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1.
Application of new procedures in the sphere of the control of sexual functions requires an extension of present knowledge of postparturient endocrinium or endogenic factors comprised in postparturient physiology of sexual activity. According to recent data, oxytocin, besides its uterotonic and luteolytic activity, acts as an ovarian factor in the local intrafollicular regulation of stereidogenesis and as a modulator of uterine secretion of prostaglandines. Based on present knowledge of oxytocin effects, this study was aimed at investigation of the influence of repeated carbetocin (Depotocin inj. Spofa) administration on the dynamics of changes in thyroxine (T4), triiodothyronine (T3), 17 beta-estradiol (E2), progesterone (P4) concentrations and their mutual correlations from the 36th hour till the 51st day after parturition. Simultaneous study of a possible delayed influence of applied carbetocin on conception of ewes after oestrus evocation on day 51 after lambing was carried out. Nineteen ewes of the Slovak Merino breed, lambed in the first decade of February, were assigned to the experimental (n = 9) and to the control group (n = 10). Experimental ewes were subjected to repeated postparturient carbetocin treatment at the dose 0.07 mg per animal. The first dose was applied i. m. in 24 hours, and the second in 72 hours after parturition. On day 51 oestrus was induced in nine ewes of each group by combined treatment with chlorsuperlutin (Agelin, vaginal pessaries, Spofa) and PMSG (500 I.U./animal). On the day of PMSG application ewes were housed together with rams for the period of the next six days. Samples of blood were taken 24 hours before parturition (-1st day), up to 36 h after parturition and on days 4, 7, 14, 17, 21, 25, 34, 42 and 51 after parturition. Concentrations of T4, T3, E2 and P4 were determined by commercial kits RIA-test-T4; RIA-test-T3; RIA-test-ESTRA and RIA-test-PROG (URVJT Kosice). Animal of the control group showed variations of T4 concentrations (Tab. I, Fig. 1) at the level of original values (59.4 +/- 9.69 nmol.l-1) up to the 21st day with the exception of temporary drop on day 4 and rise on day 7, insignificant compared to the -1st day. T4 concentrations of the control group displayed an intermittent increasing trend with the statistically insignificant peak after 36 h and on day 17, compared to the -1st day. After the 21st day controls revealed a sustained moderate increase while the experimental ewes displayed a decline of its concentrations until the 51st day.(ABSTRACT TRUNCATED AT 400 WORDS)  相似文献   

2.
Postparturient anoestry, spontaneously changing over to seasonal anoestry, represents an important reserve of full utilization of the reproductive potential of sheep. In spite of the fact that the length of gestation in sheep only amounts to 148 days (+/- 5 days), inability of most sheep to enter the cycle during the spring season acts as a factor limiting the number of lambings--and at the same time production of lambs--to one lambing per year. In order to obtain more detailed knowledge of hormonal conditions in sheep puerpery, the presented work was directed at the study of dynamic changes in concentrations of thyroxine (T4), triiodothyronine (T3), 17 beta-estradiol (E2), progesterone (P4) and cholesterol (Chol) in the blood serum of ewes and at their mutual correlative dependences between the 36th hour and the 51st postparturient day. The observation was carried out in nine nursing ewes of the Slovak Merino breed, with average weight 40-50 kg, lambed in January and February. Blood was sampled by means of jugular vein puncture 14 days (-14th day) before parturition (a. p.), up to 36 h after parturition (p. p.) and on day 4, 7, 14, 17, 21, 25, 34, 42 and 51 p. p. In the period from the 36th h to day 21 p. p., concentrations of T4 (Tab. I, Fig. 1) showed a decreasing tendency compared to the starting -14th day (69.55 +/- +/- 0.12 nmol.-1) with the exception of a temporary increase on the 7th day p. p. The lowest values were recorded on days 4 and 21 p. p. (45.66 +/- 21.61 nmol.l-1, P less than 0.05 and 54.89 +/- 11.06 nmol.l-1, P less than 0.05, resp.). An increase of these values to the starting level was observed between days 25 and 51 p. p. Compared to the values on -14th day (0.76 +/- 0.22 nmol.l-1), a significant increase of T3 concentrations (Tab. I, Fig. 2) was recorded at the 36th h and on days 4 and 7 p. p. with the highest values (1.48 +/- +/- 0.34 nmol.l-1, P less than 0.001) at 36 h p. p. After the temporary decrease between days 14 and 21 p. p. its concentrations showed a constantly rising tendency statistically significant on days 34, 42 and 51 p. p., compared to the -14th day (P less than 0.05). Concentrations of E2 (Tab. I, Fig. 3) reached the values of 0.44 +/- 0.41 nmol.l-1 on the -14th day.(ABSTRACT TRUNCATED AT 400 WORDS)  相似文献   

3.
Coxiella burnetii infection in pregnant sheep typically causes abortion or the birth of weak lambs. Two C. burnetii-related abortions in a group of 34 pregnant ewes were reported at their first lambing in our research institute. The seroprevalence of C. burnetii infection and bacteria shedding were investigated using an ELISA and PCR, respectively, during the course of two subsequent pregnancies. None of the ewes examined seroconverted from negative to positive at the time of the second and the third parturition and most of the ewes that were seropositive at the abortion episode remained positive throughout the investigation. The two successive pregnancies resulted in the birth of healthy lambs without PCR evidence of Coxiella infection from placenta and vaginal swabs taken postpartum. PCR assay performed on vaginal swabs taken from all animals 1, 5 or 12 days after the second lambing were also negative for Coxiella. However, one ewe that had previously experienced C. burnetii shedding at the first lambing excreted the bacteria in the genital tract after the third parturition. The bacteria could not be detected by PCR in milk and faecal samples taken up to 12 days after both parturitions.  相似文献   

4.
The antiproteolytic activities of the blood plasma (BP) and cervical mucus (CM) determined as trypsin inhibiting activities (TIA) where trypsin served as a model serine protease, were variable after superovulatory stimulations of ewes and after their gamma irradiation (2.45 Gy). TIA's were determined from the reduction in the bovine trypsin hydrolysis of the low-molecular chromogenic substrate N-alpha-tosyl-L-arginyl-p-nitro anilide (TAPA) (Bartík et al., 1974). The inhibition was expressed in per cent when delta A405 = 1.0 for 10-minute incubation at 25 degrees C, pH = 8.05, 0.2 mol/l tris-HCl buffer, was taken as 100%. Student's t-test was used for the statistical evaluation. A hundred ewes of the Merino breed were applied Agelin vaginal tampons (20 mg chlor-superlutin per head) on day 1 for 10 days in the anoestric period (May). A part of these ewes were subjected to whole-body gamma irradiation on days 6 to 11. When the irradiation was completed and the tampons were taken out, the ewes (three to four years old lambing ewes, yearling ewes) were stimulated to superovulations by an administration of 1500 IU serum gonadotropin (SG) or 450 IU follicle stimulating hormone (FSH). These parameters were followed in the subsequent 5-6 days: BP TIA (Figs. 1 and 4), fraction of low-molecular BP (n) TIA (Figs. 2 and 5), CM TIA (Figs. 3 and 6). Fig. 7 shows the average values of the results. The lambing ewes and yearling ewes had various responses to irradiation and superovulatory stimulation. Gamma irradiation eliminated the increase in BP TIA (P < 0.001) in the ewes after stimulations (Fig. 1a, b). The yearling ewes showed nonsignificant changes (ns) as their responses to SG stimulations and gamma irradiation, but the responses on the particular days of the trial were different (Fig. 1c, d--FSH stimulation). Similar changes were observed in the BP nTIA fraction. The changes in the average values of CM TIA were nonsignificant in the lambing ewes, the gamma irradiation reduced CM TIA only after FSH stimulation (P < 0.002). The amount of cervical mucus decreased after stimulations and irradiation, the thickness of ovarian epithelium and muscles was reduced in the particular parts, differently in lambing ewes and in yearling ewes.(ABSTRACT TRUNCATED AT 400 WORDS)  相似文献   

5.
The effects of a serum gonadotropin (SG) superovulation hormonal preparation were investigated on catecholamine levels (norepinephrine, dopamine and epinephrine) in the blood plasma of ewes with synchronized oestrus in the oestrus period. In this trial the blood plasma of eleven ewes of the Slovak Merino breed was analyzed to detect catecholamines in the oestrus period. Superovulation was induced by an i.m. administration of 1500 IU SG as soon as oestrus synchronization with Agelin vaginal tampons finished (20 mg chlorsuperlutin) which lasted for 10 days. Catecholamines were detected in the blood plasma before synchronization, on the day of Agelin vaginal tampons application, and in 48 and 72 hours after the hormone administration--on the days of the expected ovulation. Catecholamine concentrations in the blood plasma were determined by a radioenzymatic assay using a Catechola test (Praha). The results indicate that synchronization and hormonal stimulation influence plasma catecholamine levels. The norepinephrine (NE) concentration in the blood plasma of the control samples has the value of 8.31 +/- 0.732 pmol/ml. An insignificant increase in the NE levels (13.12 +/- 0.120 pmol/ml; Fig. 1) was recorded on day 1 of the trial, after the start of synchronization. On the day of the expected ovulation the NE concentrations rose to 17.12 +/- 1.289 pmol/ml (P less than 0.001) and they remained significantly increased (P less than 0.01) at the level of 12.89 +/- 1.020 pmol/ml on the following day of the experiment. The dopamine level (DA) in the plasma of a control sample is 6.42 +/- 0.350 pmol/ml (Fig. 2).(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

6.
Enzootic abortion of ewes (EAE) caused by Chlamydophila abortus is an important disease resulting in significant lamb loss in most sheep producing countries. Ewes are considered to be naturally infected with C. abortus via the oral–nasal route and may become persistent carriers, shedding during subsequent oestrous cycles and at lambing. The aim of this study was to monitor the clinical outcomes, pathological changes and shedding of C. abortus in 18 periparturient orally infected sheep for two breeding seasons. In the first season, C. abortus was detected by real-time PCR (rt-PCR) in 13/18 conjunctival swabs at oestrus. Three out of the 15 pregnant ewes gave birth to 1 live and 1 dead lamb, and 2 of them aborted. Following parturition/abortion, C. abortus was detected in 12/15 vaginal swabs and in all the collected foetal membranes. However, only those membranes containing high copy numbers of the bacterium displayed the EAE typical lesions. In the second season, none of the 13 pregnant ewes aborted, and 5 of them gave birth to dead or weak lambs. C. abortus was not detected in conjunctival or vaginal swabs at oestrus or parturition. The bacterium was detected at low levels in 36% of the foetal membranes, but with no evidence of histopathological lesions. These results indicate that C. abortus can be detected in a large proportion of animals during the first pregnancy after oral infection. However, this proportion is reduced at the subsequent breeding season, confirming the occurrence of a chronic low level persistent infection in post-abortion/lambing ewes.  相似文献   

7.
Phagocytic activity of peripheral leucocytes (PA) was measured in heifers during the luteal phase and oestrus and after administration of various doses of oestradiol, in ovariectomized heifers and cows in the early post-partum period. PA was demonstrated in 22.63 +/- 2.49% and 50.61 +/- 3.76% of phagocytes in the luteal phase and oestrus respectively (P less than 0.01, Fig. 1). The phagocytic index (PI) rose parallelly from 2.26 +/- 0.31 to 6.55 +/- 0.64 particles per cell (Fig. 2). Intramuscular administration of a single dose 3 mg of oestradiol dipropionate resulted in an increase of PA from 28.93 +/- 3.34 to 69.60 +/- 3.32 on post-treatment day 3 (P less than 0.05, Fig. 3). A nonsignificant increase of PA was observed in heifers treated with 10 mg oestradiol. Increases of PA and PI in postparturient cows, treated with various doses of oestradiol, were nonsignificant (Fig. 5, 6) owing to a wide variance of the values obtained, which might be due to individual differences in endocrine and metabolic status or to uterine bacterial contamination. The most marked of haematological changes was the increase of eosinophil counts from 317 to 525.10(6).l-1 in a group of cows treated with 10 mg oestradiol and a decrease of the lymphocyte: neutrophil ratio (Tab. I). Both endogenous and exogenous oestrogens stimulate PA of peripheral leucocytes and 3 mg of oestradiol is a sufficient dose to obtain the effect.  相似文献   

8.
The incidence of dystocia from ewes in nine lambing periods (1992-2000) was recorded at an obstetrical clinic. First we analysed parturition difficulties in normal pregnant sheep (group 1, n = 229). In the second group parturitions of ewes with vaginal prolapse ante partum were investigated (n = 129). In group 1 maternal causes of dystocia occurred more often than fetal ones (50% maternal, 45% fetal). In maternal parturition difficulties ringwomb was the dominating reason (64%), while abnormal presentations, position and/or posture of the lambs occurred most frequently in fetal dystocia (67%). But there was no statistical influence of age and number of parturitions in both groups. The average of the first notice of prolapsed vaginal tissue was 11 days before lambing. There was a predominance in the affection of sheep at first and second pregnancy (52%). Only 26% of the group 2 sheep had a spontaneous delivery. In 58% of the cases a dystocia was diagnosed. A preterm caesarean section had carried out in 12%, five ewes died before parturition because of septicemia (4%). Sheep suffering from vaginal prolapse ante partum showed maternal caused dystocia significant more frequently than members of group 1 (p < 0.001), with ringwomb as dominating reason (70%). The number of born lambs was significant higher in group 2 than in group 1 (p = 0.019).  相似文献   

9.
Objectivisation of the physiological course of puerpery and control of involution processes of uterus represent topical questions of an increased frequency of lambing. Our study was directed at the determination of the weight, length of body and horns of uterus as well as of the weight, length, width and height of ovaries, following the administration of carbetocin (Depotocin inj. Spofa), in the puerperal period of Slovak Merino sheep. The study was aimed at obtaining objective biometric data on uterus and ovaries and recording the influence of carbetocin on the involution of uterus and ovaries of sheep. Thirty ewes, divided into two groups, were included in the experiment. The animals of the experimental group (n = 15) were subjected to treatment with carbetocin (Depotocin inj. Spofa) at the amount 2 x 0.07 mg. The first dose was applied intramuscularly (i. m.) on the 2nd day after parturition and the second dose was injected subcutaneously (s.c.) on the 4th day after lambing. The second group (n = 15) served as a control. Three ewes (n = 3) were bled on each of the following days: 1, 7, 17, 25 and 34 after parturition. After bleeding the sexual organs were removed by excision and their weight and the length of the body and horns of uterus and of ovaries was determined. The number and size of follicles were determined on the surface of ovaries. The weight of uterus body showed a declining tendency in sheep of the control group with a statistically significant decrease from the 17th till the 34th day after parturition (P less than 0.01). Its weight varied from 56.0-14.6 to 5.2-0.3 g in the above-mentioned time interval. The experimental group showed a statistically significant decrease in weight as early as on the 7th day after lambing compared to the 1st day after parturition, down to the values 185.66-38.91 g (P less than 0.05). The decrease in the weight of uterus body recorded on day 17 (106.56-41.08 g) was less pronounced than in the control group. The final average weight of the body of uterus on the 34th day after parturition was 41.36-8.52 g, that means higher than in the control group (5.2-0.3 g). The weight of gravid horns in the experimental group declined significantly as early as on the 7th day after parturition to the average weight of 60.89-9.45 g and reached 9.86-3.49 g on the 34th day.(ABSTRACT TRUNCATED AT 400 WORDS)  相似文献   

10.
Biometric changes of uterus, ovaries, follicles and 17 beta-oestradiol (E2) concentrations were investigated in 15 lambing ewes of the Slovak Merino breed in the puerperal period. The sex organs were excised immediately after bleeding from ewes slaughtered on days 1, 7, 17, 25 and 34 post partum (p. p.). Biometric parameters of the body and horns of uterus were measured by a calliper. The ovaries were weighed on an analytical balance, their length, width and height were measured at the same time. The size and number of follicles were determined on the ovary surface. The blood for E2 detection was collected from vena jugularis three and one day before delivery (days -1, -3). Blood samples were also collected after delivery on days 1, 7, 17, 25 and 34. E2 concentrations in the blood serum of ewes were determined by RIA-test-ESTRA kits, designed in one institute at Kosice. The highest weight of uterus body in the test ewes was recorded on day 1 p. p. In the following days the weight of uterus body had a decreasing trend. There were significant differences in the weight of uterus body from day 17 to day 34 p. p., in comparison with the first day after lambing (P less than 0.01). A significant decrease in the length of uterus body was observed from day 17 to day 34 of observation (P less than 0.01; P less than 0.001). An increase in the length of a nongravid horn, observed on day 7 p. p., was followed by a gradual decrease until day 34, similarly like in its weight. No statistically significant differences were found out in the ovary length, width and height. Neither were any greater changes recorded in the weight of ovaries from day 1 to day 34 after delivery. The highest number of small structures (28) observed on day 7 p. p. in the ipsilateral ovary was decreasing in the course of puerperium and the number of follicles larger than 2, 4 and 5 mm was increasing. The highest concentrations of E2 were not recorded on day -1 before delivery. The significantly lowest concentrations of E2 were recorded on day 25 p. p. The above-mentioned results are preliminary and they enlarge the knowledge of biometric parameters of uterus, ovaries, follicles and E2 concentrations after delivery in ewes.  相似文献   

11.
Invasive and non-invasive strains of Chlamydia psittaci isolated from faeces of clinically healthy ewes and from vaginal swabs of ewes which had aborted were injected intravenously or intradermally into pregnant ewes. The results were studied by recording the ewes' thermal and serological responses, lambing performance and the excretion of chlamydia from the vagina. The differences between the effects of different invasive strains were greater after intradermal inoculation than after intravenous inoculation. After intradermal inoculation non-invasive strains did not disturb pregnancy (11 of 13 ewes lambed normally) whereas invasive strains induced abortion in 23 of 25 ewes, 24 of which excreted chlamydia in vaginal secretions.  相似文献   

12.
Neutrophil responses were evaluated in dairy cows at parturition and on 1, 2, 3, 5 and 7 days after they were given dihydroheptaprenol (DHP) (0.5 mg/kg body weight) at parturition. The chemiluminescent index increased significantly (P less than 0.05) from parturition to 1 day after parturition in cows injected with DHP. No significant differences were observed in the number of neutrophils between untreated and DHP-treated groups of dairy cows during the immediate postparturient period.  相似文献   

13.
Knowledge of pathogenesis of sexual dysfunctions at altered thyroid activity is limited by the knowledge of multiple and ubiquitous action of its hormones throughout the organism. One of the possibilities of modulatory influence of thyroid hormones on sexual functions can be realized through the participation of thyroxine and triiodothyronine in the synthesis and metabolism of primary substrate of steroid synthesis--cholesterol. The presented work is aimed at the study of simultaneous dynamic changes of concentrations of thyroxine (T4), triiodothyronine (T3), 17 beta-estradiol (E2), progesterone (P4) and cholesterol (Chol) during synchronization of the rutting period and gravidity at parallel correlative evaluation of mutual relations of the followed parameters in ten Merino sheep in the seasonal period. Synchronization was achieved by chlorsuperlutin (Agelin--vaginal swabs, Spofa; 20 mg of chlorsuperlutin/swab) and PMSG (500 I. U./animal). Blood was sampled by means of a jugular vein puncture at the time of swab insertion (-13th day) and after three (-10th day) and seven (-7th day) following days, at the removal of swabs and application of PMSG (-3rd day), on the day of insemination (zero day), on the 7th, 14th and 17th day and in the middle of the 2nd, 3rd, 4th and 5th month of gravidity. In the phase of oestrus synchronization a significant increase of E2 concentrations on days -7 and -3 of the experiment (0.47 +/- 0.079 and 0.542 +/- 0.177 nmol.l-1 of serum, P less than 0.001; P less than 0.001) was observed compared to the E2 values on day -13 (0.084 +/- 0.036 nmol.l-1 of serum). Parallel to these observations, marked intermittent changes of T4 (Tab. I, Graph 1) were recorded with the lowest values of this parameter observed on days -10 (41.75 +/- 20.23, P less than 0.05) and -3 (50.22 +/- 18.77, P less than 0.05) and the highest on day -7 (96.77 +/- 17.51 nmol.l-1, P less than 0.01) and day zero (85.40 +/- 19.59 nmol.l-1 of serum, P less than 0.05) in comparison with the -13th day (67.22 +/- 18.29 nmol.l-1 of serum). Concentrations of P4 (Tab. I, Graph 4) declined to the lowest values on day zero observation (0.09 +/- 0.08 nmol.l-1 of serum, P less than 0.05 vs 3.40 +/- 3.61 nmol.l-1 on day -13). No significant changes of concentrations of T3 (Tab. I, Graph 2) and Chol (Tab. I, Graph 5) were observed during oestrus synchronization. During gravidity, concentrations of E2 (Tab. I Graph 3) showed an increasing trend compared to the -13th day.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

14.
The induction and management of lambing was studied in a commercial flock of ewes. These ewes were bred at synchronized estrus and managed to lamb three times in 2 yr, with lambings occurring in the sequence of February, September and June. Ewes treated with 2 mg of estradiol benzoate in oil (i.m.) at approximately 17 d prior to term did not lamb in response to treatment. When 2 mg estradiol benzoate was given at 0800 on d 142 of gestation, lambing occurred an average of 37 +/- 5 h later in ewes treated in June or September and at 70 +/- 10 h later in ewes treated in February. The comparable figures for oil-treated ewes (control) were 70 +/- 5 h and 116 +/- 9 h, respectively. Altering the time of day of injection or using two injections 24 h apart did not alter the time for injection to lambing. Increasing the dose of estradiol benzoate to 15 mg decreased the time from injection to lambing (43 +/- 7 h, ewes treated in February) but also increased the incidence of dystocia (50% incidence). The incidence of dystocia averaged 8% for all other treatments and controls. Death loss of lambs to 1 wk of age was 12% and was not affected by treatment. The length of the lambing period was reduced from 9.0 +/- 3.3 d in control ewes to 3.6 +/- 1.1 d in induced ewes. A single injection of 2 mg estradiol benzoate given at 0800 on d 142 of gestation or a double treatment, with injections at 2000 on d 142 and 143, resulted in 53% of ewes lambing between 0800 and 1600 on each day of the lambing period, compared with 33% in control ewes.  相似文献   

15.
Three hundred three pregnant ewes were randomly allotted to treatments in a 2 (diet) X 2 (feeding time) factorial arrangement 10 d before the first lambs were due in two lambing seasons to study the effect of time of feeding and diet on time of lambing. Behavioral activities were observed to determine if there was a relationship to time of parturition. All ewes were fed .5 kg ground whole corn per day plus either: alfalfa hay fed at 2200 each day, alfalfa hay fed at 1000 each day, alfalfa haylage fed at 2200 each day or alfalfa haylage fed at 1000 each day. Lambing data from 1983 and 1984 were combined across years because no treatment X year interactions (P greater than .05) were detected. Average time of day for lambing did not differ (P greater than .05) among treatments. In general, no differences due to treatments were observed in lambing time or behavioral activities studied. When data were pooled across treatments, two peak lambing times were observed. These peak times for lambing were from 0300 to 0700 (22.1%) and from 1500 to 1900 (22.5%). During these two 4-h periods (8 h total) 44.6% of the ewes gave birth.  相似文献   

16.
The purpose of the present study was to investigate the feasibility of improving the synchronisation of lambing after oestrus synchronisation and artificial insemination (AI). To this end, low doses of dexamethasone 21-isonicotinate (DEX) alone or in combination with prostaglandin F2a (PG) were used in five treated groups (n = 20 each) and one control group (n = 136) of Chios ewes. On day 143 of pregnancy 1.5 mg DEX was given in Group 5, while on day 146 the following treatments were applied: 0.0375 mg PG in Groups 4 and 5, and 1, 1.5 and 2 mg of DEX in ewes of Groups 1, 2 and 3, respectively. The control ewes received no treatment. The 1.5 and 2 mg dose of DEX was more effective in synchronising labour as regards the treatment to lambing interval and the proportion of ewes that gave birth within 3 days. However, obstetrical manipulations were needed, and dead lambs were born when 2 mg DEX was used. It was concluded that lambing can be safely synchronised in Chios ewes with 1.5 mg DEX given on day 146, without affecting the viability of lambs and without parturition complications.  相似文献   

17.
The postpartum (PP) period in the Pelibuey ewe was studied. Laparotomies were performed on 14 ewes in the first year at d 10, 20 and 30 PP, and at d 10 and 20 PP in the second year on 17 ewes. Progesterone concentrations were determined in serum taken daily, from 4 to 7 d after parturition until estrus. Temporal fluctuation of luteinizing hormone (LH) was determined in samples taken at 30-min intervals for 4 h weekly. The mean interval from lambing to first ovulation was longer (P less than .001) in 1980 (59 +/- 4.9 d) than 1979 (26 +/- 3.1 d), the mean interval from lambing to first estrus was also longer (P less than .001) in 1980 (91 +/- 5.6 d) than 1979 (51 +/- 5.5 d). Follicles were present on the ovaries of the majority of the ewes at d 10. The mean diameter of the largest follicles on each ovary was reduced (P less than .025) in ewes in 1980 (6 mm) compared with 1979 (7.7 mm). Corpora lutea (CL) occurred in 67 and 75% of the ewes by d 20 and 30, respectively in 1979; no CL were found by d 20 in 1980. Progesterone profiles suggested that the PP period was composed of a period of anestrus, and a period of cyclic ovarian activity with one, two or three ovulations without behavioral estrus. In some ewes, the first cycle was of shorter duration, and its CL secreted less progesterone (P less than .05) relative to CL of silent and regular estrous cycles. Luteinizing hormone peaks were recorded as early as 6 d PP. When progesterone concentrations were elevated to luteal phase levels, the frequency, but not magnitude, of LH peaks per 4-h bleeding period was reduced (P less than .05) relative to anestrus. It is concluded that there are periods of anestrus and of silent cycles, which precede the first postpartum estrus in Pelibuey ewes.  相似文献   

18.
The aim of this trial was to evaluate the effectiveness (fertility and lambing) of priming with a single injection of progesterone plus PMSG in anovulatory lactating Sarda ewes subjected to the ram effect (RE) in spring. Thirty ewes (P4 group) were i.m. injected with 30 mg progesterone and 500 IU PMSG 36 h before ram introduction (d 0). This treatment was compared to a 12-day treatment with fluorogestone acetate intravaginal sponges that was followed by injections of 350 IU PMSG upon sponge withdrawal (FGA group, n=30). All ewes responded to RE, showing plasma progestrone concentrations >1 ng/mL between d 6 and 12 (FGA) or 6 and 9 (P4). Eighty-nine percent of the P4 ewes conceived at first ovulation, and 11% conceived following a short estrus cycle. Lambings occurred on d 150.4 +/- 3.9, and the lambing rate was 100%. The fertility of the FGA ewes was 83% for the induced ovulation and was 7% for the second ovulation after a normal cycle. The FGA ewes lambed on d 149.8 +/- 4.4, and the lambing rate was 83%. Two abortions were recorded for the FGA ewes, which had higher prolificacy than the P4 group (2.2 +/- 0.8 vs. 1.8 +/- 0.4, respectively; P<0.05). Both fertility and the lambing rate were high in both groups, with a high degree of estrus synchronization, and there were no significant differences between the groups. We concluded that priming of lactating Sarda ewes in spring with P4+PMSG before RE is an effective and competitive method (cheaper and more practical than FGA+PMSG) of inducing fertile ovulations in these ewes.  相似文献   

19.
Ewes selected for fertility in autumn lambing were used to evaluate correlated responses in nocturnal hormone levels. Four jugular blood samples were obtained during nighttime in August from each of 113 selected and 69 control ewes. Melatonin levels were lower for selected ewes (143 +/- 14 pg/mL) than for control ewes (184 +/- 13 pg/mL), and melatonin levels decreased with increases in estimated breeding values (EBV) for fertility (-2.23 +/- 0.79 pg mL(-1) x %(-1)). Prolactin levels were higher for selected ewes (90 +/- 7 ng/mL) than for control ewes (52 +/- 7 ng/mL), but significant line x ewe age interaction was also observed, with smaller differences in prolactin levels in 2-yr-old and older ewes (74 +/- 7 vs. 56 +/- 9 ng/mL for select and control ewes, respectively; P < 0.20 before and P = 0.05 after logarithmic transformation). Prolactin levels increased with both fertility EBV (1.23 +/- 0.53 ng mL(-1) x %(-1)) and maternal birth weight EBV (9.0 +/- 4.0 ng x ml(-1) kg(-1)). Heritability estimates were 0.43 (P < 0.02) for melatonin levels and 0.11 (P > 0.25) for prolactin levels. Thus, we conclude that selection for fertility in autumn lambing has affected patterns of melatonin and prolactin secretion during the dark phase.  相似文献   

20.
Three experiments were conducted to investigate experimentally the occurrence of periparturient nematode egg rise in ewes and the hormonal modulation of Haemonchus contortus infections. In the first experiment, fall-bred and winter-bred pregnant (n = 4 and 14, respectively) and nonpregnant (n = 5 and 29, respectively) ewes were treated with anthelmintic and were pastured together on fields that were contaminated with H contortus. Three weeks before lambing, all ewes were placed in concrete pens; fecal egg counts for the winter-bred group were obtained on alternate days. Pregnant and lactating ewes had significantly larger numbers (P less than 0.01) of H contortus eggs than did the nonpregnant controls 1 week before and after lambing. Lactating, fall-bred ewes had significantly (P less than 0.01) more adult worms in their abomasum through natural acquisition than the nonpregnant controls. In the second experiment, fall-bred and winter-bred, helminth-free, pregnant (n = 4 and 8, respectively) and nonpregnant (n = 3 and 15, respectively) ewes were inoculated on 5 alternate days, beginning 70 days after breeding with 20,000 infective H contortus larvae. The ewes were maintained on concrete pens throughout pregnancy. Fecal egg counts were significantly (P less than 0.05) greater in pregnant ewes, beginning 1 week before lambing until 1 week after lambing. Abomasums of lactating ewes from both lambing seasons yielded significantly (P less than 0.01) more adult worms at necropsy than nonpregnant ewes. In the third experiment, ewes were ovariectomized (n = 15) or sham-operated (n = 9); half of the control ewes were bred.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

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