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1.
The aim of this study was to characterize corpus luteum vascularization and its association with plasma progesterone concentration in early stages of pregnancy, when maternal recognition of pregnancy is expected to occur. In all animals, both plasma progesterone concentration and corpus luteum vascularization increased from Day 6 to Day 8 post-mating and afterwards in non-pregnant llamas they started to decrease to reach basal levels around Days 12 to 14 post-mating, while in pregnant animals, both variables remained elevated until the end of the study. A lineal positive relationship between corpus luteum vascularization and plasma progesterone concentration was observed in pregnant (r2 = .46, p < .0001) and non-pregnant llamas (r2 = .66, p < .0001). Pregnant animals showed higher plasma progesterone concentration and corpus luteum vascularization than the non-pregnant ones from Day 12 post-mating until the end of the study (p ˂ .05 and p ˂ .01, respectively). These results suggest that maternal recognition of pregnancy should occur before Day 12 post-mating in order to expand luteal lifespan, maintaining corpus luteum vascularization and progesterone production. Also, the assessment of CL vascularization area could be a useful and non-invasive method for early pregnancy diagnosis due to its association with plasma progesterone concentration.  相似文献   

2.
A cannulation technique was developed to collect blood samples from the ovarian vein of mares over an extended period. Ovarian venous cannulae placed in 4 mares remained patent for a mean (+/- SEM) duration of 36.8 (+/- 6.2) days. During mid-diestrus, concentrations of progesterone in the ovarian vein ipsilateral to the corpus luteum (1,663.8 +/- 238.8 ng/ml) were significantly (P less than 0.001) higher than concentrations measured in paired samples from the jugular vein (6.1 +/- 0.3 ng/ml). Concentration of estradiol in the ovarian vein ranged from a mean of 1,053.2 +/- 303.1 pg/ml during diestrus to 3,353.8 +/- 1,052.8 pg/ml during estrus, whereas values for 74% of samples collected concurrently from the jugular vein were near or below the sensitivity of the assay (10 pg/ml). Results of the study indicate that patent long-term ovarian vein cannulation can be achieved in mares. The cannulation technique provides access to important fundamental information on equine reproductive endocrinology, which to our knowledge, has not been available.  相似文献   

3.
Six heifers were inoculated IV at estrus with the Iowa or Colorado isolates of infectious bovine rhinotracheitis virus (IBRV). Subsequent measurements of plasma progesterone indicated that corpus luteum function was depressed in all heifers. In the 1st estrous cycle after inoculation, progesterone values did not exceed 2 ng/ml in 3 heifers given the Iowa isolate. Although maximal progesterone values were greater than or equal to 2 ng/ml in 3 heifers given the Colorado isolate, values were lower than those in later cycles. Five heifers had maximal diestrual progesterone values greater than or equal to 5 ng/ml within 5 weeks after inoculation, but in the 6th heifer, this amount of progesterone was not present until 8 weeks after inoculation. Three to 5 months after inoculation, all heifers were given 5 daily injections of dexamethasone, 2 heifers each during metestrus, diestrus, or proestrus. Subsequent recrudescence of IBRV was demonstrated in all heifers by the isolation of virus from vaginal or nasal swab samples. The heifers were killed 10 to 17 days after initiation of dexamethasone treatment and their reproductive organs were examined for lesions and IBRV. Lesions were not seen, and IBRV was isolated only from the corpus luteum of a heifer given dexamethasone during diestrus.  相似文献   

4.
A study aimed at validating a human progesterone enzyme immunoassay kit was carried out on cattle at Bambui, Cameroon. Progesterone ELISA Kits (EH-511) were obtained from Clinpro International. Forty-one cows were selected, of which 19 were pregnant and 22 within 14 days post partum. Blood samples were analysed and progesterone levels were deduced from a curve obtained from standard absorbance values (A 450). Results show that 95.5% of postpartum cows had progesterone levels below 1 ng/ml, with the highest level being 0.75 ng/ml. The mean level was 0.5 ± 0.26 ng/ml. The cows in the ‘pregnant group’ had progesterone levels ranging from 3.5 to 17.5 ng/ml. This kit can be used for measuring progesterone levels in cattle. Levels of 1 ng/ml for two consecutive samples or one sample at or above 3 ng/ml are an indication of the presence of corpus luteum, while cows below 1 ng/ml will be in anoestrus.  相似文献   

5.
In 160 cows with ovarian cysts as determined by rectal palpation, differentiation was made of follicular cyst, luteal cyst, and cystic corpus luteum on the basis of milk progesterone concentrations estimated by an enzyme immunoassay before and at 10 days after cows were treated with gonadotropin-releasing hormone. Cows having a progesterone concentration in skim milk less than 1.0 ng/ml were considered to have follicular cysts and those with concentrations of 1.0 ng/ml or higher were regarded as the cases of luteal cyst or cystic corpus luteum. Luteal cyst was characterized by progesterone values remaining high in the cows for 10 days after treatment, and cystic corpus luteum was characterized by a decrease in progesterone concentration after cows were treated. By the rectal palpation procedure it was impossible to differentiate luteal cyst and cystic corpus luteum from follicular cyst. The frequencies of follicular cyst, luteal cyst, and cystic corpus luteum were 65%, 19%, and 16%, respectively. Of 104 cows with follicular cysts as defined by milk progesterone assay result, 73 (70%) responded to the treatment with gonadotropin-releasing hormone, the milk progesterone concentration increasing from 0.7 +/- 0.2 ng/ml (mean +/- SD) to 1.8 +/- 1.1 ng/ml. The accuracy of rectal palpation 10 days after treatment for judgment of luteinization of follicular cyst confirmed by milk progesterone analysis was only 30% (48 cows of 160).  相似文献   

6.
Using rectal palpation and laparoscopy, the relationship of ovarian contents to plasma progesterone concentration during the oestrous cycle, early pregnancy and post partum periods in the swamp buffalo (Bubalus bubalis) was studied. During the oestrous cycle, four stages in the lifespan of the corpus luteum were seen laparoscopically. The mean (+/- sd) concentrations of progesterone in plasma in cows with and without a corpus luteum on their ovaries were 1.49 +/- 0.78 ng/ml (n = 31) and 0.14 +/- 0.09 ng/ml (n = 14), respectively. Plasma progesterone levels reflected age-dependent changes occurring in the cyclic corpus luteum. The accuracy of diagnosing ovarian contents was 82 and 91 per cent for rectal palpation and plasma progesterone levels respectively. Approximately 29 per cent follicles (larger than 10 mm) were incorrectly diagnosed as corpora lutea by rectal palpation.  相似文献   

7.
To determine the effect of the hyperadrenal state on corpus luteum (CL) function, we treated intact and adrenalectomized (ADRX) heifers with adrenocorticotropin (ACTH) and hydrocortisone. ACTH treatment of intact heifers by infusion of 1 mg alpha 1-24 ACTH/24 hr from day 2 to 25 of an estrous cycle increased progesterone concentrations in plasma to 4 +/- .52 ng/ml plasma on days 3 to 4. Thereafter, progesterone concentrations declined, indicating severe suppression of CL function as compared to that of control heifers. Similar infusions of ACTH to ADRX heifers did not alter CL function as reflected by progesterone concentrations in jugular plasma. Infusion of ADRX animals with hydrocortisone succinate (100 mg/24 hr) decreased progesterone in plasma during the cycle, with maximum values averaging less than 4 ng/ml, compared to concentrations of 6 to 7 ng/ml in control ADRX heifers. Chronic administration of ACTH or hydrocortisone to heifers caused a decreased progesterone secretion during the luteal phase of the estrous cycle. On the basis of these results, we suggest that stress, as indicated by the hyperadrenal state, could inhibit progesterone secretion by the corpus luteum.  相似文献   

8.
AIMS: To determine the level of agreement between transrectal ultrasonography, manual palpation and measurement of progesterone in the detection of corpora lutea in post-partum cows. To evaluate the reproductive performance of cows not detected in oestrus prior to mating, but detected with a corpus luteum at the start of mating. METHODS: Cows from seven herds which were not detected in oestrus were examined between 5 and 7 days before the herd's planned start of mating. Ovaries were examined by palpation and ultrasonography in 160 cows and plasma progesterone concentrations were also measured in 103 cows. Insemination dates and pregnancy data were recorded in 159 cows not detected in oestrus but having a corpus luteum and 1405 cycling herd mates. RESULTS: The level of agreement between ultrasonography and measurement of progesterone (kappa = 0.74) was higher than with manual palpation (kappa = 0.67) although it was significant for both techniques (p <0.001). Cows which were not detected in oestrus, but detected with a corpus luteum had a longer interval to first service (12 v. 10 days, p <0.05) and conception (19 v. 15 days, p = 0.01) than cycling herd mates and had a higher empty rate (9.7% v. 3.8%, p <0.001). CONCLUSIONS: These data indicate that ultrasonography may provide a better diagnostic tool for examining cows not detected in oestrus than manual palpation or measurement of progesterone concentration. Cows not detected in oestrus but having a corpus luteum were shown to have significantly poorer reproductive performance than cycling herd mates.  相似文献   

9.
Ovaries of unilaterally ovulated goats (n=21) were used to study follicular morphological features (proportion and degree of atresia, oestradiol production in vitro and progesterone production of granulosa cells in culture). Follicles were dissected out and classified as small (1–2 mm), medium (2–4 mm) and large (>4 mm). Morphological and physiological features were compared in each size class between ovaries bearing and not bearing corpora lutea (CLO and NCLO, respectively). Within the same size class, there was no difference in proportion or in degree of atresia, between CLO and NCLO. A significant effect of follicular size on oestradiol production in vitro was detected, but no effect of the corpus luteum was found. Finally, progesterone production of granulosa cells in culture was significantly higher in CLO than in NCLO after 24 h (p < 0.05) and also after 90 h (p < 0.01) of culture. This higher progesterone production by CLO granulosa cells in culture could be explained by local influence of the corpus luteum stimulating the steroidogenic activity but not aromatase activity. Further studies are needed to clarify possible factors and pathways for this local effect of the corpus luteum upon follicular physiology.  相似文献   

10.
Manual palpation or ultrasonographic examination of the cow's genital tract are currently used by veterinarians involved in reproductive management, but knowledge of the potential and the limitations of both methods is important to obtain an optimal accuracy in the diagnosis of physiological and pathological ovarian structures. This review presents the main features of manual and ultrasonographic characteristics of follicles, corpora lutea (with or without a cavity), follicular and lutenized cysts and the reliability of the two methods is compared. Manual diagnosis of follicles <10 mm is rather inaccurate, but ultrasound offers the possibility to diagnose follicles <5 mm and to measure their inner diameter. The predictive values of the presence or absence of a corpus luteum as determined by palpation are similar (78 vs. 75%). Manual or ultrasonographic diagnosis of the growing or regressing corpus luteum is rather difficult. The positive predictive value of a mature corpus luteum diagnosed by ultrasonography is lower (87%) than the negative predictive value (92%). Compared to manual palpation, ultrasonography permits a better estimation of the number and to determine more precisely the size of the mature corpus luteum. The positive values for follicular cysts diagnosed by palpation or by ultrasonography are 66 and 74% respectively, and for luteal cysts, the values are 66 and 85%, respectively.Manual palpation or ultrasonography are useful tools to diagnose ovarian structures in the cow. The accuracy of such methods can be enhanced by securing information on the reproductive history of the animal, palpation of uterine horns, vaginal examination or progesterone determinations.  相似文献   

11.
Trials were performed to examine the effectiveness of 250 micrograms (1 ml) of cloprostenol (Oestrophan Spofa) implantation under the mucous membrane of the vaginal vestibule of 128 cows with a clinically pronounced corpus luteum on ovaries. Within 72 hours from administration, oestrus was observed in 112 animals (85.5%). Out of the 97 cows inseminated, 63 cows (64.94%) got in calf. The effectiveness of the luteolytic action was examined on the basis of progesterone check in milk in 56 treated cows. The submucous implantation of cloprostenol rapidly degraded the function of the corpus luteum since from the original level of 14.78 ng/ml progesterone decreased to 0.87 ng/ml within 72 hours. However, luteolysis did not affect all the corpora lutea. Hence the submucous administration of cloprostenol was found to be effective, and at the same time, highly economical, owing to a substantial reduction in the costs of reproduction control as well as the costs of production.  相似文献   

12.
The skim milk progesterone profile was assessed by radioimmunoassay, without extraction, from the day of insemination (day 0) until the cows were dried off on day 225 of gestation. A total of 418 samples were collected from 154 pregnant Holstein cows. The daily variation in skim milk progesterone was recorded from day 1 until day 45 of pregnancy to detect the commencement of progesterone secretion from the corpus luteum after insemination. Subsequent determinations were made every 2 weeks from day 46 until lactation ceased. On the day of artificial insemination and for the first 2 days after insemination, all the cows had a basal progesterone concentration <0.1 ng/ml. A rise in progesterone (0.2±0.1 ng/ml) was first detected on the third day after insemination. The progesterone values then increased significantly (p<0.001) until day 15.The values then remained nearly constant (2.5–3.5 ng/ml) until day 106 of pregnancy, when they began to decline. Between days 120 and 180 of gestation, progesterone was significantly decreased (2.2–2.9 ng/ml) before it rose again to the previous plateau (3.5–3.9 ng/ml) around day 180. The progesterone concentration then remained at the higher level until the animals were dried off.Abbreviations AI artificial insemination - RIA radioimmunoassay  相似文献   

13.
黄体释放的黄体酮对母畜发情周期、启动发情行为和维持妊娠起着至关重要的作用,但目前国内外对黄体是否影响胚胎移植效果有着不同报道。本文以探究黄体对牛胚胎移植效果的影响为主线,查阅大量文献,归纳黄体的检查和级别判断方法,分别分析黄体大小、黄体位置、黄体质量和黄体生产溶解过程激素水平与胚胎移植受胎率的关系,为提高胚胎移植效果提供科学的参考依据。生产上常通过B超扫描结合直肠检查法判断受体牛黄体发育和位置作为能否移植的依据;由各学者研究结果可见,不同直径黄体的胚胎移植受胎率差异不显著,为提高受体牛的利用,在对受体牛黄体大小选择时可适当放宽标准;胚胎移植到黄体同侧的受胎率比移植到黄体对侧的高,另外,可能因为操作者左右手操作习惯不同,发现左侧黄体移植受胎率比右侧的要高;较多学者认为质量好的胚胎选择黄体质量好的受体移植才能得到更高的受胎率;胚胎移植后能否成功受孕,还与黄体生成溶解过程中孕酮含量及孕酮与雌二醇的比例等有关。  相似文献   

14.
The aim of the present study was to examine the plasma concentrations of progesterone, oestradiol-17beta and cortisol in the cows with cystic follicle and to examine its relationship with the ovulatory response to gonadotropin-releasing hormone (GnRH). Eighty-five post-partum Holstein-Friesian cows with cystic follicles regardless of the presence of corpus luteum were studied. Follicular size, presence of corpus luteum and occurrence of ovulation were checked by palpation per rectum. Blood collection and palpation per rectum were conducted on days 0, 7 and 14. Gonadotropin-releasing hormone was administered at day 7. Plasma concentrations of progesterone, oestradiol-17beta and cortisol were determined. Progesterone concentrations of <3.2, 3.2-4.8 and >4.8 nmol/l were defined as low, intermediate and high, respectively. Sixty-three (74.1%) of 85 cows showed low (<3.2 nmol/l =1 ng/ml) progesterone concentrations on day 0. Only 40 (47.1%) of them showed low-low pattern of progesterone at days 0 and 7. In 27 (31.8%) of them, progesterone concentration had increased by day 14. Of 22 cows having high progesterone concentration (>/=4.8 nmol/l) on day 0, corpus luteum was not detected in 18 cows (21.2%). Only in 10 cows, cystic follicle disappeared after GnRH administration. However, only one of 27 cows in which progesterone pattern was low-low-high at days 0, 7 and 14 experienced ovulation of the cystic follicle. Significantly lower oestradiol-17beta concentration was found on day 7 in cows showing a low-low-low pattern than a low-low-high pattern of progesterone (43.0 +/- 4.6 vs 55.8 +/- 2.8 pmol/l, p < 0.05). There was no significant difference in cortisol concentration on any days (days 0, 7 and 14) between cows showing a low-low-low and low-low-high pattern of progesterone. These results suggest that approximately one-fifth of cows diagnosed to have ovarian cysts possess luteal cysts and that a high oestradiol-17beta concentration at the time of GnRH administration is involved in the subsequent ovulation of the follicle, although ovulated follicle may not be cystic.  相似文献   

15.
The uptake of beta-carotene by reproductive tissues and the effects of beta-carotene on reproductive function in the dog are unknown. We studied the uptake of beta-carotene by blood, corpus luteum, and uterine endometrium and the role of dietary beta-carotene in influencing ovarian steroid and uterine protein production during the estrous cycle in the dog. Mature female Beagle dogs (n = 56) were fed diets containing 0, 2, 20, or 50 mg of beta-carotene daily for approximately 6 wk before estrus detection. Blood was sampled at regular intervals from estrus through d 45 after ovulation (d 0 = ovulation), when laparotomy was performed. The ovaries were obtained for the isolation of corpus luteum. The uterus was flushed with phosphate-buffered saline and the endometrium obtained by scraping. Beta-carotene was not detectable in plasma, corpus luteum, or endometrium of unsupplemented dogs. However, beta-carotene and alpha-carotene in plasma, corpus luteum, and uterine endometrium increased in a dose-dependent manner. Alpha-carotene made up a high percentage of total carotenoids even though the alpha-carotene content in the dietary source was very low. Dogs fed 50 mg of beta-carotene had significantly higher concentrations of plasma progesterone between d 12 and 26 compared with unsupplemented dogs. Dietary beta-carotene did not influence plasma estradiol-17beta and total uterine proteins. Therefore, beta-carotene is absorbed into plasma, corpus luteum, and uterine endometrium of dogs. Furthermore, dietary beta-carotene increased plasma progesterone concentrations during the estrous cycle. It is possible that dietary beta-carotene may improve reproductive function in the canine.  相似文献   

16.
Premature luteal demise or luteal insufficiency is not well characterised as a cause of pregnancy loss in domestic species, including horses. In this report, a mare inseminated with cooled‐transported semen at our facility returned for a routine pregnancy diagnosis at 15 days post ovulation. Ultrasonography per rectum revealed endometrial oedema and the absence of visual indication of a corpus luteum on either ovary. Nonetheless, an embryonic vesicle small for the gestational age was identified. Daily oral altrenogest treatment was implemented immediately. Serum progesterone concentration was 0.67 ng/ml, which is below the threshold considered adequate for pregnancy maintenance in the mare. Examinations were repeated at 17, 25, 30, 39, 49, 72 and 120 days post ovulation. At 25 days post ovulation the embryonic vesicle presented normal development for the gestational age. In addition, sequential blood samples were collected to measure progesterone, equine chorionic gonadotrophin and oestrone sulphate concentrations. Although progesterone concentration did not exceed 2 ng/ml until 72 days post ovulation, all other results were unremarkable and a healthy filly was born uneventfully at 344 days post ovulation.  相似文献   

17.
This study evaluated the structural changes in the reproductive tract of Asiatic black bears using serial transrectal ultrasonography. In addition, the ultrasonographic observations were compared with the results of vaginal cytology and hormonal analyses. The collection of blood for hormonal analysis, vaginal cytology and transrectal ultrasonography was performed in two bears (Bears 1 and 2) from June 2011 to August 2013 without mating and in a third bear (Bear 3) from April to December 2012, allowing natural mating. Serial ultrasonographic observations showed cyclic changes in ovarian structures (e.g. emergence of small follicles, growth and ovulation of dominant follicles and corpus luteum (CL) formation) during the reproductive cycles of the three bears. The diameter of the uterine horns remained similar throughout the reproductive cycle in Bears 1 and 2, and it remained similar from April until October, but an enlargement containing foetuses was observed in Bear 3 in December. The ultrasonographic observations were consistent with the data obtained through vaginal cytology and progesterone analysis during the reproductive cycle. An average of 4.0 (±0.4) dominant follicles was observed during the oestrous stage (May‐August), during which the superficial cells accounted for >90% of the total vaginal cells. In addition, the detection of an average of 2.6 (±0.2) CL was associated with increased plasma progesterone concentrations (3.0 ± 0.4 ng/ml) between June and December (near hibernation). In conclusion, serial transrectal ultrasonography demonstrated yearly oestrous (ovulation) cycles via follicular dynamics and CL formation on ovaries, accordingly with vaginal cytology and hormonal level in the Asiatic black bear.  相似文献   

18.
选择患持久黄体的不孕奶牛14头进行复方缩宫素乳剂的临床治疗试验,并利用放射免疫方法对部分患牛治疗前后血清孕酮（P  相似文献   

19.
The fate of the corpus luteum, a transient endocrine gland formed and degraded during an oestrous cycle, is decided by various physiological factors, such as luteinizing hormone (LH). As a stimulator of progesterone, LH is known to maintain corpus luteum functional and structural integrity by inhibiting apoptosis, a programmed cell death. Therefore, we aim to investigate its action during the mid-luteal phase hypothesized that LH suppresses the death mechanism of bovine luteal steroidogenic cells (LSC) by analysing the expression of proteins involved. Cultured bovine LSC obtained from corpus luteum were treated for 24 hr with recombinant TNF and IFNG in the presence or absence of LH. The result showed that LH proved to have a protective effect by increased cell viability (p < .05) and prevented DNA fragmentation (p < .05), as demonstrated by the WST-1 colorimetric assay and TUNEL assay. Expression analysis of mRNA and protein levels showed that LH altered the expression of BCL2 (p < .05), CASP3 (p < .05), FAS (p < .05), and BAX (p < .05) to support cell survival. In conclusion, our study suggests that LH prolongs the corpus luteum life span through the anti-apoptotic mechanism by increasing cell viability and suppressing apoptosis-related genes and protein expression.  相似文献   

20.
Female llamas ovulate in response to copulation, and progesterone secretion by the corpus luteum indicates recent ovulation (mating) and, or, pregnancy. The plasma progesterone concentration was 0.9 to 1.4 ng/ml in five non-pregnant llamas and 7.4 to 9.2 ng/ml in three llamas in the last month of pregnancy. After ovulation had been induced in nine of 10 llamas by a single intramuscular injection of 500 or 750 iu of human chorionic gonadotrophin, the plasma progesterone concentration increased after two days from 0.5 to 1.2 ng/ml to 4.6 to 10.3 ng/ml after six to nine days and returned to basal values after 10 to 13 days, reflecting the life-span of a corpus luteum in the absence of conception. After a male llama had been introduced into a group of 13 females, 10 matings which resulted in eight conceptions occurred in the first 11 days, and 11 of the llamas became pregnant. The llamas' progesterone concentrations increased after mating and remained high if conception had occurred: 6 to 12 ng/ml in months one to four, and 5 to 9 ng/ml in months five to nine of the 11-month gestation. Two of the 13 llamas had high concentrations of progesterone although they did not become pregnant.  相似文献   

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