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1.
奶牛胎衣不下发病机理研究进展   总被引：7，自引：1，他引：6  
奶牛胎衣在产后12h内应排出体外,未排出者称之为胎衣不下。奶牛胎衣不下已成为影响奶牛繁殖的主要疾病之一,其发病机理十分复杂。奶牛胎衣不下的发生与奶牛产后子宫收缩无力、胎盘组织结构发生异常、围产期营养代谢紊乱、生殖内分泌激素紊乱、机体免疫状态失调等关系密切。文章对奶牛胎衣不下的发病机制进行了综述,供同仁参考。  相似文献   

2.
A double blind randomised clinical trial was performed to assess the effects of oxytocin on the duration of placental retention following dystocia. If the placenta remained attached to the uterus immediately following assisted delivery of a calf, and was not expelled in the period taken to complete the protocol, an intramuscular injection of either 3 ml (60 USP units) of oxytocin or 3 ml of 0.9 per cent physiological saline was given to the cow. Each farmer was asked to observe the cow to determine the time of placental expulsion. In 55 cases available for analysis there was no significant difference between the treatment and control groups for percentage of placental retention at days 1, 2 or 3 post partum.  相似文献   

3.
Is poly(ADP-ribose) polymerase involved in bovine placental retention?   总被引：2，自引：0，他引：2  
Poly(ADP-ribose) polymerase (PARP) is the enzyme which utilises NAD to synthesise poly(ADP-ribose) polymers. This process appears in response to DNA lesions. Oxidative stress, which might be involved in bovine placental retention, is the reason for oxidative DNA injury. In this mini-review, the relationship between PARP activity and bovine placental retention is discussed. The results of our experiments on PARP activity in placental tissues showed that the enzyme of 113 kDa and its cleavage products were present in retained as well as released fetal membranes. Western blotting technique showed different intensities in the staining of bands which might suggest different activities of the enzyme.  相似文献   

4.
Two experiments were designed to determine whether prostaglandin treatment within one hour postpartum would reduce the incidence of retained placentas after induction of parturition in beef cattle. In the first experiment, 70 cows were induced on day 276-278 of gestation with the combination of 500 μg cloprostenol and 25 mg dexamethasone (CP + Dex). Within one hour after parturition, cows received either 500 μg CP or 25 mg of dinoprost (DI). The incidence of retained placenta (RP) was 64.3% in induced groups and 0% in noninduced control cows and postpartum treatment with either CP or DI had no effect on placental retention.

A second experiment, utilizing 132 cows and heifers, was conducted to determine whether induction with Dex alone, rather than with CP + Dex, would influence the rate of placental retention after postpartum treatment with either CP or DI. The incidence of retained placenta ranged from 28.5 to 58.3% in induced females but was 0% in noninduced control females. As in the first experiment, postpartum prostaglandin treatment had no effect on placental retention.

The results of these experiments do not support the use of prostaglandins within one hour of induced parturition to reduce the incidence of retained placentas.

  相似文献   

5.
随机选择1～4胎龄健康黑白花奶牛10头,设为健康对照组（A组）;选择1～4胎龄产后健康黑白花奶牛17头,产后立即灌服＂益母生化散＂250g,为中药预防组（B组）;选择1～4胎龄产后胎衣不下奶牛10头,为胎衣不下组（C组）;选择1～4胎龄产后胎衣不下奶牛26头,产犊后12h灌服＂益母生化散＂500g,设为中药治疗组（D组）。采用酶联免疫吸附法（ELISA）检测奶牛胎盘组织中孕酮、雌激素、前列腺素和血管紧张素的含量,探讨奶牛胎衣不下的发生机理及中药＂益母生化散＂的防治效果。结果表明,奶牛胎衣不下的发生与胎盘组织中孕酮、雌激素、前列腺素（PGE2）和血管紧张素Ⅱ含量变化关系密切,胎盘组织中孕酮含量的升高,雌激素、前列腺素和血管紧张素含量的降低是胎衣不下发生的重要机理之一。＂益母生化散＂对奶牛胎衣不下有较好地防治效果,其机制可能与＂益母生化散＂具有调节胎盘组织的激素分泌等作用有关。  相似文献   

6.
Reproductive performance and factors that decrease the pregnancy rate in heavy draft horses bred at the foal heat were investigated. The study was based on a total of 422 mares varying from 4 to 20 years in age, which had foaled during the period 1991 to 1994. Over the four years, the percentage of the mares bred at the foal heat was 62.6% and the pregnancy rate was 60.2%. The pregnancy rate following breeding at the foal heat in 1991 (67.7%) was significantly higher than that in 1992 (44.1%). Significant correlation was observed between the pregnancy rate and the mean placental retention time and also between the pregnancy rate and the mean temperature during the winter season. When compared on a monthly basis, the pregnancy rate following breeding at the foal heat in February was 53.3% and in May, 48.2%. The mean number of covers per mare at the foal heat was 2.3; this figure decreased to 1.8 for those bred in May. The mean number of days from parturition to the first breeding date was 11.3 days and the number of days from parturition to the last breeding day at the foal heat was 14.0 days. The number of days from parturition to the last breeding day at the foal heat decreased to 12.5 days in May. The latter may have been influenced by factors involving the stallion. When compared on a monthly basis, the mean placental retention time was longest in January (219 min.) following which it decreased gradually up to mid-summer. The mean placental retention time of mares which were not bred at the foal heat was significantly longer (197 min.) than in mares bred at the foaling heat (143 min.) and also in mares that conceived following breeding at the foal heat (135 min.). The pregnancy rate was less in mares bred shortly after parturition. The findings of this study would suggest that certain factors decrease the pregnancy rate in mares bred at the foal heat. The stress of low temperature in winter, prolonged placental retention time, breeding too early after parturition and factors pertaining to individual stallions may be involved. Expulsion of the placenta as soon as possible after foaling and appropriate breeding timing are significant factors that can influence the pregnancy rate following breeding at the foal heat.  相似文献   

7.
The relationship between placental retention, progesterone and pregnancy-specific protein B (bPSPB) was determined in 60 calving Holstein cows. The cows were divided into two groups with placental retention (WPR, n = 16) and no placental retention (NPR, n = 44). Every 4 days, until 60 days post-partum, blood samples were taken and the uteri were checked using ultrasonographv. The puerperal characteristics of NPR and WPR were as follows: mean days of abnormal vaginal discharge: 20.2+/-5 versus 35.6+/-7 (P < 0.01); mean intervals to uterine involution: 21.4+/-3.7 versus 27.6+/-7.6 days (P < 0.01); rate of endometritis: 25 versus 100% (P < 0.01). The mean numbers of oestrus cycles per cow were 1.75+/-0.5 versus 0.85-/+0.9 (P < 0.05) and the mean durations of the first oestrus cycle were 18+/-3.5 versus 16+/-2.1 days (P > 0.05). The mean intervals to first ovulation were 21.5+/-8.4 versus 35+/-19 days (P < 0.01). bPSPB blood concentrations were higher in the WPR group at calving with 955+/-170 versus 750+/-205 ng/ml (P < 0.01) and also during the first 32 days post-partum with 173.68+/-47.3 versus 131.0+/-29.2 ng/ml (P < 0.01). The mean bPSPB half-life was similar in the two groups: 6.9+/-2.5 versus 6.5+/-2.1 days (P > 0.05). In conclusion, it was found that placental retention was associated with a higher rate of endometritis, a lower number of cycles, longer interval to first post-partum ovulation and higher concentration of bPSPB at calving and during the post-partum period. The positive relationship between bPSPB concentrations and calf birth weight and their association with post-partum pathological events may be useful in monitoring animals presenting high concentrations at calving.  相似文献   

8.
A survey was conducted from July 1978 to June 1982 in six French regions with farmers and practising veterinarians (79 herds were surveyed for two to four years). Two groups of dairy herds were made up according to their placental retention incidence rate (PRI). The first group included the 10% of the herd-years with the highest PRI (PR + group, n = 24); the second one included the 24 herd-years with the lowest PRI that also matched according to the region and the period.

The data concerned: number of feeding days for 13 feedstuffs given to cows during the dry period, six periparturient disease incidences, milk yield, calving number and herd size. Data were retrieved from a database and analysed using barycentric discriminant analysis to find the variables discriminating PR− and PR+ herds.

PR+ herds were characterised by a shorter duration of concentrates and a longer one of grass silage feeding compared with PR− herds. These two variables explained 62.7% of the variation. The remaining 22 variables each explained less than 10% of the variation. A high linolenic/linoleic acids ratio in diets, including grass silage without concentrates offered to dry cows, could result in a lack of PgF2 and explain the high PRI in PR+ herds. Such diets could also lead to placental retention through energy deficiency. The relevance of these factors to the etiology of placental retention is discussed.  相似文献   


9.
Retained fetal membranes (RFM) in cattle have adverse effects on fertility and production. Understanding the pathophysiology and causes of RFM is important for managing this disease. The hormonal processes that lead to normal placental separation are multifactorial and begin before parturition. A variety of risk factors, including early or induced parturition, dystocia, hormonal imbalances, and immunosuppression, can interrupt these normal processes and result in retention of the placenta. Current research does not support the efficacy of many commonly practiced treatments for RFM. Systemic administration of antibiotics can be beneficial for treating metritis after RFM, but antibiotic administration has not been shown to significantly improve future reproduction in cows with RFM. Collagenase injected into the umbilical arteries of retained placentas specifically targets the lack of placentome proteolysis and might enhance placental release. However, such therapy is costly and its benefits in terms of improving subsequent reproductive function have not been evaluated.  相似文献   

10.
对9例产后健康奶牛和9例产后胎衣不下奶牛产后0、4、8、12、16h血浆中一氧化氮(NO)含量、谷胱甘肽过氧化酶(GSH-Px)活性和丙二醛(MDA)的含量进行了测定。结果显示,试验组血浆中NO、MDA高于对照组,差异极显著(P<0.01),GSH-Px活性低于对照组,差异极显著(P<0.01),表明血浆中NO、GSH-Px、MDA的变化参与了产后胎衣不下的发生、发展。  相似文献   

11.
A four year old cow with an enlargement of the uterus of unknown cause was submitted to the clinic. The cow had a pyonecrotizing myometritis and placental retention following an injury of the birth canal. The final diagnosis was only made after pathological examination.  相似文献   

12.
This study was designed to investigate the hormonal and metabolic factors associated with placental retention in buffaloes with respect to the roles of oxidative stress biomarkers and serotonin receptors. Blood samples were collected at weeks 3, 2 and 1 pre-partum and at calving from 37 buffaloes; thirty normally dropped their placentae (Non-RFM group) and 7 dropped their placentae after 12 hr post-calving (RFM group). Serum progesterone (P4), oestradiol, cortisol, non-esterified fatty acids (NEFA), beta-hydroxybutyric acid (BHBA), antioxidant/oxidant biomarkers and mineral concentrations were assessed. Histopathology and histochemistry were implemented to detect collagen in foetal placental tissues. Immunohistochemistry for serotonin receptors in placental tissues was performed. Significant elevations in P4, cortisol, NEFA, BHBA and oxidative biomarkers concentrations were observed in the RFM group. However, oestradiol, antioxidants and mineral concentrations were significantly lower in RFM buffaloes than Non-RFM group. Histopathological examination revealed degenerative changes and necrosis in retained placental tissue compared with that in normal placental tissues. Serotonin receptors were significantly expressed with collagen condensation in retained placental tissues. Furthermore, inferior reproductive performance was pronounced in the retained group. In conclusion, retained foetal membranes in buffaloes were associated with hormonal imbalance, metabolic perturbation, oxidative stress, serotonin receptor upregulation and markedly reduced fertility indices.  相似文献   

13.
奶牛胎衣不下与血浆NO、GSH-Px、MDA变化的关系   总被引：7，自引：1，他引：6  
选用产后健康奶牛 9例和产后胎衣不下奶牛 9例 ,于产后 0 h、4h、8h、1 2 h、1 6h采血分离血浆 ,测定一氧化氮 ( NO)、丙二醛 ( MDA)含量和谷胱甘肽过氧化酶 ( GSH-Px)活性 ,探讨血浆 NO、GSH-Px、MDA变化与胎衣不下的关系。结果表明 ,试验组血浆 NO、MDA极显著高于对照组 ,GSH-Px含量极显著低于对照组 ( P<0 .0 1 ) ,表明血浆 NO、GSH-Px、MDA的变化参与了产后胎衣不下的发生、发展。  相似文献   

14.
本试验采用终点法检测血浆中Ca2+浓度变化,分别采用免疫组织化学SP法及荧光定量PCR法检测奶牛胎儿胎盘eNOS蛋白及其mRNA的表达。通过对血浆中Ca2+浓度的检测及胎儿胎盘内皮型一氧化氮合酶(eNOS)表达量的研究,探讨奶牛胎衣不下的发生与这些物质变化的关系。结果表明,胎衣不下组奶牛血浆中Ca2+浓度在分娩前后均低于正常组;两组eNOS蛋白均在胎盘绒毛滋养层细胞和内皮细胞胞浆内表达,蛋白的表达量差异显著(P0.05);两组胎儿胎盘eNOS mRNA表达量差异显著(P0.05)。本研究证明分娩前后血浆中Ca2+水平对奶牛胎衣不下的发生有重要的调节作用,低浓度的Ca2+容易导致子宫收缩无力,同时影响eNOS在胎儿胎盘绒毛中的表达。  相似文献   

15.
Toll-like receptors (TLRs) and β-defensins are important components of the innate immune system. This study aimed to evaluate endometrial mRNA levels of TLRs (1/6, 2, 4, and 5) and β-defensin 5 in Holstein cows by quantitative real time RT-PCR. Uterine biopsies were performed from 6 to 12 h after parturition, and cows were divided into two groups: (i) cows with placental retention and clinical signs of uterine infection until 45 days postpartum (n=10) or (ii) cows with normal puerperium (n=10). All cows had detectable levels of TLRs and β-defensin 5 mRNAs, but these levels did not differ between groups (P>0.05). Levels of TLR4 mRNA had a positive and significant correlation with the time required for uterine involution in both groups.  相似文献   

16.
The aim of this study is to evaluate the influence of duration of calving and obstetric assistance on retained placenta incidence of high milk production Holstein cows. Experimental groups were determined according to the duration of the expulsive phase of calving: 2 h (n = 16), 2‐4 h (n = 16) and >4 h (n = 12), and additionally allocated in two sub‐groups: spontaneous calving (n = 22) and intervention calving (n = 22). Diagnosis of retained placenta was considered with a threshold of 8 h after the expulsive phase. Cows without obstetric intervention, with labor duration of 2 h, presented reduced time needed for placental release, in comparison to those with obstetric assistance. In the 2–4 h group and >4 h, there was no statistical difference. The 2 h and 2–4 h groups with intervention and the spontaneous >4 h group were considered retained placenta groups. On the other hand, performing obstetric intervention when calving period was superior to 4 h nulled the occurrence of retention of fetal membranes. As a conclusion, obstetric assistance predisposes placental retention to calving with <2 h of duration in dairy cows. Conversely, when calving is more than 4 h, performing fetal extraction has a beneficial influence on preventing retained placenta.  相似文献   

17.
The placenta grows rapidly for a short period with high blood flow during pregnancy and has multifaceted functions, such as its barrier function, nutritional transport, drug metabolizing activity and endocrine action. Consequently, the placenta is a highly susceptible target organ for drug- or chemical-induced adverse effects, and many placenta-toxic agents have been reported. However, histopathological examination of the placenta is not generally performed, and the placental toxicity index is only the placental weight change in rat reproductive toxicity studies. The placental cells originate from the trophectoderm of the embryo and the endometrium of the dam, proliferate and differentiate into a variety of tissues with interaction each other according to the development sequence, resulting in formation of a placenta. Therefore, drug- or chemical-induced placental lesions show various histopathological features depending on the toxicants and the exposure period, and the pathogenesis of placental toxicity is complicated. Placental weight assessment appears not to be enough to evaluate placental toxicity, and reproductive toxicity studies should pay more attention to histopathological evaluation of placental tissue. The detailed histopathological approaches to investigation of the pathogenesis of placental toxicity are considered to provide an important tool for understanding the mechanism of teratogenicity and developmental toxicity with embryo lethality, and could benefit reproductive toxicity studies.  相似文献   

18.
This study investigated the effects of administering vitamin E and selenium to pregnant heavy draft horsemares on the incidence of retained placenta and postpartum reproductive performance and on the prevention of the white muscle disease in their foals. In study A, 1,000 mg of vitamin E and 50 mg of selenium (E-SE 20 mL) were given to 22 mares 3 weeks before expected parturition (335 days counted from last mating), whereas 28 mares were used as controls. In study B, E-SE were administered 2 weeks before expected parturition at 2 dose levels, with 25 mares receiving 20 mL E-SE, 19 mares receiving 10 mL, and 29 mares kept as controls. Vitamin E and selenium were assayed in serum collected from some of the mares before administration of E-SE and again postpartum and from the foals immediately after birth. Serum selenium concentrations before E-SE administration were deficient (<65 ng/mL) in all mares (n = 48) but were increased in the postpartum sample from treated mares regardless of the dose or timing of administration (n = 31) (P = .05). Only study B mares were deficient in vitamin E prepartum, and both dose levels of E-SE had corrected this in the postpartum sample (P = .01). All foals were selenium deficient regardless of whether their dams had received E-SE or not, although concentrations were higher in foals from treated study A mares than from controls (P = .05). Mares with the highest selenium concentrations prepartum (40 ng/mL and over) had shorter placental retention times than mares with lower selenium concentrations (P = .05) and did not respond to E-SE with a further reduction in retention time. By contrast, mares with prepartum selenium concentrations between 20 and 40 ng/mL tended to respond to E-SE with a shortened placental retention time (P = .07). E-SE administration reduced the mean number of days from parturition to last mating (nonpregnant term) in study B mares (P = .05) and in mares with adequate prepartum vitamin E concentrations (>300 g/mL, P = .05). We conclude that maintaining high level serum vitamin E and selenium concentrations of prepartum mares is expected to increase fertility of selenium-deficient mares. Therefore, the regimen of vitamin E and selenium administrations to selenium deficient mares should be developed.  相似文献   

19.
主要对治疗和预防胎衣不下、子宫内膜炎、子宫积水、子宫脱出4种常见的家畜子宫疾病的方法进行介绍。治疗方法主要有采用中西药全身用药和针对子宫进行冲洗、灌注以及手术复位,以达到缓解或治愈子宫疾病的目的。在日常的饲养管理中,为母畜提供优质、营养均衡的日粮以及宽敞的运动场,保持圈舍卫生,在助产时注意做好消毒工作,可有效预防子宫疾病的发生。  相似文献   

20.
In this study we evaluated maternofetal transmission of immunoglobulins in ewes under conditions of altered placental morphology. Intravenous injection of human red blood cells was used to induce immunoglobulins in pregnant ewes. The hemagglutination test was used to detect antibody in maternal serum, fetal and placental fluids. Placental injury was induced by intravenous inoculation of Escherichia coli endotoxin or spores of Aspergillus fumigatus into pregnant ewes at days 99 or 100 of gestation respectively. Placental infarction, thrombosis of maternal placental vessels and variable neutrophil infiltrate characterized lesions produced by A. fumigatus. Endotoxin treated ewes developed marked placental edema, congestion, hemorrhage and focal loss of uterine epithelium. Human red blood cell agglutinating antibody was not detected in placental or fetal fluids obtained from ewes with either of the above placental lesions. Placentitis of undetermined etiology was observed in seven ewes. Two ewes had received A. fumigatus, two had received endotoxin and three were untreated ewes. Histological examination of their placentas revealed trophoblastic and endometrial epithelial necrosis and necrotizing vasculitis of the chorioallantois. Human red blood cell agglutinating antibody was detected only in the fetal and placental fluids of the seven ewes with these placental lesions. The nature of these lesions would have produced a functional confluence of the maternal and fetal circulations. Antibody transfer from dam to fetus was observed only in association with placental lesions which produced this confluence of circulations. The character of the placental lesions, rather than the mere presence of placental lesions apparently determined the transfer of immunoglobulins.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

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