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1.
Daily changes in the plasma progesterone concentrations were determined in eight mares treated with intramuscular injections of 250 μg cloprostenol, a prostaglandin analogue, followed five days later by 2500 I.U. human chorionic gonadotropin. A second cloprostenol injection was given 14 days after the first; the mares were then inseminated on the third and fifth day of the subsequent estrus and a second injection of human chorionic gonadotropin was administered on the fifth day. The onset of estrus following the second cloprostenol treatment was synchronized beginning three to four days after treatment in all eight mares. All eight ovulated, five mares conceived and only four foaled. Evaluation of the progesterone profiles provided reliable indicators of luteolysis, ovulation and luteal function. Decreasing plasma progesterone concentrations were associated with cloprostenol induced luteolysis or preceded spontaneous onset of estrus. The plasma progesterone concentrations increased consistently after ovulation, and in the pregnant mares, the progesterone concentrations remained high during the first month after insemination.  相似文献   

2.
In a large herd 427 cows were examined for reproductive condition 26 to 34 days after calving. Progesterone profiles were obtained from a total of over 5000 milk samples which were taken twice weekly for 4 weeks, starting at the time of examination, and again 21, 23, and 25 days later. Researchers lived on the farm during the experiment to sample cows and record all data. Electronic probe measurements of cervical-vaginal mucus also were obtained. All cows were inseminated artificially with frozen semen from one organization. Eleven percent of the cows were not inseminated in the estrual phase as determined by substantial concentrations of progesterone in milk (MP), and 2% were pregnant and aborted following insemination. The MP 23 to 25 days after insemination essentially was 100% accurate in predicting nonpregnancy and was preferable to day 21. When used in conjunction with MP on the day of insemination pregnancy prediction 23 to 25 days after insemination was 84% accurate. Non-return rate 60 days after insemination was 7% higher than palpated pregnancy rate. The use of electronic probes under large herd conditions was labor intensive and did not give repeatably distinctive values at estrus.  相似文献   

3.
An experiment was conducted to determine if concentrations of luteinising hormone or progesterone were different in pregnant or non-pregnant heifers for seven days before and 20 days after a successful or non-successful insemination. Heifers with an oestrous cycle length of 18 to 24 days only were used and they were bled at 08.00, 16.00 and 24.00 each day for seven days before and for 20 days after insemination with thawed semen (treatment 1) or semen diluent (treatment 2). Animals allocated to treatment 3 had the embryo nonsurgically flushed from the uterus at days 10 to 12 while animals allocated to treatment 4 were inseminated with semen diluent and then had a viable embryo transferred to the uterus between days 10 and 12. All animals were slaughtered between 19 and 21 days after insemination and pregnancy rate determined. There were no differences in basal luteinising hormone levels between treatments. Blood concentrations of progesterone were not different before insemination and for 16 days after insemination for pregnant (11 out of 15) and non-pregnant heifers (14) allocated to treatments 1 and 2. Between days 17 and 20, progesterone concentrations declined in non-pregnant heifers. Transfer of an embryo to non-pregnant heifers on day 10 to 12, did not affect progesterone concentrations, but non-surgical flushing of the embryo caused a decline in blood concentrations of progesterone. It was concluded that basal blood concentrations of luteinising hormone and progesterone, in samples taken three times daily were not different in pregnant or non-pregnant heifers before and for 16 days after insemination.  相似文献   

4.
Abstract

The variation in progesterone secretion during the luteal phase and pregnancy in blue fox vixens was analyzed. Progesterone was measured in blood plasma once or twice a week using radioimmunoassay. The material was allocated into three groups; five mated, but barren, blue fox vixens, six mated vixens with implantation zonès in the uterus, but no cubs at parturition, and 26 normally parturient vixens. The progesterone profiles for the three different groups of females showed a steady increase in progesterone immediately after mating. Maximum values were observed on days 8–12 of pregnancy. Then the progesterone levels decreased gradually until delivery around day 52. The levels of progesterone were found to be significantly different (P<0.05) between non-pregnant and pregnant females from day 22 after mating. The plasma progesterone level seems to be affected by the presence of conceptuses.  相似文献   

5.
To examine the efficiency of retrograde sperm transport following intraperitoneal insemination, live and dead spermatozoa were used at different concentrations, and sperm recovery from cervical mucus (0.5 ml) 2, 6, 12 and 24 h following insemination was evaluated. Forty lactating Friesian cows, in their second to fourth lactation period, were used in this experiment. Thirty-six cows received intraperitoneally either live or dead spermatozoa. Each group of six cows received one of three total sperm numbers of 30, 45 and 90 million. Four cows were inseminated with 90 million spermatozoa into the uterus and served as a control group. All cows were inseminated towards the end of oestrus. After intrauterine insemination sperm recovery declined, but motile and/or immotile spermatozoa were recovered from all cows at any time. In cows inseminated intraperitoneally, sperm was recovered from the cervix at 6-24 h when 90 million were inseminated. A greater number of spermatozoa was recovered after dead rather than after live sperm inseminations. Only immotile, intact or broken spermatozoa and tail-less heads were recovered after intraperitioneal insemination using either live or dead spermatozoa. No sperm was recovered for 30 and 45 million inseminations. Our results show that, following intraperitoneal insemination, there is passive sperm transport from the peritoneal cavity to the genital tract close to the time of ovulation, and suggest a higher sperm retention in the genital tract when live as opposed to dead spermatozoa are used.  相似文献   

6.
The results of early pregnancy diagnosis using a milk progesterone assay and a measurement of electrical resistance of the vaginal mucosa made on 135 dairy cows in two herds are compared. The tests were carried out on the day of insemination and 21 days later. Ninety-eight cows were diagnosed as pregnant by both tests. Of these, 92 calved and there were 6 cases of suspected embryonic mortality. Thirty animals were diagnosed as non-pregnant by both tests and none calved. One cow, diagnosed as non-pregnant by the vaginal electrical resistance method, calved later. Of the remaining 6 cows, 4 had extended postparturition anoestrus, one had cystic ovarian disease and another had a long oestrus cycle.The results of this study suggest that measurements of the electrical resistance of the vaginal mucosa in dairy cows may have a part to play in on-farm pregnancy diagnosis.  相似文献   

7.
A pilot experiment with heifer heat synchronization with chlorsuperlutin-soked intravaginal tampons was conducted with 254 heifers in six herds in the North Moravian region. The rubber-foam tampons, cylindrical in shape (diameter 70 mm, height 70-90 mm), were introduced into the cranial part of the vagina, using an applicator and a vaginal speculum. Sixteen days after introduction, the tampons were removed by pulling the silon thread with which the tampons were cross-stitched. The heifers were inseminated on the second to fifth day after the removal of the tampons. The average performance in the application of the tampons was 38.5 tampons per hour, and in their removal 20.7 tampons per hour. The retention rate of the tampons was 97.6%; out of this, 79.8% of the tampons were pulled out by the silon thread. The signs of heat were good, 87.9% of the heifers could be inseminated intrauterinally. All the heifers with retained tampons were inseminated. The conception rate after the first insemination was 32.7%, after the second insemination 56.4%, and after two inseminations 68.1%. Out of the synchronized heifers, 8.1% were culled for slaughter. The drawbacks of this treatment include the low conception rate of the synchronized heifers, a high requirement for repeated insemination in the synchronized oestrus, and, consequently, a high sperm consumption.  相似文献   

8.
Investigations were performed to determine the exact susceptibility of foxes to Clostridium botulinum type C and E toxins.Doses of 5 mill. MLD type C toxin mixed with the feed did not cause symptoms of botulism in either cubs or adult foxes. Subcutaneous injections of 300,100(0 MLD or more were fatal to cubs, while 750,000 MLD caused the death of all adults.Regarding type E toxin, doses of 1 mill. MLD affected neither cubs nor adults on oral administration. Subcutaneously injected doses of 5,000 MLD or more killed all cubs, while 10,000 MLD was required to produce lethal effect on adult animals.The conclusion made is that foxes are highly resistant to both type C and E Clostridium botulinum toxins following oral application. It is further revealed that foxes are 60–70 times more susceptible to type E than to type C toxin when injected subcutaneously.  相似文献   

9.
The aim of present study was to study the effect of post-ovulatory insemination on the subsequent embryonic loss, oestrous cycle length and vaginal discharge in sows. Ten Large White multiparous sows were divided into two groups. Group A sows were inseminated once at 15 h after ovulation. Thereafter, they were ovariohysterectomized on day 11 (n = 5, first day of standing oestrus = day 1) and flushed for recovery of embryos. Group B sows were also inseminated once at 15 h after ovulation. They were further observed for return to oestrus and vaginal discharge (n = 5) after insemination. The endometrium tissues were biopsied from sows with vaginal discharge, embedded with paraffin, stained with haematoxylin and eosin and examined under light microscope. Only two embryos were observed in one of four sows from group A. All embryos had a spherical shape but differed in size (range 1-2 mm). In group B, only one sow had a regular return to oestrus (i.e. on day 23) and another sow had an irregular return to oestrus (i.e. on day 27). The other two sows in this group had shown vaginal discharge on days 20 and 38 after standing oestrus. For the number of leucocytes in the endometrium of sows with vaginal discharge, a large number of lymphocytes and plasma cells were observed in the connective tissue of the subepithelial layer. In conclusion, post-ovulatory insemination resulted in early embryonic loss, a subsequent prolonged oestrus interval and also vaginal discharge (i.e. endometritis) in sows.  相似文献   

10.
The aims of this study were to assess the precision of the estimates of the time of ovulation derived by various methods, and to define the most appropriate methods for the determination of the optimal time for insemination of bitches with fresh semen (artificial insemination or natural mating), or with frozen-thawed semen. In 11 Labrador bitches, ovulation was estimated (plasma LH surge + 48 h) to occur 9 to 20 d after the start of the cycle, 0 to +4 d after the onset of positive postural reflexes (2 bitches showed no positive postural reflexes), -4 to +7 d after reaching a vaginal cytological eosinophilic index (EI) of 100%, over a range of 2.5 to 5.5 d based on plasma progesterone concentrations of 4 to 10 ng/ml, over a range of 2 to 3 or 4 d based on 2 indirect methods of estimating the time of the plasma LH surge from plasma progesterone concentrations. Assuming fertilisation occurs 2 to 3 d after ovulation, these findings indicate that for fresh semen (with an estimated lifespan of greater than 4 days) an appropriate procedure would be to inseminate/mate on the day after the onset of positive postural reflexes; then 3 days later. For bitches not showing positive postural reflexes, insemination should occur when the vaginal EI = 90% and then each 3 d until day 1 of dioestrus (D1). For frozen-thawed semen (with a lifespan of less than 24 h) insemination should occur 4 to 5 d after the plasma LH surge.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

11.
Progesterone concentrations have been measured in defatted milk of British Friesian cows of four herds during the oestrus cycles (other than short cycles) immediately before artificial insemination (AI) at oestrus and immediately after AI (in non-pregnant cows), and during early pregnancy. Differences in mean progesterone concentrations between herds were significant (P less than 0.05) on all days within the day 10-18 period after AI, both in pregnant and in non-pregnant, inseminated cows but were not significant between pregnant and non-pregnant cows within herds until day 17 or 18. It is concluded that up to this time (that of luteolysis in non-pregnant cows) undefined factors, variable among herds, can have a much greater influence on the rate of progesterone secretion by corpora lutea and consequent progesterone concentration in plasma and milk than does the presence of conceptuses. Maximum mean progesterone concentration reached during early pregnancy in two herds did not differ significantly; it was reached in the 11-15-day period in one herd but not until 46-50 days in the second. Mean progesterone concentration declined after day 90.  相似文献   

12.
Ten Hereford x Friesian cows each received 1 mg fenprostalene by a single subcutaneous injection between days 5 and 16 of their ovarian cycles and the treatment was repeated 17 days later. The cows' ovarian cycles were monitored by daily plasma progesterone measurements, and the electrical resistance of their vaginal mucosae was also measured daily, with a Wallsmeta. Luteolysis occurred after 13 of the 20 injections of fenprostalene, and vaginal resistance measurements corresponded to changes in progesterone concentrations in 14 of the 20 potential luteolytic periods. Vaginal resistance measurements decreased in three cases where progesterone concentrations did not decrease (false positive results) and failed to decrease in three cases where progesterone concentrations did decrease (false negative results).  相似文献   

13.
Changes in the electric resistance of the vaginal mucus were monitored in a large pig herd at 4-h intervals with a heat detector (Hauptner, Federal Republic of Germany) in multiparous sows (n = 16; litter size = 11.4 +/- 2.9) that showed a positive standing test and conceived. The initial value of resistance was 74.4 +/- 7.4 ohms. In 36 h this value gradually increased to 93.6 +/- 7.6 ohms. One to 2 h after the artificial inseminations (AI) lower resistance values were obtained, though the difference was not statistically significant. In the second part of the experiment 73.9% and 82.7% of the gilts (n = 92) and multiparous sows (n = 98) conceived, respectively, with an average litter size of 9.6 +/- 2.2 and 11.0 +/- 2.7, respectively. The conception rate of animals that immediately before AI had vaginal mucus resistance values between 75 and 90 ohms was about 20% higher. The only exception were 8 multiparous sows which had an average vaginal mucus resistance of 70 +/- 4.6 ohms after the first insemination. Litter size was also the biggest in sows with vaginal mucus resistance between 75 and 90 ohms. This difference was statistically significant for the multiparous sows. The heat detector is considered to be a useful complement to conventional methods of oestrus detection.  相似文献   

14.
All gilts not detected in estrus by eight months of age and any sows not observed in estrus by 14 days post-weaning, throughout a six month period in a University research herd, were bled on Monday and Thursday and plasma progesterone was measured by a solid-phase RIA. Basal concentrations of progesterone in both samples were considered indicative of true anestrus while one or more elevated values suggested that ovarian activity was present. Progesterone was basal in both samples from 44 of 70 gilts and all of the 23 sows tested. These anestrous animals were injected with either 400 IU PMSG plus 200 IU hCG or with 500 IU hCG plus 1 mg estradiol benzoate. The two treatments were equally effective with 60% of the injected females showing estrus and being successfully inseminated within ten days after treatment. Most of the gilts with elevated progesterone concentrations in the initial samples showed estrus within the following three weeks. The rapid solid-phase assay was able to differentiate between basal and luteal-phase levels of progesterone using unextracted plasma and could be a useful diagnostic aid for veterinarians attempting to determine major reasons for anestrus in gilts and sows.  相似文献   

15.
Red foxes ( Vulpes vulpes ) are a major pest species in Europe and Australia. Traditional methods of control such as hunting or poisoning are no longer sufficient or feasible. As with domestic dogs and cats, prolactin (PRL) in the vixen is an essential luteotropin during the second half of gestation. Hence, PRL inhibitors such as cabergoline have been used to induce abortions. Eighteen mated silver fox vixens (three groups of six foxes each) were treated orally with a placebo of paraffin oil (I), or with 15  μ g/kg cabergoline in feed once (II) or twice (III), on day 30 (I and II) or days 30 and 32 (III) post-coitum. Blood samples were taken prior to and after treatments and concentrations of PRL and progesterone (P4) were determined. Normal parturitions were observed in five of six, five of six and two of six vixens in groups I, II and III, respectively. In group III plasma concentrations of PRL and P4 decreased significantly but only temporarily. This drop in hormone concentrations was more pronounced in the vixens that did not carry to term. In conclusion, doses in excess of 15  μ g/kg of cabergoline are likely to prevent the development of fetuses to term in pregnant vixens.  相似文献   

16.
Our objectives were to identify stages of the estrous cycle at which initiation of a timed artificial insemination (Ovsynch/TAI) protocol may reduce pregnancy rates and to monitor ovarian follicle dynamics and corpus luteum development after initiation of the Ovsynch/TAI protocol at different stages of the cycle. Cycling Holstein heifers (n = 24) were injected twice with prostaglandin F2alpha to induce estrus and were scanned by ovarian ultrasonography to determine the day of ovulation (d 0). Heifers were assigned to initiate the Ovsynch/TAI protocol at d 2 (n = 5), 5 (n = 5), 10 (n = 4), 15 (n = 5), or 18 (n = 5) of the cycle. The Ovsynch/TAI was initiated with an injection of gonadotropin-releasing hormone agonist followed 7 d later with an injection of prostaglandin F2alpha. At 36 h after injection of prostaglandin F2alpha, heifers were injected with gonadotropin-releasing hormone agonist and inseminated 16 h later. Heifers were scanned daily during the Ovsynch/TAI protocol and every other day after insemination until 16 d later. Blood samples were collected daily starting at the 1st day heifers were scanned and continued until 16 d after insemination. Initiation of the Ovsynch/TAI protocol at d 15 of the estrous cycle caused heifers to ovulate prior to insemination. A shortened return to estrus (< 16 d) was caused by ovulation failure to the second gonadotropin-releasing hormone injection, by incomplete regression of the corpus luteum, and by short life-span of the induced corpus luteum. Day of the cycle in which the Ovsynch/TAI protocol is initiated affects dynamics of follicular development, plasma progesterone profiles, and occurrence of premature ovulation. Size of the pre-ovulatory follicle was associated positively with subsequent progesterone concentrations following insemination.  相似文献   

17.
Treatment with a progesterone-releasing intravaginal device between days 5 and 12 after estrus elevated (p less than 0.05) plasma progesterone concentrations between days 6 and 8 in comparison with controls. Treatment with injectable progesterone (200 mg) on days 5, 7, 9 and 11 postestrus did not increase plasma progesterone concentrations over controls. The administration of 1500 IU human chorionic gonadotrophin (hCG) on day 5 after estrus resulted in a sustained increase (p less than 0.01) in plasma progesterone concentrations from day 8 until day 20 when measurements ceased. Pregnancy rates, as a result of artificial insemination (AI) at the pretreatment estrus, in these treatments (n = 12-14 each), were unaffected by any of the treatments and ranged from 57.1 to 75.0% at 45-60 days post-AI. In a field trial, of 36 repeat breeder cows treated with 1500 IU hCG 5.5 days after insemination, 47.2% were pregnant at 60 days, whereas 39.5% of saline-treated controls were diagnosed pregnant. Treatment with hCG significantly (p less than 0.05) increased milk progesterone concentrations over controls on days 14 and 20 after insemination.  相似文献   

18.
The use of vaginal cytology and plasma progesterone determinations in the management of 11 bitches presented to our small animal fertility clinic are described. Nine bitches were mated or artificially inseminated and seven became pregnant. Reproductive patterns detected included failure of ovulation, prolonged pro-oestrus with late ovulation, short pro-oestrus/oestrus with early ovulation, short pro-oestrus/oestrus with late ovulation and normal pro-oestrus/oestrus with late ovulation.  相似文献   

19.
We studied the concentrations of thyroxine (T4), beta-carotene and vitamin A (vit. A) on the day (zero-th day) of the first successful and unsuccessful insemination of 63 heifers that were administered feed rations balanced according to the Czechoslovak standard CSN 46,7070, housed all the year round, inseminated at uniform time (8:00-9:00 a. m.) and with blood samplings at uniform time (10:00-12:00 a. m.). In the repeat-breeder heifers during the first insemination the above parameters were determined in the same conditions on the day of their second, or third successful and also unsuccessful insemination; the changes relevant to the first insemination were evaluated. In relation to the day of the first successful insemination, we recorded a significant increase in T4 concentration (P less than 0.001; P less than 0.001) on the day of the second, or third successful inseminations. During the second insemination we recorded significantly lower T4 concentrations in the cows which had failed to be inseminated in comparison with successfully inseminated cows; these concentrations did not differ significantly from T4 concentrations in the heifers that failed to become pregnant in the first insemination. Parallelly with the rise in T4 concentration, beta-carotene concentrations also increased during the second and third inseminations (P greater than 0.05). No difference was recorded in beta-carotene concentrations after the first and second unsuccessful inseminations.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

20.
Two experiments were conducted to evaluate the fate of sperm following uterine insemination. In Exp. I, five pairs of Holstein cows were inseminated with egg yolk-Tris extended semen (approximately 1.0 X 10(9) sperm; .5 ml) from five ejaculates from a single bull that had high levels (approximately 70%) of morphologically abnormal sperm. Cows were slaughtered 12 h after insemination. The genital tracts were removed and promptly clamped into defined regions. Sperm were recovered by flushing with 2.9% sodium citrate buffer. Proportions of abnormal sperm in the various regions were compared with those in the inseminate. Sperm numbers were also determined from each region. Regions of the tract varied in number of sperm (P less than .001), proportions of knobbed acrosomes (P less than .001), tapered heads (P less than .001), protoplasmic droplets (P less than .001), tail abnormalities (P less than .029) and total abnormalities (P less than .002). A total of 63.5 +/- 6.4 X 10(6) sperm was recovered. These sperm were distributed throughout the tract as follows: vagina, 91.8%; cervix, 5.4%; uterine horns, 2.7%, and uterotubal junctions-isthmi, .04%. No sperm were recovered from ampullae. Because retrograde movement of sperm from the uterus occurred in Exp. I, we conducted Exp. II to determine the extent of sperm loss from the genital tract following insemination. Three pairs of Holstein cows were inseminated with .42 X 10(9) sperm (.5 ml; egg yolk-Tris extender) from the same bull used in Exp. I (three ejaculates). All discharged mucus and urine was collected for 12 h after insemination for recovery of sperm. Aspirates (approximately 1 ml) of mucus from the vagina were evaluated during the 12-h post-insemination period for numbers of sperm and leucocytes. Sperm were also recovered from the tract following slaughter (approximately 12 h) to determine retention. Overall, 73 +/- 3.7% of inseminated sperm were recovered. Components were: inseminate lost from the genital tract in discharged mucus, 60 +/- 4.6%; lost in urine, .06 +/- .02%; aspirated from the vagina, 4.4 +/- 1%; adhered to equipment, 1.3 +/- .3%, and retained in the genital tract, 6.5 +/- 1.6%. Predicted numbers of sperm contained in discharged mucus 2 h post-insemination were greater (P less than .009) than at subsequent hours.(ABSTRACT TRUNCATED AT 400 WORDS)  相似文献   

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