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PubMed2002

Hysteroscopic insemination of mares with low numbers of nonsorted or flow sorted spermatozoa.

The objectives of this study were 1) to compare pregnancy rates resulting from 2 methods of insemination using low sperm numbers and 2) to compare pregnancy rates resulting from hysteroscopic insemination of 5 x 106 nonsorted and 5 x 106 spermatozoa sorted for X- and Y-chromosome-bearing populations (flow sorted). Semen was collected with an artificial vagina from 2 stallions of known acceptable fertility. Oestrus was synchronised (June to July) in 40 mares, age 3-10 years, by administering 10 ml altrenogest orally for 10 consecutive days, followed by 250 microg cloprostenol i.m. on Day 11. All mares were given 3000 iu hCG i.v. at the time of insemination to induce ovulation. Mares were assigned randomly to 1 of 3 treatment groups: mares in Treatment 1 (n = 10) were inseminated with 5 x 10(6) spermatozoa deposited deep into the uterine horn with the aid of ultrasonography. Mares in Treatment 2 (n = 10) were inseminated with 5 x 10(6) spermatozoa deposited onto the uterotubal junction papilla via hysteroscopic insemination. Mares in Treatment 3 (n = 20) were inseminated using the hysteroscopic technique with 5 x 10(6) flow sorted spermatozoa. Spermatozoa were stained with Hoechst 33342 and sorted into X- and Y-chromosome-bearing populations based on DNA content using an SX MoFlo sperm sorter. Pregnancy was determined ultrasonographically at 16 days postovulation. Hysteroscopic insemination resulted in more pregnancies (5/10 = 50%) than did the ultrasound-guided technique (0/10 = 0%; P<0.05) when nonsorted sperm were inseminated. Pregnancy rates were not significantly lower (P>0.05) when hysteroscopic insemination was used for sorted (5/20 = 25%) and nonsorted spermatozoa (5/10 = 50%). Therefore, hysteroscopic insemination of low numbers of flow sorted stallion spermatozoa resulted in reasonable pregnancy rates.

Animals↗

PubMed1989

Efficacy of fertilization in artificially inseminated turkey hens.

Research was conducted to develop an artificial insemination protocol optimizing the use of spermatozoa by turkey breeder hens. Large White turkey hens were inseminated on Days 14 and 17 postphotostimulation with 200 million spermatozoa from one male phenotype to fill the oviductal storage sites. Artificial inseminations were then performed weekly for 20 wk with different spermatozoa numbers of another male phenotype. Fertility and phenotype of each poult were determined at hatch to ascertain which insemination, initial or subsequent, was responsible for fertility. Inseminating weekly with 200 million viable spermatozoa cells resulted in better fertility but did not optimize the hen's utilization of spermatozoa from the initial inseminations. When fewer spermatozoa were inseminated weekly (50 million cells), more progeny were fertilized by spermatozoa already residing in the oviduct than would be expected. When the number of spermatozoa inseminated weekly was increased at intervals during a laying cycle, spermatozoa from the initial inseminations were utilized more efficiently, but fertility was depressed at times during the laying cycle. Gradually increasing weekly inseminated numbers of spermatozoa from 50 to 200 million viable cells/hen as the hens age results in nearly equivalent fertility to that resulting from insemination by 200 million cells each week. This represents a savings of 1.4 billion spermatozoa/hen over a 20-wk laying period.

Animals↗

PubMed2001

Intratubal insemination with fresh semen in cats.

There have been few reports of artificial insemination using fresh feline semen because of difficulties in collecting semen. It has been shown previously that the number of spermatozoa required for fertilization of cats by intravaginal insemination and unilateral intrauterine horn insemination are 8.0 x 10(7) and 8.0 x 10(6), respectively. There have been no reports of intratubal insemination of cats. Therefore, a study was designed to determine the number of spermatozoa necessary to fertilize cats by intratubal insemination with fresh semen. Four male and 25 mixed breed female cats were used. Semen was collected using an artificial vagina. Insemination was performed by laparotomy 15-30 h after administration of 100 iu hCG on day 2 or 3 of spontaneous oestrus. Cats in which ovulation had not occurred at insemination received an additional 100 iu hCG after surgery. In intratubal insemination, four groups consisting of three, seven, eight and seven cats received 5.0 x 10(3), 5.0 x 10(5), 2.0 x 10(6) and 4.0 x 10(6) viable spermatozoa, respectively, into both uterine tubes at approximately 2 cm from the fimbriae tubae. The volume inseminated was 10-20 microliters. The semen volume was adjusted with egg yolk-Tris-fructose citrate. As a result of artificial insemination, none of the cats that received 5.0 x 10(3) or 5.0 x 10(5) spermatozoa were fertilized. However, fertilization was successful in two of eight animals (25.0%) that received 2.0 x 10(6) spermatozoa and in three of seven animals (42.9%) that received 4.0 x 10(6) spermatozoa. The number of kits was 1-4 (mean +/- SE: 2.4 x 0.6). These results indicate that although large numbers of spermatozoa were inseminated into the uterine tubes, the conception rate was low. The low rate of conception may have been due to problems in inducing capacitation of spermatozoa in the uterine tubes.

Animals↗

PubMed2002

Minimum number of spermatozoa required for normal fertility after deep intrauterine insemination in non-sedated sows.

A fibreoptic endoscope procedure for non-surgical deep intrauterine insemination in non-sedated sows has been reported. However, the endoscope is an expensive and fragile instrument, and is unsuitable for use under field conditions. The aim of this study was to determine the minimum number of spermatozoa required to maintain optimal fertility using a flexible catheter (1.8 m in length, 4 mm in diameter) for deep intrauterine insemination in 2-6 parity non-sedated sows. Crossbred sows were treated with eCG 24 h after weaning and with hCG 72 h later to induce oestrus. Deep intrauterine insemination was performed 36 h after hCG treatment in 117, 126, 60 and 69 sows with 15.0, 5.0, 2.5 or 1.0 x 10(7) spermatozoa in 10 ml, respectively. Weaned sows (n = 147) not treated with hormones and used for standard artificial insemination (AI) (two inseminations per oestrus with 3 x 10(9) spermatozoa in 100 ml) served as controls. The flexible catheter was passed successfully through the cervix into one uterine horn in 95.4% of the sows in an average of 3.7 +/- 0.09 min. Farrowing rates after deep intrauterine insemination with 15 or 5 x 10(7) spermatozoa did not differ from those of the control group (82.9, 76.2 and 83.0%, respectively), but a significant decrease (P < 0.001) was observed in sows inseminated with 2.5 or 1.0 x 10(7) spermatozoa (46.7 and 39.1%, respectively). In contrast, the number of spermatozoa inseminated did not affect prolificacy. Laparotomy revealed that the tip of the flexible catheter reached approximately the anterior third of the uterine horn. Although deep intrauterine insemination was performed in only one uterine horn, the percentages of embryos collected from the tip of both uterine horns 2 days after deep insemination were not significantly different. The results show that in comparison with standard AI, a 20-60-fold reduction in the number of spermatozoa inseminated and an 8-10-fold reduction in the dose volume can be achieved without decreasing fertility when semen is deposited non-surgically into the upper first third of one uterine horn.

Animals↗

PubMed1992

A prospective, randomized study of pregnancy rates after transuterotubal and intrauterine insemination.

OBJECTIVE: To assess the relative efficacy, in terms of clinical pregnancy rates (PRs), of transuterotubal insemination versus the more traditional intrauterine insemination (IUI) procedure. DESIGN: Prospective, randomized, cross-over. SETTING: University-affiliated tertiary care center. PATIENTS: One hundred sixty infertile patients underwent 414 inseminations with or without controlled ovarian hyperstimulation. INTERVENTIONS: All patients were randomized in their initial cycle to transuterotubal insemination or IUI then crossed-over in subsequent cycles (n = 191 total cycles of transuterotubal insemination and n = 223 total cycles of IUI). Transuterotubal insemination was performed initially with ultrasound guidance, and then a tactile technique was used for the last 6 months of the study. MAIN OUTCOME MEASURES: Clinical PRs and complications after both insemination methods. RESULTS: The clinical PR per treatment cycle was 7% (13/191) after transuterotubal insemination and 7% (16/223) after IUI. The overall PR per patient was 18% (29/160). The incidence of ectopic pregnancy was 1 in 191 for transuterotubal insemination cycles and 0 in 223 for IUI cycles. Other complications included 3 vasovagal episodes with transuterotubal insemination and 1 with IUI. There was no clinical evidence of tubal infection, trauma, or perforation in either group. CONCLUSION: Transuterotubal insemination did not appear to be associated with a higher PR when compared with IUI in this study. The potential for increased risk from complications related to the more invasive tubal technique does not appear to justify its use presently.

Adult↗

PubMed1989

Factors influencing the success rate of artificial insemination with frozen semen in the dog.

The conception rate and fecundity of 36 bitches artificially inseminated with frozen semen from various sources were investigated: 8 bitches were inseminated with semen frozen at the clinic, and 28 were inseminated with imported frozen semen. The mean progressive post-thaw motility of semen was 60%. Fourteen bitches were inseminated once only and 22 bitches were inseminated twice at 1-2-day intervals. An overall conception rate of 67% (24/36) was obtained with a mean litter size of 6.4. One insemination yielded a slightly lower conception rate than 2 inseminations (64 vs 69%). Among bitches which were inseminated twice, non-pregnant bitches had significantly lower mean plasma progesterone concentrations at the second insemination than did pregnant bitches, and this indicates that the second insemination was performed too early. Correct timing of inseminations is therefore essential to obtain pregnancy with frozen semen.

Animals↗

PubMed1985

[The effect of age, weight and the breed of heifer on the concentration of thyroxine during insemination].

We determined the thyroxine (T4) concentration in 63 heifers on 0th (day of insemination), 6th and 21st day after first and in repeat-breeder cows after second and third insemination in relation with the breed, age and weight of animals. The examination was carried out with a feed ration balanced according to the Czechoslovak State Standard CSN 46 7070, with all-the-year-round housing, with keeping the uniform time of insemination (8.00--9.00 a. m.) as well as the time of blood sampling (10.00--12.00 a. m.). The animals were inseminated from August to November. The average T4 concentrations, with a successful insemination, fluctuated on 0th day after first, second and third insemination at levels of 56.15 +/- 13.6; 84.6 +/- 10.66 and 89.75 +/- 13.62 nmol X l-1 of serum. As the results show, the lowest T4 concentrations (P less than 0.001; P less than 0.001) on 0th day were recorded in animals becoming pregnant in first insemination. The comparison with non-pregnant animals did not show any statistically significant difference in T4 concentrations. On 0th day of the second insemination, the T4 concentrations in pregnant animals were higher (P less than 0.01) as compared with non-pregnant. On 6th and 21st day after successful first insemination the T4 content increased significantly (P less than 0.001). After second and third successful insemination we recorded in T4 concentrations a moderate decrease on 6th day (P less than 0.01 for third insemination), with insignificant increase on 21st day.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗

PubMed1993

[Return to estrus following first insemination in sow herds (incidence and association with reproductivity and various 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 to get an impression of the economic importance. These objectives were investigated using the reproduction results of 240 swine breeding herds in The Southern Netherlands in 1987, using their CBK plus computerized herd management records. The average incidence of return to oestrus after first insemination on a herd level was 16.9 per 100 first inseminations. An increase of 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 liveborn piglets/sow/year. Thereupon individual sows were followed in 1988 and 1989 prospectively in 37 sow herds from weaning to insemination, returning to oestrus or not after first insemination to farrowing. The investigation focused in particular on the relationship between returning to oestrus after first insemination and incident infection with porcine parvovirus (PPV) and Leptospira interrogans serovar bratislava (L. bratislava). During a number of consecutive farm visits sows were blood sampled at weaning and again a blood sample was taken 6 weeks later. The final dataset that was analysed consisted of 161 animals that did not return to oestrus after first insemination and 158 animals that returned to oestrus after first insemination.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed2004

Fertility in the ewe following cervical insemination with fresh or frozen-thawed semen at a natural or synchronised oestrus.

Artificial insemination (AI) in sheep is currently limited by the poor fertility obtained following non-surgical intracervical insemination of frozen-thawed semen. An exception to this general finding is the non-return rate of around 58% reported for large scale on-farm AI in Norway. The objective of the present study was to determine if similar results could be obtained under Irish conditions. Comparisons were made between semen collected, and frozen, from rams in Norway (NOR) and Ireland (IRL). The effects of synchronisation and inseminator were also examined. Parous ewes (n=297) of various breed types were inseminated to a natural (N) or synchronised (S) oestrus with either fresh (from Irish rams) or frozen-thawed (IRL and NOR) semen. Ewes were randomly assigned, within breed, to the following treatment groups: (i) Fresh-N: n=28, (ii) Fresh-S: n=30, (iii) IRL-N: n=62, (iv) IRL-S: n=50, (v) NOR-N: n=68, (vi) NOR-S: n=59. Within each group, ewes were inseminated by an experienced Norwegian or by an Irish inseminator. Pregnancy rate did not differ significantly between ewes inseminated to a natural or synchronised oestrus nor between Norwegian and Irish frozen semen. The proportion of ewes pregnant after insemination with fresh semen was 0.82 and 0.70 (treatments i and ii) compared with 0.40, 0.52, 0.34 and 0.37 (treatments (iii)-(vi)) for frozen semen (P<0.001). Corresponding litter sizes (+/-S.E.), adjusted for ovulation rate, were 2.9+/-0.22, 3.3+/-0.23, 2.2+/-0.21, 1.7+/-0.21, 2.2+/-0.21 and 2.1+/-0.21 (fresh versus frozen; P<0.001). There was an interaction between semen type (fresh or frozen) and oestrus type (N or S) for litter size due to an increased adverse effect of frozen semen on litter size in synchronised ewes (P<0.05). Pregnancy rate was significantly influenced by breed of ewe (P<0.01) and inseminator (P<0.05). These results suggest that ewe breed may be a critical determinant of the potential for the exploitation of cervical insemination of frozen-thawed semen in sheep breeding programmes.

Animals↗

PubMed2006

Intravaginal insemination of bitches with fresh and frozen-thawed semen with addition of prostatic fluid: use of an infusion pipette and the Osiris catheter.

One hundred fifty-two bitches of seven breeds were vaginally inseminated with fresh or frozen-thawed semen of 10 stud dogs of respective breeds. The semen was supplemented with prostatic fluid before insemination. In experiment 1 bitches of each breed were randomly assigned to three treatment groups, consisting of 29 females (group 1), 33 females (group 2) and 32 females (group 3). In group 1 bitches were inseminated into vagina with fresh semen using a bovine infusion pipette. In group 2 bitches were inseminated into vagina with fresh semen using the Osiris catheter. In group 3 bitches were inseminated with frozen-thawed semen with the Osiris catheter. The number of sperms in each insemination dose was adjusted to 300 x 10(6). In experiment two bitches were randomly assigned to two treatment groups, consisting of 30 females (group A) and 28 females (group B). In group A bitches were inseminated with fresh semen, whereas in group B with frozen-thawed semen. Osiris catheter was used in both groups. The total number of sperms was adjusted to provide 250 x 10(6) of progressively motile spermatozoa in each insemination dose. In experiment 1 the pregnancy rates/whelping rates were 86.2/82.8%, 81.8/81.8% and 59.4/59.4% for groups 1, 2 and 3, respectively. The differences between group 1 and 3 were statistically significant (p < 0.05). The litter sizes at birth/litter sizes at weaning were 5.8+/-2.3/5.4+/-2.0, 6.3+/-1.4/5.7+/-1.0 and 3.9+/-1.2/3.5+/-1.5 in groups 1, 2 and 3, respectively. The litter size at birth and at weaning was reduced (p < 0.05) when frozen-thawed semen was used for insemination (group 3). There were not significant (p > 0.05) differences in the litter size between groups 1 and 2. In experiment 2 pregnancy rates/whelping rates and litter sizes at birth/litter sizes at weaning were 86.7/86.7%, 60.7/57.1% (p < 0.05) and 6.1+/-1.6/5.7+/-1.7, 4.0+/-1.4/3.8+/-1.4 (p < 0.05) in groups A and B, respectively. This study shows that results of AI with a fresh semen using a bovine infusion pipette and the Osiris catheter are equivalent. The results of the use of the Osiris catheter for vaginal insemination of frozen-thawed dog semen extended with prostatic fluid after thawing are not encouraging. The pregnancy rate, whelping rate and litter size are reduced when frozen-thawed, prostatic fluid-supplemented semen is vaginally deposited using the Osiris catheter.

Animals↗

PubMed1999

Determinants of the outcome of intrauterine insemination: analysis of outcomes of 9963 consecutive cycles.

OBJECTIVE: Our aim was to determine which factors influence the effectiveness of intrauterine insemination. STUDY DESIGN: This article is a retrospective statistical analysis of outcomes of 9963 consecutive intrauterine insemination cycles. RESULTS: Patient age was the main determinant of pregnancy outcome (analysis of variance F ratio = 29, P <.0001), followed by the number of follicles at the time of intrauterine insemination (analysis of variance F ratio = 9, P <.0001) and sperm motility in the inseminate (analysis of variance F ratio = 4, P =.002). A total of 18.9% of all patients <26 years old conceived, compared with 13.9% of those 26-30 years old, 12.4% of those 31-35 years old, 11.1% of those 36-40 years old, 4.7% of those 41-45 years old, and 0.5% of patients >45 years old (P <.001). When analyzed by single years, ongoing pregnancy rates after intrauterine insemination remained high through age 32 years. Across all ages and causes of infertility, 7.6% of patients with 1 follicle at the time of intrauterine insemination conceived, compared with 10. 1% with 2, 14.0% with 4, and 16.9% with 6 follicles (P <.01). When ovulation occurred before intrauterine insemination (ie, no visible follicular structures), 4.6% of patients conceived. The likelihood of pregnancy was maximized when motile sperm numbers were >/=4 million and sperm motility was >/=60%. Differences in pregnancy outcomes between sperm processing options were related to differences in sperm motility after processing; use of methods incorporating motility enhancement with pentoxifylline and motile sperm concentration through silica gradients yielded the highest overall pregnancy rates. CONCLUSION: When the results of ongoing retrospective analysis of intrauterine insemination outcomes are applied, overall intrauterine insemination pregnancy rates have increased from 5.8% per cycle in 1991 to 13.4% per cycle in 1996, during which time the average age of patients undergoing intrauterine insemination has increased from 36.1 (+/-0.2) to 39.2 (+/-0.1) years.

Adult↗

PubMed1998

Donor insemination and human immunodeficiency virus transmission.

OBJECTIVE: To describe cases of AIDS attributed to donor insemination identified through national human immunodeficiency virus (HIV)/AIDS surveillance and to compare the number identified through surveillance with our estimate of the number of women infected as a result of donor insemination before the initiation of donor screening. METHODS: We reviewed national HIV/AIDS surveillance data on women reported through December 1996 and described characteristics of documented and possible cases attributed to donor insemination. We estimated the number of women infected before the initiation of widespread screening of donors using assumptions about the number of women inseminated each year, the average number of inseminations, the proportion of donors who were men who had sex with men, the prevalence of HIV among such men, and the rate of transmission per HIV-infected exposure. RESULTS: A total of six documented and two possible cases of donor insemination-associated AIDS have been reported to the Centers for Disease Control and Prevention as of December 1996. An estimated eight to 141 women were infected through donor insemination in the United States between 1980 and 1984. Reasons for this discrepancy are discussed. CONCLUSION: Based on surveillance case reports and on our estimate, the total number of women infected as a result of donor insemination before screening was recommended is low. Current sperm bank practices to prevent HIV infection will be strengthened further by a pending proposal from the Food and Drug Administration requiring infectious disease screening and testing of semen donors. The most likely source of risk of new infections associated with donor insemination is self-insemination.

Acquired Immunodeficiency Syndrome↗

PubMed2002

Intrauterine insemination of sows with reduced sperm numbers: results of a commercially based field trial.

Artificial insemination (AI) in pigs requires 2-3 billion spermatozoa to achieve consistently high fertility with current practice of inseminating into the posterior region of the cervix. We have investigated the potential advantages of inseminating through the cervix into the caudal region of the uterus using lower sperm numbers. Total sperm doses from 22 boars of 3, 2 or 1 billion spermatozoa were packaged in 80 ml volumes in X-Cell extender in gene-flat-pack (Cochette) bags. A novel inseminating device, the Deepgoldenpig, was employed which permits the ready introduction of a narrow catheter through the cervix into the uterus without traumatic injury to the mucosa. This was compared with the standard Goldenpig device that allows semen to be deposited in the posterior folds of the cervix. Sows of two different genotypes and of parities ranging from 2 to 11 were used. They were selected solely on the basis of a weaning to estrus interval of 4-6 days. Two inseminations, with a 24 h interval between them, were carried out on each sow. Pregnancy was determined at 35 days by ultrasound scan, and farrowing and litter size recorded. Pregnancy and farrowing data were very similar. The standard inseminating device produced farrowing rates of 91.1, 91.8 and 65.8% for insemination with 3, 2 and 1 billion spermatozoa, whereas the deep insemination device gave rates of 90.5, 90.5 and 86.9%. Only the 1 billion dose with the standard device was significantly different from the high dose control (P < 0.001). Similarly, the mean litter sizes with the standard device were 12.5, 12.6 and 10.3 and with the deep insemination device 12.3, 12.3 and 12.1. Only the 1 billion dose with the standard device was significantly lower (P < 0.001). None of the covariates differed significantly and there were no significant interactions with treatment. We conclude that transcervical insemination in the sow is simple, effective and safe, and allows the sperm dose to be reduced to 1 billion spermatozoa.

Animals↗

PubMed2003

Pregnancy rates in mares following hysteroscopic or transrectally-guided insemination with low sperm numbers at the utero-tubal papilla.

This study was conducted to evaluate two methods for insemination of a low number of sperm in the tip of the uterine horn, and to determine whether prebreeding intrauterine treatment with prostaglandin E(2) would improve pregnancy rates. Estrus was synchronized in 36 fertile Quarter Horse and Thoroughbred broodmares. When a dominant follicle >or=33 mm diameter was present, mares were treated with 2500 units hCG intravenously and were assigned to one of four treatment groups for insemination with five million total sperm in 200 microl extender the next day as follows: (1) Group PGE-HYS (n=9): 0.25mg PGE(2) in 1 ml 0.9% NaCl solution infused into the tip of the uterine horn ipsilateral to the dominant follicle 2h prior to hysteroscopic-guided inseminate placement onto the oviductal papilla; (2) Group SAL-HYS (n=9): 1 ml 0.9% NaCl solution infused into the tip of the uterine horn ipsilateral to the dominant follicle 2h prior to hysteroscopic-guided inseminate placement onto the oviductal papilla; (3) Group PGE-PIP (n=9): 0.25mg PGE(2) in 1 ml 0.9% NaCl solution infused into the tip of the uterine horn ipsilateral to the dominant follicle 2h prior to transrectally-guided pipette placement of the inseminate into the tip of the uterine horn; and (4) Group SAL-PIP (n=9): 1 ml 0.9% NaCl solution infused into the tip of the uterine horn ipsilateral to the dominant follicle 2h prior to transrectally-guided pipette placement of inseminate into the tip of the uterine horn. Mares in estrus were evaluated daily by transrectal ultrasonography to monitor follicular status and confirm ovulation. If mares had not ovulated within 2 days of insemination, the assigned treatment was repeated. Pregnancy status was evaluated by transrectal ultrasonography 12-14 days postovulation, and pregnancy rates were compared. No interaction between prebreeding treatment (SAL:PGE) and insemination protocol (HYS:PIP) on pregnancy rates occurred (P>0.10). Pregnancy rates did not differ between mares inseminated by HYS (12/18; 67%) or PIP (10/18; 56%) (P>0.10). Pregnancy rates did not differ between mares treated prior to breeding with PGE (11/18; 61%) or SAL (11/18; 61%) (P=1.00). In summary, satisfactory pregnancy rates were obtained when a low number of sperm were either placed directly onto the oviductal papilla using hysteroscopy or placed in the tip of the uterine horn using a transrectally-guided uterine pipette. Infusion of 0.25mg PGE(2) in the tip of the uterine horn 2h prior to insemination did not improve pregnancy rates.

Animals↗

PubMed2003

Effect of milk- and TRIS-based extenders on the fertility of sheep inseminated vaginally once or twice with liquid semen.

We studied the influence of two different extenders, a milk-based versus a TRIS-based extender, using a split-sample technique, on fertility after single and double vaginal inseminations in natural estrous in Norwegian Crossbred ewes. Semen from 21 Norwegian Crossbred rams, all aged approximately 0.5 years, was used for AI of totally 561 Norwegian Crossbred ewes housed at 37 different farms. The farmers performed the inseminations themselves. The ewes were allocated to four parallel groups based on the two extenders and single or double inseminations (2 x 2). The farmers were recommended to inseminate the ewes between 12 and 24 h after detection of natural standing estrous. Vaginal insemination with cooled liquid semen diluted in the milk-based extender resulted in a statistically significant (P<0.01) better fertility of about 10% units both as 25-day NR (non return rate)-and lambing rates, compared with semen diluted in the TRIS-based extender. Double inseminations gave significantly higher (P=0.03) fertility results for both extenders expressed as 25-day NR results, but was not quite statistically significant when expressed as lambing rates (P=0.06) compared with single insemination. The overall 25-day NR results for the milk-based extender (66.4%) after single inseminations is in accordance with both the national results (67.1%) based on vaginal inseminations of 11,377 ewes, as well as with the results from a previous study in the same region achieving a 25-day NR results of 63.3%. In conclusion, liquid ram semen diluted in a milk-based extender and vaginally inseminated once in natural heat, with a semen dose of 150 x 10(6) spermatozoa, gave acceptable fertility results and is to be recommended as the method of choice in Norway.

Animals↗

PubMed2003

Laparoscopical intrauterine insemination with different doses of fresh, conserved, and frozen semen for the production of ovine zygotes.

The objective of the present study was to increase the efficiency in the production of ovine zygotes suitable for microinjection via laparoscopical intrauterine insemination. In the first part of the study, 71 ewes of three different breeds were inseminated with one of two different insemination doses (50 x 10(6) or 300 x 10(6) sperm per inseminate) and semen was either freshly diluted, liquid conserved, or frozen/thawed, or females were mated by a fertile ram (controls). In the second part, a total of 46 ewes was inseminated with 300 x 10(6) freshly diluted sperm to verify the findings from part 1 and to unravel effects of breed and age of donor ewe. The oviducts were flushed 24-26 h after insemination and the success of insemination was assessed by microscopical examination. Recovery rates were 78.0+/-26.4 and 72.1+/-24.6% in parts 1 and 2 of the study, respectively. Of these oocytes 62.3 and 62.8% (parts 1 and 2, respectively) were fertilized. In part 1, the highest proportion (64.7%) of pronuclear stages was observed in the group inseminated with 300 x 10(6) freshly diluted semen and was significantly higher compared to the groups inseminated with 50 x 10(6) freshly diluted semen (25.5%, P<0.001), 300 x 10(6) liquid conserved semen (49.0%, P<0.001), or 50 x 10(6) frozen/thawed semen (39.6%, P<0.05). In the control group, the proportion of pronuclear stages amounted to 60.2%. Irrespective of the type of sperm conservation, the overall fertilization rate (zygotes plus 2-cell stages) was higher (P<0.05) following insemination with 300 x 10(6) sperm (68.2%) compared to 50 x 10(6) sperm (56.8%). In part 2, the proportion of pronuclear stages reached 54.2% with an overall fertilization rate of 62.9%. These results were affected by breed and age of the donor as crossbred and younger (<3 years) animals yielded the highest proportion of pronuclear stages. The present study shows that freshly diluted semen at a dosage of 300 x 10(6) sperm yields the highest fertilization rates, the greatest proportion of pronuclear stages and the lowest proportion of mature unfertilized oocytes. Further increases in yields of pronuclear stages can possibly be achieved by selection of sheep from the best suited breed and younger than 3 years of age.

Aging↗

PubMed2004

Oocyte transfer in mares with intrauterine or intraoviductal insemination using fresh, cooled, and frozen stallion semen.

The objectives were to compare embryo development rates after oocyte transfer with: (1) intrauterine or intraoviductal inseminations of fresh semen versus intraoviductal insemination of frozen semen; (2) intraoviductal versus intrauterine inseminations of cooled semen. In Experiment I, oocytes were transferred into the oviduct, and recipients were inseminated into the uterus with 1 x 10(9) fresh spermatozoa, or into the oviduct with 2 x 10(5) fresh or frozen-thawed spermatozoa. In Experiment II, semen was cooled to 5 degrees C before intrauterine insemination with 2 x 10(9) spermatozoa or intraoviductal inseminations of 2 x 10(5) spermatozoa (deposited with the oocytes). In Experiment I, embryo development rates were similar (P>0.05) for intrauterine versus intraoviductal inseminations when fresh semen was used (8/14, 57% and 9/11, 82%, respectively). However, embryo development rates were lower (P<0.05) when frozen spermatozoa were placed within the oviduct (1/12, 8%). In Experiment II, embryo development rates were higher (P<0.05) when cooled semen was used for intrauterine (19/23, 83%) versus intraoviductal (4/16, 25%) inseminations. We concluded that intraoviductal insemination can be successfully performed using fresh spermatozoa. However, the use of cooled and frozen spermatozoa for intraoviductal inseminations was less successful, and needs further investigation.

Animals↗

PubMed1998

Effect of insemination dose on pregnancy rate in mares.

Different insemination doses have been used for artificial insemination(AI) in horses. Since the insemination dose can affect the pregnancy rate, it is important to ensure that an adequate dose be used regardless of the type of inseminationprotocol used. The aim of this study was to find out if it is possible to decrease the insemination dose from 500 x 10(6) progressively motile spermatozoa to 300 x 10(6) progressively motile spermatozoa and still maintain an acceptable pregnancy rate when using extended fresh semen. Thirteen stallions of known fertility and a well-defined group of 64 mares were used in the study. The mares were randomly assigned to 1 of 2 insemination groups. Examination for pregnancy was performed by ultrasonography per rectum approximately 16 d after the last insemination. When using an insemination dose of 300 x 10(6) progressively motile spermatozoa the pregnancy rate per cycle was 75%. With an insemination dose of 500 x 10(6) progressively motile spermatozoa the pregnancy rate per cycle was 64%. There was no significant difference in the pregnancy rate between the 2 insemination doses (P = 0.341). We conclude that when using fresh extended semen it is unlikely that an insemination dose of 300 x 10(6) progressively motile spermatozoa would yield a lower pregnancy rate than a dose of 500 x 10(6) progressively motile spermatozoa if stallions with good quality semen are selected.

Animals↗