Bovine retained placenta: aetiology, pathogenesis and economic loss

Using non-steroidal anti-inflammatory drugs around calving: maximizing comfort, productivity and fertility

Non-steroidal anti-inflammatory drugs (NSAIDs) have analgesic, anti-inflammatory, anti-endotoxic and anti-pyretic effects in cattle. As such, they could be expected to have significant effects in cows and calves in the post-calving period. This review evaluates the published data on the use of NSAIDs in the dam and its calf after dystocia, the impact of NSAIDs on uterine involution, the restoration of ovarian function and prevention and treatment of the metritis complex, and the benefits of using NSAIDs in the recumbent cow. Overall, the published data are very limited, despite frequent use of NSAIDs by veterinarians in the post-calving cow, and the small number of published studies focus on blanket treatment of calving cows rather than targeted treatment after dystocia. Blanket treatment had no economic benefit; indeed, some studies reported adverse effects, such as pyrexia and increased risk of metritis. There is even less information on the value of treating calves with NSAIDs after dystocia, despite significant tissue damage which may benefit from NSAID use. Appreciably more studies have evaluated the influence of NSAIDs on uterine and ovarian function, but clinical relevance is limited. In cows with a normal puerperium, prolonged treatment with NSAIDs may slow the restoration of normal function, but most reported studies are small and use NSAIDs more frequently and for longer periods than is common in general practice. The evidence of a clinical benefit in cows with puerperal disease is limited and equivocal, and the evidence base for the use of NSAIDs in the treatment of recumbent cows is also small, even though an expert panel concluded that NSAIDs were a key aspect of veterinary treatment of downer cows. The lack of evidence identified by this review supports the contention that NSAIDs are likely to be under-used and sub-optimally prescribed in the post calving period. Further research on the use of NSAIDs in the post-calving cow and calf is required.

Avaliação da incidência e fatores de risco da retenção de placenta em vacas mestiças leiteiras

Avaliaram-se a incidência, os fatores de risco e o impacto da retenção de placenta tanto no desempenho reprodutivo quanto no produtivo de vacas mestiças leiteiras, considerando-se: ano e época de parição, ordem de lactação, escore de condição corporal (ECC), duração da gestação, tipo de parto e número e sexo dos bezerros. Utilizaram-se primíparas e multíparas, com e sem retenção de placenta, na época de chuva e de seca, para estudar: período de serviço, número de doses de sêmen/concepção e produção de leite em até 305 dias e no pico da lactação. A incidência da retenção foi de 12,8%. Os fatores de risco da retenção de placenta foram: período de chuvas, ordem de lactação - segunda, terceira e acima da quarta -, ECC abaixo de 3,5 e acima de 4,0 - aborto, natimorto, prematuro, parto auxiliado e parto gemelar. Verificou-se aumento de 51,2 e 27,5 dias no período de serviço e aumento de 1,2 e 0,6 no número de doses de sêmen, em multíparas com retenção de placenta que pariram no período de chuva ou seca, respectivamente (P<0,05).

Serological screening for Coxiella burnetii infection and related reproductive performance in high producing dairy cows

The possible relationship between Coxiella-seropositivity and the reproductive performance of cows during the previous year to the serological screening was examined in three high producing dairy herds. The herds had a history of subfertility (<25% of pregnancies for the total number of AI), abortion (>18% abortions) and a positive polymerase chain reaction test for Coxiella burnetii in the bulk tank milk with an excretion higher than 10(4)Coxiella /ml for all three herds. Antibodies against C. burnetii were detected in 50.2% of the 781 parous cows analyzed. Coxiella seropositivity was linked to placenta retention, to changes in the interval from parturition to conception (with the lowest interval parturition-conception for cows with low level of seropositivity), early pregnancy (cows becoming pregnant before Day 90 postpartum) and maintenance of gestation during the early fetal period, while it failed to affect rates of abortion after Day 90 of gestation or stillbirth.

Epidermal growth factor (EGF) induces motility and upregulates MMP-9 and TIMP-1 in bovine trophoblast cells

Differentiation and restricted invasion/migration of trophoblast cells are crucial for feto-maternal communication in the synepitheliochorial placenta of cattle. EGF is expressed in the bovine placenta and likely regulates these cell properties. As cell migration and motility rely on the degradation of extracellular matrix we hypothesize that EGF is involved in the regulation of the MMP-9/TIMP-1 balance and thus could influence trophoblast migration, tissue remodeling, and the release of the fetal membranes after parturition. The aim of this in vitro study was to examine EGF-mediated effects on cell motility, proliferation, and MMP-9 and TIMP-1 expression in cultured bovine trophoblast cells. We used a trophoblast cell line (F3) derived from bovine placentomes to examine the influence of EGF on MMP-9 and TIMP-1 expression by semiquantitative RT-PCR and MMP activity by zymography. Migration assays were performed using a Boyden chamber and cell motility was measured by time-lapse analyses. To identify the involved signaling cascades, phosphorylation of mitogen-activated protein kinase (MAPK) 42/44 and Akt was detected by Western blot. EGF treatment increased both the abundance of MMP-9 and TIMP-1 mRNAs and the proteolytic activity of MMP-9. Furthermore, EGF stimulated proliferation and migration of F3 cells. Addition of specific inhibitors of MAPK (PD98059) and/or PI3K (LY294002) activation abolished or reduced EGF-induced effects in all experiments. In conclusion, EGF-mediated effects stimulate migration and proliferation of bovine trophoblast cells and may be involved in bovine placental tissue remodeling and postpartum release of fetal membranes.

Use of the progesterone (P4) receptor antagonist aglepristone to characterize the role of P4 withdrawal for parturition and placental release in cows

In late pregnant cows, progesterone (P4) is mainly of luteal origin. However, the trophoblast may provide high local P4concentrations in the uterus. To test for the importance of a complete P4withdrawal for parturition-related processes and placental release, the P4receptor (PGR) blocker aglepristone (Ap) was administered to three cows on days 270 and 271 of pregnancy. A complete opening of the cervix was observed 46.5±7.3 h after the start of treatment. However, expulsion of the calves was impaired obviously because of insufficient myometrial activity, and placental membranes were retained for at least 10 days. Measurement of P4concentrations indicated that PGR blockage induced luteolysis. To investigate the role of P4withdrawal for the prepartal tissue remodeling of the placentomes, the caruncular epithelium was evaluated by morphometry, and the percentage of trophoblast giant cells (TGCs) relative to the total number of trophoblast cells were assessed. Caruncular epithelium in Ap-treated cows (D272+Ap) was immature (30.5±3.3%) and not different from untreated controls (elected cesarean section (CS) on day 272; D272-CS; 31.5±1.4%), whereas it was significantly reduced at normal term (D280.5±1.3; 21.0±6.1%;P=0.011). Correspondingly, the percentage of TGCs were 20.1±1.4 in D272+Ap, 22.1±4.8 in D272-CS, and 9.8±3.9 at term (P=0.001). No effect was detected on placental estrogen synthesis. The results showed that in late pregnant cows, P4withdrawal only induces a limited spectrum of the processes related to normal parturition and is not a crucial factor for the prepartal tissue remodeling in placentomes and the timely release of the placenta.

Risk factors for clinical endometritis in postpartum dairy cattle

Bacterial contamination of the uterine lumen after parturition occurs in most dairy cattle. The presence of clinical endometritis beyond three weeks post partum depends on the balance between microbes, host immunity, and other environmental or animal factors. The present study tested the hypothesis that clinical endometritis is associated with animal factors, such as retained fetal membranes, assisted calving and twins, as well as fecal contamination of the environment. The association between selected risk factors and the lactational incidence risk of clinical endometritis was examined in 293 animals from four dairy herds. Multivariate analysis was used to identify risk factors and quantify their relative risk (RR) and population attributable fraction (PAF) based on the proportion of cows exposed to each factor. The lactational incidence of clinical endometritis was 27% and significant risk factors for clinical endometritis were retained fetal membranes (RR=3.6), assisted calving (RR=1.7), stillbirth (RR=3.1), vulval angle (RR=1.3), primparity (RR=1.8), and male offspring (RR=1.5) but not the cleanliness of the environment or the animal. The highest PAF was associated with male offspring (0.6) so the use of sexed semen has the greatest potential to reduce the incidence of clinical endometritis. The dominant association between retained fetal membranes and clinical endometritis was supported by an expert panel of clinicians. The risk factors for clinical endometritis appear to be associated with trauma of the female genital tract and disruption of the physical barriers to infection rather than fecal contamination.

Effect of vitamin E and selenium supplementation on oxidative stress indices and cortisol level in blood in water buffaloes during pregnancy and early postpartum period

Pregnancy is a physiology state accompanied by high energy and oxygen demand that may lead to increased level of oxidative stress and development of metabolic and reproductive disorders in pregnant water buffaloes. In the present study, the alterations in serum cortisol and erythrocyte lipid peroxides and superoxide dismutase activities were examined in 28 pregnant water buffaloes supplemented with antioxidant nutrients, Vitamin E and selenium. Another 14 buffaloes did not receive any treatment during pregnancy to serve as negative control. Results of the present study suggested that pregnancy is associated with oxidative stress and supplementation of vitamin E and selenium may be beneficial by alleviating oxidative stress in water buffaloes.

Messenger RNA expression of angiotensin-converting enzyme, endothelin, cyclooxygenase-2 and prostaglandin synthases in bovine placentomes during gestation and the postpartum period

The bovine placenta contains local vasoactive-related systems, including angiotensin-converting enzyme (ACE), endothelin-1 (ET-1), ET-A receptor (ETAR) and ET-B receptor (ETBR), as well as arachidonic acid (AA) cascade-related enzymes, such as cyclooxygenase-2 (Cox-2), prostaglandin E-synthase (PGES) and prostaglandin F-synthase (PGFS). The mRNA expression of these molecules was examined in bovine placentomes (caruncles and cotyledons) collected immediately (0 h) and 6h after spontaneous parturition from 15 cows with early (fetal membranes released within 6 h of parturition) or late (fetal membranes released 6-12 h after parturition) detachment, as well as from 15 pregnant cows at a slaughterhouse. Significant differences were observed in expression of ET-1, ETAR and ETBR mRNAs between gestation and the postpartum period in both caruncles and cotyledons. Significant differences were also found between 0 and 6 h postpartum in the expression of ETBR mRNA in the early detachment group and PGES mRNA in the early and late detachment groups. Compared to PGFS, both Cox-2 and PGES exhibited opposite mRNA expression patterns during gestation and the postpartum period. The vasoactive-related peptide systems and AA cascade-related enzymes may mediate placental development and fetal membrane detachment after parturition in cattle.

A study on postpartum metritis in Iraqi buffalo cows: bacterial causes and treatment

The objectives of the present study were to determine the relationship between bacteriological findings, clinical signs and histopathological changes in postpartum metritis. Evaluation of the treatment efficiency of using systemic or intra-uterine infusion of antibiotics with some hormonal preparations for the treatment of postpartum metritis. Data were collected from 50 buffalo cows with history of calving of more than 1 month. All buffaloes were subjected to detailed clinical examination including external inspection, vaginoscopy and transrectal palpation of the cervix, uterus and ovaries. Swabs for bacteriology and biopsies for histopathology were collected from uterine lumen from each buffalo included in the present study. Bacteria identified using API systems following aerobic and anaerobic cultures. Vaginal mucus scored for character, odour and estimation of polymorphonuclear cells (PMNs). Treatment conducted using oxytetracycline in local intrauterine infusion or systemically with hormonal treatment including prostaglandin F2 alpha (PGF2 alpha) and oestradiol benzoate. Results revealed that the most predisposing factor for postpartum uterine infection was retained placenta and toxic puerperal metritis. The most prevalent bacteria in uterine lumen were Escherichia coli, Archanobacterium pyogenes, Bacteroides fragilis and Fusobacterium necrophorum the most prevalent bacteria in buffaloes with postpartum metritis. A. pyogenes and F. necrophorum were an important pathogens causing severe uterine inflammation as found in histopathological examinations. Buffaloes with postpartum metritis showed good clinical cure when oxytetracycline injected systemically with PGF2 alpha. Intrauterine infusion of oxytetracycline had no advantage for the treatment of uterine infection in buffalo cows with postpartum metritis. PGF2 alpha improved clinical cure of buffaloes with postpartum metritis.

Bacterial isolates associated with dystocia and retained placenta in iraqi buffaloes

The present study was conducted on 50 recently calved Iraqi Buffalo cows. Depending on the kind of parturition, buffalo cows were divided into two main groups, the first group had normal unassisted parturition (NP) (26 animals) and the second group with certain periparturent complications (PPC) (24 animals). After 24 h of parturition, these two groups were further subdivided into two groups as cows expel their foetal membranes in <24 h postpartum and referred as non-retained placenta (NRP) while cows that did not expel their foetal membrane after 24 h referred as retained placenta (RP). Sampling for bacteriology, uterine discharge for polymorphonuclear cells per cent and blood samples for polymorphonuclear neutrophil (PMN) and the enzyme creatine kinase activity were performed at 6, 24 and 48 h postpartum. In PPC group, the most prevalent bacteria after 6 h of calving were Escherichia coli, beta-haemolytic Streptococci and Lactobacillus acidophilus. Total bacterial isolates in the uterus of buffaloes with RP in PPC group after 24 and 48 h were 129 and 183 respectively. Among the isolates, Archanobacterium pyogenes, Fusobacterium necrophorum, Prevotella melaninogenicus and Staphylococcus aureus were the most prevalent isolates after 48 h of RP buffaloes in PPC group. Polymorphonuclear neutrophil were significantly (p < 0.01) increased in the uterine discharge than in blood in buffaloes with RP in both PPC and NP groups. In conclusion, uterine contamination occurs as a result of postpartum ascending contamination by non-specific environmental organisms. The presence of Lactobacillus sp. in the uterus indicated a healthy uterus. Peripartum complications followed by retention of foetal membranes with the dominance of E. coli in the uterine lumen might favour the colonization of other bacteria including facultative anaerobic and strictly anaerobic in the uterine wall of buffaloes.

Bovine caruncular epithelial cell line (BCEC-1) isolated from the placenta forms a functional epithelial barrier in a polarised cell culture model

In the bovine synepitheliochorial placenta key sites of fetal-maternal interaction are placentomes consisting of maternal caruncles interdigitating with fetal cotyledons. The aim of this study was to establish an epithelial cell line from caruncles of pregnant cows and to develop a model to study restricted trophoblast invasion, pathogenesis of pregnancy associated diseases and pathways of infection and transport. Primary epithelial cells were isolated, successfully subcultured for 32 passages and cryopreserved at various stages. The cultures were termed bovine caruncular epithelial cell line-1 (BCEC-1). Cytokeratin, zonula occludens-1 protein and vimentin but neither alpha-smooth muscle actin nor desmin were detected by immunofluorescence performed every 5 (+/-1) passages. These results were confirmed by Western blotting. BCEC-1 were then cultured either without matrix or on fibronectin or collagen coated Transwell polyester membrane inserts, respectively, enabling separate access to the basal or apical epithelial compartments. Transmission and scanning electron microscopy of BCEC-1 revealed ultrastructural features also observed in vivo, such as apical microvilli and junctional complexes. Transepithelial electrical resistance (TEER) was measured regularly and revealed an increase with advancing confluence in all cultures. Cultures on coated inserts reached confluence and corresponding TEER-levels at an earlier stage. In addition, the cells were tested negative for bovine virus diarrhoea (BVD) virus, but were permissive for the virus. In conclusion, the BCEC-1 cell line retained characteristics of maternal caruncular epithelial cells as observed in vivo and in primary cell cultures and thus will be a highly useful tool for future studies of pathways of invasion, fetal-maternal communication, transport and infection.

Clinical, Bacteriological, and Histopathological Study of Toxic Puerperal Metritis in Iraqi Buffalo

Data were collected from 42 buffalo with toxic puerperal metritis in 2 large herds, with a history of dystocia, prolapse, and retained placenta. All buffalo were subjected to detailed clinical examination including external inspection, vaginoscopy, and transrectal palpation of the cervix, uterus, and ovaries. Swabs for bacteriology and biopsies for histopathology were collected from the uterine lumen from each cow. Character, odor, and estimation of polymorphonuclear cells of the vaginal mucus were scored. Blood samples were collected from cows for creatine kinase and aspartate amino-transferase measurement. The most predisposing factor causing toxic puerperal metritis was retained placenta (52.4%), and the most prevalent bacteria in uterine lumen were Escherichia coli, Arcanobacterium pyogenes, Staphylococcus aureus, and Fusobacterium necrophorum (18.5, 16.7, 13.0, and 9.3%, respectively). High levels of polymorphonuclear cells were observed in buffalo infected with A. pyogenes and gram-negative anaerobic bacteria (62.1 and 76.4%). A high prevalence of gram-negative anaerobes was isolated from uteri harboring A. pyogenes (13.0%). Buffalo with toxic puerperal metritis had significantly higher creatine kinase and aspartate aminotransferase activities than controls (499.2 +/- 23.9 and 208.3 +/- 11.3 vs. 242.7 +/- 12.9 and 166.8 +/- 11.5 U/L, respectively). In a conclusion, gram-negative anaerobes and other facultative pathogens including A. pyogenes were important pathogens that cause severe uterine inflammation.

Comparison of Two Management Strategies for Retained Fetal Membranes on Small Dairy Farms in Germany

The objective of this study was to compare 2 strategies for the management of dairy cows having retained fetal membranes (RFM) with regard to clinical traits, milk yield, and reproductive performance. In contrast to recent studies evaluating optimal strategies for the management of cows with RFM, this trial was conducted on small dairy farms with 26 to 166 cows per herd. In the systemic (SYS) group (n = 116), cows having RFM and a rectal temperature > or = 39.5 degrees C were treated with 1 mg/kg of body weight of ceftiofur on 3 to 5 consecutive days. The RFM cows without fever remained untreated. In the intrauterine (IUT) group (n = 115), all RFM cows received an intrauterine treatment with 6 g of tetracycline on 3 consecutive days combined with an attempt to remove the fetal membranes manually. The IUT cows with a fever received an additional systemic treatment with 10 mg/kg of body weight of amoxicillin on 3 to 5 consecutive days. Body temperature, daily milk yield, prevalence of vaginal discharge 28 to 35 d in milk (DIM), and reproductive performance traits within 200 DIM were monitored. The proportion of cows experiencing fever within 5 d after enrollment was greater in SYS compared with IUT. The proportion of cows with mucopurulent or purulent vaginal discharge 28 to 34 DIM did not differ between the groups. Furthermore, no significant differences between groups were found in daily milk yield in the first 10 d after enrollment, or in reproductive performance or proportion of cows culled. Significant differences in the proportion of cows with a fever in SYS and IUT have not been reported in studies with similar study designs conducted on large dairy farms. Further results on milk yield and reproductive performance, however, support findings that a management strategy for RFM based on a selective systemic treatment of feverish cows is at least as efficacious as a strategy based on intrauterine treatments of all cows and a systemic antibiotic treatment of feverish cows.

Metabolic Changes in Cows with or without Retained Fetal Membranes in Transition Period

The purpose of the study was to evaluate the effect of retained fetal membranes (RFM) on serum minerals and energy- and protein-related metabolites in dairy cows at a herd with a recent history of fatty liver syndrome. Forty-seven multiparous Holstein cows were selected during transition period. Nine cows had RFM longer than 24 h after calving. Blood samples were obtained on prepartum days 21 and 7 and postpartum days 7 and 21. We used repeated measure procedure of anova to evaluate the effect of RFM on serum metabolites. Cows with RFM had significantly higher concentrations of beta-hydroxybutyrate, non-esterified fatty acids and triglycerides after calving, but had lower concentrations of cholesterol during transition period. The concentrations of serum albumin and blood urea nitrogen were also significantly lower in RFM-affected cows than non-affected ones after parturition. Our results suggested that negative energy balance (NEB) postpartum was associated with RFM in dairy cattle. However, our findings did not reveal a cause and effect relationship with respect to the role of NEB as a possible risk factor for RFM.

A meta-analysis of the effects of Vitamin E supplementation on the incidence of retained foetal membranes in dairy cows

A meta-analysis was performed to consolidate the results of studies which have evaluated the effects of Vitamin E supplementation during the dry period on the risk of retained foetal membranes (RFM) in the dairy cow. Twenty studies demonstrated a beneficial response to Vitamin E whilst 21 found no benefit and 3 reported an increase in the incidence of RFM in treated cows. The odds ratios (OR) of the available studies exhibited significant heterogeneity, so multivariable logistic regression analysis was performed to enable the identification of factors associated with the response to Vitamin E supplementation. Our multivariable analysis included parity and Vitamin E supplementation (control/treated) in the model, because all other factors were co-linear. Results indicated that Vitamin E supplementation led to a reduction in the incidence of RFM. A second multivariable analysis was undertaken on a subset of the data including only supplemented cows to determine the influence of supplementation factors on the risk of RFM. All factors were co-linear with each other, therefore, only type of Vitamin E supplementation was included in this analysis. The regression model demonstrated that administration of the synthetic Vitamin E alpha-tocopheryl acetate was associated with a lower risk of RFM than treatment with natural Vitamin E (alpha-tocopherol) (P=0.047, OR=0.49), whereas the difference between the synthetic Vitamin E alpha-tocopherol acetate and natural Vitamin E just failed to attain statistical significance (P=0.059, OR=0.53). Overall the analyses indicate that Vitamin E supplementation during the dry period is associated with a reduced risk of RFM, and that the synthetic forms of Vitamin E are more effective than the natural compound.

Quantitative analysis of messenger RNA expression of matrix metalloproteinases (MMP-2 and MMP-9), tissue inhibitor-2 of matrix metalloproteinases (TIMP-2), and steroidogenic enzymes in bovine placentomes during gestation and postpartum

The relationship between the mRNA expression of proteolytic and steroidogenic enzymes in bovine placentomes was examined. Caruncle and cotyledon tissues were collected every 6 hr after spontaneous parturition until the fetal membranes were released. Based on the time of fetal membrane release after parturition, the specimens were classified as follows: (1) the early group, in which the fetal membranes were released within 6 hr after parturition; and (2) the late group, in which the fetal membranes were released 6-12 hr after parturition. The placentomes from a slaughterhouse were additionally collected as samples for the examination of enzymes during the gestation period. The mRNA expression of steroidogenic enzymes in the cotyledon was observed to be higher than that in caruncle tissues; however, the mRNA expression patterns of P450scc and StAR tended to be similar in both placental tissues. On the other hand, although the expression levels of TIMP-2 mRNA in both caruncle and cotyledon tissues were similar, during gestation and postpartum the expression levels of MMP-2 and MMP-9 mRNA were approximately 10 times higher in caruncle than in cotyledon tissue. Marked contrasting changes in mRNA expression patterns between pre- and postpartum periods were observed for MMP-2 and MMP-9 in caruncle tissues and for MMP-9 and TIMP-2 in cotyledon tissues. The present study provides the first evidence that MMP-2, MMP-9, and TIMP-2 mRNAs are expressed in bovine placentomes during the gestational and postpartum periods and suggests that these enzymes, in conjunction with steroidogenic enzymes, mediate fetal membrane detachment after parturition.

The effect of nutritional management of the dairy cow on reproductive efficiency

The cause of low fertility in dairy cows is multifactorial. Poor nutrition during the dry and early postpartum periods results in reduced glucose, insulin, insulin-like growth factor (IGF-I) and low LH pulse frequency with concomitant increases in beta-hydroxy butyrate, non-esterified fatty acids (NEFA) and triacylglycerol. Cows must mobilize large lipid, but also some protein reserves, with a consequent increased incidence of such metabolic disorders as hypocalcaemia, acidosis, ketosis, fatty liver and displaced abomasums. The occurrence of milk fever and ketosis affects uterine contractions, delays calving and increases the risk of retained foetal membranes (RFM) and endometritis. The nutritional risk factors that cause RFM are hypocalcaemia, high body condition score (BCS) at calving and deficiencies in Vitamin E and selenium. The risk factors for endometritis are hypocalcaemia, RFM, high triacylglycerol and NEFA. Thus, metabolic disorders predispose cows to gynaecological disorders, thereby reducing reproductive efficiency. Cows that are overconditioned at calving or those that lose excess body weight are more likely to have a prolonged interval to first oestrus, thereby prolonging days open. Nutritionally induced postpartum anoestrus is characterized by turnover of dominant follicles incapable of producing sufficient oestradiol to induce ovulation due to reduced LH pulse frequency. High nutrition can also increase metabolic clearance rate of steroid hormones such as progesterone or oestradiol. Lower concentrations of oestradiol on the day of oestrus are highly correlated with the occurrence of suboestrus, thereby making the detection of oestrus in high yielding cows even more difficult. Nutrition also affects conception rate (CR) to AI. Cows that develop hypocalcaemia, ketosis, acidosis or displaced abomasums have lower CRs and take longer to become pregnant. Excessive loss of BCS and excess protein content of the ration can reduce CR while supplemental fats that attenuate the production of F2alpha can improve CR. The increased metabolic clearance rate of progesterone (P4), which decreases blood concentrations during early embryo cleavage up to the blastocyst stage is associated with decreased CRs. In conclusion, poor nutritional management of the dairy cow, particularly before and after calving, is a key driver of infertility.

Comparison of Two Strategies for Systemic Antibiotic Treatment of Dairy Cows with Retained Fetal Membranes: Preventive vs. Selective Treatment

The objective of this study was to evaluate the efficacy of a blanket systemic preventive treatment (PT) of cows having retained fetal membranes (RFM) with 1 mg/kg of ceftiofur administered the first day after calving regardless of their body temperature. This strategy was compared with a selective treatment (ST) strategy in which only cows having RFM and a rectal temperature > or = 39.5 degrees C within 10 d postpartum received ceftiofur. Cows that retained their fetal membranes for at least 24 h after calving were allocated to 2 groups. Rectal temperature was measured daily for 10 d postpartum. Sixty PT cows having RFM received a daily ceftiofur (1 mg/kg of body weight) treatment, administered subcutaneously during the first 3 d after diagnosis of RFM. If rectal temperature was > or = 39.5 degrees C after 3 daily treatments, cows received ceftiofur for 2 more days. Therapy in 53 ST cows was based on selective administration of ceftiofur to cows having fever during the first 10 d postpartum. Treatment was conducted for 3 to 5 consecutive days as described for PT cows, beginning on the first day of fever. In both groups, manual removal of the placenta was not attempted and antibiotic drugs were not administered into the uterus. For every cow having RFM enrolled in PT or ST, 1 cow without RFM that had calved on the same day was enrolled in a healthy control group (n = 113). All cows received two 25-mg doses of PGF(2alpha): 1 dose between 18 and 24 d and 1 dose between 32 and 38 d postpartum. The PT did not reduce the proportion of cows experiencing fever during 10 d postpartum compared with ST cows (71.7 vs. 69.8%). Results were compared using logistic regression models and survival analyses. The artificial insemination submission rate between 42 and 62 d postpartum was greater in PT (41.2 vs. 20.8 vs. 24.5%), but total conception rate was less in ST and control cows, respectively (25.0 vs. 38.9 vs. 36.2%). In this trial, a preventive systemic antibiotic treatment of all cows having RFM was not superior to a selective antibiotic treatment of cows only in case of fever.

Screening for high fertility in high-producing dairy cows

A retrospective study involving 2756 pregnancies from two commercial dairy herds in northeastern Spain determined relationships between management, production and reproductive data, and high fertility (conception before 90 days in milk) in high-producing dairy cows. High fertility was registered in 989 (35.9%) cows. The following data were recorded for each animal: herd, repeated animal (cows included two or more times within the study in which data were obtained from different lactational periods), parity (primiparous versus multiparous), previous twinning, reproductive disorders following calving (retained placenta, primary metritis) and at postpartum gynecological examination (incomplete uterine involution, pyometra and ovarian cysts), days in milk at conception, previous estrous synchronization and season of calving and conception. In order to evaluate the possible effect of high production during the peak milk yield on subsequent fertility, daily milk production at Day 50 postpartum was also recorded and cows were classified as high (> or = 50 kg) and low (< 50 kg) producers. Logistic regression analysis indicated no significant effects of herd, repeated animal, previous twinning, reproductive disorders such as primary metritis, incomplete uterine involution, pyometra and ovarian cysts, previous estrous synchronization and season of calving and insemination. Based on the odds ratio, the likelihood of high fertility increased in high-producer cows by a factor of 6.8. High fertility was less likely for multiparous cows (by a factor of 0.35) and for cows suffering placenta retention (by a factor of 0.65). High fertile cows produced a mean of 49.5 kg milk at Day 50 postpartum, in contrast to that 43.2 kg milk of the remainder cows. These findings question the negative effect of high production on fertility. Our results indicated that high individual cow milk production can be positively related to high fertility.

Strategies to Improve the Therapy of Retained Fetal Membranes in Dairy Cows

In this field trial, a protocol for the treatment of retained fetal membranes (RFM) without any intrauterine therapy was compared with 3 protocols based on the intrauterine use of antibiotic pills (AP), the manual removal (MR) of the fetal membranes, or the combination of both (PR). The study was conducted on 5 commercial dairy farms in Germany. Cows with RFM for at least 24 h after calving were assigned to 1 of 4 treatment groups. Cows of all groups with a rectal temperature >or= 39.5 degrees C received a systemic antibiotic treatment with ceftiofur (1 mg/kg per d) for 3 to 5 consecutive days. In case of continued fever after 5 treatments, cows received a different antibiotic as an escape therapy. In the reference group (REF; n = 131), cows did not receive any additional treatment. All cows in group AP (n = 119) received intrauterine treatment with antibiotic pills consisting of 1,000 mg of ampicillin and 1,000 mg of cloxacillin for 3 consecutive days. In group MR (n = 121), an attempt was made to remove the fetal membranes manually, but uterine pills were not administered. In group PR (n = 130), an attempt was made to remove the fetal membranes manually and all cows received a local antibiotic treatment as in group AP. All cows received 2 doses of 25 mg of PGF(2alpha): one dose between 18 and 24 d and another between 32 and 38 d postpartum. Statistical analyses were performed using binary logistic regression models and survival analyses with group REF as reference. Of all animals, 79.8% had a body temperature of >or= 39.5 degrees C at least once within 10 d postpartum and were treated with ceftiofur. Occurrence of fever within 10 d postpartum was significantly lower in groups AP and PR compared with reference group REF, but was not different between groups MR and REF. Risk of receiving an escape therapy in case of fever after 5 treatments with ceftiofur did not differ among groups. Reproductive performance measures did not differ significantly between group REF and any of the comparison groups. Compared with a treatment protocol based only on systemic treatment with antibiotics for cows with a fever, neither intrauterine antibiotics nor manual removal of fetal membranes alone or in combination reduced proportions of cows needing an escape therapy nor did those treatments improve reproductive measures in the current lactation. Systemic treatment alone based on elevated rectal temperature was effective and reduced use of antibiotics compared with therapies that included intrauterine antibiotics.

Prepartum Intake, Postpartum Induction of Ketosis, and Periparturient Disorders Affect the Metabolic Status of Dairy Cows

Nutritional management during the dry period may affect susceptibility of cows to metabolic and infectious diseases during the periparturient period. Thirty-five multiparous Holstein cows were used to determine the effect of prepartum intake, postpartum induction of ketosis, and periparturient disorders on metabolic status. Cows were fed a diet from dry-off to parturition at either ad libitum intake or restricted intake [RI; 80% of calculated net energy for lactation (NEL) requirement]. After parturition, all cows were fed a lactation diet. At 4 d in milk (DIM), cows underwent a physical examination and were classified as healthy or having at least one periparturient disorder (PD). Healthy cows were assigned to the control (n = 6) group or the ketosis induction (KI; n = 9) group. Cows with PD were assigned to the PD control (PDC; n = 17) group. Cows in the control and PDC groups were fed for ad libitum intake. Cows in the KI group were fed at 50% of their intake on 4 DIM from 5 to 14 DIM or until signs of clinical ketosis were observed; then, cows were returned to ad libitum intake. During the dry period, ad libitum cows ate more than RI cows; the difference in intake resulted in ad libitum cows that were in positive energy balance (142% of NEL requirement) and RI cows that were in negative energy balance (85% of NEL requirement). Prepartum intake resulted in changes in serum metabolites consistent with plane of nutrition and energy balance. Prepartum intake had no effect on postpartum intake, serum metabolites, or milk yield, but total lipid content of liver at 1 d postpartum was greater for ad libitum cows than for RI cows. The PD cows had lower intake and milk yield during the first 4 DIM than did healthy cows. During the ketosis induction period, KI cows had lower intake, milk yield, and serum glucose concentration but higher concentrations of nonesterified fatty acids and beta-hydroxybutyrate in serum as well as total lipid and triacylglycerol in liver than did control cows. Cows with PD had only modest alterations in metabolic variables in blood and liver compared with healthy cows. The negative effects of PD and KI on metabolic status and milk yield were negligible by 42 DIM, although cows with PD had lower body condition score and BW. Prepartum intake did not affect postpartum metabolic status or milk yield. Periparturient disorders and induction of ketosis negatively affected metabolic status and milk yield during the first 14 DIM.

Effect of Vitamin E and selenium supplementation on concentrations of plasma cortisol and erythrocyte lipid peroxides and the incidence of retained fetal membranes in crossbred dairy cattle

The objectives were to: (i) determine the effect of prepartum supplementation of Vitamin E (Vit E) and selenium (Se) on plasma cortisol, erythrocyte peroxidation and the incidence of retained fetal membranes (RFM); (ii) estimate myeloperoxidase (MPO), lysozyme, elastase, and acid phosphatase (ACP) enzyme activities in the cotyledons of cows with or without RFM; and (iii) determine the molecular weight (SDS-PAGE) of proteins present in the cotyledons of cows with or without RFM. Fifty dairy (Friesian x Sahiwal) cows were equally allocated to one of two treatments, given as an im injection 3 week before calving: 1100 IU of DL alpha-tocopherol acetate (Vit E) and 30 mg of sodium selenite (Se), or saline (control). Concentrations of plasma cortisol (20 cows) were determined on days 21, 7, 3, 2, 1, and 0 prepartum, and erythrocyte lipid peroxide (all cows) was determined on days 21 and 7 prepartum. Treatment with Vit E and Se did not affect (P = 0.23) the incidence of RFM (12% versus 0%, respectively) but decreased (P < 0.05) erythrocyte lipid peroxide concentrations on day 7 prepartum compared with day 21 prepartum. Plasma cortisol concentration increased (P < 0.05) from day 21 prepartum to the day of parturition in Vit E+Se and control cows. However, on day 0, plasma cortisol concentrations were lower (P<0.05) in cows given Vit E+Se than in control cows (with or without RFM). To investigate enzyme activity and peptides in cotyledons, cotyledons were collected (from cows that were not part of the principal experiment), homogenised with PBS, and the supernatant used for the estimation of cationic peptides. Cotyledons of cows with RFM (n = 8) had lower (P < 0.01) MPO and greater (P < 0.05) lysozyme and ACP enzyme activities than those from non-RFM cows (n = 6). A band at <10 kDa in the SDS-PAGE indicated the presence of cationic peptides. In conclusion, a single treatment of Vit E and Se at 3-week prepartum reduced concentrations of plasma cortisol and erythrocyte peroxide. Altered enzyme activities in the fetal membranes indicated the involvement of leukocytes and trauma at the fetomaternal junction and warrant further investigation.

Effect of inbreeding on the incidence of retained placenta in Friesian horses1

This study was motivated by the hypothesis that the incidence of retained placenta (RP) in Friesian horses is associated with inbreeding. The objectives were to 1) calculate the inbreeding rate in the total registered Friesian horse population; 2) study the association of the inbreeding coefficient of the foal and the mare with the incidence of RP; and 3) study the heritability of RP in Friesian mares after normal foalings. Data from the total registered Friesian horse population from 1879 to 2000 (52,392 individuals) were collected from the registration files of the Friesian Horse Studbook. In 1999 and 2000, 495 parturitions in 436 mares were studied. From 1979 to 2000, the inbreeding rate of the total population was 1.9% per generation. The regression coefficients for the regression of the incidence of RP on inbreeding coefficients of the foal and the mare were 0.12 +/- 0.052 and -0.016 +/- 0.019, respectively. Mean heritability estimates of RP as a foal trait and as a mare trait were 0.046 +/- 0.088 and 0.105 +/- 0.123, respectively. It was concluded that, in order to avoid a further increase in the incidence of RP in Friesian mares, a decrease in the inbreeding rate by increasing the effective breeding population is required. Furthermore, the findings indicate that the high incidence of RP in Friesian horses is at least partly a result of inbreeding.

Retained placenta in Friesian mares: incidence, and potential risk factors with special emphasis on gestational length

During the foaling seasons of 1999 and 2000, the incidence of retained placenta in 495 normal parturitions of 436 Friesian brood mares was studied. Retained placenta was defined as a failure to expel all fetal membranes within 3 h of the delivery of the foal. Furthermore, the sex of the foal, month of breeding, sire and dam's sire, age of the mare, and time of day of foaling, were studied as factors that might be associated with retained placenta in Friesian mares after normal foalings, and with gestational length. The analysis was carried out using marginal logistic regression, and mixed linear regression, respectively. The incidence of retained placenta was 54%. Mean length of gestation was 331.6 days. Colts were carried 1.5 days longer than fillies. Mares bred in July-September had a 4-day shorter gestation period (329 days) than mares bred earlier in the year. There was a mare, sire, and dam's sire effect on gestational length, and a mare effect on the occurrence of retained placenta. Mares foaling at 4 and >17 years of age, tended to have a lower incidence of retained placenta than mares foaling at 5-17 years of age. No association was found between the occurrence of retained placenta, and gestational length, sex of the foal, month of breeding, dam's sire, and time of day of foaling. It was concluded that the observed high incidence of retained placenta indicates that the Friesian breed of horses has a higher risk for retained placenta than other breeds of horses.

Effects of retention of fetal membranes on subsequent reproductive performance of dairy ewes

Seventy-one pairs of ewes with or without retention of fetal membranes in the previous lambing season, were included in a cohort study of 25 flocks in southern Greece; in 27 pairs regulation of the breeding cycle was applied, whilst in the other 44 pairs natural mating took place. The following measures of reproductive performance were calculated: cycling rate, mating rate, return-to-estrus rate, abortion rate, lambing rate, total lambs born per ewe, liveborn lambs per ewe, stillbirth rate, lamb-bodyweight per ewe; furthermore, the incidence risk of retention of fetal membranes during the lambing examined in this study was also calculated. No statistically significant differences were observed in the reproductive performance among ewes that had or had not retained their fetal membranes during the previous lambing, whether the breeding cycle was regulated or not. The incidence risk of retention of fetal membranes among ewes that had not retained its placenta in the previous lambing was 1.6%, whilst that among ewes that had retained its placenta in the previous lactation was 0%. It is concluded that retention of fetal membranes did not appear to adversely affect subsequent reproductive performance of ewes.

Comparison of two protocols for the treatment of retained fetal membranes in dairy cattle

Two protocols for the treatment of retained fetal membranes in dairy cattle were evaluated in a field trial. Cows that retained the fetal membranes for more than 12h were assigned to two treatment groups in an alternating order. In both groups rectal temperature was measured daily for 10 days after enrollment. In Group 1 (n=35) cows with a rectal temperature >or=39.5 degrees C received a systemic antibiotic treatment with 600mg ceftiofur intramuscularly on three consecutive days. No manual removal of the fetal membranes or intrauterine treatment was conducted. In case of elevated temperature of >or=39.5 degrees C on Day 3 treatment was conducted for another 2 days. In Group 2 (n=35) cows received a local antibiotic treatment (2500 mg ampicillin, 2500 mg cloxacillin) and an attempt was made to remove the fetal membranes manually. In case of a rectal temperature >or=39.5 degrees C 6000 mg of ampicillin were administered intramuscularly. Treatment was repeated on three consecutive days. If temperature did not decrease below 39.5 degrees C systemic treatment was extended for another 2 days. During 10 days of observation 33 and 34 cows showed fever, i.e. a body temperature >or=39.5 degrees C in Groups 1 and 2, respectively (94.3 versus 97.1%). The proportion of cows considered as cured (temperature <39.5 degrees C on Day 10 after enrollment) was 65.7 and 68.6% in Groups 1 and 2, respectively. All cows showed signs of chronic inflammation of the genital tract on Day 14 after calving. Within 4 weeks postpartum three (8.6%) and four (11.4%) cows were culled in Groups 1 and 2, respectively. Days to first service and days open did not differ significantly between the groups. Proportion of cows pregnant on Day 200 postpartum was 71.4 and 54.3% for Groups 1 and 2, respectively (P>0.05). Results indicate that treatment of retained fetal membranes without intrauterine manipulation and treatment can be as effective as conventional treatment including detachment and local antibiotic treatment.

Fertilidade de novilhas após aborto induzido com cloprostenol

O efeito da interrupção da gestação sobre a fertilidade foi avaliada em 50 novilhas da raça Holandesa, gestantes de fetos do sexo masculino entre 55 e 90 dias de idade. O aborto foi induzido pela administração de cloprostenol sódico, após o diagnóstico do sexo fetal. Os animais foram inseminados no segundo estro normal após o aborto. A interrupção da gestação ocorreu em 86% dos animais tratados e a via de administração, intramuscular ou intravulvar, não afetou a taxa de aborto. Os intervalos do aborto à primeira inseminação e do aborto à concepção foram de 38,94± 4,96 e 47,32± 15,89 dias, respectivamente. Não houve diferença no número médio de serviços por concepção pré e pós-interrupção da gestação (1,22 vs. 1,34; P>0,05). Conclui-se que a indução do aborto no terço inicial da gestação em novilhas não compromete a fertilidade dos animais.

Bovine retained placenta: hormonal concentrations in fetal and maternal placenta

The aim of this study was to evaluate the relationship between the occurrence of retention of the fetal membranes (RFM) and the hormonal concentrations of progesterone, estradiol-17beta, prostaglandin E(2) (PGE(2)), prostaglandin F(2alpha) (PGF(2alpha)), oxytocin (OT), oxytocin receptor (OT-R), endothelin-1 and angiotensin II (Ang II) in the placental tissues of cattle. Parturition was induced in nine Holstein cows by a single injection of PGF(2alpha) on Day 274 of gestation. Six out of nine cows in the induced group did not release the fetal membranes within 12 h after parturition and served as the RFM group, and the remaining three cows in that group, which released their fetal membranes within 12 h, served as the non-RFM group. Five other cows calved spontaneously and served as controls. The placental tissues were collected immediately (0 h) and at 6 h after parturition. The hormonal concentrations were measured by enzyme immunoassay in maternal and fetal placental tissues from RFM, non-RFM and control cows. There were no differences in P4 and E2 concentrations among the RFM, non-RFM and control groups. The mean PGF(2alpha) concentration of the RFM group was lower than those of the non-RFM and control groups in the maternal part of the placenta. In maternal tissues, the OT and OT-R concentrations in the RFM group were lower than those at 0 and 6 h after parturition in the non-RFM group. Additionally, the Ang II concentration of the RFM group in both the maternal and fetal parts of placental tissues tended to be higher than those of the other groups. In conclusion, the present results suggest that ET-1 and Ang II may play differential tissue-specific roles in the placental unit that may amplify the local endocrinological cascade involving OT, OT-R and PGF(2alpha) interactions which are necessary for normal placental separation in the cow.

Occurrence of estrogen receptor alpha in bovine placentomes throughout mid and late gestation and at parturition

The bovine placenta produces estrogens from the first trimester until the end of its life span. However, with the exception of the immediate prepartal and intrapartal phases, in which an involvement of placental estrogens has been suggested for the preparation of parturition, their function has not been elucidated yet. To test for a role of placental estrogens as local factors regulating placental growth and differentiation, placentomes from cows that were pregnant for 150, 220, 240, and 270 days, and parturient cows (3 animals per group) were screened immunohistochemically for the expression of estrogen receptor alpha (ERalpha). Indirect immunoperoxidase staining methods were applied using primary monoclonal antibodies (pmAbs) directed against the C-terminus (AER311, HT277) or the N-terminus (AER314, 1D5) of the ERalpha molecule. Both types of pmAbs identified ERalpha in stromal cells and capillary pericytes of the maternal caruncular septae. Using pmAb 1D5, the mean percentage of ERalpha-positive caruncular stromal cells decreased from 39.0% +/- 5.9% in pregnant cows to 17.5% +/- 8.3% at parturition (P = 0.011). Only pmAb recognizing the C-terminus identified ERalpha in the caruncular epithelium, in which positive reactions were found in all cells, with the exception of areas adjacent to the chorionic plate and to major chorionic villi, where the specific signal gradually faded and occasionally disappeared. No positive reactions were observed in the fetal part of the placentomes. The expression of ERalpha in bovine placentomes was further confirmed by the detection of ERalpha-specific mRNA by reverse transcriptase-polymerase chain reaction and by Western blot analysis. The results suggest a role for placental estrogens as paracrine factors involved in the regulation of placental growth and differentiation.

Decreased neutrophil function as a cause of retained placenta in dairy cattle

It is unclear why some cows fail to expel the placenta following calving. One theory suggests the fetal placenta must be recognized as "foreign" tissue and rejected by the immune system after parturition to cause expulsion of the placenta. We hypothesized that impaired neutrophil function causes retained placenta (RP). We examined the ability of neutrophils to recognize fetal cotyledon tissue as assessed by a chemotaxis assay, which utilized a placental homogenate obtained from a spontaneously expelled placenta as the chemoattractant. Neutrophil killing ability was also estimated by determining myeloperoxidase activity in isolated neutrophils. Blood samples were obtained from 142 periparturient dairy cattle in two herds. Twenty cattle developed RP (14.1%). Neutrophils isolated from blood of cows with RP had significantly lower neutrophil function in both assays before calving, and this impaired function lasted for 1 to 2 wk after parturition. The addition of antibody directed against interleukin-8 (IL-8) to the cotyledon preparation used as a chemoattractant inhibited chemotaxis by 41%, suggesting that one of the chemoattractants present in the cotyledon at parturition is IL-8. At calving, plasma IL-8 concentration was lower in RP cows (51 +/- 12 pg/ml) than in cows expelling the placenta normally (134 +/- 11 pg/ml). From these data, we suggest that neutrophil function is a determining factor for the development of RP in dairy cattle. Also, depressed production of IL-8 may be a factor affecting neutrophil function in cows developing RP.

Reduced phagocytotic activity of macrophages in the bovine retained placenta

This study was carried out to investigate the distribution of immune cells in the bovine placenta during the postpartum period and to compare these cells between normal and retained placenta. Within 1 h after normal calving, biopsy samples of placentomes were collected from 10 cows. The occurrence of retention of fetal membranes was monitored for more than 8 h post-calving, and the samples obtained were divided into two groups: normally discharged and retained placenta (n = 5 each). Immunohistochemical procedures were utilized to detect macrophages and T lymphocytes. Numerous CD14-positive macrophages were found in the stroma of both normal placenta and retained placenta whereas only a few CD3-positive T lymphocytes were found in both cases. However, histochemical staining for acid phosphatase, a predominant lysozomal enzyme, revealed that almost all macrophages showed strong enzyme activity in the normally discharged placentas, whereas in retained placenta the activity of acid phosphatase was conspicuously decreased in intensity. These results indicate that there are functional differences in placental macrophages between normal and retained placenta.