseminated at low sperm concentrations were, however, characterized by the absence of multiple sperm penetrations of their zonae and by the retention of an intact cumulus oophorus during culture. Penetration levels were similar in eggs inseminated with and without an intact cumulus, although increases in supernumerary and supplemental sperm were observed with partly denuded ova. The distribution of sperm found within eggs inseminated in vitro was compared with a distribution predicted by chance alone. The similarity in observed and expected distributions indicated that a functional zona reaction was absent in eggs inseminated in vitro. Sperm binding to zonae of cumulus-free unfertilized mouse eggs was shown to be related to sperm concentration over the range 10(3)-10(6) cells/ml. Zonae sperm binding sites, while too numerous for accurate quantitation, exceeded 100 per zona. The interrelationships between sperm penetration of and sperm binding to the zonae of cumulus-free eggs were examined. At low sperm concentrations, the ratio of sperm/zonae with bound sperm to sperm/penetrated egg approached one, although the total number of bound sperm exceeded the total number of penetrating sperm. That proportion of cells in a preincubated epididymal sperm suspension, capable of binding to the zona was determined and employed in an estimation of the extent of sperm capacitation.

Animals↗

Capacitation potential of the fallopian tube: a study involving surgical insemination and the subsequent incidence of polyspermy.

In an attempt to demonstrate limitations in the capacitating potential of the Fallopian tube, ejaculated boar spermatozoa were introduced directly into the isthmus at varying intervals before ovulation. The incidence and degree of polyspermy subsequently observed were taken as indicators of the population of capacitated spermatozoa confronting the newly ovulated eggs: the more extensive the condition of polyspermy, the greater the number of capacitated spermatozoa presumed to have been available at the site of fertilization. Results are based on 673 eggs from 53 animals. When suspensions containing 2.21-3.87 x 10(8) sperm per ml were introduced 36-40 hours and 26-30 hours before ovulation, 85% and 61% respectively of the eggs were polyspermic, such eggs exhibiting mainly dispermy and trispermy. By contrast, when comparable sperm suspensions from the same boar were instilled 17-18 hours before ovulation, 70% of the eggs were polyspermic but the degree of polyspermy had increased dramatically: most eggs contained 40 or more sperm heads in the vitellus, invariably forming swollen chromatin aggregates rather than male pronuclei. Surgical insemination at times closer to ovulation significantly reduced the incidence and degree of polyspermy, reaching a low of 2% with insemination 1-2 hours before ovulation. These results therefore support the concept of a limited capacitation potential of the Fallopian tube. In a separate series of observations, mating animals shortly before surgical insemination with sperm suspensions from the same boar markedly reduced the incidence of polyspermy. This latter observation may be of clinical significance in procedures of laparoscopic or transcervical insemination into the tubes to alleviate human infertility. The manner whereby myosalpingeal physiology could be modified in response to coital stimulation is discussed.

Animals↗

Basal serum follicle stimulating hormone (FSH) and estradiol levels as predictors of pregnancy in unstimulated donor insemination cycles.

PURPOSE: The purpose of this study was to evaluate the utility of basal serum follicle stimulating hormone and estradiol levels in predicting pregnancy in women undergoing artificial insemination with donor sperm for severe male factor infertility. METHOD: A retrospective chart review of 48 women who had at least 2 cycles of artificial insemination with donor sperm and who had undergone testing for basal serum follicle stimulating hormone and estradiol levels prior to or during therapy. RESULTS: There was no difference in age or mean basal serum follicle stimulating hormone between women who conceived (clinical pregnancy) and those who did not. Women who conceived had significantly lower mean serum basal estradiol levels (P = 0.02) and significantly fewer numbers of treatment cycles (P = 0.041). The highest pregnancy rate was among those women with normal basal serum follicle stimulating hormone and estradiol levels. Receiver operating characteristic curve analysis revealed basal serum estradiol to be a more reliable predictor of pregnancy than follicle stimulating hormone. CONCLUSIONS: Basal serum follicle stimulating hormone and estradiol levels may be useful in predicting success with artificial insemination with donor sperm. It may be useful to obtain basal serum follicle stimulating hormone and estradiol prior to initiating artificial insemination with donor sperm.

Adult↗

Failure of artificial insemination of husband's semen in the treatment of male infertility.

In the management of infertility, in case semen quality is found insufficient and could not be improved by medical means, handling the available spermatozoa in the most beneficial way has been aimed. Thus, artificial insemination with low quality semen has become a therapeutic alternative. In this study homologous artificial insemination has been used to treat infertility caused by oligoasthenospermia. Eighteen couples have been treated for 58 cycles by intrauterine or paracervical insemination using cervical cups. During the same period 42 cycles with timed vaginal intercourse have been assessed. Though no pregnancies could be obtained following artificial insemination, one pregnancy occurred during no-treatment cycles.

Adult↗

Effect of controlled ovarian hyperstimulation on pregnancy rates after intrauterine insemination.

OBJECTIVE: Our objective was to evaluate the effect of controlled ovarian hyperstimulation on pregnancy rates after intrauterine insemination of washed husband's sperm. STUDY DESIGN: In a private practice setting at the Infertility, Gynecology, and Obstetrics Medical Group in San Diego, 79 treatment programs included intrauterine insemination during natural cycles, 195 included clomiphene stimulation, and 53 had human menopausal gonadotropin stimulation. Pregnancy rates and monthly fecundabilities were calculated by life-table analysis and compared by the Z test. RESULTS: By life-table analysis the cumulative probability of pregnancy after intrauterine insemination with no ovulation induction is 21.0% after six cycles with a monthly fecundability of 3.4%. With clomiphene the pregnancy rate is 32.7% with a monthly fecundability of 6.1%, and with human menopausal gonadotropin the pregnancy rate is 60.7% with a monthly fecundability of 13.0%. The human menopausal gonadotropin group had a significantly higher pregnancy rate and monthly fecundability as compared with the other two groups. There were no differences between the no-stimulation and the clomiphene groups. CONCLUSIONS: Human menopausal gonadotropin stimulation results in a significantly higher pregnancy rate and monthly fecundability after intrauterine insemination as compared with no stimulation or clomiphene use.

Female↗

Pregnancy rates in gonadotrophin stimulated cycles with timed intercourse or intrauterine insemination for the treatment of male subfertility.

OBJECTIVE: To compare the pregnancy rates achieved by intrauterine insemination or timed intercourse in gonadotrophin stimulated cycles in couples whose only detectable abnormality was poor sperm quality. DESIGN: Sixty-two couples with primary or secondary infertility due to male factor entered the study. The 62 couples were randomly equally divided into two groups. Each group began one of the two treatment modalities (controlled ovarian hyperstimulation in conjunction with timed intercourse or intrauterine insemination) for three consecutive cycles and then switched to the alternative treatment after one rest cycle, if pregnancy was not achieved. RESULTS: Five pregnancies (3.9%) were achieved after 128 cycles with timed intercourse and 15 pregnancies (11.5%) after 130 cycles with intrauterine insemination. The difference was found to be statistically significant (P < 0.05). CONCLUSION: We suggest that intrauterine insemination during hMG stimulated cycles improves the pregnancy rates of couples whose only detectable abnormality is poor sperm quality.

Adult↗

Effect of time of artificial insemination on embryo sex ratio in dairy cattle.

The objective of the present study was to examine whether different intervals between insemination and ovulation have an influence on the sex of seven-day-old embryos in dairy cattle. Cows were inseminated once with semen of one of two bulls of proven fertility between 36 h before ovulation and 12 h after ovulation. Time of ovulation was assessed by ultrasound at 4-h intervals. In total, 64 embryos were determined to be male or female. Of these 64 embryos, 51.6% were female. The sex ratio in the various insemination-ovulation intervals (early: between 36 and 20 h before ovulation; intermediate: between 20 and 8 h before ovulation; late: between 8 h before and 12 h after ovulation) did not significantly differ from the expected 1:1 sex ratio (50, 50 and 55% females, respectively). Bull (Bull A and B) and Parity (primiparous and multiparous) had no influence on the expected 1:1 sex ratio either. The number of cell cycles was similar for male and female (P = 0.23) embryos when quality of the embryo (P < 0.0001) was included in the model. The results of this study indicate that, in cattle, the interval between insemination and ovulation does not influence the sex ratio of seven-day-old embryos.

Animals↗

Synchronization of estrus and ovulation in sows not conceiving in a scheduled fixed-time insemination program.

A field study was conducted to investigate the effectiveness of a treatment with altrenogest, eCG and hCG or the GnRH-analogue D-Phe(6)-LHRH to synchronize estrus and ovulation of sows diagnosed as non-pregnant in order to reintegrate them back into a scheduled fixed-time insemination program. Sows (n=531) diagnosed as non-pregnant by ultrasonography on days 21-35 after insemination were subjected to one of three treatments: (1) 16 mg altrenogest/day/animal orally for 15 days to block follicular growth, followed by injection of 1000 IU eCG intramuscularly (i.m.) 24h after withdrawal of altrenogest to stimulate follicular growth and 500 IU hCG i.m. 78-80 h after eCG to induce ovulation; (2) similar to (1) except that 20mg altrenogest and 800 IU eCG were used and (3) similar to (2) except that 50 microg D-Phe(6)-LHRH was used to induce ovulation. Females were artificially inseminated (AI) twice at 24 and 40 h, respectively, after hCG/D-Phe(6)-LHRH. Success of treatments was checked by ultrasonography of the ovaries. Rates of conception and farrowing (CR, FR), and number of total and live born piglets (TB, LB) were recorded and compared to those of synchronized first served sows. Females had differing ovarian structures prior to treatment. Altrenogest effectively blocked follicular growth in >80% of the females irrespective of dosage, but 16 mg increased the development of polycystic ovarian degeneration. Four to 18% of the females still had corpora lutea after altrenogest. Most females ovulated either between both inseminations or thereafter (P<0.05). Females treated with D-Phe(6)-LHRH tended to ovulate earlier than those injected with hCG. The CR and FR were up to 25% lower for sows diagnosed as non-pregnant than for sows after first service (P<0.05). Among sows diagnosed as non-pregnant the CR was higher in females treated with D-Phe(6)-LHRH (P<0.05). No differences were found in regard to numbers of TB and LB. In conclusion, a treatment with 20mg altrenogest per day per animal, followed by 800 IU eCG and 50 microg the GnRH-analogue D-Phe(6)-LHRH is appropriate to synchronize estrus and ovulation of sows diagnosed as non-pregnant. Whether there might be a need to feed altrenogest for a longer interval of 18 days has to be investigated.

Animals↗

Influence of supplemental dietary sprouted wheat on reproduction in artificially inseminated doe rabbits.

The sprouted wheat contains great amounts of 6-methoxybenzoxazolinone (6-MBOA) a phenol compound that stimulates reproduction in certain small wild herbivorous mammals. The objective of the present study was to evaluate the effect of dietary sprouted wheat as supplement on reproduction in artificially inseminated doe rabbits. Two-month-old New Zealand White doe rabbits (n = 48) were randomly allocated to one of two treatments: (1) pelleted diet plus sprouted wheat for 6 consecutive days prior to service, (2) pelleted diet only (control). First insemination occurred when does reach 3200g body weight and bred 6 days after parturition across 6 months period during summer and autumn. Records from 41 does completing the experiment accounted for 192 inseminations and 142 kindlings equivalent to 4.6 +/- 0.15 and 3.5 +/- 0.15 litters per doe, respectively. Mean daily intake of sprouted wheat on wet and dry matter bases were 196.1 +/- 7.5 and 75.4 +/- 2.9g, respectively. The number of young born produced per doe during the trail was significantly (P = 0.02) greater in does fed sprouted wheat (28.1 +/- 1.2 versus 23.6 +/ -1.3 control). Does fed sprouted wheat had 0.65 +/- 0.06 receptivity rate at AI over 28 per cent greater (P = 0.001) than does in the control treatment. Sexual receptivity was not influenced by physiological status of does and season (P > 0.05). Diet and season had no effect (P>0.05) on kindling rate. However, physiological status had an effect (P = 0.002) on this variable. Kindling rates for nulliparous, lactating and non-lactating does were 0.95 +/- 0.08, 0.63 +/- 0.04 and 0.78 +/ -0.11, respectively. Sexually receptive does had a greater (P = 0.0001) kindling rate (0.95 +/- 0.05) than non-receptive females (0.63 +/-0.05). Does fed sprouted wheat produced larger (P = 0.02) litters than those in the control group: 7.7 +/- 0.30 and 6.8 +/- 0.32, respectively. There was an effect of season (P = 0.04) on the size of the litter at birth. Largest litters were born during autumn (7.9 +/- 0.37) than during summer (6.6 +/- 0.41). Receptive does had more (P = 0.002) young in the litter (7.9 +/- 0.28) than non-receptive (6.6 +/- 0.35). Feeding sprouted wheat as a source of biological 6-MBOA enhanced sexual receptivity and prolificacy in artificially inseminated doe rabbits bred in summer and autumn.

Animals↗

The validity of air and saline hysterosalpingo-contrast sonography in tubal patency investigation before insemination treatment.

OBJECTIVE: To compare the prognostic significance of tubal patency investigation by means of laparoscopy, hysterosalpingo-contrast sonography (HyCoSy) with air and saline as a contrast medium, and hysterosalpingography (HSG) in relation to the outcome of intrauterine insemination (IUI) treatment. STUDY DESIGN: A retrospective study of 559 consecutive women attending the university hospital infertility clinic for infertility treatment in 1996-2003. Tubal patency was evaluated by laparoscopy in 261 women, by HyCoSy in 217 and by HSG in 81 women before insemination treatment. Altogether, 1240 insemination cycles were evaluated and the results were compared in the three study groups. RESULTS: The clinical pregnancy rates per cycle were 14%, 18% and 18% in the laparoscopic, HyCoSy and HSG groups, with no statistically significant difference between the groups. The cumulative pregnancy rates (mean 2.3 cycles) were 30%, 41% and 38%, respectively, with a significant difference between the study groups. In cases of unilateral patency, cumulative pregnancy rates after two cycles were 18% (laparoscopy), 29% (HyCoSy) and 29% (HSG). The numbers of tubal pregnancies were similar in the subgroups. CONCLUSIONS: Hysterosalpingo-contrast sonography with air and saline as a contrast medium is a very cost-effective tubal investigation method as regards selection of subjects for insemination.

Adult↗

Analysis of factors influencing pregnancy rates in homologous intrauterine insemination.

OBJECTIVE: To identify predictors of pregnancy rate (PR) among women undergoing homologous IUI. DESIGN: Cross-sectional analysis of IUI cycles carried out from January 2000 to September 2002. SETTING: Private infertility center in Alicante, Spain. PATIENT(S): Four hundred seventy women undergoing 1,010 cycles of IUI. INTERVENTION(S): Single IUI with ovarian stimulation using hMG. MAIN OUTCOME MEASURE(S): Preovulatory follicles (>15 mm), motile spermatozoa count, type and duration of infertility, female age, insemination timing, and cycle number. RESULT(S): Overall PR per cycle and multiple pregnancy and miscarriage rates were 9.2%, 8.6%, and 11.8%, respectively. Three significant predictors of pregnancy were identified by multiple logistic regression analysis: preovulatory follicles, spermatozoa count, and infertility duration. Interuterine insemination with three follicles almost tripled the PR with respect to only one, odds ratio (OR) = 2.89 (95% confidence interval [CI], 1.54-5.41). Compared with insemination with a motile sperm count >30 x, 20.1-30, 10.1-20, 5.1-10, and < or =5 x10(6), insemination progressively decreased the PR, from 15.3% in the highest category to 3.6% in the lowest (OR lowest/highest = 0.20 [95% CI: 0.09-0.45]), with a statistically significant dose-response trend. Infertility duration > or =3 years was marginally associated with a lower PR, OR = 0.65 (95% CI, 0.40-1.04). Overall, female age was not a significant predictor of pregnancy, and although PR slightly decreased beyond two IUI cycles and when a single IUI was performed 36-40 hours after hCG administration, results were not statistically significant. CONCLUSION(S): Homologous IUI achieves the best results with two or three induced follicles, a high motile spermatozoa count, and infertility duration <3 years, irrespective of female age and fertility history.

Adolescent↗

Performance of the postwash total motile sperm count as a predictor of pregnancy at the time of intrauterine insemination: a meta-analysis.

OBJECTIVE: To assess the performance and clinical value of the postwash total motile sperm count (postwash TMC) as a test to predict intrauterine insemination (IUI) outcome. DESIGN: Meta-analysis of diagnostic tests. SETTING: Tertiary fertility center. PATIENT(S): Patients undergoing IUI. INTERVENTION(S): None. RESULT(S): We detected 16 studies that reported on postwash TMC at insemination and IUI outcome. Summary receiver operating characteristics (ROC) curves indicated a reasonable predictive performance toward IUI outcome, and, at cut-off levels between 0.8 to 5 million motile spermatozoa, the postwash TMC provided a substantial discriminative performance. At these cut-off levels, the specificity of the postwash TMC, defined as the ability to predict failure to become pregnant, was as high as 100%; the sensitivity of the test, defined as the ability to predict pregnancy, was limited. CONCLUSION(S): The postwash TMC at insemination could potentially be used in counseling patients for either IUI or IVF. However, to enable patient counseling before the start of treatment, further studies are needed to establish the accuracy of a postwash TMC during the fertility workup rather than at insemination.

Female↗

Use of semen quality scores to predict pregnancy rates in couples undergoing intrauterine insemination with donor sperm.

OBJECTIVE: To establish semen quality scores in a population of sperm donors and determine whether the scores can be used to predict pregnancy rates after donor insemination. DESIGN: Retrospective study. SETTING: Infertility clinic at a tertiary care teaching hospital between 1993-2001. PATIENT(S): One hundred eleven women who underwent IUI with sperm from 27 anonymous donors. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): The semen analysis results before freezing and after thawing were analyzed, and overall donor insemination semen quality (DI-SQ) and donor insemination relative quality (DI-RQ) scores were calculated. After adjusting for female characteristics, the scores were compared with samples that did and did not result in pregnancy. RESULT(S): Of 111 patients, 70 had at least one pregnancy, and 60 had at least one live birth, with a mean of 6.52 +/- 4.67 IUI cycles per patient. Five significant risk factors for low pregnancy and live birth rates were identified: female infertility factor, positive laparoscopy, older maternal age, low number of previous births, and lack of ovulatory stimulation. After adjusting for these factors, both prefreeze and postthaw DI-SQ scores were statistically significantly associated with IUI live birth rates. Using only the samples with a DI-SQ score of >110 doubled the expected live birth rate, compared with using samples with a DI-SQ score less than 100, from 8.5% to 16.1%. CONCLUSION(S): The DI-SQ score was an effective predictor of pregnancy and live birth outcomes in IUI patients who underwent artificial insemination with anonymous donor semen. The DI-SQ score could also be used by sperm banks to help select donors.

Adult↗

Comparison of fallopian tube sperm perfusion and intrauterine tuboperitoneal insemination: a prospective randomized study.

OBJECTIVE: To evaluate the results of two different methods of insemination: fallopian tube sperm perfusion (FSP) with 4 mL of inseminate and intrauterine tuboperitoneal insemination (IUTPI) with 10 mL of inseminate. DESIGN: Prospective randomized clinical study. SETTING: Private infertility center. PATIENT(S): Two hundred seventy-six couples, undergoing 403 cycles, with unexplained infertility, mild or moderate male infertility, or mild or moderate endometriosis. INTERVENTION(S): Patients were assigned randomly to either FSP (group A, n = 138) or IUTPI (group B, n = 138) treatment. Both groups followed the same mild ovarian stimulation protocol. MAIN OUTCOME MEASURE(S): Ninety-five overall pregnancies: 35 in group A (FSP) and 60 in group B (IUTPI). RESULT(S): The pregnancy rate per cycle (presence of gestational sac with heart beats) was 17.6% in group A (n = 199) and 29.4% in group B (n = 204). These differences were statistically significant (P < .007). The odds ratio of getting pregnant, per patient, in group B was 2.26 (95% confidence interval 1.36-3.77) compared with group A. CONCLUSION(S): The results of this study indicate that IUTPI may prove to be a useful technique in the treatment of unexplained infertility, mild or moderate male infertility, and mild or moderate endometriosis. Three attempts of IUTPI may be beneficial before moving on to more invasive and expensive methods of assisted reproduction techniques.

Adult↗

The non-linear effect (determined by the penalised partial-likelihood approach) of milk-protein concentration on time to first insemination in Belgian dairy cows.

The time to first insemination in dairy cows depends partly on the energy balance of the cow. Because milk-protein concentration is related to the energy balance, we investigated whether milk-protein concentration predicted the hazard of being inseminated. The main objective of the paper is to demonstrate that the relationship between milk-protein concentration and the hazard of being inseminated was not linear and that this non-linear relationship was modelled adequately using cubic-splines. The semiparametric Cox model was used to introduce protein concentration into the model as a time-varying covariate and additionally herd was added to the model as a frailty term to adjust for the clustering of the cows within a herd. We extended the penalised partial-likelihood technique to fit the frailty model with cubic-splines for the effect of the protein concentration. The model was fitted for a large database consisting of 5114 multiparous cows from 181 different farms. Low milk-protein concentration (<2.7%) was associated with a negative energy balance and this probably led to the decreased hazard. On the other hand, high milk-protein concentration (>4.0%) was linked with low milk production and it was probably a farmer's decision not to inseminate such cows, leading to the observed decreased hazard.

Animals↗

Effect of insemination with doses of 2 or 15 million frozen-thawed spermatozoa and semen deposition site on pregnancy rate in dairy cows.

The effects of low-dose artificial insemination (AI) on pregnancy rates have seldom been studied in lactating dairy cows. We evaluated the pregnancy results after AI with doses of 2 and 15 million frozen-thawed spermatozoa and the effect of semen deposition in lactating dairy cows. A total of 284 first inseminations with 2 million spermatozoa and 312 first inseminations with 15 million spermatozoa were performed on 480 dairy farms. Low-dose inseminations (2 million spermatozoa) under field conditions in commercial dairy herds, without estrus synchronization, generally resulted in significantly reduced pregnancy rates compared with normal doses (15 million spermatozoa). The bull x technician effect on fertility was statistically significant. This finding indicates that there is a high variability in fertility among bulls using 2 million spermatozoa per dose. The semen deposition site did not influence pregnancy rates. It is concluded that a dose of 2 million frozen-thawed spermatozoa is probably too low for most bulls to achieve acceptable pregnancy rates in dairy cows.

Animals↗