Pre-partum leucocytic activity and retained placenta

An investigation concerning the association of the leucocytecotyledon reaction and the expulsion of the placenta is described. The in vitro reaction does not appear to be individual-specific. It is thus possible to determine the activity of the leucocytes against a cotyledon before parturition. The leucocytes of cows which will develop a retained placenta have lowered activity against the chemotactic stimulus of a cotyledon; this reduced activity of the leucocytes can be observed some days before parturition.     

A hospital-based study of the relationship between retained placenta and mastitis in dairy cows

We investigated the relation between retained placenta and mastitis in Holstein dairy cows admitted to the New York State College of Veterinary Medicine. Cows with retained placenta were three times more likely to develop mastitis during hospitalization than animals without retained placenta. Since the hospital population was not representative of the general population, the possibility of a bias existed; a large bias was not likely because most distorting variables occurred equally in animals both with and without retained placenta. The literature suggests that the relationship between retained placenta and mastitis may be mediated through activity of the peripheral leukocytes. Further research is necessary to test this hypothesis.     

The relationship between bovine clinical mastitis at the time of parturition and retained placenta]

868 parturitions were examined to determine the relation between the clinical mastitis around partition and the loosening process of the placenta in the bovine. The occurrence of mastitis in heifers and cows around parturition was 18.7%. The frequency of retained placenta in animals with mastitis was significantly higher (p less than 0.01) than that in animals without mastitis influenced the loosening process of the afterbirth. The results support an hypothesis, that mastitis and retentio secundinarum can regard as signs of the decrease in the activity of the immune system.     

The relationship between mastitis and retained placenta in a commercial population of holstein dairy cows

The relationship between retained placenta and mastitis was studied in a population of dairy cows on commercial farms. Only mastitis cases which occurred shortly after calving were studied. The cows with retained placenta were at a higher risk of developing non-severe mastitis (relative risk = 1.5) and at a much higher risk of developing severe mastitis (relative risk = 5.4). There was a differential effect of long-term (> 6 days) versus short-term (< 5 days) retained placenta.It is suggested that the relationship between retained placenta and mastitis is moderated by the prepartum peripheral leukocyte activity.     

Economic and reproductive consequences of retained placenta in dairy cattle

The financial losses due to retained placenta in Dutch dairy cattle were estimated by using two different methods of calculation. A data-set containing the birth records of 160,188 Meuse-Rhine-Yssel cows provided data on the reproductive performance of cows with and without retained placenta. The fertility of cows after retention of the placenta appeared to be affected. An economic calculation made by adding the losses due to increased calving interval, increased culling rate, loss of milk production and the costs of veterinary treatment and drugs revealed that the total loss due to retained placenta was 471 pounds per year for a 100-cow farm with an average incidence of the condition (6.6 per cent). For a 'problem' farm with a 30 per cent rate, the loss was 2139 pounds per year. A computer farm simulation model, based on a stochastic determination of events, was used to make calculations for circumstances closely resembling those on farms. A 6.6 per cent rate of retained placenta caused a small but significant decrease in net return on labour and management; however, a 30 per cent rate caused highly significant changes. The economic effects of retained placenta were similar in magnitude in herds of high or low productivity and high or low fertility. Sensitivity analysis showed that the greatest financial losses were caused by loss of milk production, followed by the number of animals suffering from complications. The financial losses in herds with an average rate of retained placenta were thus of limited economic importance and therapeutic measures alone should be adequate.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of twinning on gestation length, retained placenta, and dystocia

Constraints to maximal productivity from twinning in beef cattle include increased incidence of dystocia and retained placenta, longer postpartum interval, and lower conception rate. Incidence and cause(s) of the shorter gestation length and of the increased retained placenta and dystocia associated with twinning were evaluated for 3,370 single and 1,014 twin births produced in a population of cattle selected for natural twin births. Gestation length was shorter for twin than for single pregnancies (275.6 vs. 281.3 d, P<.01) and likely contributed to the higher incidence of retained placenta associated with twin births (27.9 vs. 1.9%; P<.01). Incidence of retained placenta was also higher in the spring (March-April) than in the fall (August-September) calving season (18.3 vs. 11.4%; P<.01). The higher incidence of dystocia with twins than with singles (46.9 vs. 20.6%, P<.01) was primarily due to abnormal presentation (37.0 vs. 4.5%, respectively) of one or both twin calves at parturition. First- (40.5%) and second- (22.7%) parity dams with a single birth had more (P<.01) dystocia than older dams (13.4%), whereas dystocia was not affected (P>.10) by parity with twin births. Because of the shorter gestation length and the increased incidence of retained placenta and(or) dystocia, achievement of increased productivity with twinning in cattle necessitates intensive management of twin-producing dams and their calves during the calving season. Management of the increased dystocia can be facilitated by preparturient diagnosis of twin pregnancies, enabling timely administration of obstetrical assistance to facilitate delivery of twin calves and to increase their neonatal survival.     

Post-partum ovarian activity in Finnhorse mares with special reference to seasonal effects.

In a previous study, times from parturition to the first ovulation were followed in 55 Finnhorse mares on the basis of milk progesterone determinations. Ninety-six per cent of mares had ovulated by day 20 post-partum. If intervals of more than 19 days are excluded from the data, the time from parturition to 1st ovulation was 117 days. However, in cases of foaling before and after the beginning of June the times were 13.0 days and 8.8 days, respectively (p less than 0.001). Long intervals (over 16 days) occurred mainly before 1st May (in 6 out of 7 cases). In a 2nd study, 25 post-partum Finnhorse mares were examined by rectal palpation and ultrasonic scanning. Five and 7 days post partum, but not 2 days post partum there was a statistically significant difference between ovulatory ovaries and non-ovulatory ovaries regarding size of whole ovary and the largest follicle. Six to 8 days before the first post-partum ovulation, the size of the preovulatory follicle was greater in mares which had foaled before the middle of May (32 mm) than in those which had foaled after the middle of May (20 mm) (p less than 0.05). Within 2 days before ovulation there was no statistical difference between the sizes (43 mm and 42 mm, respectively). The growth rate was therefore slower in cases of early foaling (1.8 mm/day) than in cases of late foaling (3.7 mm/day).     

Rationale for treatment of retained placenta in cows with neomycin and metronidazole.

A combination of neomycin and metronidazole was compared with oxytetracycline for its activity against the intrauterine flora of 10 cows with retained placenta. In vitro the metronidazole/neomycin combination reduced the numbers of aerobic and obligately anaerobic bacteria much more effectively than did oxytetracycline.     

Cow-specific risk factors for retained placenta,metritis and clinical mastitis in Holstein cows

The objective of this study was to evaluate the association between cow-specific risk factors and the lactational incidence risks of retained placenta (RP), metritis (MET) and clinical mastitis (CM) in 57,301 dairy cows on 20 large dairy herds in Iran between January 2005 and June 2009. A multivariable logistic regression model was used to identify risk factors for MET, RP and CM and quantify their odds ratio (OR). The lactational incidences of MET, RP and CM were 8%, 5.2% and 18.9%, respectively, and significant risk factors for MET were dystocia (OR = 4.32), stillbirth (OR = 6.26), RP (OR = 27.74), twin births (OR = 6.57), primiparity (OR = 1.68), calving during winter season (OR = 2.45) and male calves (OR = 2.41). Significant risk factors for RP were dystocia (OR = 3.17), stillbirth (OR = 3.18), abortion (OR = 8.46), milk fever (OR = 3.66), twin births (OR = 2.76), pluriparity (OR = 2.69), calving during winter season (OR = 1.86) and shorter gestation length of dairy cows (OR = 3.82). Also, significant risk factors for CM were RP (OR = 9.45), milk fever (OR = 12.36), pluriparity (OR = 2.83), calving during winter season (OR = 1.68) and the first months of lactation (P < 0.001)) and SCC concentrations at previous lactation (OR = 1.82). The current study indicates that differentiation can be made among cows in the risk of having MET, RP and CM based on a combination of cow factors. These differences among cows could be useful to aid the better detection of these diseases in the dairy herds.     

Patterns of protein glycosylation in bovine placentomes as a function of gestational age and in retained versus non‐retained placenta

The formation of placenta at the beginning of pregnancy and its separation at parturition require not only deep remodelling of extracellular matrix, which mainly consists of proteins conjugated with sugar moieties, but also the cooperation with cells from both maternal and foetal parts of placenta. The aim of the study was to compare the patterns of selected conjugated proteins with sugar moieties between pregnant and term placenta as well as between released and retained placenta in cows. Placental samples from healthy pregnant cows (3–5 months of pregnancy) were collected at a slaughterhouse (n = 6), and parturient samples were collected during caesarean section at term and retrospectively divided into retained (n = 6) and released (n = 6). The pattern of selected sugar moieties conjugated with proteins was detected by use of lectin blotting with Phaseolus Vulgaris leucoagglutinin, Maackia Amurensis and Sambucus Nigra (Elderberry). The comparison and analysis of obtained band patterns showed differences between their number, molecular weight and abundance related to the intensity of staining. Samples from 3 to 4 months showed similarities, while at the 5th month, clear differences were visible in all 3 lectins, which were used in this study. Samples from retained/released placenta expressed significant differences in PHA‐L and SNA pattern in the foetal part. Obtained results indicate that the development of placenta related to extracellular matrix and accompanying cells from both sides of placenta shows dynamic changes during pregnancy. Moreover, in the case of animals with the retention of foetal membranes the patterns of proteins conjugated with sugar moieties are altered, suggesting that the changes in extracellular matrix metabolism can be involved in the attachment and detachment of the placenta in cows.     

Reduced concentrations of apolipoproteins B-100 and A-I in serum from cows with retained placenta.

The purpose of the present study was to evaluate apolipoprotein B-100 and A-I concentrations in cows with retained placenta. Animals used were cows with retained placenta alone (n = 10), those with both retained placenta and ketosis (n = 7), and controls (n = 10). Apolipoprotein B-100 concentrations at 2 to 4 d after parturition were significantly (P < 0.01) decreased in cows with retained placenta alone (mean +/- SD, 0.084 +/- 0.029 mg/ML of serum) when compared with those in control cows (0.154 +/- 0.022 mg/mL). Apolipoprotein A-I concentrations (0.713 +/- 0.177 mg/ML) were also significantly (P < 0.05) lower than those of controls (0.895 +/- 0.159 mg/mL). These decreases were more distinct for apolipoproteins B-100 (55% of controls) than A-I concentrations (80% of controls). Concentrations of apolipoprotein B-100 (0.071 +/- 0.032 mg/mL; P < 0.01) and A-I (0.708 +/- 0.189 mg/mL; P < 0.05) in the cows with both retained placenta and ketosis were also reduced, when compared with values in controls. Other than apolipoproteins, cows with retained placenta alone had significantly (P < 0.01) higher serum nonesterified fatty acids, and lower triglyceride concentrations. Significantly (P < 0.01) higher nonesterified fatty acids and lower triglyceride concentrations were similarly observed in cows with both retained placenta and ketosis.     

Post-partum and post-conceptional ovarian activity of dairy cows: evaluation based on progesterone profiles.

The progesterone level of milk was measured daily in 20 Icelandic dairy cows for 50-90 days post-partum and for 30-50 days post-conception by radioimmunoassay. In 40% of the cows the 1st post-partum ovarian cycle was shorter and the progesterone level lower than in normal cycles. The average duration of the 1st post-partum luteal phase was significantly shorter and the progesterone values lower than in the 2nd and 3rd phases. The progesterone level rose to a plateau at the onset of luteal function within 5 +/- 2 (mean +/- s.d.) days, whereas the decrease in progesterone at the end of the luteal phase was more rapid i.e. 3 +/- 1 days. The progesterone value for a normal interluteal phase was 1.5 +/- 1.3 nmol/l. However in 9 of 48 interluteal phases the progesterone values did not decline below 3 nmol/l. The average progesterone concentration was significantly increased during the first 30 days post-conception. In 4 of 20 cows a significant drop in progesterone concentration was found 15-19 days post-conception. The results indicate that the luteal activity of the 1st post-partum ovarian cycle is inferior to that of the following cycles. There is a significant correlation in the intensity of the luteal activity between cycles. Ovarian cyclicity continues in early pregnancy in, at least, 20% of cows. The sampling frequency is of importance in studies concerning the luteal activity.     

Strategy for the treatment of puerperal metritis and improvement of reproductive efficiency in cows with retained placenta

The objective of this study was to improve the reproductive efficiency of dairy cows with puerperal metritis (PM) subsequent to retained placenta (RP) using a two-step treatment strategy. A total of 188 postpartum cows, aged from 2 to 8 years, were utilised for 2 experiments. In Experiment 1, cows affected with RP/PM were randomly assigned to two treatment groups. Cows in Group A (n = 17) were treated with 600 mg of ceftiofur intramuscularly for 3 days followed by intrauterine lavage with 0.1% chlorhexidine and infusion with 0.5% povidoneiodine, while cows in Group B (n = 16) received two intrauterine infusions, first with 5 g of oxytetracycline and then with 0.5% povidone-iodine. Cows with normal postpartum findings were regarded as the healthy control group (n = 26). Ultrasonographic examination revealed that the ovarian activities including the appearance of a dominant follicle and days to first ovulation of the cows in Group A during the early postpartum period differed from those of Group B (P < 0.05), which coincided with the results of uterine swabbing for bacteriology. In Experiment 2, cows with normal postpartum findings were allocated to Group D (n = 78), which received an ovulation protocol (GnRH - 7 d PGF2α - 48 h hCG - 24 h AI) on day 50 ± 2 postpartum. Cows affected with PM were randomly divided into two groups, Group E (n = 25) combined the treatments applied in Groups A and D, while Group F (n = 26) repeated the treatment administered in Group E except for uterine lavage. The results indicated that the pregnancy rate within 150 days postpartum and the mean days open in Group E (76.0% and 106.3 ± 4.6 days, respectively) were significantly different from those in Group F (38.5% and 137.9 ± 10.9 days, respectively) (P < 0.05). This study suggests that reproductive efficiency could be improved by using the two-step treatment to regulate uterine involution and an early resumption of ovarian function in cows with RP/PM.     

Free amino-acid concentrations in the equine placenta: relationship to maternal and fetal plasma concentrations

Free amino-acid concentrations were measured in maternal venous and fetal umbilical vein plasma, and in the allantochorion, of Thoroughbred mares at term. Concentrations in maternal and fetal plasma were similar to those reported previously in equids. The concentrations of free amino-acids in the allantochorion were higher than those in the maternal and fetal plasmas and were characterised by high levels of the nonessential amino-acids as observed in other species. Fourteen of the 20 amino-acids measured had similar allantochorion/umbilical vein concentration ratios suggesting that simple gradient diffusion might play a part in their transfer from the placenta to the fetus.     

酚类饲料抗氧化剂及其构效关系研究

脂类氧化酸败是饲料加工、储运和使用过程中经常发生的一种化学变化,是导致饲料品质恶化的主要原因之一。脂类化合物和氧分子之间的氧化反应主要是自由基连锁反应,反应产生的自由基通过与油脂或单质氧作用,或相互作用,加剧了油脂氧化链反应的传递速度,对油脂的氧化又起到了促进     

归芎益母散对血瘀型胎衣不下临床疗效及与Th1/Th2细胞因子的相关性

筛选45头血瘀型胎衣不下奶牛,随机分为4组,分别为归芎益母散高、中、低剂量组(800,400,200 g/头)、药物对照组(250 g/头,益母生化散),经口灌服给药,用药1～3 d,另设1个空白对照组(健康奶牛10头)。结果表明,与空白对照组比较,用药前,血清中IL-2、TNF-ɑ显著降低(P0.01,P0.05),IL-4、IL-10显著升高(P0.01),Th1/Th2型细胞因子显著偏小(P0.01),用药后,高、中剂量组患牛日均产奶量,产褥期子宫炎发生率及产后180 d繁育性能指标与其相当(P0.05),血清IL-2、TNF-ɑ水平上升(P0.01,P0.05),IL-4、IL-10水平降低(P0.01),Th1/Th2细胞因子趋于平衡,其中,高剂量组Th1/Th2细胞因子与空白对照组差异不显著(P0.05);与药物对照组比较,高、中剂量组治愈率升高18.2%,19.7%,产褥期子宫炎发生率降低了9.1%,11.4%,归芎益母散中剂量组配种次数显著减少(P0.05),空怀时间明显缩短(P0.01),高剂量组空怀时间显著缩短(P0.05)。说明归芎益母散不仅具有调节患牛的子宫收缩和整体免疫机能的潜在药理效应,还促进滞留胎衣及早排出,降低受试奶牛继发感染产褥期子宫炎,有效提高了奶牛的繁殖性能,还具有促进患牛泌乳的作用。调节外周血中Th1/Th2细胞因子趋于平衡,是归芎益母散治疗奶牛胎衣不下重要机理之一。