Concentrations of spermatozoa in the vagina of heifers after deposition of semen in the uterine horns, uterine body or cervix

In Exp. I, virgin Holstein heifers (N = 18) were induced into oestrus with PGF-2 alpha. Animals which stood to be mounted were paired for insemination approximately 8 h later with 56.1 x 10(6) spermatozoa from a single bull. Semen was deposited in the uterine body of one female. Each matched female was inseminated by deposition of one-half of the inseminate into the right uterine horn and one-half into the left uterine horn approximately 7.0 cm anterior to the internal cervical os. In Exp. II, additional heifers (N = 18) were induced into oestrus and inseminated by deposition into the uterine horns or cervix (2.0 cm anterior to the external cervical os). A 1.0 ml aspirate of vaginal mucus was collected at hourly intervals for 8 h after insemination. Concentration of spermatozoa was determined by haemocytometry. In Exp. I, cumulative percentage spermatozoa recovered in an 8 h collection period were similar (P greater than 0.10) for insemination into the uterine horns (17.9 +/- 2.9%) and uterine body (18.5 +/- 4.5%). In Exp. II, cumulative % sperm recovery from the vagina was greater (P less than 0.10) for cervical deposition (59.1 +/- 14.1%) than for that into the uterine horns (30.9 +/- 7.8%). In Exp. II, the insemination treatment x hour of sample interaction was significant (P less than 0.08). Recovery of spermatozoa from the vagina was greatest (P less than 0.05) within 3 h after cervical insemination (31.4 +/- 9.9% compared to 9.4 +/- 2.5% for uterine horn deposition). Percentage recovery of spermatozoa from the remaining hourly collections were similar (P greater than 0.10).(ABSTRACT TRUNCATED AT 250 WORDS)     

Fertilization rates and embryonic development in superovulated cattle inseminated in different sites within the reproductive tract

Superovulated Jersey and Holstein heifers and cows were bred 9.7 ± 2.7 h after the first observation of estrus with a single dose of frozen semen. Animals were grouped by site of insemination: 1) right uterine horn (n = 5), 2) left uterine horn (n = 4), 3) mid- uterine body (n = 5), and 4) mid-cervix (n = 6). The number of unfertilized ova, normal and abnormal embryos were recorded for each horn at slaughter 115.8 ± 18.6 h after insemination. All viable embryos were cultured in vitro and assessed for development. The overall fertilization rate was 76.8%, with the ipsilateral horn being higher than that of the contralateral horn (P < 0.05). Similar fertilization rates resulted among all treatments except those inseminated in the contralateral horn (P < 0.05). In vivo development of embryos was higher for the ipsilateral horn inseminations than those of the body of the uterus or cervical inseminations (P < 0.05), but it was not higher than the contralateral horn inseminations (P > 0.05). Under the conditions of this study with superovulated cows, these results suggest than 1) spermatozoa migrate from one horn to the other and 2) inseminating too deep into one horn may reduce the chances for concention when ovulation occurs contralaterally.     

Distribution of sexes within the left and right uterine horns of cattle

In cattle, limited data are available regarding the sex ratio of the offspring in relation to the horn of gestation. Therefore, the objective of this study was to evaluate the sex ratio of fetuses gestated in the left and right uterine horns of cattle (Bos taurus, Bos indicus and crosses). The distribution of male and female fetuses in the left and right uterine horn was analyzed on gravid, abattoir-derived reproductive tracts and artificially inseminated crossbred cows. The total number of fetuses/calves and the sex of the fetuses/calves gestated in each uterine horn were used as the end point for side comparisons using the Glimmix Procedure. Of 64 gravid reproductive tracts evaluated, 29 (45.3%) pregnancies occurred in the left uterine horn, whereas 35 (54.7%) occurred in the right. The sex ratio (% males) of fetuses in the left uterine horn (37.9%) was significantly lower than the sex ratio detected in the right uterine horn (65.7%). Of 113 pregnancies evaluated in artificially inseminated heifers, 53 (46.9%) occurred in the left uterine horn, whereas 60 (53.1%) occurred in the right uterine horn. The sex ratio of calves gestated in the left uterine horn (35.8%) was significantly lower than the sex ratio of calves gestated in the right uterine horn (63.3%). In conclusion, in these experiments, a significantly greater proportion of males were gestated in the right uterine horn of cattle and a greater proportion of females in the left uterine horn. Further investigation is needed to determine the mechanisms underlying the observed disparity of the expected sex ratio within the uterine horns of cattle.     

Artificial insemination of ewes with frozen-thawed semen at a synchronised oestrus. 2. Effect of dose of spermatozoa and site of intrauterine insemination on fertility

Three experiments were conducted to examine the effect of dose of inseminate, number of uterine horns inseminated and site of insemination on subsequent fertility of Merino ewes after synchronisation of oestrus, with progestagen-impregnated sponges (inserted for 12 days) and an injection of PMSG, and intrauterine insemination with frozen-thawed semen.The percentages of ewes lambing after insemination with 0.5, 5, 25 and 50 × 10⁶ spermatozoa were 29.3, 26.8, 56.3 and 62.1% respectively. A similar trend was observed in a second test resulting in 23.5, 38.8 and 53.1% ewes lambing after insemination with 5, 10 and 20 × 10⁶ spermatozoa respectively.The percentage of ewes lambing was higher for ewes inseminated in two uterine horns than one horn (76.8 vs. 44.9, P < 0.001). When semen was deposited in the tip, middle and bottom of the uterine horn, the percentages of ewes lambing and lambs born per ewe inseminated were 43.6 and 52.7, 52.8 and 84.9, and 41.2 and 64.7% respectively. Although site of insemination did not affect the percentage of ewes lambing, the percentage of lambs born per ewe inseminated was higher after insemination in the middle of the uterine horn than at the other sites (P < 0.001).     

Side of gestation in dairy heifers affects subsequent sperm transport and pregnancy rates after deep insemination into one uterine horn

Effects of side of previous gestation on sperm transport and pregnancy rates after deep cornual insemination were evaluated in 1686 Friesian cows in their first lactational period. Only single ovulating animals were used. At insemination, semen was deposited deep into the uterine horn ipsilateral or contralateral to the preovulatory follicle. A total of 876 cows (52%) ovulated in the ovary ipsilateral to the postgravid horn, and 810 cows ovulated in the contralateral ovary. Semen was deposited into the previously nongravid uterine horn of 832 cows, and into the gravid horn of 854 cows. The pregnancy rate was higher (P < 0.00001) for semen deposition into the previously nongravid horn (46.6%) than for semen deposition into the gravid horn (35.7%). For inseminations ipsilateral to the side of impending ovulation, pregnancy rates were higher (P = 0.0004) when ovulations occurred on the opposite side to the postgravid horn than on the same side. Pregnancy rates were higher (P = 0.002) for contralateral inseminations when ovulations occurred on the same side to the postgravid horn than on the opposite side; they were higher (P = 0.0001) for total ipsilateral than for total contralateral inseminations. There was no difference between ipsilateral and contralateral inseminations (P = 0.64) when ovulation occurred ipsilateral to the postgravid horn, but pregnancy rates were higher (P < 0.00001) when ipsilateral insemination was carried out into the nonpostgravid horn. Results indicate that the side of gestation in dairy heifers affects subsequent pregnancy rates after deep insemination into one uterine horn, possibly by affecting sperm transport.     

Effect of a deep uterine insemination on spermatozoal accessibility to the ovum in cattle: a competitive insemination study

A competitive insemination study was conducted to determine the effect of a deep uterine insemination on accessory sperm number per embryo in cattle. Cryopreserved semen of a fertile bull characterized by spermatozoa with a semi-flattened region of the anterior sperm head (marked bull) was matched with cryopreserved semen from an unmarked bull having spermatozoa with a conventional head shape. Using 0.25-mL French straws and a side delivery embryo transfer device, deep uterine insemination (0.125 mL deposited in each horn) was performed 2 cm from the uterotubal junction. Immediately after, the uterine body was artificially inseminated using semen (0.25 mL) from an alternate bull and a conventional insemination device. The complete dose (both inseminations) was 50x10(6) total sperm cells consisting of an equal number of spermatozoa from each bull. Single ovulating cows (n = 95) were inseminated at random with either the unmarked semen in the uterine body and marked semen in the uterine horn, or the unmarked semen in the uterine horn and marked semen in the uterine body. Sixty-one embryos(ova) were recovered nonsurgically 6 d post insemination, of which 40 were fertilized and contained accessory spermatozoa. The ratio and total number of accessory spermatozoa recovered was different among treatments: 62:38 (326) for the unmarked semen in the uterine body and marked semen in the uterine horn, and 72:28 (454) for the unmarked semen in the uterine horn and marked semen in the uterine body (P<0.05). Deep uterine insemination using this semen in a split dose and a side delivery device favors accessibility of spermatozoa to the ovum compared with conventional uterine body insemination.     

Increase of pregnancy rate in dairy cattle after preovulatory follicle palpation and deep cornual insemination

A total of 334 first-service lactating cows in natural estrus were used in the study. Semen was deposited into the uterine body of 174 cows and deep into the uterine horn ipsilateral to the side of impending ovulation of 160 cows. In both groups, insemination was performed within the interval of 50 to 100 d postpartum at 8 to 15 h after estrus detection and after preovulatory follicle palpation. Pregnancy rates were determined by palpation per rectum 50 d post insemination. The pregnancy rate was higher (P < 0.05) for deep uterine horn insemination (70.62%) than for uterine body insemination (60.34%).     

Effect of the bovine viral diarrhea (BVD) virus on preimplantation bovine embryos: A preliminary study

Five crossbred-Holstein cows, approximately three to seven years of age, were superovulated using pregnant mare's serum gonadotropin (PMSG) and prostaglandin F_2α (Prostin F_2α). At the induced estrus, each cow was artificially inseminated with frozen semen. Seven days after insemination, the lumen of the right uterine horn of each cow was inoculated with BVD virus in Eagle's minimum essential tissue culture medium, and the lumen of the left horn was infused with tissue culture medium only. Three days later, each cow was subjected to midventral laparotomy under general anesthesia and embryos were collected. A total of 22 embryos were recovered; 12 were from infected uterine horns and ten were from non-infected uterine horns. All embryos from the non-infected uterine horns were in the late blastocyst stage without the zona pellucida. Of the embryos collected from the infected uterine horns, eight of 12 (66.6%) still possessed zona pellucida and appeared in a degenerative state. The remaining four embryos were morphologically similar to those from the non-infected uterine horns. Electron microscopic examination of the degenerated embryos from the infected uterine horns demonstrated the presence of a structure which morphologically resembled the BVD virus. The results of this preliminary study indicate that the BVD virus within the uterine horns may interfere with normal development of preimplantation bovine embryos. Therefore, it is proposed that the BVD virus could adversely affect early stages of gestation in the cow, resulting in infertility.     

Transuterine transport of spermatozoa after artificial insemination in heifers

Eight heifers were artificially inseminated with frozen-thawed semen during heat. Semen was deposited in one of the uterine horns. The animals were slaughtered 2 h after insemination and the genital tract was flushed. Sperm concentration in the flushing fluid was estimated by haemocytometric counting.There was a considerable transport of spermatozoa from the site of semen deposition to the uterine horn and oviduct on the opposite side. Spermatozoa were recovered from all parts of the oviduct (infundibulum, ampulla and isthmus) and distal and proximal parts of the horn on the non-inseminated side. In 7 out of 8 heifers more spermatozoa were recovered from the side of the tract opposite to insemination than from the inseminated side, although the differences were small in 2 animals. No clear relationship could be seen between ovarian activity and distribution of spermatozoa.     

Assessment of a new utero-tubal junction insemination device in dairy cattle

A new artificial insemination device for semen deposition near the utero-tubal junction in cattle (Ghent device) has been developed at the Ghent University (Belgium). In this study, the effect of the new insemination device on sperm quality was evaluated. Moreover, in a field trial 4064 dairy cows were inseminated by 12 inseminators to examine the efficacy of the device under field conditions.The Ghent device is a disposable plastic catheter which can easily follow the curvature of the uterine horns and thus reach the utero-tubal junction (UTJ). After expulsion of the inseminate with 0.7 or 1.7 ml of air, 19.0% of the insemination dose remained in the insemination catheter. Sperm loss can be diminished to 9.0% of the original insemination dose when the insemination catheter is flushed with 0.1 ml of air, followed by 0.6 ml of physiological saline solution. No toxic effect of the insemination catheter on sperm quality or fertilizing capacity was found. In the field trial, sperm were inseminated in dairy cattle which were divided in three groups. The first group was inseminated in the uterine body with the conventional insemination device, the second group in the uterine body with the Ghent device, and the third group in the tip of both uterine horns with the Ghent device. Each insemination was performed with 10 x 10(6) to 15 x 10(6) frozen-thawed spermatozoa. The pregnancy rates (PRs) were significantly affected by the insemination technique (P = 0.02), by the inseminator (P = 0.01), by heifer or cow (P < 0.01), and by the insemination number (P < 0.01). Pregnancy rates obtained with the conventional insemination device (57.6%) were significantly better than those obtained with the Ghent device in the uterine body (52.7%) (P < 0.01), but did not differ significantly from those obtained after deep insemination into both uterine horns (53.8%) (P = 0.27). It can be concluded that the Ghent device is suitable for utero-tubal junction insemination of dairy cattle under field conditions. Whether the Ghent device is also suitable for insemination with lower insemination doses is at present under investigation.     

Embryo production from superovulated Holstein-Friesian dairy heifers and cows after insemination with frozen-thawed sex-sorted X spermatozoa or unsorted semen

The aim of this study was to evaluate embryo production in superovulated Holstein-Friesian dairy heifers and cows inseminated with either X-sorted spermatozoa (2 million/dose) or unsorted semen (15 million/dose). Experiment 1 at the research farm involved eight heifers, six cows and semen of one Holstein bull. All transferable embryos were diagnosed for sex. Experiment 2 included embryo collections on commercial dairy farms: X-sorted spermatozoa from three Holstein bulls were used for 59 collections on 28 farms and unsorted semen from 32 Holstein bulls were used for 179 collections on 79 farms. Superovulations were induced by eight declining doses of FSH (total of 12 ml for heifers and 19 ml for cows) starting on days 8-12 of the estrus cycle. Inseminations began 12h after the onset of estrus and were performed two to four times at 9-15 h intervals. Low-dose X-sorted inseminates were deposited into uterine horns and unsorted semen was placed into the uterine body. In Experiment 1, on average 70.3 and 75.0% of embryos recovered from heifers, and 48.4 and 100% of embryos recovered from cows were of transferable quality in X-sorted and unsorted groups, respectively. The proportion of transferable female embryos produced approximately doubled when insemination was with X-sorted spermatozoa compared to insemination with unsorted semen (heifers 96.4% versus 41.1%; cows 81.1% versus 39.8%). In Experiment 2, estimated 53.9 and 65.5% of embryos recovered from heifers, and 21.1 and 64.5% of embryos recovered from cows were of transferable quality in X-sorted and unsorted groups, respectively. Proportions of unfertilized oocytes were 21.1 and 10.6% for heifers and 56.0 and 14.4% for cows in X-sorted and unsorted groups, respectively. Consequently, cows inseminated with X-sorted spermatozoa produced significantly smaller proportions of transferable embryos (p<0.005) and significantly larger proportions of unfertilized oocytes (p<0.001) than those inseminated with unsorted semen. Proportions of quality 1 or degenerated embryos were similar for the two treatments in both heifers and cows. Within treatments, bulls did not significantly affect the proportions of transferable, unfertilized or degenerated oocytes/embryos. It was concluded that using low-dose X-sorted spermatozoa rather than normal-dose unsorted semen for the insemination of superovulated embryo donors can improve the proportion of transferable female embryos produced but this potential may not be achieved in commercial practice, particularly in cows, because of reduced fertilization rates when using low doses of X-sorted spermatozoa.     

Pregnancy rates in cattle with cryopreserved sexed sperm: effects of sperm numbers per inseminate and site of sperm deposition

In six field trials, doses between 1.0 and 6.0 x 10(6) total sexed, frozen-thawed sperm were inseminated into the uterine body or bilaterally into the uterine horns of heifers and nursing Angus cows 12 or 24h after observed estrus. Except for one comparison in one trial in which uterine body insemination was slightly superior (P<0.05) to uterine horn insemination, there was no significant (P>0.1) difference between sites of semen deposition. Additionally, except for one small study with limited numbers, there was essentially no difference in pregnancy rates in the range between 1.5 and 6 x 10(6) sexed, frozen-thawed sperm per inseminate. Pregnancy rates with smaller doses of sexed sperm averaged about 75% of controls of 20 x 10(6) total frozen-thawed, unsexed sperm. While 1.0 x 10(6) sexed, frozen-thawed sperm per insemination dose resulted in decreased pregnancy rates compared to larger doses, the lesser fertility with sexed sperm could not be compensated by increasing sperm numbers in the range of 1.5-6 x 10(6) sperm per dose. Pregnancy rates with 2 x 10(6) sexed, frozen-thawed sperm per dose were not markedly less than control pregnancy rates with 20 x 10(6) frozen-thawed unsexed sperm/dose in well-managed herds.     

Low semen dose intracornual insemination of cows at fixed time after PGF2alpha treatment or at spontaneous estrus

The numbers of spermatozoa per insemination and the site of semen deposition in the uterine horn appear to interact to influence pregnancy rate. In two experiments, the effect of a single low dose (2 x 10(6) spermatozoa) intracornual insemination (LD-ICI) on bovine pregnancy rate was compared with that of intracornual (SD-ICI) and conventional (SD-AI) inseminations of 40 x 10(6) spermatozoa. In Experiment 1, 157 cows were treated twice with PGF(2)alpha at a 14-day interval and inseminated at a fixed time (80-82 h) after the second PGF(2)alpha injection using LD-ICI (n=44), SD-ICI (n=61) or SD-AI (n=52). In LD-ICI and SD-ICI groups, semen was deposited in the horn ipsilateral to the ovulatory follicle close to the utero-tubal junction (LD-ICI-UTJ, n=33 and SD-ICI-UTJ, n=41) or in the middle part of the horn (LD-ICI-MH, n=11 and SD-ICI-MH, n=20). Pregnancy rates after LD-ICI-UTJ, LD-ICI-MH, SD-ICI-UTJ and SD-ICI-MH were 27%, 27%, 39% and 35%, respectively (P>0.05). The total pregnancy rate after LD-ICI (27%) did not differ (P>0.05) from that after SD-ICI (37%) or SD-AI (34%). In Experiment 2 (field trial), 362 cows were allotted, at spontaneous estrus, to LD-ICI-UTJ (n=86), LD-ICI-MH (n=97) or SD-AI (n=179). Pregnancy rates after LD-ICI and SD-AI were 47% and 45%, respectively (P>0.05). After LD-ICI-UTJ, the pregnancy rate (54%) did not differ significantly (P>0.05) to that obtained after LD-ICI-MH (41%) and after SD-AI (45%). The results of the study show that the single intracornual insemination of cows with 2 x 10(6) spermatozoa at fixed time, 80-82 h after the second PGF(2)alpha injection or at spontaneous estrus resulted in similar pregnancy percentage as intracornual and conventional inseminations with 40 x 10(6) spermatozoa per semen dose. With intracornual insemination using low or standard dose of spermatozoa, the pregnancy rates were not significantly affected by the exact site of semen deposition in the uterine horn, near the utero-tubal junction or in the middle part.     

Sperm distribution and fertilization after unilateral and bilateral laparoscopic artificial insemination with frozen-thawed goat semen

Generally, laparoscopic artificial insemination (LAI) provides a higher success rate than of cervical insemination in goats. However, the sperm distribution after LAI in goats remains unknown, particularly when frozen-thawed semen is used. This study evaluated the distribution of frozen-thawed goat spermatozoa after LAI and compared the effects of sperm numbers and deposition sites (unilateral and bilateral sites) on pregnancy rate. In experiment 1, the frozen-thawed spermatozoa were stained either with CellTracker Green CMFDA (CT-Green) or CellTracker Red CMPTX (CT-Red), and in vitro evaluations of viability and motility were performed. In experiment 2, the labeled spermatozoa were deposited via LAI into the left (CT-Green) and right (CT-Red) uterine horns (n = 4). After ovariohysterectomy (6 hours after insemination), the distributions of green- and red-colored spermatozoa were assessed via tissue section, flushing, and the oviductal contents were also collected. Experiment 3 was designed to test the pregnancy rates in a group of 120 does after LAI using different numbers of spermatozoa (60 and 120 × 10⁶ sperm per LAI) and different deposition sites. The results demonstrated that the fluorochromes used in this study did not impair sperm motility or viability. Frozen-thawed goat spermatozoa can migrate transuterinally after LAI, as evidenced by the observations of both CT-Green– and CT-Red–labeled spermatozoa in both uterine horns. Lower numbers of spermatozoa (60 × 10⁶) that are inseminated unilaterally (either ipsilateral or contralateral to the site of ovulation) can efficiently be used for LAI in goats (with a 56.67% pregnancy rate).     

Characterization of intrauterine mobility of the early equine conceptus

Intrauterine mobility patterns of the embryonic vesicle were characterized on Days 9 to 17 after ovulation in pony mares using real-time ultrasonography (n=5 or 7 mares per day). The location of the vesicle was determined by dividing the uterus into right horn, left horn, and body. Each uterine horn was further divided into three approximately equal portions (cranial third, middle third, caudal third), yielding seven segments (body plus three portions of each horn). Location of the vesicle within the uterus was recorded every five minutes for two consecutive hours (25 location determinations per trial). The number of times the vesicle was found in the uterine body versus one of the uterine horns was greater for the body on Day 9 (15.2 vs 9.8; not significant) and Day 10 (17.3 vs 7.7 P<0.05) and greater (P<0.05) for the horns on Days 12 (7.3 vs 17.7) through 17 (0.0 vs 25.0). Averaged over all days, when the vesicle was in one of the uterine horns it was present 56% of the time in the caudal third, 30% of the time in the middle third, and 14% of the time in the cranial third. Mobility was determined by the number of times the vesicle changed locations during successive examinations. On Day 9, the mean number of location changes per trial was minimal (horn to horn, 0.2; body to horn or vice versa, 1.8; between two segments, 4.2). The extent of mobility increased on Day 10 and reached an apparent plateau from Day 11 to Day 14. The mean number of location changes per trial during the plateau was as follows: horn to horn, 1.6; body to horn or vice versa, 5.6; between two segments, 10.7. Fixation (cessation of mobility) occurred in one of the horns in 5 7 mares on Day 15 and in 7 7 mares by Day 16. Mobility was present on the earliest day the embryonic vesicle was detected (Day 9), but Days 11 to 14 were characterized as the days of maximum mobility.     

Effect of intrauterine treatment with prostaglandin E2 prior to insemination of mares in the uterine horn or body

Two trials were conducted to investigate the effects of intrauterine infusion of PGE2 and uterine horn insemination on pregnancy rates in mares achieved by breeding with a suboptimal number of normal spermatozoa. Estrus was synchronized and mares were teased daily with a stallion to detect estrus. Mares in estrus were examined by transrectal palpation and ultrasonography to monitor follicular status. On the first day a 35-mm diameter follicle was present, hCG (1500 IU, iv) was administered and the mares were bred the next day. Mares (Trial 1, n = 34; Trial 2, n = 28) were inseminated with 25 million total spermatozoa from either a stallion with good semen quality (Trial 1) or poor semen quality (Trial 2). In each trial, mares were assigned to 1 of 4 treatment groups as follows: Group PGE-HI - infusion of 0.25 mg PGE2 into the proximal end of the uterine horn ipsilateral to the dominant follicle 2 h prior to insemination in the proximal end of the same uterine horn; Group PGE-BI - infusion of 0.25 mg PGE2 into the proximal end of the uterine horn ipsilateral to the dominant follicle 2 h prior to insemination in the uterine body; Group SAL-HI - infusion of 1 mL sterile saline into the proximal end of the uterine horn ipsilateral to the dominant follicle 2 h prior to insemination in the proximal end of the same uterine horn; or Group SAL-BI - infusion of 1 mL sterile saline into the proximal end of the uterine horn ipsilateral to the dominant follicle 2 h prior to insemination in the uterine body. After breeding, mares were examined daily by transrectal ultrasonography to confirm ovulation, and were re-examined 14 to 16 d after ovulation for pregnancy status. Data were analyzed by Chi-square. Overall pregnancy rates were 59% for stallion 1 and 29% for stallion 2. Group pregnancy rates did not differ for mares bred by either stallion (P > 0.10). Pregnancy rates were not altered by horn insemination for either stallion (P > 0.10). Intrauterine infusion of PGE2 improved pregnancy rate in mares bred by the stallion with good quality semen (P < 0.05), but did not alter pregnancy rate in mares bred by the stallion with poor quality semen (P > 0.10). Further research is warranted to determine if intrauterine infusion of PGE2 will enhance spermatozoal colonization of the oviduct and pregnancy rates in mares, and if PGE-treatment will improve pregnancy rates achieved by subfertile stallions.     

Triplex Doppler evaluation of uterine arteries in cyclic and pregnant domestic cats

The aims were to determine resistance index (RI) and pulsatility index (PI) in the uterine arteries of cyclic and pregnant domestic cats comparing the left and right uterine horns, as well as the majority or minority uterine horns, based on fetus number per horn; to determine the presence or absence of an early diastolic notch (EDN) in the uterine artery of pregnant queens. Ten domestic cats were followed during one cycle and one pregnancy until 63rd days after mating. The estrous cycle length was 16 ± 9.57 days. The uterine horn with the highest number of fetuses (majority uterine horn - MUH) presented 2.0 ± 1.0 fetus and the lower (minority uterine horn - miUH) presentes 0.78 ± 0.67 fetus. There were no differences in indexes between uterine arteries during the cycles and pregnancies. The RI and PI of MUH were lower than miUH (P<0.05). Uterine artery of the MUH presented lower indexes than miUH during the acceptance period (P<0.05). On D14 of pregnancy, uterine artery presented reductions in both indexes for the miUH. On D56, the PI was reduced in the miUH. The indexes depended on the week of pregnancy. EDN was present on the uterine arteries of all cats until D35, but disappeared by D49. The blood flow varied according to the category of horn.     

Fertilized and unfertilized ova are transported at different rates by the hamster oviduct

To determine if the egg provides any clues for the regulation of ovum transport in the hamster, oocyte and embryo transport were compared. On the evening preceding ovulation, the animals were randomly assigned to one of five groups. They were caged overnight with a male of proven fertility (Group 1) or they were isolated (Group 2). Other females were artificially inseminated in both uterine horns at 2200 h either with fertile epididymal spermatozoa (Group 3), spermatozoa rendered infertile by freezing and thawing (Group 4), or with fertile spermatozoa in one uterine horn and infertile spermatozoa in the contralateral horn (Group 5). The number, condition, and distribution of ova in the genital tract were assessed at various intervals during the next 4 days. The rate of fertilization and normal development in females or sides inseminated with fertile or infertile spermatozoa was over 90% and 0% respectively. Embryos in Groups 1 and 3 reached the uterus 1 day earlier than unfertilized oocytes in Groups 2 and 4. In group 5, the transport of embryos resulting from insemination with fertile spermatozoa followed a pattern similar to those in Groups 1 and 3; the oocytes in the contralateral tract resembled those of Groups 2 and 4. The different transport rates of embryos and oocytes were not associated with the reproductive state of the female but with the condition of the ova. Moreover, the different transport rates were observed in animals transporting the two types of eggs simultaneously on different sides indicating that there is a local recognition of some unidentified factor unequally present in fertilized and unfertilized eggs.     

Fertility of weaned sows after deep intrauterine insemination with a reduced number of frozen-thawed spermatozoa

The present study evaluates the effectiveness of the transcervical deep intrauterine insemination (DUI) with a reduced number of frozen-thawed boar spermatozoa in weaned sows. DUI was performed using a specially designed flexible device (length 180 cm, outer diameter 4mm, working channel 1.8mm, working channel's volume 1.5 ml) that was inserted through an artificial insemination spirette to cross the cervix lumen and moved into one uterine horn as far as possible. Spermatozoa diluted in 7.5 ml of BTS were flushed into the uterine horn by a syringe attached to the working channel. In Experiment 1, 111 hormonally treated (eCG/hCG) weaned sows were inseminated once using one of the following three regimens: (1) DUI with frozen-thawed spermatozoa (1000 x 10(6) cells per dose; n=49); (2) DUI with fresh semen (150 x 10(6) cells per dose; n=29, as control of DUI procedure); and (3) cervical insemination with frozen-thawed spermatozoa (6000 x 10(6) cells diluted in 100ml; n=33). No differences (P>0.05) were found for farrowing rates (77.55, 82.76, and 75.76, respectively) or litter sizes (9.31+/-0.41, 9.96+/-0.32, and 9.60+/-0.53 piglets born per litter, respectively) among the groups. In Experiment 2, DUI was performed on the spontaneous estrus in weaned sows (2-6 parity) with 1000 x 10(6) frozen-thawed (40 sows) or 150 x 10(6) fresh spermatozoa (38 sows). The farrowing rate of sows inseminated twice with frozen-thawed spermatozoa (70%) was significantly (P<0.05) lower than with fresh semen (84.21%). No significant difference (P>0.05) was found in litter size between frozen-thawed spermatozoa (9.25+/-0.23 piglets born per litter) and fresh semen (9.88+/-0.21 piglets born per litter). These preliminary results indicate that application of DUI provides acceptable fertility in weaned sows using a relatively low number of frozen-thawed spermatozoa.     

Transuterine sperm transport is not affected by bilateral asymmetry of the reproductive system in dairy cows

Effects of right versus left side activities of the reproductive organs on sperm transport after deep cornual insemination were evaluated in 1686 Friesian cows in their first lactational period. Only single ovulating animals were used. At insemination, semen was deposited deep into the uterine horn ipsilateral or contralateral to the preovulatory follicle. Pregnancy rates were used as measurement of the success of sperm transport. The reproductive history of each cow included that of the side of the previous gestation. A higher activity of the right versus left side was registered. Following calving and after uterine involution, activities of the right versus left side reproductive organs remained constant independently of the side of previous pregnancy, and did not affect transuterine sperm transport. The data indicate that after uterine involution sperm transport is not affected by bilateral asymmetry of the reproductive system in cattle.