Evaluation of intrauterine antibiotic treatment of clinical metritis and retained fetal membranes in dairy cows

Retained fetal membranes (RFM) and clinical metritis (CM) are frequently diagnosed disease conditions in dairy cows and considered of major economic impact due to negative effect on reproduction and milk production. The objective of this study was to evaluate the efficacy of i.u. tetracycline for the treatment of RFM and CM in dairy cows. Affected cows were randomly assigned to two groups; treatment group animals received i.u. 5 g chlortetracycline twice weekly for 2 wks, and no treatment group.A total of 1416 cows and 804 heifers in 5 herds calved during the study period. CM was diagnosed in 18.6% (inter farm range; 15.2–23.5%) and 30% (19.4–42.3%) of cows and heifers, respectively. RFM was diagnosed in 13.1% (9.4–18.1%) and 9.2% (3.6–13.8%) of cows and heifers, respectively. Conception rates after first insemination were 38.3%, 42.5% and 18% in normal, treated and non-treated CM cows, respectively. Numbers of days open were 140.5, 136.2 and 165.5 in normal, treated and non-treated CM cows, respectively. Based on 305-d corrected milk yield, cows and heifers affected by RFM and CM produced 300–500 kg less milk compared with their normal herd mates. Cows treated for CM produced 654 kg more milk per 305-d corrected lactation compared to non-treated control cows. Treatment of RFM had no effect on reproductive performance or milk production. In conclusion, i.u. chlortetracycline treatment was proven to prevent the detrimental effect of CM on reproductive performance in heifers and cows and on milk production in cows only.     

Evaluation of intrauterine antibiotic treatment of clinical metritis and retained fetal membranes in dairy cows

Retained fetal membranes (RFM) and clinical metritis (CM) are frequently diagnosed disease conditions in dairy cows and considered of major economic impact due to negative effect on reproduction and milk production. The objective of this study was to evaluate the efficacy of i.u. tetracycline for the treatment of RFM and CM in dairy cows. Affected cows were randomly assigned to two groups; treatment group animals received i.u. 5g chlortetracycline twice weekly for 2 wks, and no treatment group. A total of 1416 cows and 804 heifers in 5 herds calved during the study period. CM was diagnosed in 18.6% (inter farm range; 15.2-23.5%) and 30% (19.4-42.3%) of cows and heifers, respectively. RFM was diagnosed in 13.1% (9.4-18.1%) and 9.2% (3.6-13.8%) of cows and heifers, respectively. Conception rates after first insemination were 38.3%, 42.5% and 18% in normal, treated and non-treated CM cows, respectively. Numbers of days open were 140.5, 136.2 and 165.5 in normal, treated and non-treated CM cows, respectively. Based on 305-d corrected milk yield, cows and heifers affected by RFM and CM produced 300-500kg less milk compared with their normal herd mates. Cows treated for CM produced 654kg more milk per 305-d corrected lactation compared to non-treated control cows. Treatment of RFM had no effect on reproductive performance or milk production. In conclusion, i.u. chlortetracycline treatment was proven to prevent the detrimental effect of CM on reproductive performance in heifers and cows and on milk production in cows only.     

Duration of retained fetal membranes and subsequent fertility in dairy cows

Lactations from 1,111 heifers and 2,493 cows were evaluated for the effects of the duration of retained fetal membranes on subsequent fertility. Cows or heifers with metritis, ovarian cyst, both metritis and cyst, or neither were evaluated in separate strata in order to control for the effects of parity, metritis, and cyst on fertility. Duration of retention had no effect on fertility if an animal had metritis or cyst. There was a suggestion that retained fetal membranes in heifers free of metritis and cyst decreased conception rate at first service. In multiparous cows free of metritis and cyst there was a significant decrease in conception rate at first service when retention exceeded 5 days, and delays of +18 days to 1st service and +57 days to conception when retention exceeded 7 days.     

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.     

Variables associated with peripartum traits in dairy cows. V. Hormonal profiles associated with retained fetal membranes

Profiles of certain hormones measured by radioimmunoassay in 41 Holstein cows and heifers with retained fetal membranes (RFM; >12 hr postpartum) were compared to 41 peers without RFM (NRFM). Peers were matched by parity, season of calving, gestation length, dystocia and parturient paresis within prepartum diet group. Linear covariates of natural photoperiod, mean daily temperature, calf birth weight, length of gestation, and age and body weight of cow were included in the leastsquares analyses of data. Plasma profiles of prolactin and estrone were nearly identical from day 8 prepartum to day 2.5 postpartum. Plasma estradiol-17α was approximately one-third higher each day in group RFM (P<.05 across days) but estradiol-17β (Eβ) tended to be lower until day 2 prepartum (not significant). Also, plasma progesterone (P) was higher in group RFM between days 8 to 3 prepartum (p<.05 across days).Relationships between plasma P and Eβ were indicative of subsequent RFM (>24 hr rather than >12 hr), but only on day 6 prepartum. Three of four cases of 12 to 24 hr RFM had P and Eß profiles similar to NRFM. Either a combination of low P (<3.0 ng/ml) and low Eß (<100 pg/ml) or only high P (>7.9 ng/ml) were associated with a ten-fold higher rate of RFM (>24 hr) than when P was intermediate (4 to 8 ng/ml) and Eß exceeded 99 pg/ml. These results are in agreement with prior data wherein RFM were induced at premature births either by ovariectomy during pregnancy or by glucocorticoids.     

Comparison of antioxidative/oxidative profiles in blood plasma of cows with and without retained fetal placental membranes

Ante- and postpartum antioxidative/oxidative profiles in blood plasma of cows with and without retained placental membranes (RFM) were investigated. Twenty-two healthy pregnant cows were included in the study. Seven animals out of 22 suffered from RFM. Blood samples were obtained at 4, 3, 2, 1 weeks and 5 days antepartum (a.p.), at parturition and 1, 3, and 5 weeks postpartum. The following antioxidative parameters were measured using spectrophotometric methods: total antioxidant activity (TAC), β-carotene, vitamin A, vitamin C, and ceruloplasmin. The oxidative profile was based on the content of intermediates and end products of lipid and protein peroxidative processes which were measured by spectrophotometric and spectrofluorimetric methods. The examined parameters revealed a dynamic profile within the experimental period. The highest antioxidant and oxidant activity was noted at 2 and 1 week a.p. with a drop towards parturition suggesting the presence of oxidative stress during this time period and an apparent appropriate metabolic response of the macroorganism. Except for TAC and vitamin A, the contents of oxidative and antioxidative blood constituents did not differ between cows with and without RFM. A TAC and vitamin A by time interaction indicated higher antepartal concentrations of TAC and vitamin A in cows without RFM than in cows with RFM suggesting a possible role of antioxidative/oxidative imbalances in the aetiology of RFM.     

Serum alkaline phosphatase and lactic dehydrogenase activity in cows with retained fetal membranes

Serum alkaline phosphatase (AKP) and lactic dehydrogenase (LDH) activities were determined for 15 cows with retained fetal membranes (RFM) and 15 cows without retained fetal membranes (WRFM). The results revealed that the levels of both AKP and LDH were significantly higher in cows with RFM during late gestation and continued to be higher until 5th day postpartum. The usefulness of these findings for the prediction of RFM before parturition and for evaluating the therapeutic response of RFM is discussed.     

Oxytocin treatment immediately after calving does not reduce the incidence of retained fetal membranes or improve reproductive performance in crossbred Zebu cows

The objective was to determine the effect of oxytocin treatments after calving on the incidence of RFM and reproductive performance in dual purpose cows under tropical conditions. Five hundred thirty six pluriparous, crossbred Zebu cows were randomly assigned to two groups: Oxy (n = 280): cows were given 30 IU of oxytocin im immediately after normal unassisted calving, and again 6 h later; C (n = 256): control. Expulsion of fetal membranes was evaluated 24 h after delivery. After a 30-d voluntary waiting period, AI was done 12 h after cows were detected in estrus. Oxytocin had no effect on the incidence of RFM (4.6 vs. 3.1% for Oxy and C, respectively, P > 0.05). Cows in Oxy and C had similar first service and overall pregnancy rates (54.0 vs. 47.8% and 75.4 vs. 73.4%; respectively, P > 0.05). There were no differences between Oxy and C for calving to first estrus (83.6 ± 3.7 vs. 77.2 ± 3.8 d) and calving to conception intervals (113.6 ± 5.0 vs. 110.5 ± 5.2 d), as well as rates of anestrus (13.6 vs. 13.7%), repeat breeding (21.8 vs. 20.7%), and culling (15.7 vs. 16.4%). In conclusion, oxytocin treatment after normal unassisted calving did not significantly reduce the incidence of RFM or improve reproductive performance in crossbred Zebu cows under tropical conditions.     

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.     

Recombinant bovine somatotropin: association with reproductive performance in dairy cows

A clinical trial was performed to determine the effect of bST on reproductive performance in dairy cows on 4 Michigan dairy farms when bST was used according to labeled directions. Holstein cows (n = 555) at 4 Michigan dairy farms were randomly assigned to receive bovine somatotropin (bST) or to serve as untreated controls. Bovine somatotropin (500 mg, s.c.) was administered every 14 d beginning at 63 to 69 d of lactation and continuing until approximately 21 d prior to the end of lactation or until the producer removed the animal from the herd. A total of 229 (42.57%) animals consisting of 112 (48.91%) controls and 117 (51.09%) bST-treated cows were not diagnosed pregnant and were considered as having reproductive failure by 150 d of lactation and 92 (17.10%) of the animals consisting of 45 (48.91%) controls and 47 (51.09%) bST-treated cows had reproductive failure at the end of their lactation. No significant difference in the incidence of reproductive failure existed between the study treatment groups during either time frame. Cows with cystic ovarian disease had more instances of reproductive failure at 150 d of lactation than cows without this disease. Cows with dystocia, twin births, metritis, displaced abomasum and cystic ovarian disease had more instances of reproductive failure by the end of lactation than cows without these diseases. The bST-treated cows developed more nonspecific off feed conditions during the study lactation and had more twin births at the calving following bST administration compared to control cows. No differences were found between the study treatment groups in calculations of reproductive parameters. Logistic regression analysis found no significant effect of bST on reproductive failure; the odds ratios for the bST treatment effect on reproductive failure at 150 d of lactation and reproductive failure at the end of lactation were 0.95 (95% CI 0.67 to 1.36) and 0.95 (95% CI 0.59 to 1.54), respectively. Overall, bST was not found to have a significant impact on reproductive performance in the herds studied.     

Progesterone profiles in postpartum Holstein dairy cows as an aid in the study of retained fetal membranes, pyometra and anestrus

This study was carried out to investigate the utility of enzymeimmunoassay (EIA) - derived progesterone profiles in the investigation of postpartum reproductive abnormalities and the effect of their use on reproductive performance in Holstein cows. Whole milk samples, collected twice weekly from parturition until confirmation of pregnancy or removal from the herd, were assayed for progesterone (P4) concentration using a commercially available microtitre plate EIA. The sensitivity, specificity, precision and accuracy were satisfactory to distinguish cyclic changes of P4 reflecting ovarian activity. The P4 profiles indicated that retained fetal membranes and anestrus were associated with increased mean intervals to first ovulation and first estrus (P < 0.05). The first luteal phase of cows with pyometra was prolonged compared with that of normal herdmates (P < 0.05). Anestrus cows had an increased number of ovulations before first service and before pregnancy (3.9 and 5.9) in comparison with normal herdmates (2.1 and 3.5; P < 0.05). Calving to pregnancy interval was increased above normal (74.8) for pyometra (125.0) and anestrus (152.7) (P < 0.05). Pregnancy rate for anestrus cows (82%) was lower than for normal cows (100%) and more anestrous cows were culled (27%) than normal cows (5%) (P < 0.5). The P4 profiles indicated that the major problem in the herd studied, anestrus (32% incidence rate), was most likely due to the failure to observe estrus rather than acyclicity.     

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(2alpha) (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.     

Mechanisms and therapy for retained fetal membranes and uterine infections of cows: A review

Literature pertaining to retained fetal membranes and postpartum uterine infections of cows was reviewed. Many therapeutic failures are explained by the effects of the uterine environment on antibacterials, the effects of therapy on the uterine defense mechanism, bacterial resistance patterns and the failure to recognize normal physiological processes in the postpartum period. Prostaglandin F(2)alpha and its analogues provide effective alternatives to antibiotic and antibacterial therapy for most postpartum disorders.     

The effect of a monensin controlled-release capsule on the incidence of retained fetal membranes, milk yield and reproductive responses in Holstein cows

The objective of this study was to determine the effect of a monensin controlled-release capsule on the incidence of retained fetal membranes (RFM), milk yield and conception rate at first service (CRFS). The study was conducted during May to August 2004 in a large dairy herd in Chihuahua, Mexico. Cows (n = 2,025) from 20 to 30 d before expected parturition were randomly assigned to either a treatment or a control group. The treated group (n = 1,010) received orally a capsule of monensin that released 335 mg/d for 95 d. Control cows (no capsule, n = 1,015) were randomly assigned and matched by parity. Outcome variables were the incidence of RFM, first three test day milk and CRFS. Monensin decreased the incidence of RFM by 3.9% only in multiparous cows. Therefore, multiparous cows treated with monensin were 0.78 times (95% C.I. = 0.71-0.86) as likely as control multiparous cows to develop RFM. Overall, milk yield was negatively affected by the RFM condition, but it was improved by monensin only in multiparous cows with RFM at test day 1. Conception rate at first service was depressed by 10.6% in multiparous cows with RFM. However, in RFM cows treated with monensin, CRFS improved to the level of treated cows without RFM.     

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 E₂ (PGE₂) and plasma 13,14-dihydro-15-keto-PGF_2α (PGFM) concentration were also measured by radioimmunoassay. For caruncular tissue, less thromboxane B₂ (TXB₂) 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 TBX₂ synthesis. For the allantochorion, more PGE₂, leukotriene B₄ (LTB₄) and PGIM and less TXB₂, 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 LTB₄ and decreased TXB₂ 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.     

Plasma concentrations of estradiol 17beta and PGF2alpha metabolite and placental fatty acid composition and antioxidant enzyme activity in cows with and without retained fetal membranes

Fetal membrane retention is one of the most common problems in Holstein cattle after parturition. To investigate mechanisms involved, the following parameters were studied in the peri-parturition period: plasmatic concentrations of estradiol-17beta (E2) and PGFM (PGF2alpha metabolite), activity of antioxidant enzymes (superoxide dismutase-SOD, catalase-CAT and glutathione peroxidase-GSH-Px), thiobarbituric acid reagent substances (TBAR) concentrations and fatty acid composition of the placentae. E2 at parturition in the NPR group (control cows, n = 10) was higher than in PR cows (placental retention, n = 10) (P < 0.05). Activity of SOD in fetal tissue of NPR animals was higher than that of the PR group. In contrast, there was no difference between the two groups in activity of GSH-Px and CAT and the TBAR content of placental tissues. PR maternal tissues had proportionally more arachidonic and linoleic acid than tissues from NPR cows. Therefore, a complex of sequential events may cause placenta retention, starting with an unbalance of antioxidant capacity of the placenta, followed by a decrease in production of estrogen, which leads to the accumulation of arachidonic and linoleic acid in placental tissues.     

Comparison of reproductive performance in Belgian dairy and beef cattle

A computerized program was written to collect, evaluate and compare reproductive performance data of 2004 beef (Belgian Blue breed) and 1649 dairy (Friesian Holstein and German Red) cattle in 35 Belgian herds (6 suckler beef herds, 9 milked beef herds and 20 dairy herds). Reproduction data were collected at monthly herd health visits. No difference in age at first calving was observed. Significant differences were observed among the 3 kinds of herds, and the best results were obtained in dairy herds for the calving interval, interval from calving to the first estrus, interval from calving to the first service and average number of days open. Concerning these parameters, first calvers had lower results than multiparous cows, mainly in suckler and milked beef herds. Significant differences were noted in the number of services per pregnancy. Heifers that had never calved presented the highest fertility. Primiparous beef cows had higher fertility than pluriparous cows. In dairy herds, pluriparous cows had higher fertility than primiparous cows. Estrus detection was better in milked beef herds than in suckled beef and dairy herds. Suckled beef herds had the lowest incidence of metritis and ovarian cysts of the three types of herds. Rates of abortion, overall culling and retained fetal membranes were similar in all the herds. The percentage of animals removed for infertility was highest in milked beef herds and lowest in dairy herds. Because 90% of the 1159 calvings recorded in the beef herds required a caesarean section, the reproductive performance of beef cattle represent results after caesarean section.     

Prevalence of endometritis and its effects on reproductive performance of dairy cows

Hostein cows (n=141) in five commercial dairy herds in central New York were examined for endometritis by examination of endometrial aspirates for presence of inflammatory cells, principally neutrophils, by endometrial cytology at 40-60 days postpartum. The prevalence of cytologically-diagnosed endometritis was 53%; within herds the prevalence varied from 37 to 74% (P=0.02). There was excellent agreement between two examiners (Kappa=0.864; P<0.0001). Parity did not influence prevalence of endometritis (P=0.53). Cytologically diagnosed endometritis was associated with profoundly impaired reproductive performance; Kaplan-Meier survival analysis revealed lower overall pregnancy rate (P<0.0001). Median days open was 206 for cows with endometritis and 118 for cows free of the condition. Overall, 76% of cows in this study became pregnant by 300 days postpartum; 63% of cows with endometritis and 89% of cows without endometritis were confirmed pregnant by 300 days postpartum (P<0.003). (For these two groups, 69, and 90% respectively, became pregnant during the duration of the study). Pregnancy to first service percentage was lower (11 versus 36%; P=0.001) for cows with than without endometritis, and these cows required more services before 50% became pregnant (3 versus 2; P=0.006). In a second study using 22 cows in a university-owned herd, the prevalence of cytological evidence of inflammation was 100% at 2 weeks postpartum, and dropped to 89, 58, and 41% at 4, 6, and 8 weeks, respectively. Endometritis diagnosed by endometrial cytology late in the voluntary waiting period was highly prevalent and exerted a profoundly detrimental effect on subsequent reproductive performance, making this condition potentially extremely costly to the North American dairy industry.     

Management practices associated with reproductive performance in Holstein cows on large commercial dairy farms

As a result of the increase in herd size and the intensification of production, the complexity of reproductive management has been growing in dairy herds. The aim of our study was to examine the associations of management practices and reproductive performance in Holstein cows on large commercial dairy farms. Management practices applied to cows were surveyed between 22 May and 6 November 2015 in 34 large Holstein-Friesian dairy herds in Hungary. Individual data of 23 784 cows that calved between 1 January 2014 and 31 December 2014 in the surveyed herds were gathered. Associations between the management practices and the reproductive parameters were analyzed by mixed effects models. Regarding heat abatement we found that ventilation with sprinklers was associated with the shortest breeding interval (P<0.01), the shortest calving to conception interval (P<0.01), and the highest odds of being pregnant by 200 days in milk (P<0.01). Solely ventilation showed similar (P>0.05) results to lack of heat stress protection. It was also revealed, that lack of a well-established voluntary waiting period (VWP) or a VWP shorter than 50 days was associated with less days to first service (P<0.01), shorter breeding interval (P<0.01) and calving to conception interval (P<0.05), as well as higher odds of carrying a calf by 200 days in milk (P<0.01) compared with those using a VWP of at least 50 days. Those farms that applied transrectal ultrasonography were more likely to use ventilation with sprinklers (P<0.05), hormonal synchronization (P<0.01) and to perform early pregnancy diagnosis followed by pregnancy recheck (P<0.05). The application of transrectal ultrasonography with one of the aforementioned practices was associated with reduced days to first service (P<0.05), shorter breeding interval (P<0.05) and higher odds of pregnancy at 200 days in milk (P<0.05). Our study highlights the management practices most closely related to improved reproductive performance, which are, therefore, suggested to be applied on dairy farms, considering the local circumstances of the individual farms.     

Effects of estradiol cypionate and natural and synthetic prostaglandins on myometrial activity in early postpartum cows

The objectives of this experiment were to compare the effects of prostaglandin F(2alpha) (PGF(2alpha)) and its synthetic analogue treatment on postpartum bovine myometrial activity with and without estrogen priming. Sixteen multiparous, normal postpartum Holstein cows were randomly assigned to the following four treatment groups: saline PGF(2alpha), cloprostenol and fenprostalene. Myometrial activity was recorded using a catheter containing a miniature pressure transducer placed in the previously gravid horn via the cervix. Spontaneous myometrial activity was recorded at 48 h post partum for 60 min in all cows. Saline (5 ml,i.m.), PGF(2alpha) (25 mg,i.m.), cloprostenol (500 ug,i.m.) or fenprostalene (1 mg, s.c.) was administered to the cows according to the group. Myometrial activity was recorded until it returned to baseline. At the end of myometrial activity recording, 10 mg of estradiol cypionate (ECP) was injected i.m. to each cow. The same treatment schedule was repeated 12 h later. Results from this study indicate that PGF(2alpha) or its analogues, with or without ECP priming, do not increase myometrial activity in the postpartum cow. After ECP administration, both spontaneous and drug-induced myometrial activity increased; however, this increased myometrial activity was not statistically significant.