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.     

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 side of insemination on transuterine transport of spermatozoa in superovulated dairy cattle

Eleven superovulating Friesian lactating cows were inseminated deep into one uterine horn with one unit of frozen semen, containing 2.5 million total spermatozoa, with more than 40% postthaw progressive motility and with 14% morphologically abnormal spermatozoa. Semen was deposited into the right or left uterine horns of alternate cows. There was no difference in the proportions of fertilized recovered ova from ipsilateral horns between right and left inseminations (P>0.05). The fertilization rate in the contralateral horns was higher (P<0.01) for right uterine horn insemination (50%) than for left uterine horn insemination (15.6%).     

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.     

Effect on pregnancy rate of nonestrus insemination in previously inseminated dairy cows

Lactating dairy cows (n = 157) designated for slaughter under the 1986 U.S. Dairy Termination Program were utilized in two trials to determine the effects of a second insemination on fertility. Cows that had been previously inseminated at estrus were inseminated again at 12-24 d later, when not in estrus. Cows that were reinseminated into the uterine body had significantly lower pregnancy rates (4% vs 40.6% for controls). Differences in pregnancy rates when the reinsemination was performed in the mid-cervical region were not significant (34.8% vs 50% for controls). Based upon these studies, intrauterine insemination of cows displaying questionable signs of estrus should be avoided in previously inseminated cows.     

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.     

The accuracy of enzyme-linked immunosorbent assay and latex agglutination progesterone test for the validation of estrus and early pregnancy diagnosis in dairy cattle

The accuracy of the enzyme-linked immunosorbent assay (ELISA) and the latex agglutination (LA) on-farm progesterone kit for detecting estrus and diagnosing early pregnancy was investigated in this study. Italian Friesian dairy cows (n=82) from 6 dairy herds were used for the collection of foremilk samples at the time of breeding and at 19, 21, and 23 days post insemination. Pregnancy status was ascertained by uterine palpation per rectum 40 to 60 days post insemination. Progesterone levels were affected by herd, percentage of milk fat, and the day of testing x diagnosis interaction. Validation of estrus by qualitative on-farm tests was 74.6% (LA) and 100.0% (ELISA) accurate using 0.5 ng/ml of progesterone as the RIA estimate for estrus. The accuracy rate for early pregnancy diagnosis by RIA was 68.4 to 83.8% for day 19 and day 21, respectively, while the detection rate for nonpregnancy was 84.6 to 100% on day 19 and day 21, respectively, as compared with uterine palpation per rectum. The average accuracy rate for early pregnancy diagnosis ranged from 84.7 to 92.3% for the LA and ELISA tests, respectively; the nonpregnancy rate was correctly predicted 93.9% to 68.2% for the LA and ELISA tests, respectively.     

Milk progesterone measurement in dairy cows: Correlation with estrus and pregnancy determination

Progesterone levels in fore milk, determined by a highly specific radioimmunoassay, were compared for the assessment of estrus by a veteran herdsman and an experienced inseminator, in cows presented for insemination. In addition, an examination was made of the relative accuracy of using milk progesterone levels for the determination of pregnancy at 24, 40 and 44 days after insemination, as compared with rectal palpation at 45–50 days post-breeding.Fat-free fore milk progesterone levels were similar to jugular plasma levels at 24 days post-insemination and reached roughly 60% of the level of unextracted fore milk at this time. Accuracy of estrus diagnosis by herdsman, inseminator and milk progesterone level was 84%, 93% and 96%, respectively. For pregnancy diagnosis, milk progesterone determination in 85 cows showed 78% accuracy in predicting pregnancy and 100% accuracy in predicting non-pregnancy. At 40 days post-insemination false positives dropped to 10% and at 44 days only 7% of the cows were incorrectly diagnosed as pregnant. The false positives in this study were largely due to embryonic mortality as reflected by abnormal intervals of return to estrus. Two milk progesterone determinations, at 24 and either 40 or 44 days post-insemination ensure maximum reliability for early pregnancy diagnosis.     

Effects of Alfaprostol and uterine palpation on postpartum interval and pregnancy rate to embryo transfer in Brahman influenced beef cows

Two trials were conducted to determine the effects of Alfaprostol, a prostaglandin F2 alpha analogue, and uterine palpation on reproductive performance in postpartum beef cows. In Trial J, 143 multiparous and 132 primiparous Brahman crossbred embryo recipient cows were assigned to receive one 5 mg injection of Alfaprostol between 29 and 65 d postpartum or to serve as controls. Alfaprostol treatment between 29 and 42 d postpartum decreased (P < 0.05) postpartum interval in multiparous but not primiparous cows. Alfaprostol treatment increased pregnancy rate to embryo transfer. Trial II utilized 369 multiparous Brangus cows, 17 to 49 d postpartum, that were assigned to one of three groups: 1) Alfaprostol plus uterine palpation (APP), 2) Uterine palpation only (UP) or 3) Control. Completion of uterine involution was determined at treatment. Alfaprostol plus uterine palpation decreased postpartum interval regardless of uterine involution, while UP had a greater effect if uterine involution was not complete. Both APP and UP increased the number of cows which were detected in estrus by 80 d postpartum. Alfaprostol and uterine palpation, alone or in combination, can increase postpartum reproductive performance in Brahman crossbred and Brangus beef cows.     

Intraperitoneal insemination in repeat-breeder cows: a preliminary report

Intraperitoneal insemination of 62 repeat-breeder dairy cows resulted in 9 pregnancies. The pregnancy rate was not different for intraperitoneal or uterine inseminations. In nonpregnant cows, reproductive variables such as the percentage of cows returning to estrus, the average interval from insemination to the next estrus, and the pregnancy rate following subsequent uterine insemination were not influenced by intraperitoneal insemination. Our results suggest that intraperitoneal insemination could be an alternative procedure to the usual deposition of semen into the uterus in repeat breeder cows.     

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.     

Does intrauterine site of insemination in cattle really matter?

Two trials were conducted to determine the influence of semen placement on pregnancy rate in dairy heifers and cows. Seventy-two dairy heifers were artificially inseminated (AI) 10 to 12 h after the first detection of estrus. Control heifers (n = 25) were inseminated at the junction of the uterine body and internal cervical os. The remaining heifers were inseminated deep in one uterine horn, 3 to 5 cm anterior to the external bifurcation. Twenty-three heifers were inseminated in the horn ipsilateral to the ovary bearing the ovulatory follicle, and 24 heifers were inseminated in the contralateral horn. Pregnancy rates did not differ for the three groups of heifers. In a second trial, 64 inseminations were performed in 38 nonlactating, adult dairy cattle. Thirty-one inseminations were made deep in the uterine horn ipsilateral to the ovary bearing the ovulatory follicle and 33 in the contralateral horn. Pregnancy rates were similar for both groups. Combining both trials, pregnancy rates for ipsilateral and contralateral inseminations were equal (32 54 = 59% and 34 57 = 60% , respectively). Therefore, placement of semen in one horn of the uterus does not appear to be a cause of decreased or increased pregnancy rate with AI.     

Pregnancy percentage following deposition of sex-sorted sperm at different sites within the uterus in estrus-synchronized heifers

Our objective was to assess the effect on heifer pregnancy rate of deposition at three sites within the uterus of frozen-thawed sex-sorted sperm at a fixed time after estrus synchronization. Estrus was synchronized in 209 heifers by administration of PGF2a 14 days apart. At 80-82 h after the second PGF2a injection, X-chromosomes bearing fractions of semen with 2.2 x 10(6) sperm in insemination dose were used for single insemination into the uterine body (UB-AI, n=91) or for intracornual deposition in the middle of the uterine horn (MH-AI, n=57) or close to the utero-tubal junction (UTJ-AI, n=61). The overall pregnancy rate was 43.1%. Pregnancy rates did not differ (P>0.05) among sites of sperm sperm deposition, between the two farms at which the heifers were kept or between the two bulls producing the semen. Within UB-AI, MH-AI and UTJ-AI treatments, pregnancy rates were 41.8%, 49.1% and 39.3%, respectively (P>0.05). Pooled across classes for deposition site, pregnancy rate was 25.1% higher (P<0.01) for heifers showing strong signs of estrus than for heifers showing weak signs of estrus (45.9 versus 20.8%, respectively). Embryonic and fetal loss from diagnosis of pregnancy to term and at calving equalled 5.6%. Of 88 calves of identified sex, 93.2% were female. In conclusion, pregnancy rates of heifers did not differ significantly following deposition of 2.2 x 10(6) sex-sorted sperm 80-82 h after the second PGF2a injection near the utero-tubal junction, in the middle of the horn or into the uterine body.     

Descriptive epidemiology of anestrus in Michigan Holstein-Friesian cattle

Twenty-two Michigan Holstein-Friesian herds were studied to determine the incidence and epidemiology of anestrus. In 3,309 lactations studied, 42% were classified as having exhibited preservice anestrus (no estrus detected by 70 d after calving). Organic reasons (pyometra, cystic follicles, static ovaries) were identified by palpation per rectum for 237 (23%) of the cows with preservice anestrus that were examined by a veterinarian. Postservice anestrus, defined as failure to show estrus within 35 d after an unsuccessful insemination, was identified in 790 (47%) of 1,691 lactations. Veterinary examination identified 104 (20%) of postservice anestrous cows as having this condition because of organic causes. The average cow with preservice anestrus had an increase of 30 d open compared to her herdmates, and the average cow with postservice anestrus had an increase of 37 d open. Anestrous cows produced more milk than their unaffected herdmates in both the current and the previous lactation. Analysis of composite lactation curves indicates that, for preservice anestrus, this additional milk production was obtained gradually over the entire lactation. Anestrous cows were culled at a significantly higher rate than their herdmates. Cows with preservice anestrus were more likely to have begun their lactation in the spring months.     

Effect of repeated administration of PGF2alpha in the early post partum period on the prevalence of clinical endometritis and probability of pregnancy at first insemination in lactating dairy cows

Two experiments were performed to determine the effects of repeated administration of PGF2alpha in the immediate post partum period on the prevalence of clinical endometritis at 22 and 58 days post partum, and the probability of pregnancy at first insemination, in post partum dairy cows. In Experiment 1, 228 cows on day 7 post partum were used. Cows in Group 1 (n = 114) were treated twice with PGF2alpha (25 mg, im) 8 h apart on days 7 and 14 post partum, and only once on days 22 and 35 post partum. Cows in Group 2 (n = 114) served as untreated controls. Vaginoscopy and transrectal palpation of the genital tract were done on days 22 and 58 post partum. Cows in both groups were inseminated at estrus after a voluntary waiting period of 100 days. Pregnancy was determined by transrectal palpation between 45 and 50 days after insemination. Repeated administration of PGF2alpha in the immediate post partum period did not reduce the prevalence of clinical endometritis on days 22 or 58 post partum (65 versus 62% on day 22 and 28.3 versus 35.2% on day 58 in Groups 1 and 2, respectively). There was no significant difference in the probability of pregnancy at first insemination between cows in both groups. In Experiment 2, 418 cows on day 7 post partum were used. Cows in Group 1 (n = 209) were treated twice with PGF2alpha (25 mg, im) 8h apart on days 7 and 14 post partum, and only once on days 22 and 35 post partum. Cows in Group 2 (n = 209) served as untreated controls. Cows in both groups were subjected to the Presynch and Ovsynch protocols on days 49 and 75 post partum, respectively. Pregnancy was determined by transrectal ultrasonography between days 29 and 32 after timed insemination. There was no significant difference in the probability of pregnancy at first insemination between cows in both groups. In conclusion, repeated administration of PGF2alpha to cows in this herd had no effect on the prevalence of clinical endometritis at 22 and 58 days post partum, and that there was no effect on the probability of pregnancy after insemination at estrus among cows with a voluntary waiting period of > 100 days, or at timed AI at 85 days in milk when Presynch was employed.     

The development and marketing of estrus synchronization in cattle in Australia using prostaglandins

Estrus synchronization using prostaglandins was applied to a well-developed system of AI in beef cattle. Cows and heifers were selected to be free from infectious disease. Cows were run at pasture in a single group and estrus was detected visually twice a day without the use of any aids. Estrous cows were removed from the group each morning. Cows detected in estrus in the morning were inseminated that afternoon and cows detected in the afternoon were inseminated the next morning. The AI program ran for 25 to 42 days and was evaluated by rectal pregnancy palpation about 42 days after the last insemination. Calves were produced at an average cost of $26. The only management systems of synchronization using prostaglandins that could match this cost was the 10 day program with one treatment of 10 or 12.5 mg prostaglandin F2α on day 5. Management systems using two treatments of PGF2α, 12 days apart, increased calf costs to $160, $100, and $45, respectively, with two or one timed insemination or insemination after detection of estrus.The most significant efficiency factor was the ratio of the number of cows inseminated to the number of cows put into the AI program and this ratio was statistically the same in normal AI (72%) and AI with synchronization and detection of estrus (74%). About half of the cattle not inseminated had ovarian activity, palpable follicles or corpora lutea but had not yet come into estrus. Pregnancy rates per insemination and the number of cows pregnant per 100 cows in an AI program were the same but the labor input was reduced by synchronization.Responses to prostaglandin F2α treatment were the same over the range of dose rates from 8 to 20 mg. The 10 day AI program with a single treatment of 10 or 12.5 mg PGF2α has been used commercially in Australia for 6 years with other management systems being tailored to particular needs.     

The effect of a progesterone releasing intravaginal device (PRID) on pregnancy risk to fixed-time insemination following diagnosis of non-pregnancy in dairy cows

The objective was to compare the probability of pregnancy after fixed-time insemination in cows diagnosed as non-pregnant and re-inseminated following the Ovsynch protocol, with or without exogenous progesterone. Cows (n=415) used in this study originated from 25 farms. Upon diagnosis of non-pregnancy between 30 and 60 days after AI, cows were randomly assigned to receive either a progesterone releasing intravaginal device (PRID; n=208) or a placebo intravaginal device (PID; n=207). All cows received GnRH at enrollment (Day 0), PGF(2alpha) concurrent with intravaginal device removal 7 days later, GnRH on Day 9 and fixed-time insemination 16h later (Day 10). Cows observed in estrus prior to Day 7, had the device removed and were inseminated. Ovaries were examined by transrectal palpation at the time of enrollment and the prominent structures were assessed and recorded. Body condition score, lameness status, interval from previous insemination, and times bred at enrollment were recorded. At intravaginal device removal, the occurrence and intensity of vaginitis was determined according to the amount of debris on the device. Overall, the intravaginal device retention rate was 91%. A total of 5.2% of PID-treated cows and 2.9% of PRID-treated cows were detected in estrus within the 7 days treatment period. Pregnancy status was diagnosed between 30 and 56 days after insemination and all cows were followed for a minimum of 150 days after enrollment. Approximately 28% of cows had evidence of mild vaginitis in response to the intravaginal device, whereas 6% of cows had copious debris associated with the intravaginal device at removal. The probability of pregnancy after fixed-time insemination was 43.8% versus 34.9% in PRID-treated versus PID-treated animals. Exogenous progesterone provided through an intravaginal device to non-pregnant cows that had not displayed estrus improved the probability of pregnancy after fixed-time AI.     

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)     

Location and status of embryos in the genital tract of superovulated cows 4 to 6 days after insemination

Sixty lactating Holstein cows were treated, in 3 groups, with Folltropin and Estrumate to induce superovulation and then bred by artificial insemination (AI). Embryos were collected at slaughter on D 4, 5 or 6 after insemination by flushing separately the oviducts, uterine tip and the remainder of the uterine horn. The embryos and ova recovered accounted for 64.6 ± 4.3% of the ovulations, and there were no differences due to day, side or group. On D 4, 60% of the embryos were found in the oviducts; on Days 5 and 6, 80 and 91%, respectively, were found in the tip of the uterine horn. Viability was independent of the site of recovery; over 91% of the embryos grew and developed in culture for at least 3 d.     

Transvaginal transplantation of an extra egg to obtain twinning in cattle

An attempt was made to produce twin pregnancies by adding one ovum to the uterus of 17 cows presumed pregnant from insemination 5 to 10 days earlier. The ovum was placed in the uterine horn contralateral to the corpus luteum. All transferred eggs were'transported approximately 50 kilometers and were exposed to ambient temperature during the process of inovulation. Twin pregnancies occurred in 3 of 8 recipients having a naturally-occurring estrus. The ambient temperature was between 9° and 23°C, and the eggs were 6.5 to 8 days old. No pregnancies resulted in 9 cows brought into heat with prostaglandin. In this case the ambient temperature was 5–6°C and the eggs were 6 days old.