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1.
Experiments were conducted to determine the effect of additional gonadotropic support on induced corpora lutea of anestrous ewes. In one series of experiments, ewes were superovulated and half the ewes received an i.v. injection of 500 IU human chorionic gonadotropin (hCG) on day 5 after ovulation. Corpora lutea were collected from both groups on day 10 after ovulation. Dissociated corpora lutea collected from ewes which received additional hCG contained proportionately more large luteal cells than did those from control ewes (P<.05). In neither cell type was content of receptors for luteinizing hormone (LH) or secretion of progesterone in response to LH affected by an additional injection of hCG. Large cells from anestrous ewes produced more progesterone in response to LH (P<.05) than did large cells from similarly treated ewes during the breeding season. Small cells collected during either season responded similarly to LH. In another series of experiments, anestrous ewes were induced to ovulate and were exposed to fertile rams. Half the ewes received an i.v. injection of 500 IU hCG on day 5 after ovulation. Serum content of progesterone was higher on day 10 in ewes which received hCG 5 days earlier than in control ewes, although progesterone levels declined to generally nondetectable levels in nonpregnant ewes of both groups by day 16. Pregnancy rates in the two groups were not different. We concluded that additional gonadotropic support affects the morphology and function of corpora lutea from anestrous ewes and may be useful for enhancing fertility during the nonbreeding season.  相似文献   

2.
As dogs experience oestrus only once or twice a year, it is necessary to establish an effective method of oestrous induction for efficient breeding. In the present study, we evaluated inhibin antiserum (IAS) on oestrous induction in anoestrous females. Bitches were administered 0.5 ml/kg IAS or a mixture of 50 IU/kg equine chorionic gonadotropin (eCG) and 0.5 ml/kg IAS and 500 IU human chorionic gonadotropin (hCG) administered 7 days after the mixture injection. As a control, bitches received 50 IU/kg eCG, with 500 IU hCG administered 7 days after eCG injection. Blood-tinged vaginal discharge, vulvar swelling, plasma progesterone concentrations and ovarian follicular development were assessed from day 0 to day 14. IAS alone injection did not induce oestrus in bitches at the anoestrous stage. Conversely, vulvar swelling, blood-tinged vaginal discharge and an estimated luteinizing hormone (LH) surge appeared on days 3–7, days 3–6 and days 7–9 after the IAS+eCG mixture injection, respectively, in all five bitches at the anoestrous stage. The average number of developing and ovulated follicles in bitches administered IAS+eCG was 8.8 and 9.6 respectively. A single eCG injection followed by hCG induced oestrous signs, with an average of 8.3 developing follicles and 4.5 ovulated follicles. This study revealed that IAS alone did not induce oestrus, but when IAS was used in combination with eCG, it induced oestrus and promoted a considerable number of ovulations in anoestrous dogs.  相似文献   

3.
A trial was conducted during the anestrous period in female goats to determine: (a) whether estrus can be induced in anestrous goats by administration of equine chorionic gonadotropic hormone (eCG) and PGF2α under pen conditions and (b) whether these sexually active female goats can elicit sexual arousal in sexually inactive bucks. One hundred and fifteen pluriparous, nonlactating mixed-breed female goats were randomly assigned to one of four treatment groups: (1) administration of a single dose of 240 IU of eCG, 50 μg PGF2α i.m., and 25 mg progesterone (P4) (eCG; n?=?30); (2) administration of P4 and exposure to female goats treated with eCG–PGF2α (P4; n?=?39); (3) administration of 0.5 ml saline and P4 (Sal; n?=?23); and (4) P4 plus exposure to female goats treated with saline (Con; n?=?23). After hormone administration, all goats were put together with adult sexually inactive bucks for 15 days. The percentage of goats in estrus during these 15 days was similar in eCG-treated animals and untreated animals exposed to the eCG animals (97 and 95 %). Pregnancy rate was also similar (63 vs. 64 %) between these two groups. eCG-treated goats exhibited estrus earlier (P?<?0.05) than the treated goats in contact with the eCG goats. Furthermore, eCG-treated goats had larger litters (1.9?±?0.2 vs. 1.6?±?0.1, P?<?0.05) than the untreated goats in contact with the eCG goats. These results show that fertile estrus can be induced in anestrous female goats by exposing them to female goats induced to estrus with eCG. This female–female interaction triggers the stimulation cycle leading to the sexual arousal of bucks.  相似文献   

4.
The influence of varying doses of human chorionic gonadotropin (hCG) on the preovulatory luteinizing hormone (LH) surge, estradiol-17 beta (E2) and progesterone (P4) was studied in synchronized gilts. Altrenogest (AT) was fed (15 mg X head-1 X d-1) to 24 cyclic gilts for 14 d. Pregnant mares serum gonadotropin (PMSG; 750 IU) was given im on the last day of AT feeding. The gilts were then assigned to one of four groups (n = 6): saline (I), 500 IU hCG (II), 1,000 IU hCG (III) and 1,500 IU hCG (IV). Human chorionic gonadotropin or saline was injected im 72 h after PMSG. No differences in ovulation rate or time from last feeding of AT to occurrence of estrus were observed. All gilts in Groups I and II expressed a preovulatory LH surge compared with only four of six and three of six in Groups III and IV, respectively. All groups treated with hCG showed a rapid drop (P less than .01) in plasma levels of E2 11, 17, 23 h after hCG injection when compared with the control group (35 h). The hCG-treated gilts exhibited elevated P4 concentrations 12 h earlier than the control group (3.1 +/- .5, 3.4 +/- .72, 3.1 +/- .10 ng/ml in groups II, III and IV at 60 h post-hCG vs .9 +/- .08 ng/ml in group I; P less than .05). These studies demonstrate that injections of ovulatory doses of hCG (500 to 1,500 IU) had three distinct effects on events concomitant with occurrence of estrus in gilts: decreased secretion of E2 immediately after hCG administration, failure to observe a preovulatory LH surge in some treated animals and earlier production of P4 by newly developed corpora lutea.  相似文献   

5.
为了提高乏情母狐的利用率,第1年对50只没有发情表现的青年母蓝狐同时一次注射PMSG200IU/只,5d后再注射HCG100IU/只,有42只出现明显发情症状并接受公狐爬跨,发情率84%。对发情母狐实施子宫内输精,结果无一产仔;第2年对50只非典型发情的青年母蓝狐同时一次注射PMSG200IU/只,5d后再注射HCG100IU/只,全部出现明显的发情症状并接受交配。对其实施子宫内输精3次,结果有24只产仔,产仔率48%。试验结果表明,在母狐繁殖末期,联合使用PMSG和HCG对没有发情表现的青年母蓝狐有促使其发情的作用,但不能使其产仔;对有发情表现但不明显的青年母蓝狐有促进其发情并能使其部分怀孕和产仔的作用。  相似文献   

6.
Ovarian sensitivity to exogenous gonadotropin stimulation (equine chorionic gonadotropin [eCG] and human chorionic gonadotropin [hCG]) following pre-treatment with a progestin (levonorgestrel) versus GnRH antagonist (antide) was studied in cats known to be induced versus spontaneous ovulators. Queens were assigned to one of three treatments: (1) levonorgestrel implants+eCG/hCG (n=7 cats); (2) antide injections+eCG/hCG (n=7) or (3) eCG/hCG alone (control; n=7). Hormonal metabolites were assessed in fecal samples collected daily for 60 days before and during the 37 days inhibitory pre-treatment and for more than 60 days after eCG/hCG. Fecal metabolites of estradiol and progesterone were measured by radioimmunoassay. Females that maintained baseline progesterone were considered induced ovulators, whereas cats that exhibited a luteal phase before inhibition treatment were classified as spontaneous ovulators. Based on fecal hormone profiles, levonorgestrel thoroughly inhibited ovarian activity, whereas antide synchronized follicular phases but did not induce complete ovarian down-regulation. Both treatments prevented ovulation in spontaneous ovulators, but neither caused regression of existing corpora lutea (CL). Levonorgestrel, but not antide, pre-treatment resulted in a quiescent ovary at the time of eCG injection, yet endocrine responses to eCG/hCG were not different among treatments. Interestingly, spontaneously ovulating females exhibited a prolonged estradiol response to gonadotropin stimulation compared to induced ovulators, and this prolonged estradiol surge was replicated by levonorgestrel pre-treatment. Thus, the progestin levonorgestrel effectively suppresses follicular and luteal activity in the cat, resulting in a more consistent response to gonadotropin stimulation, even in females prone to spontaneous ovulation.  相似文献   

7.
The objective of this study was to determine the effect of additional human chorionic gonadotrophin (hCG) on the ovarian response of gilts previously treated with 200 IU hCG combined with 400 IU equine chorionic gonadotrophin (eCG) (eCG/hCG). Seventy-one prepuberal gilts (105 ± 7.5 kg) were assigned to groups: i) eCG/hCG (hCG-0; n = 25); ii) eCG/hCG followed by 100 IU of hCG at 24 h (hCG-100; n = 24); iii) eCG/hCG followed by 200 IU hCG at 24 h (hCG-200; n = 10); and iv) controls (CON; n = 12). Ovulation response was assessed by ovarian dissection or real-time ultrasonography. Additional hCG did not significantly improve numbers of gilts ovulating. Numbers of corpora lutea increased with hCG, and was higher in hCG-200 (P < 0.01). Compared to hCG-0, the frequency of cysts in gilts was higher in hCG-100 (P < 0.05) and further increased in hCG-200 (P < 0.01). The number of cysts per gilt was dose-dependently increased by additional hCG. We conclude that supplemental hCG will increase the number of corpora lutea but will be associated with follicular cyst development in a dose dependent manner.  相似文献   

8.
Thirty reproductively sound mares were divided into treatment and control groups. In the treatment group, consisting of 14 mares, 2500 I.U. of human chorionic gonadotropin (hCG) was administered intravenously during estrus, in the presence of a 35 mm follicle over five successive cycles in 1987, and at least two cycles in 1988. Beginning with the second cycle of treatment in 1988, these mares were bred to a fertile stallion. The control group, consisting of 16 mares, was followed for two to five cycles in either the 1987 or 1988 season and six of these mares were bred to fertile stallions. Throughout the study period, blood was collected from the mares in the treatment group for analysis of anti-hCG antibodies and cross reactivity of the antibody to purified equine lutenizing hormone (eLH) and equine chorionic gonadotropin (eCG).In 1987, after the first three injections of hCG, mean duration of estrus in treated mares tended to be shorter than in control mares (P<.10). After all five hCG injections in 1987, mean ovulation time for treated mares was shorter than in control mares (P<0.01). However, after two to five hCG injections in 1987, seven treated mares (50%) had some individual ovulation times that did not differ from the control mares.Initially, following the first three injections of hCG in 1988, mean duration of estrus tended to be shorter (P<0.1) in treated mares compared to control mares. A reduction in mean ovulation time was observed after the first two hCG injections of 1988 (P<0.01). However, after one to four hCG injections in 1988, eight treated mares (57.1%) had some individual ovulation times that did not differ from controls.In 1987, all 14 treated mares developed significant levels of antibodies to hCG after one to four injections, and again in 1988, were positive for anti-hCG antibodies after one to three injections. However, no correlation was observed between magnitude of the immune response and duration of ovulation time or pregnancy rate. In cross reactivity studies, no significant binding of plasma anti-hCG antibodies to either eLH or eCG was observed in vitro.Overall, pregnancy and foaling rates of treated (85.7%) and control mares (83.3%) did not differ. Additionally, no difference was observed in number of inseminations per estrus between treated and control mares. In this study, with successive injections of hCG, the expected shortened time to ovulation was not elicited consistently in all mares. However, mares continued to ovulate, conceive and foal in the presence of significant levels of anti-hCG antibodies.  相似文献   

9.
Gilt oestrus and ovulation responses to injection of a combination of equine chorionic gonadotrophin (eCG) and human chorionic gonadotrophin (hCG) (PG600) can be unpredictable, possibly reflecting inadequate circulating LH activity. The objective of this study was to determine the effect of PG600 followed by supplemental hCG on gilt ovarian responses. In experiment 1, 212 Hypor gilts (160 day of age) housed on two farms in Spain received intramuscular (i.m.) injections of PG600 (n = 47), or PG600 with an additional 200 IU hCG injected either concurrently (hCG‐0; n = 39), or at 24 h (hCG‐24; n = 41) or 48 h (hCG‐48; n = 45) after PG600. A further 40 gilts served as non‐injected controls. Ovulation responses were determined on the basis of initial blood progesterone concentrations being <1 ng/ml and achieving >5 ng / ml 10 d after the PG600 injection. The incidence of ovulating gilts having progesterone concentrations >30 ng/ml were recorded. During the study period, 10% of control gilts ovulated whereas 85–100% of hormone‐treated gilts ovulated. There were no significant differences among hormone groups for proportions of gilts ovulating. The proportions of gilts having circulating progesterone concentrations >30 ng/ml were increased (p ≤ 0.02) in all hCG treated groups compared with the PG600 group. In experiment 2, a total of 76 Hypor gilts at either 150 or 200 days of age were injected with PG600 (n = 18), 400 IU eCG followed by 200 IU hCG 24 h later (n = 20), PG600 followed by 100 IU hCG 24 h later (n = 17), or 400 IU eCG followed by 300 IU hCG 24 h later (n = 21). Blood samples were obtained 10 days later for progesterone assay. There were no effects of treatment or age on incidence of ovulation, but fewer 150‐day‐old gilts treated with PG600 or 400 IU eCG followed by 200 IU hCG had progesterone concentrations >30 ng / ml. We conclude that hCG treatment subsequent to PG600 treatment will generate a higher circulating progesterone concentration, although the effect is not evident in older, presumably peripubertal, gilts. The mechanism involved and implications for fertility remain to be determined.  相似文献   

10.
At the beginning of the breeding season, most beef herds consist of a population of cyclic and anestrous postpartum cows. To be most effective and economical, an estrous synchronization method for postpartum beef cows must be capable of synchronizing estrus in cyclic cows and inducing estrus in anestrous cows. In the first of two experiments, the combination of melengestrol acetate (MGA) fed for 9 d and prostaglandin F2 alpha (PGF2 alpha) administered on the last day of MGA feeding synchronized estrus in cyclic cows (94%) and induced estrus in anestrous cows (66%) as effectively as combining PGF2 alpha with a progestin implant (97 and 75%, respectively). In the second experiment, MGA treatment was necessary for 7 d prior to administering PGF2 alpha to maximize the expression of estrus in cyclic and anestrous cows. In both experiments the proportion of cows exhibiting a synchronized estrus and the pregnancy rates tended to be higher for cows that were cyclic prior to treatment. However, the MGA-PGF2 alpha treatments consistently induced estrus in more than 50% of the anestrous cows and approximately one-third of the cows that were anestrous prior to treatment conceived during the synchronized breeding period. The MGA-PGF2 alpha treatment was 33 to 46% less expensive than a comparable estrous synchronization method that is approved by the U.S. Food and Drug Administration. If feeding MGA and administering PGF2 alpha is approved, it may be the treatment of choice for synchronizing estrus in cyclic cows and inducing estrus in anestrous cows when supplemental feeding is feasible.  相似文献   

11.
We examined the relationship between the time elapsed after human chorionic gonadotropin (hCG) administration and developmental stage of porcine embryos after collection. Prepubertal gilts, 7 to 8 months old, were given 1500 IU equine chorionic gonadotropin (eCG) intramuscularly, followed by 500 IU hCG 72 h later. The treated gilts were inseminated artificially on Day 1 (Day 0=the day of hCG administration) and on Day 2. Embryos were collected surgically on Day 6 (140, 144, and 147 h after hCG administration) or on Day 7 (164, 168, and 171 h), and the developmental stages of the collected embryos were examined. From 75.2% (276/367) of the prepubertal gilts treated with hormones, we collected an average of 20.7 embryos per gilt with normal morphology. At 140 h after hCG administration, morulae (54.4%) could be collected. At 144 h, morulae and early blastocysts (57.7% and 28.9%, respectively) were collected. By 147 h, the proportion of embryos at the blastocyst to expanded blastocyst stages had increased (10.0%). From 164 h to 171 h, expanding or expanded blastocysts of more than 200 microm in diameter and hatched blastocysts could be collected. The proportion of hatched blastocysts increased from 3.2% (164 h) to 41.0% (171 h). These results suggests that although the number of ovulations differed among gilts, porcine embryos at the appropriate stages can be collected efficiently by controlling the time elapsed between hCG administration and embryo collection.  相似文献   

12.
To meet weekly breeding targets, it is occasionally necessary to inject exogenous gonadotrophins to induce oestrus in prepubertal gilts. However, the gilt oestrus response to equine chorionic gonadotrophin (eCG) either alone or in combination with human chorionic gonadotrophin (hCG) can be unpredictable. The objective of the present study was to examine possible reasons for this unpredictability. Prepubertal gilts (90 kg and 153 days of age, n = 109) received an injection of either 600 IU eCG or a combination of 400 IU eCG and 200 IU hCG (PG600), or were non-injected controls, and were then exposed to a mature boar for 15 min daily for 7 days for oestrus detection. At the time of injection, real-time ultrasound revealed that the gilt ovaries had primarily 1–2 mm follicles. Blood samples were obtained at time of hormone injection (day 0) and at days 3, 7 and 10 for assay of serum progesterone concentrations. The oestrus responses by 7 days were15.5%, 73.3% and 0%, for eCG, PG600, and control gilts, respectively (p < 0.001). The oestrus response improved (p < 0.05) with increasing body weight. Based on circulating progesterone levels, all oestrous gilts ovulated except for four of the PG600 gilts. Failure to express oestrus in PG600 gilts was not associated with a premature rise in progesterone.  相似文献   

13.
Fertility in cattle is related positively to concentrations of progesterone in blood during the estrous cycle preceding insemination. This study determined whether treatment of heifers with prostaglandin F2 alpha (PGF2 alpha) or human chorionic gonadotropin (hCG) during d 2 to 4 of an estrous cycle affected progesterone during that cycle and whether hormone secretion during the cycle and onset of subsequent estrus were related to progesterone secretion. Nine Holstein heifers were assigned to an experiment designed as a triplicate Latin square, and each heifer received each of three treatments during three consecutive estrous cycles. Treatments were: saline (control, 1 ml) on d 2, 3 and 4 after estrus; hCG, 1000 IU on d 2, 3 and 4; and PGF2 alpha, 25 mg on d 3 with repeated doses 12 and 24 h later. Progesterone throughout the estrous cycle was higher in heifers given hCG than in those given saline. Progesterone during the first week of the cycle was lower in heifers given PGF2 alpha than those given saline, but means for these two groups were similar thereafter. Number of peaks of 15-keto,13,14-dihydro-PGF2 alpha (PGFM) during 24 h after onset of luteolysis was lower in heifers given hCG than in those given saline or PGF2 alpha. Patterns of secretion of luteinizing hormone and estradiol at subsequent estrus were not affected by treatment. Temporal relationships among hormone secretion and onset of estrus were unaffected by treatment.  相似文献   

14.
In 3 adult female cheetahs, induced-superovulation treatment was conducted, by means of 200 IU of pregnant mare serum gonadotropin (PMSG) and 100 IU of human chorionic gonadotropin (hCG) 80 hr after PMSG. The administration of PMSG created a sharp increase in the estradiol-17beta concentration, resulting in 232 pg/ml 8 hr later in one specimen out of three. The hCG administration showed an increase in the progesterone concentration of 2.29 ng/ml 46 hr later. In addition, after direct observation of the ovary surface by laparoscopy, 5 follicles in the right ovary over 2 mm in diameter, and 7 corpora lutea (5 in the right ovary and 2 in the left) were found. It is assumed that ovulation can be induced with hCG after 80 hr on PMSG during a cheetah's diestrus or proestrus.  相似文献   

15.
Adult goats (n = 32) were randomly assigned to one of four treatments (n = 8, each): (i) progesterone (P4) + equine chorionic gonadotropin (eCG), treated with 25 mg progesterone intramuscularly (i.m.) + 250 IU eCG 24 h later; (ii) cronolone + eCG, treated with vaginal sponges ‐ 20 mg cronolone × 7 days + 250 IU eCG at pessary removal; (ii) P4 + estradiol (E2), treated with 25 mg progesterone i.m. + 1 mg estradiol 24 h later; (iv) cronolone + E2, treated with vaginal sponges ‐ 20 mg cronolone × 7 days + 1 mg of estradiol i.m. at pessary removal. Goats were tested for estrus throughout the presence of a buck. Seven days prior and after treatment, an ovarian ultrasonographic scanning was performed to determine ovarian function and structures. An ultrasonographic pregnancy diagnosis was performed on day 30 post‐service. In all groups, 100% estrus response was observed within 96 h post‐treatment. While ovulation occurred in 100% of P4 + eCG and cronolone + eCG treated goats, the other groups only depicted 50% ovulatory activity (P < 0.05). Pregnancy rate was higher (P <0.05) in the P4 + eCG and cronolone + eCG groups (88 and 100%, respectively), compared with 38% in P4 + E2 and cronolone + E2 groups. The best treatments were those in which eCG was applied. The P4 + eCG treatment was a pessary‐free, cheaper and effective protocol to induce ovulation in goats during the seasonal anovulatory period.  相似文献   

16.
The present experiment aims to examine the efficiency of estrus synchronization using progesterone and equine chorionic gonadotrophin (eCG) and to look at luteal function. During the non-breeding and breeding season, 5 adult female Korean native goats were injected intramuscularly with 2.5 ml of physiological saline as the control. A progesterone impregnated intravaginal sponge was then kept in the same goats for 10 days followed, after a week, by an intramuscular injection of 500 IU eCG. Five adult female Nubian goats were mated with a fertile buck during the non-breeding season. During the non-breeding season 2 of the 5 goats showed a normal estrous cycle (ranging from 18 to 21 days) and 3 a short estrous cycle (ranging from 3 to 6 days). During the breeding season the equivalent figures were 1 and 2. The major axes of the corpus luteum (CL) were measured by means of calipers built into the ultrasonography system, and the concentrations of plasma progesterone (P4) were determined by double antibody radioimmunoassay. The mean major axes of the CL in goats showing the short cycle (6.1 ± 0.5 mm) was significantly smaller than in those showing the normal cycle (8.9 ± 0.5 mm; p < 0.01) and also the value of P4 in goats showing the short cycle (4.2 ± 2.1 ng/ml) was significantly lower than for those showing the normal cycle (10.3 ± 4.3 ng/ml; p < 0.05) at day 3 following ovulation. Three out of 5 Nubian goats became pregnant but only one goat carried to full term. The present experiment indicated that a combination of progesterone and eCG was effective in inducing estrus, although it resulted in a high incidence of short luteal lifespan. The low kidding rate and high incidence of embryonic loss may be due to the instability of the luteal lifespan.  相似文献   

17.
The effects of passive immunoneutralization of endogenous inhibin on ovulation rate in immature rats were investigated. Efficiency of superovulation on production of fertilized oocytes was compared between the inhibin antiserum (inhibin-AS) and equine chorionic gonadotropin (eCG) protocols. Immature female Wistar strain rats were superovulated with a single injection of 100-200 microl inhibin-AS, with and without an injection of human chorionic gonadotropin (hCG). A total of 77.8% of the 26-30-day-old rats treated with a single injection of 100-200 microl inhibin-AS ovulated 72 h after treatment, while rats given normal goat serum (NGS; 200 microl) did not ovulate. At 28 days of age, all of the inhibin-AS treated rats ovulated when additional hCG treatment was given, whereas the number of ovulated oocytes was not affected. The number of ovulated oocytes in the inhibin-AS-hCG treated groups was significantly higher than that of the NGS-hCG treated group. In addition, plasma concentrations of FSH in the inhibin-AS-hCG treated group significantly increased compared with the NGS treated group. While the percentage of mated rats in the 200 microl inhibin-AS-hCG treated group was significantly lower than that of the 15 IU eCG-hCG treated group, the fertilization rate was comparable between the two groups. The number of fertilized oocytes in the 200 microl inhibin-AS-hCG treated group was significantly higher in comparison with the 15 IU eCG-hCG treated group. These results suggest that immunoneutralization of endogenous inhibin could be a reliable method for induction of superovulation to collect a large number of normally fertilized oocytes in immature rats.  相似文献   

18.
为探讨昆明鼠超数排卵的最佳条件,提高超排效果,比较促性腺激素使用剂量、孕马血清促性腺激素(PMSG)与人绒毛膜促性腺激素(hCG)注射间隔时间、超排小鼠所处发情周期阶段及小鼠周龄等因素对昆明鼠超数排卵结果的影响。PMSG 8IU+hCG 8IU、间隔46h～48h注射组超排效果最好;3周龄、8周龄～10周龄雌鼠较4周龄～7周龄雌鼠超排效果好,小鼠发情间期或发情前期开始超排的效果显著高于发情周期的其他时期。  相似文献   

19.
Potential treatments for anestrus in gilts and sows   总被引：1，自引：1，他引：0       下载免费PDF全文
Pregnant mares' serum gonadotrophin (400 IU) combined with human chorionic gonadotrophin (200 IU) was administered to anestrous gilts (n=31) and sows (n=20) in commercial herds. Two-thirds of the treated animals were mated successfully within seven days and, although no control animals were included, the response indicated that this hormone combination would be useful in herds with anestrous problems. A second experiment was conducted to evaluate the occurrence of estrus and/or ovulations in prepuberal gilts (n=eight/treatment) following injection with pregnant mares' serum gonadotrophin/human chorionic gonadotrophin or other hormones that might stimulate ovarian activity. The pregnant mares' serum gonadotrophin/human chorionic gonadotrophin combination and follicle-stimulating hormone produced estrus within ten days of injection in at least half of the treated gilts but the response was lower with gonadotrophin-releasing hormone and a prostaglandin analogue. Combinations of human chorionic gonadotrophin with small amounts of estradiol benzoate stimulated estrus and ovulation in most of the treated gilts.  相似文献   

20.
In four Kenyan pig breeding units the pregnancy diagnosis of sows has been carried out in two groups: Group 1 (n = 1911): the sows were transrectaly pregnancy tested between Days 17-22 post-mating by ultrasound. Sows testing non-pregnant immediately received one dose of 400 IU pregnant mare serum gonadotropin (PMSG) (equine chorion gonadotropin, eCG) and 200 IU human chorion gonadotropin (hCG). On showing signs of oestrous, the animals were subsequently artificially inseminated (AI). Group 2 (n = 1923): sows were pregnancy tested by serum progesterone (P4)-based enzyme-linked immunosorbent assay (ELISA) on Day 17 post-breeding. P4 concentrations were categorized as positive (> 5 ng/ml) or negative (< 5 ng/ml). Sows testing nonpregnant immediately received one dose of 400 IU PMSG and 200 IU hCG by injection, and were subsequently artificially inseminated. The following parameters were evaluated: sows diagnosed non-pregnant, days from first post-weaning insemination until the sows were inseminated at their first return to oestrus; farrowing rate and total piglets born and number of live-born piglets in litters. The percentage of sows diagnosed non-pregnant in the two groups, as well as the totals of born piglets and of live-born piglets in litters did not differ significantly between the two groups. The number of days from the first post-weaning mating until the sows were artificially inseminated at their first return to oestrus and the administration of eCG and hCG was shorter (P < 0.01) and farrowing rate was higher (P< 0.01) in the ELISA-tested sows.  相似文献   

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