Retained Fetal Membranes Research Articles

Effect of intrauterine antibiotic treatment on reproductive performance of dairy cows following periparturient disease

AIMS: To quantify the effect of treating lactating dairy cows that had histories of periparturient disorders or disease with a single intrauterine infusion of 0.5 g cephapirin, 3–6 weeks prior to the start of the seasonal breeding period. METHODS: Cows (n=690) from spring-calving dairy herds (n=22) were enrolled in a prospective case-control study if they had a history of dystocia, a dead calf at calving or within 24 h of calving, retained foetal membranes (RFM), metabolic disease, twins or a vulval discharge >13 days postpartum. Cows were blocked by age, periparturient condition and calving date, and randomly assigned to be either treated with 0.5 g of cephapirin by intrauterine infusion, or left as untreated controls. Treatment occurred 24–42 days before the planned start of mating (PSM) within each herd. In addition, the reproductive tracts of 91 cows from 4 herds were examined using a vaginal speculum and rectal palpation and cervical-os discharge was scored on a scale from 0 (nil) to 3 (purulent). RESULTS: Overall, more treated cows were retained in the trial herds until pregnancy testing than control cows (p<0.05). Average 28-day submission rate was higher (93.1% vs 87.1%; p<0.05) and PSM-to-first-service interval was shorter (9 ± 1 vs 11 ± 1 days; p<0.05) in treated than control cows. The percentage of cows not pregnant at the end of the mating period was not affected by treatment overall. However, amongst cows diagnosed with RFM, a dead calf, or vulval discharge, pregnancy rates 28 and 56 days after PSM were higher for treated than control cows (p<0.05). Cows with a purulent cervical-os discharge had lower 28-day submission rates (p<0.01), lower 28-day pregnancy rates (p<0.05) and higher non-pregnant rates at the end of mating than cows with nil or mucoid cervical-os discharges. CONCLUSIONS: Intrauterine treatment with 0.5 g cephapirin improved reproductive performance of dairy cattle, especially those that had a history of RFM, a calf dead at calving or within 24 h of calving, or a vulval discharge.

Effects of periparturient diseases and conditions on the reproductive performance of New Zealand dairy cows

AIM: To determine the effect of retained foetal membranes (RFM), periparturient recumbency, calf mortality, dystocia, twin births and induction of parturition on submission and pregnancy rates of pasture-fed, seasonally-calving dairy cows in New Zealand. METHODS: Data were retrospectively collected for 2652 cows from 11 herds on the occurrence of periparturient diseases and condition, calving date, age and treatment for anoestrus prior to the planned start of mating (PSM). The effects of each disease or condition on submission and pregnancy rate by 28 days after PSM, final pregnancy rate, and the proportion of cows that conceived more than 50 days after PSM were examined using separate logistic regression models. Results are expressed as odds ratios (OR). Additionally, the effect of each disease or condition on the interval from PSM to conception was examined using survival analysis. Age, herd and late calving (i.e. cows calved ≤40 days before PSM) were included as factors in the models examined. RESULTS: Induction of parturition increased the risk of RFM (OR=3.3, p<0.01). The 28-day submission rate was affected by age and herd but not by any of the periparturient conditions examined. The 28-day pregnancy rate was reduced by RFM (OR=0.04, p<0.05), induction of parturition (OR=0.67, p<0.01), assisted calving (OR=0.61, p<0.01), late calving (OR=0.55, p<0.05) and anoestrus (OR=0.27, p<0.05). The final pregnancy rate was reduced by RFM (OR=0.013, p<0.01), induction (OR=0.25, p<0.05), assisted calving (OR=0.30, p<0.005) and anoestrus (OR=0.32, p<0.05), and was increased if the cow was submitted for mating within 28 days after PSM (OR=2.72, p<0.05). Effects of recumbency and twinning were not significant in any of the models. CONCLUSIONS: Cows that had had RFM or were assisted, induced or late to calve, had significantly lower pregnancy rates or took longer to conceive than unaffected herd-mates. CLINICAL RELEVANCE: Intervention programs aimed at the examination and treatment of cows with periparturient conditions may improve the reproductive performance of New Zealand dairy herds. Investigations of poor reproductive performance of a herd should include analysis of the prevalence and effects of periparturient diseases and conditions.

15-Ketodihydro-PGF2α, Progesterone and Cortisol Profiles in Heifers after Induction of Parturition by Injection of Dexamethasone

In order to study rapid changes in 15-ketodihydro-PGF2α, cortisol and progesterone in the period preceding parturition in cattle, pre-term parturition was induced in 4 late pregnant heifers. Parturitions were induced by 2 intramuscular injections of 20 mg dexamethasone with a 24-h interval. The first injection was made on days 254, 258, 264 and 265 in gestation, respectively. Twenty-four h before the first injection an intravenous polyurethane cannula was inserted. Blood samples were collected at least every hour until 12 h after parturition and during the second stage of labour at least 6 times per hour. Plasma was analysed for 15-ketodihydro-PGF2α and progesterone by radioimmunoassays, and for cortisol by an ELISA. The average time from injection to parturition was 7.7 (6.6–8.9) days (mean (range)). Two of the heifers had retained foetal membranes (RFM). At the start of the experiment the levels of PGF2α metabolite were low (< 300 pmol/L) and increased slowly to levels between 1000 and 2000 pmol/L at one day before parturition. During the last day, however, the levels increased rapidly and the highest levels (>10000 pmol/L) were reached at the time of delivery. No pulsatile release was seen. Immediately after foetal expulsion the PG-metabolite levels decreased rapidly in all animals. In the 2 animals with RFM, however, this decline ceased within a few h. The PG-metabolite levels in these animals then started to increase and reached levels as high as during parturition. Luteolysis occurred between 1.6 and 0.4 days before parturition in all animals. The cortisol profile showed a distinct peak at the time of parturition in the RFM heifers. This peak was absent in the non-RFM heifers. This study shows that the PGF2α release at prepartal luteolysis and parturition is not pulsatile in cattle and that cortisol profiles in heifers with retained foetal membranes might differ from the profiles in non-RFM heifers at the time of parturition.

Effect of Calcium Propionate plus Propylene Glycol on the incidence of Calving-related Disorders in Transition Florida Dairy Cows fed Anionic Salts

Transition period in the dairy cow is characterized by tremendous physiological demands. Calving-related disorders (CRD) such as milk fever (MF), retained fetal membranes (RFM), metritis, fatty liver, ketosis, left and right displacement of abomasum (DA), mastitis, and lameness are common features. These disorders are interrelated and have a significant negative economic impact in dairy cattle operations. Any attempt to decrease the incidence of CRD will positively affect milk yield and reproductive performance.&#x0D; The following field trial was conducted to determine the effect of a calcium-energy supplement on the incidence of calving-related disorders in Florida dairy cows.

Induction of parturition with prostaglandin f2 alpha as a possible model to study impaired reproductive performance in the dairy cow.

Parturitions were induced in five cows, 2 weeks before term using prostaglandin (PG) F(2alpha). Two i.m. injections were performed with an interval of 24 h. All cows calved within 5 days (average 2.7 days) after the first injection of PGF(2alpha). Out of five cows, four had retained fetal membranes (RFM). Each animal was sampled for bacteriological examination using uterine biopsies twice a week during 42 days postpartum (PP). Jugular vein blood samples were withdrawn for PGF(2alpha)-metabolite and progesterone analyses five times per day during the first week PP and eight times per 24 h during the 2nd and 3rd weeks PP. From the 4th week, the sampling interval was reduced back to five times per day. From the 5th week PP, the sampling was reduced to two times per day and sampling was terminated after day 46 PP. Only morning samples were used for progesterone analyses. From day 10 PP, ultrasonography (US) was performed every 3rd day until day 39 PP for detection of ovarian activity and follicular dynamics. The highest incidence of bacteriological species was found during the first 3 weeks PP. After the 5th week of collection, all animals were free from bacteria. The species of bacteria found were Arcanobacterium (Actinomyces) pyogenes, Escherichia coli, alpha-hemolytic streptococcae and Pasteurella multocida. Immediately after parturition, very high levels of the PG-metabolite were seen in all animals, with a sharp decrease to line of significance around days 9-12 PP. Small increases above the line of significance were detected up to day 27 PP in cows with RFM, and after that time the levels were considered to be at baseline. Low levels of progesterone were seen in four animals during the whole experimental time. In one animal, an increase was seen on day 43 PP, which was maintained until the end of the experimental period on day 46 PP. Based on US, follicular waves were detected in all animals during the experimental period. In three animals, three non-ovulatory follicular waves were detected and in two animals, four non-ovulatory follicular waves were detected during 39 days of ultrasound sessions. Based on progesterone levels, only one animal was considered to have ovulated around day 40 PP. Results from the present study indicate that reproductive performance of cows after PG-induced parturitions differs from those of spontaneous cases of RFM. Differences regarding the resumption of ovarian activity were also observed between previous studies of dexamethasone-induced parturitions and the present study.

Effect of Calcium and Energy Status During the Postpartum Period on Reproductive Performance in Dairy Cows

Pregnancy rate, a function of heat detection and conception rate, determines the number of days postpartum at which cows become pregnant from the voluntary waiting period.67 Cows expressing one or more estruses during the first 30 days postpartum had improved pregnancy rates compared with anestrous cows.83 This observation indicates that the physiological and hormonal events associated with estrus help restore uterine and ovarian function to a state conducive to pregnancy. A number of studies have demonstrated the relationship between hypocalcemia and parturient disorders such as dystocia, retained fetal membranes (RFM), and ketosis.13,30,68 These disorders predispose the cow to metritis, which can affect the energy status of the cow. This influences ovarian activity and resumption of cyclicity during the postpartum period.&#x0D; The energy status of the lactating dairy cow has differential effects on early follicular development and competence, ovulation and subsequent corpus luteum (CL) function during the postpartum period. As our understanding of the endocrinology and reproductive physiology of the postpartum cow has advanced, it is clear that reproductive and nutritional management systems need to be integrated to achieve optimal reproductive efficiency.&#x0D; Objectives of this presentation are 1) to describe the association between calcium status and periparturient disorders 2) to relate the differences in ovarian activity to energy status in postpartum dairy cows 3) to examine the effects of protein and fat on reproductive function during the postpartum period, and 4) to document the beneficial effects of bovine somatotropin (bST) on first-service pregnancy rates when integrated into a reproductive management program for timed insemination.

Endocrine Aspects of Uterine Involution in the Cow

AbstractThe postpartum period (PP) (=puerperium) is characterized by involution of the uterus and recyclicity of the ovarian functions to prepare the animal for a new pregnancy period. The time required for the genital organs to become normalised is influenced by breed, management including feeding regimens and environmental factors. This period is also strongly influenced by periparturient diseases such as dystocia, paresis (puerperalis), mastitis, endometritis, etc. The period is also influenced by several hormonal changes. During the postpartum period in the cow, a massive release of PGF2α occurs concomitantly with the uterine involution. In cows with retained foetal membranes (RFM), a second pulsatile release of PGF2α is seen concomitant with the growth and final elimination of bacteria. A similar pattern is seen in cows with induced parturitions with e.g. dexamethasone, indicating the occurrence of RFM/endometritis as a consequence of the induction. The duration of these prostaglandin releases are negatively correlated to uterine involution in normal cows and positively correlated in cows with RFM/endometritis respectively. As long as the release is maintained, the cow is unable to ovulate and it therefore seems likely that PGF2α or other products in the arachidonic acid cascade can inhibit the ovarian activity. Onset of ovarian cyclicity influences to a high degree the uterine involution, however most common is that the first ovarian cycle is shorter than seen during the normal oestrous cycle. The uterine involution process can be enhanced by treatments with exogenous PGF2α‐ No effect on uterine involution in healthy cows, or a slight positive effect, is seen after treatment with prostaglandin synthesis inhibitors (e.g. flunixin meglumine). The aim of this presentation is to review some of the knowledge of the interactions between the uterus and ovaries during the postpartum period in cattle.

Effect of oral administration of a calcium chloride gel on blood mineral concentrations, parturient disorders, reproductive performance, and milk production of dairy cows with retained fetal membranes

Objective To assess the effect of oral administration of CaCl2 gel on blood mineral concentrations, parturient disorders, reproductive performance, and milk production of dairy cows with retained fetal membranes (RFM). Design Randomized field trial. Animals 20 cows that calved normally and were not treated with CaCl2 gel (group 1), 20 cows with RFM that were treated with CaCl2 gel (group 2), and 20 cows with RFM that were not treated with CaCl2 gel (group 3). Procedure Group-2 cows were treated orally with CaCl2 gel (54 g of calcium) 24 and 48 hours after parturition. Results Administration of CaCl2 gel 24 and 48 hours after parturition did not have a significant effect on serum normalized calcium, total calcium, magnesium, or phosphorus concentrations or on incidence of metritis or left displacement of the abomasum, days to first insemination, pregnancy status after first insemination, or milk production. Conclusions and Clinical Relevance Administration of CaCl2 gel 24 and 48 hours after parturition did not have significant effect on blood mineral concentrations, parturient disorders, reproductive performance, and milk production in dairy cows with RFM. (J Am Vet Med Assoc 1999;215:72-76)

Treatment of dairy cows at parturition with prostaglandin F2α or oxytocin for prevention of retained fetal membranes

Objective To evaluate the effects of treatment at parturition with dinoprost tromethamine, fenprostalene, or oxytocin on postpartum disease and reproductive performance during the subsequent breeding season in dairy cows. Design Prospective study. Animals 1,400 Holstein cows from 5 commercial dairies. Procedure Cows were assigned within 2 hours after calving to serve as untreated control cows or to be treated with 1 mg of fenprostalene, SC; 25 mg of dinoprost tromethamine, IM; or 20 IU of oxytocin, IM. Cows were confined to treatment pens and monitored daily until fetal membranes were expelled. Cows with retained fetal membranes (RFM) were treated according to existing treatment protocols for the dairy, with the provision that intrauterine infusions were not allowed. All other disease conditions were recorded, and appropriate treatment was administered. Postpartum reproductive examinations were performed 28 to 56 days after parturition. Breeding records were maintained for all cows until pregnancy was confirmed or the cow was removed from the herd. Results Fetal membranes were retained in 12.1% of all cows, and this outcome was unaffected by treatment. Compared with cows without RFM, cows with RFM had longer intervals to first insemination (76.4 vs 82.0 days), reduced first insemination conception rates (46.8 vs 28.0%), and increased number of days not pregnant (103.2 vs 127.4 days). Farm, as a variable, significantly affected development of RFM and postpartum disease conditions as well as reproductive performance during the subsequent breeding season. Fetal membranes were retained in 12.4, 15.2, 8.7, 6.3, and 16.9% of cows on farms 1, 2, 3, 4, and 5, respectively. Mean days to first insemination varied from 64.5 days (farm 3) to 91.5 days (farm 1). Mean number of days not pregnant varied from 94.8 days (farm 3) to 115.9 days (farm 4). Clinical Implications Administration of prostaglandins or oxytocin at the time of calving does not reduce the incidence of RFM or improve reproductive performance. Farm management practices have the greatest impact on dairy cow performance. (J Am Vet Med Assoc 1997;211:1280–1284)

Prostaglandin F2αMetabolite and Progesterone Profiles in Post-partum Cows with Retained Foetal Membranes

Post-partum prostaglandin release and resumption of cycli-cal ovarian activities were studied in 11 Swedish dairy cows with retained foetal mem-branes (RFM), leaving the RFM untreated. The main PGF2α metabolite, 15-ketodihy-dro-PGF2α, was measured in blood plasma collected twice daily during the first 50-60 days after delivery. Progesterone was monitored from all morning samples to evaluate the resumption of ovarian activity. The plasma levels of 15-ketodihydro-PGF2α were ar-bitrarily considered to be significantly elevated between 6-24 days when they exceeded the mean basal value + 2 standard deviations. Comparison between this duration in days of the post-partum PGF2α release and the time required for the completion of uterine in-volution, placental shedding and last day of post-partum clinical signs showed no sig-nificant relations. However, prior to a final decrease below a line of significance of 233-590 pmol/1, pronounced sustained and pulsatile release of PGF2α occurred in relation to the increased frequency of the bacteriological findings. These additional periods of PGF2(X release were described as the “total” duration of post-partum release, and were found to be positively correlated with the time required for uterine involution from the stand point of rectal palpation (p<0.05), while a tendency towards a positive relationship existed for the last day post-partum of clinical signs (p = 0.11). Progesterone analysis revealed resumption of ovarian activity and the first ovulation occurred between 19-29 days in 70% of the cows. The levels of the PGF2α metabolite were again high at the time of luteolysis, thus terminating the luteal phase in the ovulating animals. Thus, it is seen that non-removal of the RFM or the resultant intrauterine infection do not prolong the duration of the immediate post-partum release of PGF2α as compared to normal ani-mals. However, a second release is associated with the increased frequency of uterine infections, indicating that PGF2α may play a role for the early elimination of the infec-tions.

Ovine placenta related to binucleated cells in fetal membrane retention

Placentomes were collected from 28 Iraqi Awassi ewes which had retained their fetal membranes after; (a) normal birth ( n = 6); (b) abortion ( n = 6), (c) dystocia ( n = 10), and (d) Caesarean section ( n = 6). Histologic changes in placentomes obtained from ewes with retained fetal membranes (RFM) after normal birth included vascular changes (edema, hyperemia and hemorrhages), hemosiderin pigmentation, necrosis in the maternal villi and presence of moderate to large numbers of binucleate cells (BNC). In placentomes obtained from ewes having RFM after abortion, there were vascular changes in both maternal and fetal connective tissues. Necrosis and massive bacterial colonies were seen in the caruncles and cotyledons. Few numbers of BNC and infiltration of polymorphonuclear and mononuclear cells in the caruncles and cotyledons were observed. The changes in placentomes obtained from ewes having RFM after dystocia (treated by assisted delivery) included the presence of vascular changes, hemosiderin pigmentation, moderate degree of necrosis and few bacterial colonies in the caruncles and cotyledons. Moderate numbers of BNC were observed. On the other hand, in cases of dystocia (treated with a Caesarean section), vascular changes, moderate degrees of necrosis and few numbers of bacterial colonies were observed in caruncles and cotyledons and only few BNC. It was concluded that BNC are involved in the process of placental separation in ewes.

Isolation and antimicrobial susceptibility of [formula omitted] recovered from the uterus of dairy cows with retained fetal membranes and post parturient endometritis

The minimal inhibitory concentrations (MICs) of 14 antimicrobial agents for Actinomyces pyogenes isolates recovered from the uterus of cows with retained fetal membranes (RFM) and post-parturient endometritis (PPE) were determined. Cows with RFM received a course of intrauterine tetracycline therapy, whereas some cows with PPE received a similar treatment and others did not. Samples of uterine exudate were aseptically collected at least 10 d after the last treatment. A profuse growth of A. pyogenes was observed on blood agar plates inoculated with uterine exudate from 72% of the 54 cows sampled. Differences were not observed in the type and characteristics of bacterial growth in the exudate of cows with PPE which were sampled before and after antibiotic treatment. The MIC of penicillin G, amoxycillin, cephalothin lincomycin and tylosin for 90% of the isolates was <0.5 μg/ml; the corresponding value for streptomycin, oxytetracycline (OTC), chloramphenicol, norfloxacin and sulfadiazine/trimethoprim was >10.0 μg/ml. The MIC of OTC for 90% of the A. pyogenes isolates was >100 μg/ml. The susceptibility of 14 A. pyogenes isolates of bovine udder origin and 3 A. pyogenes ATCC isolates from the bovine udder and abscesses in sheep and swine to antibiotics was determined, for comparative purposes. Most of the isolates recovered from the uterus were resistant to OTC and sulpha/TMP whereas this was not the case for isolates recovered from other sources.

Activity of placental 15-hydroxy-prostaglandin dehydrogenase in cows with and without retained fetal membranes

The aim of the following study was to test the hypothesis that an increased local catabolism of prostaglandin F2α might at least in part be responsible for the lower placental tissue concentration of PGF2α found in cows with retained fetal membranes (RFM) compared with that of cows without RFM. Activity of 15-hydroxy-prostaglandin dehydrogenase (15-PGDH) was measured in fetal and maternal placental tissue from cows with spontaneous parturition at term, with Cesarian section at term as well as before term either without (Groups A, C, E) or with RFM (Groups B, D, F), respectively. Furthermore, the concentration of progesterone and total estrogens in peripheral blood and degree of placental maturation were determined at the time of tissue sampling. Activity of 15-PGDH was higher in fetal part of the placenta than in the maternal part (P<0.0001). In Groups A and C, enzyme activity was higher than in Groups E and F (P<0.05). Enzyme activity in fetal and maternal placental tissue was positively correlated. A negative correlation was found between enzyme activity in maternal placental tissue and concentration of progesterone, and between concentration of progesterone and total estrogen. Degree of placental maturation was lower in cows with RFM than without RFM. Furthermore, degree of placental maturation was lower in cows calving before term than in cows delivering at term. In conclusion, an increased local catabolism of PGF2α might not be involved in lowering PGF2α concentration in placental tissue from cows with RFM. Activity of 15-PGDH seems to be influenced by stage of gestation and hormonal environment.

Intrauterine bacterial findings in postpartum cows with retained fetal membranes.

Eleven Swedish postpartum cows with retained fetal membranes (RFM) were studied to determine the intrauterine bacterial flora. Bacteriological examination was performed from twice weekly uterine biopsies. A total of 161 biopsies were collected during the first 8 weeks postpartum of which 82 (50.9%) were found with bacterial growth. Seventy-one of the 82 bacteria-positive biopsies (86.6%) showed mixed infections whereas the remaining 11 (13.4%) were pure cultures. Generally, a total of 322 isolates belonging to 12 different genera of bacteria, 6 facultative and 6 obligate anaerobic pathogens were identified. Mixed infections were most frequent for Actinomyces pyogenes together with obligate anaerobic bacteria, especially Bacteroides levii/spp. and Fusobacterium necrophorum. All of the studied cows had an infection that involved the first two genera of bacteria, whereas F. necrophorum was found in 8 of the 11 animals. The present work suggests that a possible pathogenic synergism between A. pyogenes and the two main Gram-negative anaerobes might have caused early endometritis and/or persistent infection.

Ultrasonography of the bovine postpartum uterus with retained fetal membranes.

The aim of this study was to describe the potential application of ultrasound in combination with the rectal palpation method and to compare the results to determine the involution period in 11 Swedish dairy cows with retained fetal membranes (RFM). The animals were examined three times a week during the first 8-week postpartum (PP) period. Significant quantity of abnormal vaginal discharges with concomitant accumulation of snowy fluid and thickening of the endometrial and uterine walls were interpreted as evidence of endometritis. The discharges decreased most markedly during the third week PP concomitantly with a marked decrease in the cervical and uterine size. Resumption of cyclical ovarian activity occurred within a month in 7 animals. Five of these cows had 2 ovulations and two animals had 1 and 3 ovulations, respectively. A slight increase of the cervix and uterine size was observed in all ovulating animals in relation to the oestrous periods. Several different calculation methods of the ultrasonographic results were evaluated to describe the completion of uterine involution and compared with findings at rectal palpation. The best congruency with rectal palpation was found to use a 0.5 cm difference for comparison of the previous pregnant and non-pregnant uterine horns in singleton cows and an 80% reduction of the uterine size in all studied animals.

Metabolism of arachidonic acid by caruncular and allantochorionic tissues in cows with retained fetal membranes (RFM)

The metabolism of arachidonic acid (AA) by caruncular and allantochorionic tissues and its regulation was studied in normal cows (n=13) and those with retained fetal membranes (RFM; n=9). Tissues were taken via the vagina about 6 hours postpartum and incubated for 6 hours in minimum essential medium containing tritiated AA alone or in the presence of oxytocin, platelet activating factor (PAF), epidermal growth factor (EGF) or ionophore calcium (A23187). The metabolites of AA were separated by reverse phase-high pressure-liquid chromatography. Tissue concentrations of prostaglandin F 2α (PGF 2α) and prostaglandin E 2 (PGE 2) and plasma 13,14-dihydro-15-keto-PGF 2α (PGFM) concentration were also measured by radioimmunoassay. For caruncular tissue, less thromboxane B 2 (TXB 2) and more 6-keto prostaglandin F 1α (PGIM) was synthesized in tissue from the animals with RFM than in the controls. Oxytocin, PAF, EGF and A23187 increased only PGIM production in the control animals; A23187 also decreased TBX 2 synthesis. For the allantochorion, more PGE 2, leukotriene B 4 (LTB 4) and PGIM and less TXB 2, PGF 2α and hydroxyecosatetranoic acids (HETE) was synthesized in tissue from cows with RFM than from animals that delivered normally. All of the substances used in this study increased PGIM, PGF 2α and LTB 4 and decreased TXB 2 production by the allantochorionic tissue in control animals. The metabolism of AA by the allantochorionic tissue seems quantitatively under hormonal control. The metabolism of AA at the level of both maternal and fetal components of the placenta in cows with RFM differed from that seen in animals that expelled the membranes normally.

Factors Influencing Periparturient Neutrophil Function in Dairy Cows

Many diseases and conditions of economic importance in dairy cattle occur most commonly during the immediate postpartum period. Kehrli et al1 found neutrophil function to be impaired during this period. These authors described periparturient depression of random migration, bacterial ingestion, chemiluminescence, iodination and cell-mediated cytotoxicity. In this study, heifers which had postparturient intramammary infections also suffered the most severe peripartum alteration of neutrophil function. This supports the contention that neutrophil function is an important element in the first-line defense of the body against bacterial infection. Impaired neutrophil function during the periparturient period may contribute to the peculiarly high incidence of bacterial infections during this period.1&#x0D; The incidence of disease in periparturient cows is further influenced by other factors, including parity and the occurrence of retained fetal membranes (RFM). Epidemiological studies have linked advancing parity to an increasing incidence of several disorders. Thus the lactational incidence risk of retained fetal membranes and ovarian cysts increased with advancing parity in a study of over 61,000 lactations in a population of Finnish Ayrshires.2 A separate study found that advancing age of dairy cows was associated with increased incidence of retained fetal membranes and mastitis. Retained fetal membranes, in turn, predispose to a host of other reproductive disorders including metritis, silent heat and undiagnosed infertility2 and mastitis.4,5 Even when controlling for the effects of specific, diagnosed diseases, advancing parity was associated with reduced reproductive efficiency. These authors speculate that this may be related to subclinical reproductive tract lesions. In itself, RFM is relatively innocuous. The retained membranes are unsightly, often fetid, and aesthetically objectionable for many milkers, but the effect of uncomplicated RFM on the cow is minimal. The major significance of RFM is in the mediation of more severe conditions. Thus, cows which have suffered retention of fetal membranes are at significantly increased risk for developing metritis2,3,7, ketosis3, mastitis2,4,5 and even subsequent abortion in the following pregnancy.2 Schukken, Erb and Smith5 studied the relationship between RFM and mastitis in a population of commercial dairy cows. They found that cows which retained the fetal membranes were at a higher risk (relative risk= 1.5) of developing mild mastitis, and at a much higher risk (relative risk = 5.4) of developing severe mastitis with systemic manifestation than were cows not retaining the membranes. A further finding was that longer duration of placental retention was associated with greater likelihood of mastitis. In a follow-up study in a hospital-based population, this group confirmed these results.4 These authors speculate that the relationship between retained placenta and mastitis is mediated by deficient peripartal peripheral neutrophil phagocytic activity.&#x0D; In 1984 Gunnink proposed that deficient neutrophil activity was a factor in the pathogenesis of RFM in cattle.8-10 He showed that circulating leukocytes from cows with RFM showed diminished chemotactic responses to cotyledon suspensions in vitro.8 He further demonstrated that this impaired chemotactic response existed before parturition9 and that it persisted at least 10 days into the post-partum period.10 Heuwieser and Grunert11 have also reported impaired neutrophil migration in cows which retained fetal membranes.&#x0D; We therefore designed experiments to determine whether periparturient neutrophil function was influenced by parity of the cow or by RFM as part of a project aimed at illuminating pathophysiological factors with epidemiological observations.

Comparison of fenprostalene and oxytetracycline as treatment for retained fetal membranes in dairy cows

Retained fetal membranes (RFM) is a common postpartum disorder of the reproductive system of dairy cows. The incidence, etiology, consequences, treatment and prevention of RFM have been thoroughly discussed. Agreement on the best way to manage and treat RFM is not unanimous. Management and treatment schemes are numerous, and there are proponents of each. Regimes of therapy include no treatment, intrauterine antibacterials, systemic antibacterials, uterine contractants, manual removal, no manual removal and various combinations. At the present time the most widely used treatment for RFM is probably intrauterine tetracycline with or without manual removal of the membranes; however, there is an apparent trend away from manual removal. The ideal therapy for RFM would be non-irritating to the endometrium, non-depressing to the uterine defense mechanism, prevent the development of metritis and promote uterine tone and contractions to discourage the accumulation of fluid. To achieve these desired effects, it would appear that both the proper antibacterials and uterine contractants would be needed. Thus far, the various treatments employed have not consistently brought about the desired results.&#x0D; Fenprostalene, an analogue of prostaglandin F2 alpha, has recently been advocated as a treatment for RFM. At least 3 reports indicate the beneficial effects of fenprostalene as therapy for RFM in dairy cows. In another trial, however, there was no benefit.&#x0D; The purpose of this study was to compare fenprostalene and oxytetracycline for the treatment of RFM noting in particular the effect on body temperature, days to expulsion, incidence of postpartum metritis and subsequent fertility.

Reproductive performance of dairy cows after early detection and oxytetracycline treatment of post-partum metritis

The effect of oxytetracycline intra-uterine infusion on reproductive performance of 20 Holstein and Ayrshire cows with retained fetal membranes (RFM), or with post-partum metritis (47 cows) was studied in comparison to 37 normal post-partum cows. Cows with post-partum metritis were those found to have an abnormal cervical and uterine involution and/or abnormal vaginal discharge, based on weekly palpation and daily appraisal. Cows with RFM were those that had no expelled the membranes by 12 hours and were treated sooner than cows with evident metritis. Also, more treatments were given to the RFM cows. In addition RFM cows completed treatment sooner after calving than non-RFM cows. Palpable cervical and uterine involution (diameter) during the first 40 days was not different among normal cows, cows with RFM and post-partum metritic cows. Reproductive performance as characterized by interval to first estrus, services per conception, post-partum interval to conception and percentage cows conceiving were comparable between normal cows and those treated for metritis with or without RFM.

Retained fetal membranes in cows: Manual removal versus nonremoval and its effect on reproductive performance

Sixteen primiparous Holstein cows with retained fetal membranes (RFM) were studied for postpartum prostaglandin release, uterine infection and resumption of estrous cyclicity after manual removal of RFM (eight cows) versus leaving the RFM untreated (eight cows). The RFM were results of induced parturition on Day 274 of gestation. Seventeen non-RFM primiparous cows were controls. The 15-keto-13, 14-dihydro-metabolite of prostaglandin F 2α (PGFM) was measured in daily blood samples. Aerobic and anaerobic bacteria were cultured from weekly uterine swabs from Week 3 until results were negative. Resumption of estrous cyclicity was determined by milk progesterone three times weekly. Manual removal caused an immediate and large but short-lived increase in PGFM, probably due to the physical damage of uterine tissue. No sustained difference in postpartum PGFM release between cows with RFM manually removed and cows with RFM left untreated was detected. Non-RFM controls had lowest PGFM concentrations. Uterine infections were more frequent and more severe after manual removal of RFM. Untreated RFM-cows and controls were similarly affected. Most infections involved Actinomyces (formerly Corynebacterium ) pyogenes and/or Fusobacterium necrophorum . Actinomyces pyogenes was isolated in the third week postpartum in 5 8 cows with RFM manually removed versus 2 8 cows with RFM left intact and in 2 17 controls. Manual removal prolonged the interval from calving to first functional corpus luteum by 20 d. This study, using RFM resulting from induced parturition, shows that manual removal of RFM can delay the postpartum return to normal reproductive status without altering PGFM profiles.