Cervical Penetration Research Articles

104 Administration of carbetocin prior to timed artificial insemination in ewes increases cervical penetration and prolificacy but not fertility following cervical insemination with frozen-thawed semen

104 Administration of carbetocin prior to timed artificial insemination in ewes increases cervical penetration and prolificacy but not fertility following cervical insemination with frozen-thawed semen

The use of oxytocin to cause cervical dilation for transcervical insemination in nulliparous goats: Improving pregnancy and kidding rates

To evaluate the effect of oxytocin as a cervical dilator, a study was carried out on nulliparous goats inseminated transcervically at the beginning of the breeding season. One hundred sixteen nulliparous goats with a mean live weight of 33.4±0.68kg and an age of 13.7±0.37months were used. The goats were exposed to active bucks of proven fertility for a period of 14 d in order to induce oestrus. One week later, the Ovsynch protocol was applied, which consisted of the application of 20mg of gonadorelin (Day Zero), 0.075mg of cloprostenol (Day 7) and of a second dose of 20mg of gonadorelin applied on Day 9. Artificial insemination (AI) was performed 16hr later. Three treatments were evaluated: T1=50IU saline, T2=25IU oxytocin; T3=50IU of oxytocin, intravenously applied 10-15min before AI. The time required to inseminate each treated goat from groups T2 and T3 was 49.56 and 56.25s, respectively, versus 85.78s needed for the goats from group T1 (p<.0001). In the T1 group of goats, the insemination catheter was inserted 2.1cm into the cervical canal and in goats from groups T2 and T3 it reached 3.41 and 3.77cm into the cervical canal, respectively (p=.02). Pregnancy rates and prolificacy (kids/doe) were higher (p=.02) for groups T2 (82.93%; 1.16) and T3 (76.92%; 1.21) respectively than for control goats (61.11%; 0.69). In conclusion, the intravenous administration of oxytocin led to greater dilation and depth of cervical penetration, obtaining higher pregnancy rates and prolificacy.

The Design of a New Catheter for Transcervical Artificial Insemination in Ewes.

Simple SummaryIn ovine species, transcervical artificial insemination is not easy to apply, due to the tortuous lumen of the cervix that does not allow the passage of routinely used catheters. Moreover, the quality of frozen–thawed semen in small ruminants is poor and these factors negatively affect the wide spreading of superior genotypes. The aim of this study was therefore to preliminarily test three newly designed insemination catheters, with bent tips of different lengths, in terms of reproductive performances in pluriparous ewes inseminated with frozen–thawed semen. Afterwards, the outcomes of insemination with the best performing catheter were compared to those obtained in ewes previously submitted to surgical incision of cervical folds, a technique that allows transcervical intrauterine deposition of semen. The results obtained indicated that a catheter with a bent tip of 5.0 mm allowed deep and fast intrauterine insemination, leading to pregnancy rates similar to those obtained following surgical incision of the folds. Further tests on the efficiency of the catheter are needed in field conditions and on a larger number of animals to assess the feasibility of the method in wide commercial insemination campaigns.In ovine species, transcervical artificial insemination (TCAI) is limited by the poor quality of frozen–thawed semen and by the convoluted cervical lumen hampering the passage of inseminating devices. The aim of the study was to test the efficiency of three newly designed catheters with bent tips of 3.5 mm, 5.0 mm or 8.0 mm in terms of reproductive performances (experiment 1) and to compare the results of TCAI with the best performing catheter of experiment 1 to those obtained in ewes submitted to surgical incision of cervical folds (SICF) prior to insemination (experiment 2). The following parameters were assessed: time to pass the cervix; depth of cervical penetration; site of deposition of semen; pregnancy (PR); and lambing rates (LR). The results of experiment 1 indicated that the 5.0 mm tip catheter resulted in deeper and faster TCAI and higher PR and LR compared to 3.5 mm and 8.0 mm tip catheters (p < 0.05). In experiment 2, TCAI with the 5.0 mm catheter did not differ from TCAI after SICF in terms of depth of semen deposition, time to pass the cervix, PR and LR (p < 0.05). In conclusion, the use of a catheter that allowed transcervical uterine deposition of semen without excessive manipulation led to satisfactory pregnancy rates.

Carboxymethyl cellulose and glycerol act synergistically as cryoprotectant during cryopreservation of ram semen

Wider implementation of AI in sheep in the field condition has not been possible till date due to very poor conception rate after cervical insemination with cryopreserved semen. Poor cervical penetrability in ewe and diminished sperm functions in cryopreserved semen are considered responsible for it. In the present study, effect of carboxymethyl cellulose (CMC) on post-thaw qualities of ram semen was investigated. Ejaculates from eight adult Malpura rams were pooled and diluted (800 × 106 sperm mL−1) with TES-Tris-fructose-egg yolk extender having either 5 or 6% glycerol and supplemented with 0, 0.25, 0.5, 0.75 and 1.0% (w/v) CMC and packaged into 0.25 mL French mini straws. The straws were progressively cooled to 5 °C inside a cold cabinet (5 °C) and then equilibrated for 22 h inside a refrigerator (2–5 °C). Straws were frozen at −25 °C min−1 up to −125 °C using a programmable cell freezer (Planer Biomed R-204, UK) and finally plunged into liquid nitrogen. The post-thaw progressive motility was higher (P < 0.05) in 0.75% CMC-treated group compared to control. Overall, both pre-freeze and post-thaw sperm kinetics was comparable between CMC-treated and control groups. The post-thaw sperm viability, acrosomal integrity and sperm with high mitochondrial membrane potential (hMMP) were relatively higher while sperm with high membrane cholesterol was significantly (P < 0.05) higher in presence of 0.25% CMC compared to the control. Both sperm having hMMP and non-capacitated sperm were significantly (P < 0.05) higher in presence of 5% glycerol than 6% glycerol. Similarly, functional membrane integrity (FMI) was higher in presence of 5% glycerol than 6% glycerol when CMC was added at 0.5% to extender. In conclusion, both 0.25% CMC and 5% glycerol resulted in improvement in several post-thaw sperm functions in cryopreserved ram semen. Thus CMC demonstrated cryoprotective effect on ram sperm in a synergistic manner with glycerol.

Studies on Equine Embryo Transfer: Effect of Flushing Media and Environment in Maiden and Adult Arabian Mares

The advances in equine embryo transfer (ET) allowed its application in small facilities with promising results. ET has been carried in 27 donor mares where the procedures were applied in 2 facilities; 1) farm group (n=18) where the ET was carried out in stable confined group. 2) procedures were applied in the lab (lab group, n=9). Two solutions, phosphate buffered saline (PS) or ringer lactate (RL), were used as flushing media. ET was applied by directing the pipette with finger through the cervix. In farm group 39 flushes resulted in 17 embryos with 43.6% recovery rat with 63.2% pregnancy rate. In lab group 16 flushes resulted in 14 embryos with recovery rat 87.5% and pregnancy rate 71%. In conclusion, ET could be conducted in equine farms without affecting recovery or pregnancy rate, RL could be used as flushing media without decreasing pregnancy rate, and cervical penetration dose not decreasing pregnancy rate.

Effects of cervical ripening treatments on pregnancy rates following transcervial artificial insemination in ewes

The study was aimed to identify the effective cervical ripening treatment to increase the pregnancy rates following transcervical artificial insemination (TC-AI) in indigenous ewes of Bangladesh. Three treatments schedules were compared, G1 (n = 6, control), G2 [n = 6, prostaglandin E1 (PGE1) as Misoprostol-Cytomis®] and G3 (n = 6, estrogen as Oestriol-Ovestin® + oxytocin as Linda-S® Vet). Ewes (n=18) were synchronized for estrus using two doses of 100 µg prostaglandin (PGF2α; Ovuprost®) 9 days apart. The cervical ripening treatments were administered just after the onset of estrus and left for 12 h before TC-AI. The cervical ripening was reflected with the depth of cervical penetration. The depth of cervical penetration in G1, G2 and G3 both before and after cervical ripening treatments were 0.33 ± 0.10 cm vs 0.43 ± 0.07 cm, 0.41 ± 0.09 cm vs 3.50 ± 0.26 cm and 0.43 ± 0.09 cm vs 1.54 ± 0.14 cm, respectively. The depth of cervical penetration increased significantly (p

Reproductive performance and luteal function of Santa Ines ewes inseminated by cervical retraction with fresh or frozen semen

SUMMARY The artificial insemination (AI) by cervical retraction using fresh or commercially available frozen semen was evaluated. Santa Inês ewes (n=151) were assigned in five groups. Natural mating (NM) composed the control group. Four groups were submitted to hormonal treatment and timed insemination by cervical retraction (CRI) or laparoscopy (LAI), using fresh or frozen semen. To perform CRI, the ewes were kept in standing position. The time required to penetrate the cervical canal and to perform CRI were recorded; local deposition of semen and the reaction intensity of the ewe (weak, moderate or strong) were measured. Blood samples were collected to perform the progesterone dosage at days 0, 3, 5, 12 and 17 (day 0 = AI/NM). Non-return to estrus rate (NRE), pregnancy (at D35) and fertility (birth / mated ewes) were evaluated. Mean time for cervical penetration and CRI were 52.8 ± 21.2s and 3:26min ± 47s, respectively. Reaction intensity to CRI was weak or moderate in 92.3% of the ewes. Serum levels of progesterone after CRI, LAI or NM were similar. NRE of the inseminated ewes were similar, except for CRI with frozen semen, which was lower (P&lt;0.05). Fertility rates were similar between CRI and LAI (35.4% and 42.2%, respectively). Artificial insemination by cervical retraction with ewes in a standing position is practical, and does not change the progesterone profile, providing reproductive rates similar to laparoscopy. However, the use of this technique along with commercial frozen semen presents low fertility rate.

Cervical penetration rates and efficiency of non-surgical embryo recovery in estrous-synchronized Santa Inês ewes after administration of estradiol ester (benzoate or cypionate) in combination with d-cloprostenol and oxytocin

The effects of estradiol esters, d-cloprostenol and oxytocin on induction of cervical dilation prior to non-surgical embryo recovery in Santa Inês ewes (Days 6–7 estrous cycle) were assessed in this study. In Trial 1, transcervical embryo flushing was performed in estrous-induced ewes administered 37.5 μg of d-cloprostenol i.m. 10 h before and 50 IU of oxytocin i.v. 20 min before uterine flushing with (EB-PGF-OT; n = 13) or without (PGF-OT; n = 11) 1 mg of estradiol benzoate i.m. administered concurrently with d-cloprostenol injection. In Trial 2, the estrous-synchronized animals were treated with 1 mg of estradiol benzoate (EB-PGF-OT; n = 12) or estradiol cypionate (EC-PGF-OT; n = 12) i.m. along with 37.5 μg of d-cloprostenol i.m. 16 h before and 50 IU of oxytocin i.v. 20 min before uterine flushing. In Trial 1, uterine flushing could be accomplished in 38% of ewes in the EB-PGF-OT and 27% those in the PGF-OT (P>0.05) group. Flushing fluid recovery averaged 90% and there were 1.0 ± 1.1 embryos/ewe collected with mean duration of the flushing procedure being ˜36 min. In Trial 2, uterine flushing was accomplished in 78% of ewes in the EB-PGF-OT and 44% of those in the EC-PGF-OT group (P>0.05) with mean flushing fluid recovery rate being 88% and time elapsing to complete flushing being ˜33 min. Within the subsets of animals treated with EB, the percentages of successful transcervical penetrations were 38% compared with 78% in Trials 1 and 2, respectively (i.e., with EB administered 10 h compared with 16 h before uterine flushing: P<0.05). The interval from EB administration to the beginning of transcervical penetration can affect the efficacy of embryo recovery procedures utilizing a combined EB/d-cloprostenol/oxytocin pre-treatment.

Pancreaticopleural and pancreaticomediastinal fistula extending to the cervical region, with dysphagia as initial symptom

Rationale:Pancreaticopleural and pancreaticomediastinal fistulas are rare complications of pancreatitis. They are often misdiagnosed and there are no strict guidelines of treatment. In this study, we present a brief report of a combined pancreaticopleural and pancreaticomediastinal fistula extending to the cervical region, causing dysphagia and cervical swelling as initial symptoms.Patient concerns:A 36-year-old female with history of alcohol abuse and pancreatitis presented progressing dysphagia and mild dyspnea on admission.Diagnosis:Chest X-ray and chest and abdominal computed tomography scan (CT) indicated pancreaticopleural fistula combined with pancreaticomediastinal fistula, a diagnosis confirmed by high amylase levels in pleural fluid.Interventions:Conservative treatment was administered and ERCP was performed but pancreatic duct stenting was impossible. The patient presented rapid anterior cervical swelling with progressing dysphagia and dyspnea. CT showed fistula penetration to the cervical region. The patient underwent urgent surgery and pancreaticojejunal anastomosis was performed.Outcomes:The surgery led to recovery. Six months later, the patient reported good health and weight gain.Lessons:Coexistence of pancreaticopleural and pancreaticomediastinal fistula with cervical penetration is an extremely rare pancreatitis complication. It presents with dysphagia and anterior cervical swelling as initial symptoms. It is important to consider this complication in all patients with history of pancreatitis, presenting with dysphagia.

Factors influencing the pregnancy rate in indigenous ewes following AI using frozen semen

Study was conducted to observe the influence of different factors on pregnancy rate in 24 indigenous ewes following artificial insemination (AI) with frozen semen. The ewes were synchronized by intra-muscular injection of Prostaglandin F2α (Ovuprost® Bayer, New Zealand). The onset and intensity of oestrus were determined by oestrus behaviour of ewes with vasectomized ram. VER values were measured immediately before AI using electrical heat detector (DRAMINSKI®, Owocowa 17, Poland). Twelve ewes were inseminated trans-cervically and 12 laparoscopically. Five ewes were treated with Misoprostol (Cytomis® 200 µg tablet; Incepta Pharmaceuticals Ltd. Bangladesh) to relax the cervix 12 hours before TCAI, and cervical penetration depth was measured by a steel rod. Pregnancy was confirmed by ultrasonography at 40 – 45 days after AI. Cervical penetration depth was significantly increased (P&lt;0.05) (0.48 ± 0.04 vs. 3.52 ± 0.17 cm) in treatment group. The pregnancy rate tended to be higher in treatment group (60.0 vs. 28.6%). In treatment group cervical penetration was significantly increased (P&lt;0.05) (0.35 ± 0.08 vs. 3.52 ± 0.17 cm) immediately before AI compared with before oestrus synchronization. The pregnancy rate was significantly higher (P&lt;0.05) (75.0 vs. 28.6%) in LAPAI than TCAI without treatment. The pregnancy rate tended to be higher (75.0 vs. 55.6%) in ewes with high oestrus intensity than in those with medium intensity. The pregnancy rate was significantly higher (P&lt;0.05 : 70.0 vs. 20.0%) in lower VER group (230 - 280 Ω) compared with higher VER group (331 – 380 Ω.) Although LAPAI was superior to TCAI, TCAI in ewes treated with misoprostol giving a pregnancy rate of 60% could be acceptable, until the LAPAI could be made simpler to be used in field. The oestrus intensity and low VER values could be used to select ewes to be inseminated to increase the pregnancy rate.Bangl. vet. 2016. Vol. 33, No. 2, 33-38

Reproductive features and use of an anti-inflammatory drug in estrus-induced dairy goats artificially inseminated in a standing position with cervix immobilization

This study evaluated reproductive features and role of Flunixin-Meglumine at timed artificial insemination (AI), using a new technique of standing position with cervix immobilization. In Experiment 1, 10 goats (n=5 nulliparous [Null] and 5 pluriparous [Plu]) were evaluated after estrus induction by recorded reproductive parameters to define the ideal time for AI. In Experiment 2, goats were artificially inseminated 51–54h after sponge removal with frozen–thawed semen. At AI, 1mL saline (CONTROL; 18 Null and 14 Plu) or 50mg Flunixin-Meglumine (FLUNIXIN; 15 Null and 18 Plu) was administered i.m. Location of semen deposition was recorded for both groups. In Experiment 1, all sexual behavior and ovulatory parameters were similar between Null and Plu for estrus response and ovulation (100%), interval from sponge removal to ovulation (∼64.2h), largest ovulatory follicle diameter (∼6.6mm), and number of ovulations (∼2.0). In Experiment 2, pregnancy rate was superior (P<0.01) for CONTROL (62.5%; 10 Null and 10 Plu) than FLUNIXIN (30.3%; 3 Null and 7 Plu) goats. Regardless of the treatment, intrauterine AI was more frequent (P<0.01) in Plu (100.0%; 32/32) than in Null (69.7%; 23/33) goats. Moreover, AI was more time-consuming (P<0.01) in Null (44±37s; 4–139s) than in Plu (21±19s, 4–78s) goats. Therefore, administration of Flunixin-Meglumine at the time of AI adversely affected pregnancy rate. High rates of intrauterine cervical penetration were obtained, achieving good pregnancy rates in goats not receiving Flunixin-Meglumine.

Assessing the usefulness of prostaglandin E2 (Cervidil) for transcervical artificial insemination in ewes

The underlying theme of this study involved the evaluation of the dilatory effects of prostaglandin E2 on the ovine cervix and thus the assessment of its potential applicability to transcervical artificial insemination (TCAI) in ewes. A novel method of prostaglandin E2 administration (controlled slow-release vaginal inserts) was examined, and the practical implications of this approach including cervical penetrability and posttreatment pregnancy rates were evaluated. The Guelph method of TCAI was performed during the seasonal anestrus (n = 40) and the breeding season (n = 40) on multiparous Rideau Arcott × Polled Dorset ewes, with or without the pretreatment with Cervidil (for a duration of 12 hours or 24 hours before TCAI). Cervical penetration rates averaged 82.5% (66 of 80), and they varied neither (P > 0.05) between the two seasons nor between Cervidil-treated ewes and their respective controls. Cervidil priming significantly reduced the total time required for TCAI during the breeding season in comparison with controls (54 vs. 98 seconds), especially after the 24-hour exposure (38 vs. 108 seconds). The time taken to traverse the uterine cervix was negatively correlated (P < 0.05) with the breed (percentage of Rideau Arcott genotype) and lifetime lamb production in seasonally anestrous ewes. Four out of 36 (11%) successfully penetrated ewes in the breeding season (three ewes allocated to the 12-hour control group and one ewe that had received Cervidil for 12 hours) became pregnant and carried the lambs to term. Vaginal mucus impedance at TCAI was significantly and positively correlated with the total time required to complete the procedure in cyclic ewes, and the negative correlation between vaginal mucus impedance and total time values at the time of controlled intravaginal drug release device removal approached to significance in anestrous ewes. The present results indicate a moderate benefit of using Cervidil for inducing cervical dilation before TCAI in ewes, mainly in the breeding season. The specific reason(s) for impaired fertility after the TCAI using frozen–thawed ram semen remains to be elucidated.

Penetración espermática intracervical e intrauterina en la infertilidad funcional por factor cervical

En 14 mujeres con infertilidad funcional por factor cervical se realizaron 30 pruebas postcoitales en días preovulatorios, con recuentos exactos de espermatozoides en moco cervicaI y contenido intrauterino. Los valores se comparan con los de 19 mujeres senos, multíparas. Una paciente normal y dos infértiles fueron seguidas con determinaciones seriadas a través de un ciclo completo. La cuantificación exacta de la cristalización del moco, realizada mediante un nuevo método, resultó ser un buen criterio de evaluación de la penetrabilidad cervical. A nivel intracervical los resultados del grupo infértil no fueron significativamente diferentes de los controles; una leve disminución de los espermios móviles direccionales carece de valor práctico. Por el contrario, a nivel intrauterino, en el grupo infértil se detectaron espermios sólo en 7 de los 30 casos, con concentraciones muy bajas; en el grupo control fueron 18 de 19 casos. Se insiste en el valor del recuento espermático intrauterino, muy superior a las pruebas intracervicales. La técnica empleada permite obtener resultados cuantitativos más exactos que los reportados por la literatura. El tratamiento consistió principalmente en estrógenos a dosis baja en días 8 o 14 del ciclo. Se consiguió mejoría de la calidad del moco en 11 pacientes y gestación en 8 (57%).

Seminal plasma aids the survival and cervical transit of epididymal ram spermatozoa

Seminal plasma purportedly plays a critical role in reproduction, but epididymal spermatozoa are capable of fertilisation following deposition in the uterus, calling into question the biological requirement of this substance. Through a combination of direct observation of spermatozoa in utero using probe-based Confocal Laser Endomicroscopy, in vivo assessment of sperm fertility and in vitro analysis of various sperm functional parameters, this study investigated the role of seminal plasma in spermatozoa transit through the cervix of the ewe. Following deposition in the cervical os, epididymal spermatozoa previously exposed to seminal plasma displayed an enhanced ability to traverse the cervix as evidenced by both significantly higher pregnancy rates and numbers of spermatozoa observed at the utero-tubal junction when compared with epididymal spermatozoa not previously exposed to seminal plasma. The beneficial effect of seminal plasma on sperm transport was clearly localised to transit through the cervix as pregnancy rates of spermatozoa deposited directly into the uterus were unaffected by exposure to seminal plasma. This phenomenon was not explained by changes to sperm motion characteristics, as seminal plasma had no effect on the motility, kinematic parameters or mitochondrial membrane potential of spermatozoa. Rather, in vitro testing revealed that seminal plasma improved the ability of epididymal spermatozoa to penetrate cervical mucus recovered from ewes in oestrus. These results demonstrate that the survival and transport of ram spermatozoa through the cervix of the ewe is not linked to their motility or velocity but rather the presence of some cervical penetration trait conferred by exposure to seminal plasma.

Seminal plasma aids the survival and cervical transit of epididymal ram spermatozoa.

Seminal plasma purportedly plays a critical role in reproduction, but epididymal spermatozoa are capable of fertilisation following deposition in the uterus, calling into question the biological requirement of this substance. Through a combination of direct observation of spermatozoa in utero using probe-based Confocal Laser Endomicroscopy, in vivo assessment of sperm fertility and in vitro analysis of various sperm functional parameters, this study investigated the role of seminal plasma in spermatozoa transit through the cervix of the ewe. Following deposition in the cervical os, epididymal spermatozoa previously exposed to seminal plasma displayed an enhanced ability to traverse the cervix as evidenced by both significantly higher pregnancy rates and numbers of spermatozoa observed at the utero-tubal junction when compared with epididymal spermatozoa not previously exposed to seminal plasma. The beneficial effect of seminal plasma on sperm transport was clearly localised to transit through the cervix as pregnancy rates of spermatozoa deposited directly into the uterus were unaffected by exposure to seminal plasma. This phenomenon was not explained by changes to sperm motion characteristics, as seminal plasma had no effect on the motility, kinematic parameters or mitochondrial membrane potential of spermatozoa. Rather, in vitro testing revealed that seminal plasma improved the ability of epididymal spermatozoa to penetrate cervical mucus recovered from ewes in oestrus. These results demonstrate that the survival and transport of ram spermatozoa through the cervix of the ewe is not linked to their motility or velocity but rather the presence of some cervical penetration trait conferred by exposure to seminal plasma.

The pattern of cervical penetration and the effect of topical treatment with prostaglandin and/or FSH and oxytocin on the depth of cervical penetration in the ewe during the peri-ovulatory period

Artificial insemination in sheep has two major limiting factors: the poor quality of frozen-thawed ram semen and the convoluted anatomy of the sheep cervix that does not allow transcervical passage of an inseminating catheter. It has been demonstrated that in the ewe during estrus, there is a degree of cervical relaxation mediated by ovarian and possibly gonadotrohic hormones, and we set out to investigate factors that might enhance cervical relaxation. Five experiments were conducted on ewes of different breeds to determine: 1) the pattern of cervical penetration during the periovulatory period in ewes of several breeds (Welsh Mountain, Île-de-France, Vendéenne, Romanov and Sarda); 2) the effect of the “ram effect” a socio-sexual stimulus, on cervical penetration; and 3) the effects of the intracervical administration of follicle-stimulating hormone (FSH), oxytocin and a prostaglandin E agonist (misoprostol) on the depth of cervical penetration during the periovulatory period. The results showed that during the periovulatory period in all breeds examined, there was increased penetration of the cervical canal (P < 0.05) by an inseminating catheter. Cervical penetration increased to a maximum 54 h after the removal of progestagen sponges and then gradually declined. Furthermore, the depth of cervical penetration but not its pattern, was affected (P < 0.05) by the breed of ewe. The maximum depth of cervical penetration was lower (P < 0.05) in the Vendéenne breed compared to the Île-de-France and Romanov breeds, which did not differ from one another. In the presence of rams, the depth of cervical penetration was increased at 48 and 54 h after removal of sponges (P < 0.05) and reduced at 72 h (P < 0.05). The local administration of hormones FSH, misoprostol (a PGE agonist) and oxytocin alone and in various combinations did not have any significant effect on the depth of cervical penetration during the periovulatory period. In conclusion, the natural relaxation of the cervix observed in ewes of several breeds occurs at a time during estrus, 54 h after the removal of progestagen sponges, which is the most suitable for artificial insemination. The effect was enhanced by the presence of a ram but not by the local intracervical administration of FSH, misoprostol and oxytocin even though oxytocin and PGE2 are involved in cervical function. The time of maximum cervical penetration in the preovulatory period (54 h) coincides with high LH and estradiol concentrations suggesting they might be responsible for the relaxation of the cervix probably through an oxytocin-PGE mediated pathway.

Effect of site of deposition on the fertility of sheep inseminated with frozen-thawed semen

The widespread use of artificial insemination (AI) in sheep is currently prevented due to the lack of a cost effective insemination technique utilising frozen-thawed semen. The objective of the present study was to determine if the deposition of frozen-thawed semen in the vaginal fornix would result in a pregnancy rate comparable to that achieved following cervical insemination. Multiparous ewes of various breeds were synchronised and inseminated into either the vaginal fornix (n=78) or the cervix (n=79), at 57h post sponge removal, with frozen-thawed semen. Information on mucus secretion and the depth to which it was possible to penetrate the cervix at insemination (cervically inseminated ewes only) was recorded at the time of AI. Pregnancy rate was subsequently determined either by return to service (oestrus) or after slaughter 30 days post insemination. Insemination site did not significantly influence pregnancy rate using frozen-thawed semen (36.2% compared to 27.6% for cervical and vaginal fornix insemination, respectively; P=0.26). Whilst depth of cervical penetration was positively associated with pregnancy rate (P<0.05), this association needs to be interpreted with caution as none of the ewes where the cervix could not be penetrated (score=0) was pregnant. In conclusion, pregnancy rate following insemination of frozen-thawed semen into the vaginal fornix was within 10% points of that obtained following cervical AI of frozen-thawed semen. As insemination into the vaginal fornix is technically easier than cervical insemination, it may be more practical for use in large scale applications.

Design and “in vivo” evaluation of two adapted catheters for intrauterine transcervical insemination in sheep

In order to obtain better fertility, we evaluated two ovine artificial insemination (AI) catheters that were manufactured according to the anatomical structure of the ewe cervix. Morphometric data of the cervix in Churra and Assaf breeds were used to design two types of curved catheters: CAT06 with one curvature and ZIGZAG with five curvatures in a zigzag shape. Two commercial catheters (IMV® and Minitüb®) were used as controls. In experiment 1, cervical penetration and the degree of reflux were measured in a Cervical AI simulated assay both Churra (n=28) and Assaf ewes (n=28). In experiment 2, a fertility study was performed with three catheters (only one commercial control catheter – IMV) in 465 inseminations (Assaf); and a second study analyzed only the top two catheters (IMV and CAT06) in 428 inseminations (210 Assaf and 218 Churra). The ewes were synchronized using intravaginal sponges (40 FGA mg during 14 days) and 500IU of eCG. Deeper penetration of the cervix was obtained with the new catheters compared with the commercial ones (1.5, 1.3, 3.5 and 3.2cm for the IMV, Minitüb, CAT06 and ZIGZAG catheters, respectively). The cervical penetration and the reflux grade of each catheter showed no differences between breeds. In experiment 2, the degree of penetration had no correlation with fertility of different catheters. The best percentage of lambing ewes was obtained with the IMV and CAT06 catheters (39.5 and 48.1%, respectively. vs 27.2% for ZIGZAG catheter, in the Assaf breed). Regarding effect of breed, Assaf (39.3% and 49.5 for IMV and CAT06, respectively) showed better lambing rates than Churra (29.0% and 39.0%, respectively), and the CAT06 catheter showed significantly higher rates for each breed.

Effects of exogenous oxytocin on cervical penetration of Iranian ewes

The objective of this study was to determine the effect of exogenous oxytocin (OT) treatments on the cervix dilation of three breeds of Iranian ewes. Cervix dilation was measured by transcervical passage of scaled bovine catheter into the uterus of the ewes. Fifty four healthy Zandi ewes were equally assigned to six groups in the late breeding season. Thirty healthy Lori-bakhtiari breed ewes were equally assigned to six groups during anestrous. The ewes received 100, 80 and 60 IU of intravenous (i.v) and intramuscular (i.m) OT. In the breeding season, 120 healthy Zell breed ewes were equally assigned to six groups and received 150, 100 and 50 IU of i.v and i.m OT. Cervix dilation was examined before OT injection 10 to 15 min following treatment. This study indicates that injection of more than 80 IU OT can completely dilate the cervix of Iranian ewes (P < 0.05) and the reproductive seasons (anestrous, late breeding season and breeding season) and the type of injection (i.v or i.m) has no significant effect on induced cervix penetration by OT. Therefore, this dose is the applicable dose for the cervix dilation and transcervical artificial insemination and embryo recovery in Iranian ewes. Key words: Iranian ewes, oxytocin, cervical dilation, transcervical artificial insemination, transcervical embryo transfer.

Direct venous spinal reabsorption of cerebrospinal fluid: a new concept with serial magnetic resonance cisternography in rabbits

For nearly 100 years it has been believed that the main reabsorption of CSF occurs in arachnoid projections into the superior sagittal sinus, but a significant number of experiments and cases conflict with this hypothesis. According to recently published studies, CSF is permanently produced and absorbed in the whole CSF system. Clusters of arachnoidal villi, which are speculated to have a role in the reabsorption of CSF, have recently been revealed in the dorsal root of the spinal nerves. Huge absorptive surface areas of microvessels have been suggested to serve a putative role in reabsorption. The authors' aim was to observe direct venous connections between the subarachnoid space and the perispinal veins. Eleven adult (6 months old) New Zealand white male rabbits weighing approximately 3.0 kg each were used in this experiment. After obtaining precontrast MR cisternography images, subarachnoid access was gained percutaneously via a cisternal approach by using a 20-gauge intravenous indwelling cannula. One rabbit died as a result of brainstem trauma during percutaneous cannulation before contrast administration, but contrast agent was still injected to see the possible MR imaging results of spinal CSF reabsorption after death. Magnetic resonance imaging was performed at 15, 60, 120, and 180 minutes after the administration of contrast agent. After intramuscular injections of anesthetic, 2 rabbits died 120 and 150 minutes after contrast injection, but the MR imaging study at 180 minutes after contrast injection was still performed. Direct connections between the subarachnoid space and the perispinal veins were observed in all rabbits during serial MR cisternography. The enhancement power was not affected by the amount of injected contrast agent or by cervical or lumbar penetration but was increased at higher contrast concentrations or upon seizure (physical activity). Extracranial reabsorption of CSF has been finally proved with direct radiological confirmation of spinal venous reabsorption of CSF using serial MR cisternography. The authors believe that this study can help to develop a more accurate model of CSF dynamics, which will allow understanding of many CSF-related diseases, as well as the development of new strategies for treatment.