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Seasonal effects of semen collection and artificial insemination on dairy cow conception.

The effects of four seasons of semen collection and of artificial insemination on conception in dairy cows were studied. The solstices and equinoxes (December, March, June and September) defined the beginning and/or end of each season. Semen was collected from 973 progeny-test bulls over 8 years at the two Norwegian AI stations at 60.8 degrees N and 63.4 degrees N where artificial light was used to provide a minimum photoperiod of 10 h/day. The effect of using semen of elite bulls during progeny testing and after selection as elite sires also was investigated. Norwegian Red (NRF) cows were inseminated over a 7-year period using progeny test semen and over the last 4 years of the same period using the semen of the elite sires. The probability of conception to only first inseminations for cows up to, and including, the fifth lactation was assessed by 56-day non-return rate (56d NRR) and calving rate. Two data sets were analysed which excluded cows culled within 270 days of AI or included such cows as non-calving. The reasons for culling were categorised as those for fertility problems or all other reasons. Semen was used for AI irrespective of the season in which it had been collected. Season of semen collection did not affect 56d NRR but calving rate was significantly higher (by 0.5-0.8%, approximately; P < 0.01) for semen collected in the December-March period, when photoperiod was increasing, than at other times of the year. The season in which AI was performed showed a peak of 56d NRR in spring for heifers (P < 0.01) and in summer for parous animals (P < 0.01). For calving rate, however, no seasonal peak was found in heifers, whereas pluriparous cows had much higher calving rates in summer and autumn/early winter than late winter and spring (P < 0.01). Semen of elite sires resulted in higher calving rates by 0.5 (NS) to 1.9% (P < 0.01) when used after selection than when used during progeny testing. The difference between the calving rate achieved when the semen from elite sires was used during progeny testing and after selection indicates that farmers select different classes of cows for submission to AI by progeny test bulls and sires. The 56d NRR was not as good as calving rate for assessing seasonal and other effects on conception rates.

Animals↗

Induction of estrus in suckled female yaks (Bos grunniens) and synchronization of ovulation in the non-sucklers for timed artificial insemination using progesterone treatments and Co-Synch regimens.

The objectives of the present study were to evaluate the induction of estrus and fertility in yak cows treated with Co-Synch regimens or progesterone (P(4)). In Experiment 1, postpartum suckled yaks were assigned to three treatments: (1) A (n=28), insertion of an intravaginal device containing P(4) (CIDR) on Day 0, PGF(2alpha) (i.m.) on Day 6 and PMSG (i.m.) at the time of CIDR removal on Day 7 (P(4)-PGF(2alpha)-PMSG); (2) B (n=21), PGF(2alpha) (i.m.) on Day 6 and PMSG on Day 7; (3) C (n=26), control group. Seven yak bulls were grazed with the cows for natural breeding. Rate of estrus within 96h of the end of treatment was greater (P<0.05) in A (100.0%) than in B (28.6%) or C (0.0%). First service conception rate (CR) determined by serum P(4) on Day 21 after breeding was greater (P<0.05) in A (78.6%) than in B (22.2%). Also, pregnancy rate (PR) during the breeding season was greater (P<0.05) in A (82.1%) than in B (19.0%) and C (7.7%). In Experiment 2, non-suckled yaks that calved in previous years but not in the current year were assigned to three treatments: (1) A (n=31), GnRH (i.m.) on Day 0, followed by PGF(2alpha) on Day 7 and timed artificial insemination (TAI) concurrently with GnRH treatment on Day 9 (Co-Synch regimen); (2) B (n=50), a CIDR device for 7 days plus PGF(2alpha) and PMSG at the time of CIDR withdrawal on Day 7 and TAI on Day 9 (P(4)-PGF(2alpha)-PMSG); (3) C (n=50), yak cows were artificially inseminated at spontaneous estrus. Frozen semen of Holstein and Jersey were used for insemination in Experiment 2. The CR assessed by rectal palpation 35 days after TAI was not different in A (22.6%), B (30.0%) and C (33.3%), but PR was greater in A and B than in C, when based on those cows presented for estrous synchronization programs. It is concluded that P(4)-PGF(2alpha)-PMSG protocol could efficiently induce estrus and result in an acceptable pregnancy rate in postpartum suckled yak cows. This technique and Co-Synch regimen can be applied successfully for TAI of non-suckled yak cows.

Animals↗

Effect of sperm numbers and time of insemination relative to ovulation on sow fertility.

We examined the effect of inseminating mixed parity sows (n=231) once with fewer sperm at different times relative to ovulation. Lactation length was 19 days and sows received an IM injection of 600 IU equine chorionic gonadotrophin (eCG) 12 h before weaning. At 80 h after eCG injection, sows received an IM injection of 5 mg porcine luteinizing hormone (pLH). Predicted time of ovulation (PTO) was 38 h after pLH injection. Sows were assigned by parity to receive a single transcervical artificial insemination (AI) at either 6 or 24 h before PTO with semen doses containing either 2.5 or 1.25x10(9) sperm. A positive control group of sows (n=49) was subject to conventional AI 24 and 6 h before PTO. Detection of estrus was performed in the presence of a boar and only sows exhibiting estrous behavior at the assigned time of AI were included in the study. Farrowing rate for sows receiving 2.5x10(9) sperm at 6 h before PTO was greater than that for sows receiving 1.25x10(9) sperm at 24 h before PTO (85% versus 61%, P<0.05). All other groups were intermediate. There was no effect of time of AI or sperm numbers on subsequent litter size. These data indicate that single insemination of fewer sperm may compromise sow fertility, even when performed transcervically, if not appropriately timed relative to ovulation.

Animals↗

Advanced insemination techniques in mares.

Advanced artificial insemination techniques, such as deep uterine,hysteroscopic, oviductal, and intrafollicular insemination, are described in the context of the different types of spermatozoa that are now available for insemination, including fresh, chilled, frozen,sex-sorted, and epididymal spermatozoa. The implementation of these new technologies answers and poses questions about the interactions of sperm and oocytes in vivo.

Animals↗

Offspring created as a result of donor insemination: a study of family relationships, child adjustment, and disclosure.

OBJECTIVE: To compare the quality of family relationships and children's socioemotional adjustment in families created by donor insemination where parents tended either toward disclosure or nondisclosure. DESIGN: A study of 46 families with a child aged 4-8 years who was conceived through donor insemination. The study used standardized interview data from mothers and fathers, teachers, and the children themselves. SETTING: An assisted conception unit endorsing openness. PATIENT(S): Parents and their 4- to 8-year-old child conceived through donor insemination. INTERVENTION(S): Parents were interviewed, and children were administered psychological tests. MAIN OUTCOME MEASURE(S): Interviews and questionnaires assessing the quality of the marital relationship, parent-child relationships, and child psychological adjustment. RESULT(S): Mothers from disclosing families reported significantly less frequent and less severe arguments with their children and considered their children to show a lower level of conduct problems and to be less of a strain. The disclosing parents viewed themselves as more competent at parenting. CONCLUSION(S): The differences that were identified indicated more positive parent-child relationships in the disclosing than in the nondisclosing families. However, this did not represent dysfunctional relationships in the nondisclosing families but instead reflected particularly positive ratings in the disclosing group.

Adaptation, Psychological↗

Timing of intrauterine insemination: where are we?

Correct timing of insemination remains a controversial aspect of IUI cycles associated with ovarian hyperstimulation. Although it is currently believed that insemination at 32-38 hours after hCG administration provides the best results, clinical evidence supporting this conclusion is scarce. Double insemination might be an alternative, effective strategy, but studies on this topic are few, heterogeneous, and controversial.

Female↗

Hormonal induction of ovulation and artificial insemination in suckled beef cows under nutritional stress.

The objective was to develop a program for inducing estrus (followed by insemination) of suckled beef cows under nutritional stress (poor body condition). A total of 123 cows, from 60 to 75 days postpartum, were classified according to their body condition score (BCS; range from 1 to 5, in increments of 0.5) and allocated into two groups. On Day 0 (without regard to stage of the estrous cycle), cows (n = 59) in the hormone induction (HI) treatment group were given an intravaginal device (IVD) containing 250 mg of medroxiprogesterone acetate (MAP) and an i.m. injection of 2.5 mg estradiol benzoate (EB). On Day 6, these cows were given 500 IU eCG i.m. and calves were weaned for 96 h. The IVD were removed on Day 7. Cows detected in estrus by 45 h after IVD removal were inseminated 12 h after standing estrus; cows not in estrus by 45 h after IVD removal received an i.m. injection of 100 microg gonadorelin (GnRH) and were inseminated 16-18 h later. In the control group (C), cows (n = 64) only had their calves weaned at Day 6 (for 96 h), with estrus detection and AI from Days 6 to 11. Overall, the BCS ranged from 2.0 to 3.0. In the treatment group, estrus and pregnancy rates in cows with BCS 2.0 (20 and 30%, respectively) was lower (P < 0.05) than those with BCS 3.0 (50 and 66.6%, respectively), but did not differ (P > 0.05) from BCS 2.5 (23.3 and 47.6%). In C group, only 2 of 66 cows were detected in estrus and bred (neither was pregnant). In conclusion, the program for induction of ovulation using MAP, EB, eCG and GnRH increased the pregnancy rate in beef cows in poor body condition, enabling AI to be done in a 63-h interval.

Administration, Intravaginal↗

How the FSH/LH ratio and dose numbers in the p-FSH administration treatment regimen, and insemination schedule affect superovulatory response in ewes.

We wished to evaluate the effects of FSH/LH ratio and number of doses of p-FSH during a superovulatory treatment on ovulation rate and embryo production (Experiment I). In Experiment II, we studied the efficacy of fertilization after various insemination schedules in superovulated donors. In Experiment I estrus was synchronized in 40 ewes (FGA, for 9 days plus PGF2alpha on Day 7) and the ewes were randomly assigned to four treatment groups as follows (n = 10 ewes each): Group A: four p-FSH doses with the FSH/LH ratio held constant (1.6); Group B: four p-FSH doses with the FSH/LH ratio decreasing (FSH/LH 1.6-1.0-0.6-0.3); Group C: eight p-FSH doses with the FSH/LH ratio held constant (1.6); Group D: eight p-FSH doses and FSH/LH ratio decreasing (1.6-1.6, 1.0-1.0, 0.6-0.6, 0.3-0.3). p-FSH administrations were performed twice daily 12 h apart. The ewes were mated at the onset of estrus and again after 12 and 24 h; then, one ram per four ewes was maintained with the ewes for two additional days. Ovarian response and embryo production were assessed on Day 7 after estrus. Experiment II. Three groups (n = 10 each) of superovulated ewes were inseminated as follows: Group M: mated at onset of estrus; Group AI: artificial insemination 30 h after onset of estrus; M + AI) mating at onset of estrus and intrauterine AI performed 30 h from estrus with fresh semen. Results of Experiment I showed that treatment (D) improved (P < 0.05) ovulatory response in comparison to Groups (C) and (A). The fertilization rate was lower (P < 0.01) in Group D) than Group (A). Also the proportion of transferable embryos was lower in Group (D) in comparison to all the other treatments (P < 0.01). Group A gave the best production of embryos (7.3/ewe; 89.0% transferable). In Experiment II, combined mating plus AI improved fertilization rate (80.3%) compared to both mating (P < 0.01) and AI (P < 0.02) alone.

Animals↗

Differences between Belclare and Suffolk ewes in fertilization rate, embryo quality and accessory sperm number after cervical or laparoscopic artificial insemination.

Ewe breed has been shown to have a major effect on pregnancy rates following cervical AI using frozen-thawed semen. The main objective of this study was to examine the differences between purebred Belclare and Suffolk ewes (multiparous) in fertilization rate, number of accessory sperm and stage of embryo development on day 6 after cervical or laparoscopic AI with frozen-thawed semen. In experiment 1, Belclare and Suffolk ewes were synchronized for 12 days and were either cervically inseminated (year 1: n=28 and 31; year 2: n=16 and 15, respectively) or laparoscopically inseminated (year 2: n=13 and 14). In experiment 2, superovulated Belclare (n=4) and Suffolk (n=13) ewes were laparoscopically inseminated. All ewes were slaughtered 6 days after AI; oocytes/embryos were recovered, morphologically graded and stained to assess the number of cells and accessory spermatozoa. Data from both experiments were combined for statistical analysis. The proportion of ewes with fertilized oocytes was significantly higher following laparoscopic AI compared with cervical AI (54% versus 19%). More Belclare than Suffolk ewes yielded fertilized oocyte(s) after cervical AI (34% versus 10%, P<0.02) but there was no difference after laparoscopic AI (62% versus 60%). From the ewes that yielded at least one fertilized oocyte the proportion of Belclare ewes with embryos at the morula/blastocyst stage was significantly greater than for Suffolk ewes (94% versus 59%, P<0.02). A higher proportion of Belclare than Suffolk ewes had evidence of sperm reaching the site of fertilization following cervical AI (39% versus 15%, P<0.02) but there was no difference after laparoscopic AI (62% versus 64%, P>0.8). Amongst the ewes with evidence of sperm at the site of fertilization, laparoscopic AI resulted in a higher number of sperm per oocyte/embryo or per ewe than cervical AI (P<0.01). These results suggested that the difference in pregnancy rate between Suffolk and Belclare ewes following cervical AI was due to: (i) sperm traversing the cervix and uterus in a higher proportion of Belclare than Suffolk ewes, leading to a higher incidence of fertilization and (ii) the lower developmental competence of fertilized oocytes from Suffolk ewes.

Animals↗

Fertility following fixed-time AI or insemination at observed estrus in Ovsynch and Heatsynch programs in lactating dairy cows.

The objective of this study was to compare the conception rate for fixed-timed artificial insemination (FTAI) and observed heat artificial insemination (HAI) prior to the scheduled FTAI in Ovsynch and Heatsynch synchronization protocols. In Experiment 1, lactating dairy cows (n=535) received two set-up injections of 25mg prostaglandin F(2alpha) (PGF(2alpha)) i.m., 14 days apart starting at 36+/-3 days in milk (DIM). Cows were blocked by parity and were randomly allocated to either Ovsynch or Heatsynch groups. All cows received 100 microg of GnRH i.m. 14 days after the second set-up injection of PGF(2alpha), followed by a third injection of 25mg PGF(2alpha) i.m., 7 days later. In the Ovsynch group, HAI cows (n=29) were bred on standing estrus after the third PGF(2alpha) before the scheduled second GnRH, whereas FTAI cows (n=218) that were not observed in estrus, received a second injection of 100 microg of GnRH i.m., 48 h after the third PGF(2alpha) and received TAI 8 h after the second GnRH. In the Heatsynch group, all cows (n=288) received 0.5 mg of estradiol cypionate (ECP) 24 h after third PGF(2alpha) and HAI cows (n=172) were bred on standing estrus and FTAI cows (n=116) that were not observed in estrus, received TAI 72 h after the third PGF(2alpha). In Experiment 2, repeat breeder cows (n=186) were randomly assigned to either Ovsynch or Heatsynch groups. The FTAI and HAI cows were inseminated similar to Experiment 1. All cows were observed for estrus three times daily. The associations with the conception rate were modeled with logistic regression separately for Experiments 1 and 2. Of all the variables included in the model in Experiment 1, type of AI (HAI versus FTAI, P=0.0003) and parity (primiparous versus multiparous, P=0.05) influenced the first service conception rate. Over-all conception rate and first service conception rate for HAI cows were higher compared to FTAI cows (33.8% versus 21.3%, and 35.3% versus 21.0%; P=0.001). In the Heatsynch group, cows that received HAI had significantly higher over-all conception rate and first service conception rate compared to FTAI (35.2% versus 17.3% and 36.0% versus 15.5%; P=0.0001). The conception rates in repeat breeder cows for HAI and FTAI (30.1% versus 22.3%) were not different (P>0.1). In conclusion, it was recommended to include AI at observed estrus and fixed-time AI for cows not observed in estrus in order to improve the conception rate in synchronization protocols.

Animals↗

Efficacy of the Ovsynch protocol for synchronization of ovulation and fixed-time artificial insemination in Murrah buffaloes (Bubalus bubalis).

Two experiments were conducted to assess the timing and synchrony of ovulation, plasma LH concentrations, and pregnancy rate in Murrah buffaloes (Bubalus bubalis) treated with the Ovsynch (GnRH-PGF(2 alpha)-GnRH) protocol. In Experiment 1, 10 non-lactating cycling buffaloes received 10 microg of a GnRH analogue i.m. (buserelin acetate) without regard to the stage of the estrous cycle (day of treatment, day 0), followed by 25mg of PGF(2 alpha) i.m. (dinoprost thromethamine) 7 days later. A second-treatment of the same GnRH analogue (10 microg, i.m.) was given 48 h after PGF(2 alpha). Ovulation was confirmed by transrectal palpation (at 2-h intervals) from the second-GnRH treatment to detection of ovulation or up to 96 h after the second-GnRH treatment. Plasma LH concentrations were determined in blood samples collected at 15-min intervals for 6h, starting at the second-GnRH treatment, and thereafter at 2-h intervals until 2h after detection of ovulation. Ovulation occurred in 9/10 buffalo (90%) 23.3+/-1.3h (mean+/-S.E.M.; range 20--32 h) after the second-GnRH treatment. Peak LH concentrations 13.5+/-3.5 ng/mL (range 3.9--40.0 ng/mL) occurred 2.1+/-0.1h (range 1.2-3.0 h) after the second-GnRH treatment. In Experiment 2, 15 lactating, cycling buffaloes were subjected to the Ovsynch protocol, with fixed-time AI 12 and 24h after the second-GnRH treatment and 75 lactating buffaloes were inseminated, approximately 12h after detection of spontaneous estrus. Pregnancy rates were 33.3% for TAI and were 30.7% for buffaloes inseminated following spontaneous estrus (P=0.84). In conclusion, the Ovsynch protocol effectively synchronized ovulation in Murrah buffaloes and resulted in conception rates (to two fixed-time inseminations) that were comparable to those achieved with a single AI after detection of spontaneous estrus.

Animals↗

Fertility after deep intra-uterine artificial insemination of concentrated low-volume boar semen doses.

UNLABELLED: Boar semen can be successfully frozen - highly packed - in small containers (medium-straw, MS or MiniFlatPack, MFP). The use of deep intra-uterine artificial insemination (DIU-AI) can make possible the deposition of small volumes of this thawed, non re-extended semen deeply intra-uterine, close to the sperm reservoir. The present experiments studied the fertility achieved after single or double DIU-AI per oestrus, with special attention to the interval between AI and spontaneous ovulation. Semen from two boars of proven fertility was frozen in MS or MFP holding 1 x 10(9) total spermatozoa. Multiparous (2-5 parity, n=42) crossbred sows were checked for oestrous behaviour after weaning and the occurrence of spontaneous ovulation was checked with transrectal ultrasonography (TUS) to establish the mean interval between onset of oestrus (OO) and ovulation which was found to be when approximately 2/3 of the oestrus period has passed. The sows were, in the following standing oestrus, subjected to DIU-AI using thawed semen from either MS (n=20) or MFP (n=22), inseminated without further re-extension. The sows were randomly allotted to one of three groups: (1) single DIU-AI 8 h before expected ovulation (control group, n=19); (2) single DIU-AI 4 h before expected ovulation (treatment group S, n=15); and (3) double DIU-AI 12 and 4 h before expected ovulation (treatment group D, n=8). Occurrence of spontaneous ovulation was confirmed by TUS, performed as during the first oestrous period and used to determine the real interval of DIU-AI and ovulation. Pregnancy was also confirmed by TUS 28 days after OO in those sows not returning to oestrus. These sows were slaughtered (30-45 days of pregnancy), and the appearance of the reproductive tract and ovaries, the number of live and dead foetuses, of implantation sites and of corpora lutea (CL) were recorded. Sows (n=9) returning to oestrus ("open") were re-inseminated (either once [n=4] or twice [n=5]) the following oestrus with either MFP (n=5) or MS (n=4) and slaughtered 12-14 h post-ovulation for recovery of tubal oocytes and of spermatozoa from the uterotubal junctions (sperm reservoir), to assess the degree of effectiveness of sperm transport. Post-thaw sperm motility was 44.3+/-3.21% in MFP and 42.8+/-0.72% for MS (LSmean+/-S.E.M., n.s.), and did not significantly change from thawing to AI. The DIU-AI could be performed in all sows, but insertion was difficult (slow >5 min) in 5/42 sows. Four of these sows returned to oestrus. Pregnancy rate averaged 35% (group D: 25%, group S: 40%, control: 36%, n.s.). The interval between DIU-AIs and spontaneous ovulation varied largely, ranging from -13 to -3 h for group C, for group S from -11 to +3 h and for group D from -17 to -4 h. Pregnancy rates were clearly related to the interval DIU-AI and ovulation, being highest (60%, 12/20) when AI occurred between 8 and 4 h before spontaneous (not expected) ovulation. The number of implantation sites ranged 6-22 (n.s. among groups), and the number of alive foetuses 2-11 (n.s. among groups). Implantation rate (total number of implantations/CL) ranged 48.0-69.7% being highest in the D-group (P<0.05). The examination of the "open" sows slaughtered 12-14 h post-ovulation revealed few recovered oocytes were fertilized (approximately 10%). Only 40% of oocytes had spermatozoa bound to the zona pellucida, not more than two spermatozoa per oocyte. Moreover, low sperm numbers (approximately 4000) were found in the sperm reservoirs (UTJs), irrespective of using single or double DIU-AI (n.s.). The highest values (P<0.05) for these variables were recorded when DIU-AI (either single or double [second AI]) occurred 4-8 h before ovulation, especially when MFP-semen was used (P<0.05). IN CONCLUSION: (1) DIU-AI can be easily performed in most sows; (2) pregnancies can be obtained by the DIU-AI of low volumes of highly concentrated frozen-thawed boar semen, once or twice during oestrus, but fertility is still low, probably owing to an unsatisfactory sperm transport when expected and real ovulation differ; and (3) fertility is related to the interval DIU-AI and ovulation which should be -8 to -4 h of spontaneous ovulation and to the package, MFP having shown better results in vivo. The results stress the need for careful, and frequent, control of oestrus signs.

Animals↗

Changes in the expression of estrogen receptor mRNA in the utero-vaginal junction containing sperm storage tubules in laying hens after repeated artificial insemination.

The objective was to determine whether expression of estrogen receptor (ER) mRNA in the utero-vaginal junction (UVJ) of laying hens was altered after repeated artificial insemination (AI). Semi-quantitative RT-PCR was used to determine the expression of mRNA of the two types of receptor, ERalpha and ERbeta. Only ERalpha mRNA was expressed in all segments of the oviducts of both virgin and artificially inseminated birds, whereas ERbeta mRNA was expressed in ovarian follicles but not in the oviduct. The expression of ERalpha mRNA in the UVJ was significantly decreased after repeated AI, whereas that in the uterus was not significantly different between virgin and inseminated birds. Since estrogen may be involved in maintaining the sperm storage function of sperm storage tubules, the decreased expression of ERalpha mRNA in the UVJ after repeated AI may contribute to reduced fertility in these birds.

Animals↗

Single, transcervical insemination using frozen-thawed semen in the Greyhound: a case series study.

Transcervical insemination (TCI) has generated recent interest as an assisted reproductive technique in the dog. A case series study was performed to determine if TCI using frozen-thawed semen was a viable technique to offer in a general veterinary practice setting. Over a period exceeding 28 months, 137 Greyhound bitches were presented for assisted breeding. A single, timed insemination using a rigid cystoscope to aid in transcervical deposition of a frozen-thawed semen dose was given within 72 h after the behaviorally estrual bitch had a > 4 ng/mL serum progesterone concentration and estrus-categorized vaginal cytology. Litter size, pregnancy and whelping rate were collected; their association to semen center and stud dog were quantified. Of the 137 bitches, 117 were bred for one cycle and 20 were bred for two or more cycles, giving a total of 161 single, timed inseminations. Pregnancy rate was 89.4%, with 141 (87.5%) whelping. Litter size was 6.9+/-2.7 (mean+/-S.D.) pups. Semen center (P=0.84) and stud (P=0.79) had no effect on pregnancy. These results were quite favorable when compared to prior TCI studies, and are possibly due to the use of a single breed (i.e., Greyhound) with good fertility. This study supported the application of TCI, in Greyhounds, as a successful and viable service to offer in private practice. Additionally, these results have value in their use for benchmarking future breed-specific and TCI research. Serendipitously, the apparent fecundity results obtained in this observational study suggests a possible greater appreciation be given to breed composition and choice in assisted reproductive technique studies.

Animals↗

Comparison of pregnancy rates in dromedary camels (Camelus dromedarius) after deep intra-uterine versus cervical insemination.

The ovarian follicular wave patterns of sixty adult female camels were monitored by serial trans-rectal ultrasound examinations and when the dominant follicle reached 1.3-1.8 cm in diameter they received a single intravenous injection of 20 microg buserelin, to induce ovulation, and were inseminated with a known number of spermatozoa 24 h later. Ejaculates were collected from the male camels and diluted 1:1 in Green Buffer with 20% egg yolk (v:v) added. Sperm concentration and motility were assessed and a dose of 40, 80 or 150 x 10(6) motile spermatozoa were deposited either just through the cervix into the uterine body or at the tip of the horn ipsilateral with the ovary containing the dominant follicle. Insemination of 150, 80 and 40 x 10(6) spermatozoa into the uterine body resulted in conception rates of 53, 7 and 0%, respectively, whereas insemination at the tip of the uterine horn resulted in conception rates of 43, 40 and 7%, respectively.

Animals↗

Artificial insemination increases the probability of a male calf in dairy and beef cattle.

The objective of this study was to determine if natural mating affected secondary sex ratio. Data consisting of 642,401 calving records from the Irish national database, during the years 2002-2005, were used in the analysis. Factors affecting the logit of the probability of a male calf being born were determined using multiple regression generalised estimating equations with sire of the calf included as a repeated effect. Month of the year at calving, sex of the previous calf born within dam, breed of service sire, parity of dam and type of mating (i.e., natural or artificial insemination) significantly (P<0.05) affected the likelihood of a male calf being born. Male calves were more likely to be born in the warmer months of the year, when the sex of the previous calf born to the same dam was male, in older cows and when the service sire was a beef breed. No significant interaction between the main effects existed. The odds of a male calf being born, following adjustment for confounding effects, varied from 1.04 to 1.08 (P<0.01) across the years of analysis when artificial insemination was used compared to natural mating. This equates to a 1% unit increase in the probability of a male calf being born following artificial insemination.

Animals↗

Multiple pregnancies conceived with intrauterine insemination during superovulation: an evaluation of clinical characteristics and monitored parameters of conception cycles.

The use of human menopausal gonadotropins to induce superovulation in conjunction with intrauterine insemination as treatment for infertility is associated with an increased incidence of multiple gestation. Identification of clinical characteristics and/or monitored parameters of the stimulation cycles highly associated with multiple gestation would enable cancellation of these cycles. We retrospectively evaluated the clinical profiles and conception cycle characteristics of 48 infertile women undergoing the induction of superovulation and intrauterine insemination. We compared 14 of these women who conceived multiple gestations (eight twins and six triplets) with 34 who conceived singleton gestations. We found no differences between the groups in age, parity, cause or duration of infertility, duration or amount of human menopausal gonadotropin administration, serum estradiol concentrations on the day of human chorionic gonadotropin injection, number of preovulatory-sized follicles, or number of motile sperm inseminated. We conclude that neither the patients' clinical characteristics nor the parameters evaluated in monitoring human menopausal gonadotropin cycles provide information helpful in predicting which superovulation cycles will result in multiple pregnancy.

Adult↗

Artificial insemination in rabbits.

Artificial insemination (AI) in rabbits can be a useful aid to colony management. In this review, simple non-invasive techniques for semen collection and AI are described. Conception rates following AI can be equivalent to, or better than, those achieved by natural mating, with the added advantage that contact between animals is avoided. Ovulation can be induced reliably by the administration of a gonadotrophin releasing hormone analogue, buserelin, as an alternative to the use of a vasectomized buck or the injection of luteinizing hormone. The use of enzyme-linked immunoassay kits for progesterone assay can assist colony management by rapidly identifying non-pregnant animals for re-insemination. Frozen-thawed sperm have been inseminated but careful attention to the cryopreservation technique is required to ensure good conception rates.

Animals↗