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1.
The objective of this study was to test the efficacy of a compounded long-acting progesterone formulation (BioRelease P4 LA 150; BETPHARM, Lexington, KY) containing 150 mg progesterone/ml for pregnancy maintenance in mares after prostaglandin (PG) F2α-induced luteolysis. On day 18 of gestation, mares were randomly assigned to one of four groups (n = 7/group): (1) saline-treated control (Saline); (2) PGF2α-treated control (PGF); (3) PGF2α- and Regu-Mate-treated (Regu-Mate); and (4) PGF2α- and BioRelease P4 LA 150-treated (BioRelease). On day 18, Saline mares received 1 ml sterile saline IM, whereas PGF, Regu-Mate, and BioRelease mares received 250 μg cloprostenol IM. Beginning on day 18, Regu-Mate mares received 10 ml Regu-Mate orally once daily and BioRelease mares received 10 ml BioRelease P4 LA 150 containing 150 mg/ml progesterone IM once every 7 days; treatments were continued until day 45 or until pregnancy loss occurred. Pregnancy diagnosis was performed every 3 days between days 18 and 45 (or until pregnancy loss). Pregnancy loss was defined as complete absence of a discernible embryonic vesicle as determined with transrectal ultrasonography. Pregnancy loss rates between days 18 and 45 were: Saline, 1/7; PGF, 7/7; Regu-Mate, 1/7; and BioRelease, 0/7. The pregnancy loss rate was higher (P < .01) in PGF2α-treated control mares compared with the other groups. There were no differences (P > .1) in pregnancy loss rates among the saline-treated control, Regu-Mate-treated, and BioRelease P4 LA 150-treated mares. These results indicate that intramuscular administration of BioRelease P4 LA 150 containing a total of 1.5 g progesterone every 7 days provided a sufficient level of progesterone to maintain pregnancy between days 18 and 45 of gestation in mares that lacked an endogenous source of progesterone; therefore, this long-acting formulation of progesterone appears to be an efficacious and suitable alternative to currently available progesterone formulations that require daily administration.  相似文献   

2.
The effect of excess arachidonic acid or oxytocin on equine endometrial prostaglandin F2α(PGF2α) synthesis was measured in vitro under physiologic and pathophysiologic conditions. Endometrial tissues obtained by uterine biopsy at 5, 10, 12, 14, 16 and 20 days post-ovulation from cycling mares, after 0, 2, 4, 6, 8, 10, 12, 14 or 16 days of progesterone (P4) in ovariectomized mares and at 30 days postovulation in mares undergoing spontaneously prolonged corpus luteum (SPCL) activity were incubated in vitro with and without added arachidonic acid or oxytocin. Endometrial PGF2α content and synthetic capacities were determined by radioimmunoassay. PGF2α production increased significantly at Days 12–16. Arachidonic acid did not alter this effect. Oxytocin stimulated additional PGF2α production on Days 5, 16, and 20. SPCL tissues had minimal PGF2α production which was increased significantly by arachidonic acid but not oxytocin. PGF2α synthesis in ovariectomized P4 treated mares was minimal and did not vary with length of progesterone exposure or addition of arachidonic acid. These results suggest that a) oxytocin may play a role in luteolysis in the equine, b) although arachidonic acid appears not to be limiting to PGF2α production under normal physiological conditions, its absence may play a role in pathophysiological conditions, c) factors in addition to progesterone and arachidonic acid are required to initiate PGF2α synthesis in the mare.  相似文献   

3.
Estradiol and progesterone concentrations were evaluated from diestrous embryo transfer recipient mares (5 to 14 days post-ovulation) which were treated with an exogenous hormone regimen. Upon detection of the donor mare's ovulation (0 hours), 10 mg PGF2α was given to the recipient mare; at 12, 24 and 36 hours 20 mg estradiol cypionate; at 48 hours, 500 mg progesterone in oil and then 22 mg altrenogest at 60, 72 and 96 hours. Altrenogest (22 mg/day) was continued until end of the trial (detection of a fetal heart beat). Embryos were transferred non-surgically 6 or 7 days after the start of treatment.Plasma samples were evaluated over three periods; period 1-between recipient mare ovulation and prior to PGF2α period 2-between PGF and embryo transfer and period 3-post-transfer. During periods 2 and 3, estradiol was higher (P<.05) for mares which were 10 to 14 days post-ovulation (late diestrous) as compared to mares which were 5 to 9 days post ovulation (mid-diestrous) when treatment began. Progesterone concentrations were higher (P<.05) for the mid-diestrous mares in the same periods. The pregnancy rate was higher for the late diestrous mares than the mid-diestrous mares (58% (7/12) vs 10% (1/10)). However, no difference (P>.05) was detected in estradiol or progesterone in the late diestrous mares which were pregnant or open. During period 2, estradiol was higher (P<.05) in the pregnant than open mares. Whereas, during period 3, progesterone was higher (P<.05) in the open mares.These data suggest that estradiol is important for the establishment of pregnancy in the mare. Furthermore, hormone treatment developed in this study appears to have some potential in synchronization of diestrus mares to be used as embryo recipients.  相似文献   

4.
Reasons for performing the study: During embryo transfer (ET) the equine embryo can tolerate a wide degree of negative asynchrony but positive asynchrony of >2 days usually results in embryonic death. There is still confusion over whether this is due to the inability of the embryo to induce luteostasis or to an inappropriate uterine environment. Objectives: To assess embryo survival and development in an advanced uterine environment. Hypothesis: Embryo–uterine asynchrony, not the embryo's inability to induce luteostasis, is responsible for embryonic death in recipient mares with a >2 days chronologically advanced uterus. Methods: Experiment 1: Thirteen Day 7 embryos were transferred to the uteri of recipient mares with luteal prolongation, occasioned by manual crushing of their own conceptus, such that donor–recipient asynchrony was between +13 and +49 days. Experiment 2: Day 7 embryos were transferred to recipient mares carrying their own conceptus at Days 18 (n = 2), 15 (n = 2), 14 (n = 4), 12 (n = 4) or 11 (n = 4) of gestation. In addition, Day 8 embryos were transferred to 4 pregnant recipient mares on Day 11 of gestation. Results: No pregnancies resulted following transfer of Day 7 embryos to recipients in prolonged dioestrus with asynchronies between +13 and +49 days. However, the use of early pregnant mares as recipients resulted in 5/20 (25%) twin pregnancies, 4 of which came from the transfer of a Day 8 embryo to a Day 11 recipient. All transferred embryos showed retarded growth, with death occurring in 4/5 (80%). Conclusions and potential relevance: The results emphasise the importance of an appropriate uterine environment for embryo growth and the inability of equine embryos to survive transfer to a uterus >2 days advanced even when luteostasis is achieved. It is possible that in normal, non‐ET equine pregnancy, embryo–uterine asynchrony may account for some cases of embryonic death.  相似文献   

5.
The use of equine FSH (eFSH) for inducing follicular development and ovulation in transitional mares was evaluated. Twenty-seven mares, from 3 to 15 years of age, were examined during the months of August and September 2004, in Brazil. Ultrasound evaluations were performed during 2 weeks before the start of the experiment to confirm transitional characteristics (no follicles larger than 25 mm and no corpus luteum [CL] present). After this period, as the mares obtained a follicle of at least 25 mm, they were assigned to one of two groups: (1) control group, untreated; (2) treated with 12.5 mg eFSH, 2 times per day, until at least half of all follicles larger than 30 mm had reached 35 mm. Follicular activity of all mares was monitored. When most of the follicles from treated mares and a single follicle from control mares acquired a preovulatory size (≥35 mm), 2,500 IU human chorionic gonadotropin (hCG) was administered IV to induce ovulation. After hCG administration, the mares were inseminated with fresh semen every other day until ovulation. Ultrasound examinations continued until detection of the last ovulation, and embryo recovery was performed 7 to 8 days after ovulation. The mares of the treated group reached the first preovulatory follicle (4.1 ± 1.0 vs 14.9 ± 10.8 days) and ovulated before untreated mares (6.6 ± 1.2 vs 18.0 ± 11.1 days; P < .05). All mares were treated with prostaglandin F2α (PGF2α), on the day of embryo flushing. Three superovulated mares did not cycle immediately after PGF2α treatment, and consequently had a longer interovulatory interval (22.4 vs 10.9 days, P < 0.05). The mean period of treatment was 4.79 ± 1.07 days and 85.71% of mares had multiple ovulations. The number of ovulations (5.6 vs 1.0) and embryos (2.0 vs 0.7) per mare were higher (P < 0.05) for treated mares than control mares. In conclusion, treatment with eFSH was effective in hastening the onset of the breeding season, inducing multiple ovulations, and increasing embryo production in transitional mares. This is the first report showing the use of FSH treatment to recover embryos from the first cycle of the year.  相似文献   

6.
Ultrasonographic pregnancy records of 195 mares from six Thoroughbred stud farms, over a period of 7 years were retrospectively analysed to assess the effect of various factors on embryonic vesicle (EV) fixation pattern and pregnancy outcome. Of the total of 746 pregnancies analysed, significantly (p < 0.01) more EV fixations were evident in the right uterine horn than in the left (53.35% vs 46.65% respectively). There was no significant effect of either, the side of ovulation, or age of the mare, on the side of EV fixation. However, EV fixation, was significantly (p < 0.001) more likely to occur in the right uterine horn in maiden and barren mares (65.75% vs 57.45% respectively). The age and reproductive status of the mare as well as foal heat breeding failed to demonstrate a consistent effect on pregnancy loss relative to the side of EV fixation. In lactating and foal heat bred mares, EVs were significantly (p < 0.0001) more frequently established in the contralateral horn to the one from which the mare delivered her most recent foal. In lactating mares, significantly (p < 0.05) higher embryonic and pregnancy losses were observed in the ipsilateral horn. In conclusion, (a) side of EV fixation was (i) independent of the side of ovulation and mare age (ii) significantly (p < 0.001) affected by reproductive status, (b) neither age of mare nor reproductive status had any effect on pregnancy loss rates relative to the side of EV fixation and (c) in lactating mares the EV had a greater chance of fixation and survival in the horn contralateral to the one from which the mare delivered her most recent foal.  相似文献   

7.
The concentrations of androstenedione, estradiol-17β, progesterone and PGF2α contained in the follicular fluid produced by the follicles in collected ovaries of mares that have had estrous phase during the breeding season were measured and analyzed the relation between the growth stage of follicles and the hormone levels in the follicular fluid. An ultrasonographic diagnostic instrument was used to measure the diameter of the follicles in order to categorize the follicles into three groups the following: 8 small follicles (from 1.0 to less than1.5 cm), 8 medium follicles (from 1.5 to less than 3.0 cm), and 8 large follicles (from 3.0 to 5.0 cm), respectively. The analysis of the follicular fluid in ovaries of estrous mares showed that the concentrations of androstenedione were significantly higher in the medium or large follicles than in the small follicles and the concentrations of estradiol-17β were significantly higher in larger follicles than in the small or medium follicles (P<0.05). The concentrations of progesterone and PGF2α, on the other hand, did not significantly vary regardless of follicluar size. In the follicles within the mare ovaries that have had estrous stage, the concentrations of the hormones related the ovulation, namely androstenedione and estradiol-17β, were higher with larger follicles.  相似文献   

8.
This prospective field study was designed to describe the incidence of early embryonic mortality (EEM) and factors associated with the cause of EEM on three equine breeding farms in Ontario during the 1989 breeding season. Early embryonic mortality was defined as the loss of a single embryo during the first 40 days of pregnancy (day 0 = day of ovulation or last breeding). Pregnancy diagnoses and subsequent embryonic losses were observed by serial trans-rectal ultrasonography between days 12-20 (PD1) and 21-30 (PD2), and by trans-rectal ultrasonography or palpation per rectum between days 31-40 (PD3). Information on pregnancy status of a mare (or cycle) at 40 days after the last breeding was recorded when available. Nonpregnancy rates were calculated on a per cycle basis, to account for mares with no ultrasonic evidence of an embryo at the initial pregnancy examination. Embryonic mortality rates per cycle were calculated cumulatively (EMR(40)) for the entire 40 day embryonic period and during the specific time periods when a pregnancy diagnosis took place (EMR(PD1), EMR(PD2), EMR(PD3)). Embryonic mortality rates were also calculated on a per mare basis for mares experiencing EEM on either their first (EMR(f)) or any (EMR(a)) breeding cycle. Per cycle mare withdrawal rates were calculated cumulatively for the entire 40 day embryonic period (MWR(40)), and at each specific pregnancy diagnosis time period (MWR(PD1), MWR(PD2), MWR(PD3)) to account for those breeding cycles in which mares were not able to be observed for the entire forty days of the embryonic period. Records from a total of 699 mares involving 1014 breeding cycles were examined and analyzed. Per cycle risk rates for nonpregnancy (NP) were 36.4%, 45.0%, and 22.1%, for farms 1,2 and 3, respectively. Per cycle EMR(40) ranged from 8-17%. Per cycle MWR(40) ranged from 56.5-98.9%, indicative of a high rate of mare withdrawal from the study for the duration of the “embryonic” period. Significant differences (p < 0.05) in EMR(f) and EMR(a) per mare existed between two farms, indicative of a farm effect on EMR. Multivariable forward stepwise logistic regression analyses revealed that mares bred on foal heat were 1.9 times more likely than mares not bred on foal-heat to experience EEM (p = 0.008).  相似文献   

9.
Holstein heifers were randomly allotted by weight, age and body condition score to one of three treatments to test the hypothesis that GnRH administration concurrent with PGF2α injection would advance follicle or corpus luteum (CL) development parallel to an induced luteolysis of the pre-existing CL. Heifers in the control group (n = 14) received two treatments of PGF2α(25 mg, im) given 10 days apart. Groups 2 (n = 14) and 3 (n = 14) received an additional treatment of GnRH (100 μg, im) after the first and second PGF2α respectively. Estrus detection began immediately after PGF2α and continued for 80 h. Blood sampling was initiated 7 days prior to the first PGF2α (day − 7) and continued on days 0, 7, 10 (prior to the second PGF2α), 17 and 24. Heifers were artificially inseminated after the second PGF2α and pregnancy diagnosed at 60 days. There was a trend (P < .10) toward a lower estrus response in group 3 when compared to the other groups. Pregnant heifers in group 2 had lower progesterone (0.44 ± 0.09 vs. 1.72 ± 0.56 ng/ml) a week after the second PGF2α than the non-pregnant animals in that group (P < .05). Similar results were observed in the control group but only within the responding heifers (0.61 ± 0.08 vs. 0.93 ± 0.03 ng/ml; P < .05). Progesterone in heifers in group 2 remained high on day 0, 7, and 10 (1.48 ± 0.37, 1.23 ± 0.39, 1.96 ± 0.36 ng/ml) in spite of the treatment with PGF2α. This data suggest that administration of GnRH following PGF2α alters bovine luteal and/or follicular cell function.  相似文献   

10.
Since the 1970s, luteolytic doses used for synchronizing estrus in dairy cattle have remained unchanged. This study aimed to evaluate the dose-response effect of prostaglandin F2α (PGF2α), which is used for synchronizing estrus, and subsequent fertility in cows with two or more corpora lutea (CL). The study population consisted of 1,683 cows with a single CL (1CL), 501 cows with multiple CL receiving a single dose of PGF2α (2CL1), and 252 cows with multiple CL receiving a 1.5 × PGF2α dose (2CL1.5). Cows with a single CL (n = 1,245) showed estrus significantly (P < 0.01) earlier (3.01 ± 1.23 days; mean ± SD) than cows with multiple CL (n = 287; 3.33 ± 1.69 days). Using 1CL cows as reference, the odds ratio (OR) for the estrus response in 2CL1 cows was 0.13 (P < 0.0001), whereas the ORs for estrus response and pregnancy of 2CL1.5 cows were 1.8 (P = 0.0001) and 1.7 (P = 0.001), respectively. Based on the results for only the 2CL1 cows, the OR for the estrus response was 0.7 (P = 0.01) for cows producing ≥ 45 kg of milk at treatment, compared to the remaining cows producing < 45 kg of milk. Our results showed that the presence of multiple CL reduced the estrus response to that induced by a single PGF2α dose and milk production was inversely associated with this response, whereas an increased PGF2α dose improved the estrus response. Therefore, an increase in the standard PGF2α dose is recommended.  相似文献   

11.
Sixty nonlactating light-horse mares were used to compare the efficacy of hCG, buserelin (a GnRH analog) and luprostiol (a PGF2α analog) for induction of ovulation in cycling mares. Mares were assigned to 1 of 4 treatments: 1) controls; 2) 40 μg buserelin IM at 12 hr intervals during estrus until ovulation; 3) 7.5 mg IM luprostiol; and 4) 3,300 IU hCG. Treatments were given once a mare obtained a ≥35mm follicle and had been in estrus ≥2 days. Both buserelin and hCG shortened (p<0.05) the interval from treatment to ovulation compared to controls; whereas, luprostiol failed to hasten ovulation. Number of follicles ovulated was similar among all 4 groups. Although buserelin and hCG were equal in their ability to induce ovulation, an average of 3.8 injections of buserelin was required for hastening of ovulation.  相似文献   

12.
Luteal dysfunction has been observed in mares with defective uterine clearance. Association of low ovarian reserve with luteal dysfunction and abnormal endometrial thickness has been reported in bovine. Anti-Müllerian hormone (AMH) has been indicated as a marker for ovarian reserve in bovine and originates primarily from the ovary in equine. The present study evaluated serum AMH concentration in mares with delayed uterine clearance versus that in mares without delayed uterine clearance. Of 49 mares assigned to the study, 12 and 37 mares were diagnosed with and without delayed uterine clearance, respectively. Delayed uterine clearance was determined based on history and the observation of intrauterine fluid in ultrasonographic examination 24 hours after natural breeding. Serum AMH concentration was measured during estrus. Concentration of AMH was lower in mares with delayed uterine clearance (0.4 ± 0.1 ng/mL) than in those without delayed uterine clearance (1.1 ± 0.1 ng/mL). In conclusion, the present study indicated possible associations between ovary-lined mechanisms and uterine clearance failure in mares.  相似文献   

13.
Fifteen Holstein cows were treated with two doses of 25 mg of a prostaglandin F2α (PGF2α as dinoprost tromethamine) administered intramuscularly 11 days apart. The cows were then divided into three groups and inseminated either at 72, 80 or 72 and 96 hours after the second dose of PGF2α. Thirteen cows ovulated after the second prostaglandin treatment. Eight cows were diagnosed pregnant by rectal palpation 42 days after insemination but only five calved. PGF2α induced luteolysis in cows with active corpora lutea as evidenced by the dramatic decreases in the plasma progesterone concentrations after treatment. In contrast, following PGF2α administration to cows in follicular or late luteal phase the concentrations of plasma progesterone either increased gradually or remained low for several days before increasing to maximal levels. The ovulatory rate after the two doses of PGF2α11 days apart was high. However, the pregnancy rate after this treatment was influenced by other factors including abnormal ovarian function.  相似文献   

14.
A preliminary trial was performed to evaluate the ability of sustained release preparations of estradiol-17β or progesterone plus estradiol-17β to synchronize estrus in cyclic mares. Group 1 mares were treated with a 50 mg intramuscular (IM) injection of sustained release estradiol-17β, while group 2 mares were treated with estradiol plus 1.5 g of sustained release progesterone. All mares received an IM injection of 10 mg of prostaglandin-F2α (PGF2α) 10 days after steroid treatment. Mares were examined by transrectal ultrasonography on Days 1 and 10 of treatment and then at ≤2 day intervals to monitor follicle size. Once a follicle ≥30 mm diameter and uterine edema were detected, 0.5 mg of the GnRH analog histrelin was administered IM. Mares were examined daily thereafter to detect ovulation. Group 1 mares did not exhibit ovulation synchrony (ovulations occurred 12-22 days after steroid treatment), whereas ovulation synchrony was satisfactory in group 2 mares (interval to ovulation being 20.4 ± 1.5 days, range 17-22 days). Using sustained release preparations of progesterone plus estradiol-17β, with PGF2α administered on Day 10, could eliminate the need for daily injections of steroid preparations in oil when synchronizing estrus and ovulation.  相似文献   

15.
Topical application of prostaglandin E2 (PGE2) gel to the surface of the uterine tubes via a laparoscopic procedure improved embryo recovery rates or pregnancy rates in 28 subfertile mares suspected of uterine tubal pathology. Gelatinous masses may occlude the lumen of the uterine tube and prevent sperm from reaching the site of fertilization or prevent embryos from reaching the uterus. PGE2 is secreted by the early equine embryo, promoting passage of the embryo into the uterus; topical administration of PGE2 onto the surface of the uterine tube has been shown to stimulate early transport of the embryo into the uterus. Embryos were produced or a pregnancy was obtained from 24 of the 28 barren mares treated with direct laparoscopic application of 0.2 mg of PGE2 to their uterine tubes. Mares had been barren for an average duration of 1.9 ± 0.6 years and an average of 6.9 ± 3.8 estrous cycles prior to treatment, without donating an embryo or becoming pregnant. Seventeen of 20 mares bred as embryo donors produced one or more embryos with an average of 2.1 ± 1.9 embryos collected per mare (0.45 embryos per cycle) after PGE2 treatment. Seven of 8 mares bred to carry their own pregnancy became pregnant within the first two cycles following PGE2 treatment. These 8 mares were bred an average of 5.6 ± 1.8 cycles without a pregnancy prior to treatment. The laparoscopic PGE2 procedure was performed during various stages of the estrous cycle; the stage varied among treated mares.  相似文献   

16.
Reduced pregnancy rates often occur in ruminants grazing endophyte-infected (EI) tall fescue. The objectives were to characterize basal and oxytocin-induced PGF2α concentrations in serum and reproductive function in ewes fed tall fescue seed and to determine whether addition of fish meal (FM) to a diet of EI fescue would alter PGF2α production. Ewes were fed a diet with novel or non-toxic endophyte-infected (NE) or EI tall fescue seed containing either corn gluten meal (CG) or FM. Serum concentrations of prolactin, a measure of severity of fescue toxins, were reduced in ewes fed EI compared with NE forage seed (forage × day, P < 0.02) and were greater in NEFM than NECG-fed ewes (P < 0.03). Size and number of corpora lutea (CL), determined by trans-rectal ultrasonography, were similar between diets (P > 0.10). Serum concentrations of progesterone were reduced in ewes with two CL fed EI compared with NE seed (forage × CL number × day, P < 0.001). Oxytocin-induced PGFM concentrations during the luteal phase were determined as a measure of uterine function. On the day of oxytocin administration, peak plasma concentrations of PGFM were reduced in EI compared with NE-fed ewes (forage × time, P < 0.003), but FM did not influence PGFM concentrations. Estrous cycle length was more variable in EI than NE-fed ewes. There appears to be some asynchrony between NE and EI-fed ewes leading to changes in uterine responsiveness to oxytocin. Inclusion of FM did not alter uterine responsiveness to oxytocin.  相似文献   

17.
The aim of this study was to clarify the relationship between the placental retention time (PRT) and the reproductive performance following mating at the foal heat in Thoroughbreds. For this purpose, we interviewed 292 farmers over a period of 3 years with questionnaires evaluating foaling, expulsion of placenta and reproductive performance at the foal heat in 1,432 mares. The obtained data were later compared with a previous study of heavy draft mares. The average of the PRT of the 1,432 Thoroughbred mares was 58 ± 88 min (mean ± SD). The mean PRT of Thoroughbreds was significantly shorter than that of the148 min of heavy draft mares. The incidences of retained placenta (RP) occurring in the Thoroughbred mares were 5.2 and 4.0%, for over 3 and 4 hr after foaling, respectively. The incidence of RP over 4 hr was significantly lower than that of 25% in heavy draft mares. The pregnancy rate at foal heat of the mares in which PRT was less than 3 hr was 37%, and it significantly decreased to 11% for those with PRT of more than 3 hr. In the comparison of the reproductive performance between Thoroughbred and heavy draft mares, the pregnancy rate of Thoroughbreds dropped drastically to 10% when PRT exceeded 40, and in consequence, the pregnancy rate of Thoroughbreds was significantly lower than the 30% of heavy draft mares, which had a PRT of over 4 hr. In conclusion, the Thoroughbred mares had a low incidence of RP, however, a PRT exceeding 3 hr severely affected the reproductive performance at the foal heat.  相似文献   

18.
The study was designed to determine differences between normal mares and mares with endometrial pathology in the inflammatory response after bacterial challenge. Six normal mares (biopsy category I) and 4 mares with pathological endometrial changes (biopsy category II) were given an intrauterine infusion of β-hemolytic streptococci on the second day of estrus. All mares had a similar kind of inflammatory response after the bacterial inoculation as assessed by rectal and vaginal examinations. There were no significant differences in the amount of discharge, uterine tone, uterine size and cervical relaxation between the groups. Leukocytic response, as determined by endometrial smears and biopsies, was of the same magnitude in both groups. Two mares from the pathological group were not able to eliminate the infection, but had vaginal discharge and bacteriologically positive uterine swabs until the end of the experiment. It is concluded that the inability of some mares to clear uterine infections cannot be explained by a deficient inflammatory response.  相似文献   

19.
Over the past few decades, the luteolytic dose of prostaglandin F2α (PGF2α) and its analogs, used to synchronize estrus for fixed-time insemination in dairy cattle, have remained unchanged. Given the beneficial effects of PGF2α on a young corpus luteum and on multiple ovulations in a fixed-time insemination protocol, and its therapeutic abortive effects on multiple ovulations in pregnant cows, we propose the use of a double PGF2α dose or two PGF2α treatments 24 hours apart. Ultrasonography procedures serve to identify luteal structures and may therefore help to determine the best PGF2α dose to improve the fertility of high-producing dairy cows.  相似文献   

20.
Ultrasonically detectable characteristics of the uterus and embryo and palpable uterine tone were assessed in 10 postpartum mares. A bright fern-like pattern of ultrasonic uterine echogenicity, outlining the endometrial folds, was observed for an average of 2.1 ±0.2 days following parturition (range, 1 to 3 days). Unexpectedly, the uterus was quiescent throughout the postpartum interval, based on daily one-minute contractility scans. Contractility was maximal on Days 12 to 15 of pregnancy in both postpartum (n=7) and nonparturient (n=7) mares. The mean diameter of ultrasonically detectable intrauterine fluid collections increased (P<0.05) abruptly between days 1 and 2 postpartum and gradually decreased (P<0.05) between days 4 and 7; no collections were detected after day 16. There was no effect of day on echogenicity of the intrauterine fluid collections; on all days, fluid was relatively black or nonechogenic, suggesting that puerperal endometritis was not a problem in this group. Because the increase in intraluminal fluid occurred after parturition and in temporal association with a decrease in diameter and tone of the uterus, the fluid collections apparently represented a physiologic influx from the involuting uterus rather than residual placental fluid. Involution of the horns was completed by day 27 (formerly nongravid horn) and day 31 postpartum (formerly gravid horn), based on failure to detect further significant decreases in diameter. However, the formerly gravid horn was larger (P<0.05) in diameter than the formerly nongravid horn on each of Days 1 to 35 postpartum (end of experiment), indicating residual effects on uterine size. When averaged over both horns, uterine diameters were larger on Days 0 to 24 (Day 0=day of ovulation) of pregnancy in postpartum mares than in nonparturient mares; by Day 25, diameters were similar between statuses. By approximately Day 6 of pregnancy, uterine contractility and ultrasonic endometrial exhotexture were similar between postpartum mares and nonparturient mares. Uterine tone was greater (P<0.05) in postpartum mares than in nonparturient mares on all days between Day 0 and 25. An unexpected, transient increase in uterine tone was detected on Day 5 of pregnancy in both postpartum mares and nonparturient mares. No differences were found between reproductive statuses in patterns of embryo mobility, the day of fixation of the embryonic vesicle (postpartum, Day 15.3 ±0.4; nonparturient, Day 15.0 ±0.3), and diameter of the embryonic vesicle on the day of fixation (postpartum, 22.1 ±1.4 mm; nonparturient, 19.4 ±l.6mm). However, mean uterine tone and mean horn diameters on the side of fixation were greater (cranial and middle cornual segments; P<0.05) or tended to be greater (caudal segment; P<0.1 ) on the day of fixation in postpartum mares than in nonparturient mares. In all postpartum mares, fixation occurred in the formerly nongravid horn. Enhanced uterine tone in postpartum mares may account for the occurrence of fixation on the same day for the two reproductive statuses, despite the larger uterus in postpartum mares.  相似文献   

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