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

Propaedeutic and Therapeutic Practices Used for Retained Fetal Membranes by Rural European Veterinary Practitioners

The present study aimed to monitor the practices of European veterinarians for the diagnosis and treatment of retained fetal membranes in cattle. A questionnaire was established and distributed to veterinarians from five European countries. A total of 700 veterinarians participated in the survey. A vaginal examination, general examination and uterine palpation are carried out by 71%, 38% and 23% of veterinarians, respectively. Moreover, half of the veterinarians attempt to remove the placenta manually, 70% of them administer a combined local and general treatment if the cow has a fever (more than 39.5 °C), and 50% of them only administer IU treatment if no fever is observed. Tetracyclins, cefapirin and penicillins are the most used intrauterine (IU) antibiotics, whereas penicillin is the most used parenteral one. All other European veterinarians were less likely to use cefapirin and more likely to use oxytocin, Ca perfusion and NSAID than French and Walloon veterinarians. In conclusion, our study confirms the necessity of improving and rationalizing the diagnostic and therapeutic approach of the RFM, mainly to reduce the important problem of antibiotic resistance.

Assessing the consequences and economic impact of retained placenta in Holstein dairy cattle

Retained placenta (RP) is as an important reproductive disorder which adversely affects the economic performance of dairy cows. Understanding the consequences and economic losses associated with RP can persuade dairy farmers to consider it more effectively in their management decisions. Hence, the aims of this research were to assess the effect of RP on production and reproduction attributes as well as economic losses in Iranian Holstein cows. The data was collected from nine Holstein dairy herds in Isfahan province of Iran. The final dataset comprised of 139,508 records of 58,086 cows which calved between March 2011 and December 2018. A linear mixed model was developed to evaluate the effect of RP on individual performance of primiparous and multiparous cows. The economic losses associated with the RP were finally estimated. The average incidence of RP per cow over a year was 12.3% (ranged between 9.0 and 15.4%). Each incidence of RP significantly reduced milk, fat and protein yields in primiparous and multiparous cows (P < 0.05). The adverse effect of RP on the milk production was much higher in the cows at the early phase of lactation (i.e. 100-d lactation group) than the cows in mid or late lactation. The estimated production losses (±standard deviation) due to the RP event were 282.1 ± 43.0 and 295.7 ± 40.8 kg per cow for a 305-d lactation period in primiparous and multiparous cows, respectively. However, the fertility performance was less affected by the RP in primiparous compared to multiparous cows. The average of days open increased by 8.3 ± 5.3 and 19.8 ± 7.1 d in primiparous and multiparous cows, respectively. The financial losses associated with RP were on average US$ 350.4 and US$ 481.2 per incidence in primiparous and multiparous cows, respectively, ranged from US$ 311.9 to 456.2 depending on the parity number (primi- or multiparous) and herd management. The highest financial losses due to RP were associated with reduction in milk production (38.5% of total loss) and low fertility (28.5% of total loss) had the highest contribution in in primiparous and multiparous cows, respectively. The results of our research highlight the economic importance of improved calving management to reduce RP occurrence in dairy cows.

Treatment practices after calving-related events on 45 dairy farms in California

Retained fetal membranes (RFM), dystocia, and twinning are common postpartum events that increase the risk of metritis, impair reproductive performance, and contribute to antimicrobial use on dairies. The overall objective of this study was to describe treatment decisions after RFM, severe dystocia (cesarean section and fetotomy), nonsevere dystocia (nonmechanical and mechanical assistance to extract the calf), and twinning. A total of 44 dairies from California's San Joaquin Valley (39 Holstein and 6 Jersey or crossbreed herds) with 450 to 9,500 lactating cows were enrolled in this study. Researchers visited each dairy once to observe cow-side fresh cow health evaluations and to interview health evaluators and maternity workers, using a standardized survey tool. The survey included questions about antimicrobial (class, dose, and duration) and nonantimicrobial therapies for calving-related events. Antimicrobial therapy was used in all 44 dairies to treat RFM at 24 (n = 23), 48 (n = 10), or 72 h (n = 5) after calving, or when puerperal metritis signs were observed (n = 6). Antimicrobial therapy was used after all severe dystocia cases, and after nonsevere dystocia (n = 27) and twinning (n = 15). Ceftiofur products were the most common antimicrobial class; they were used to treat RFM cases (n = 29), nonsevere dystocia (n = 13), and twinning (n = 10). Supportive therapy for calving-related events included nonantimicrobial intrauterine treatments, nonsteroidal antiinflammatory drugs, oxytocin, i.v. calcium, or oral drenches. Our study highlights opportunities to reduce extra-label use of antimicrobials in postpartum cows affected with RFM, and the need for education and outreach efforts on judicious use of antimicrobials. Furthermore, antimicrobial treatment choices differed largely across dairies, indicating a need to reach consensus and promote standardized practices within the industry.

Treatment protocols and management of retained fetal membranes in cattle by rural practitioners in Belgium

Retained fetal membranes (RFM) is a frequent postpartum disorder in cattle causing considerable economic losses, and a common indication for antibiotic (AB) administration. There is controversy with regard to the treatment of RFM, and scientific recommendations are often in conflict with current legislation on AB use and practical routines in the field. The aim of this study was to assess the therapeutic approaches of RFM by Belgian rural veterinarians. A digital survey was sent to 468 Belgian veterinarians; 149 complete questionnaires (Wallonia: 78; Flanders: 71) were obtained. Survey questions captured socio-demographic characteristics, case definition, therapeutic approaches and treatment options for RFM. Questions on treatment were duplicated for dairy and beef cattle. When confronted with dairy cows suffering from RFM without fever, 35.6 % of vets do not treat with AB, while the majority administers AB, either intrauterine (47.6 %), systemically (10.7 %) or both (6.1 %). Dairy cows with RFM and fever receive a systemic (33.5 %), intrauterine (2.7 %) or combined (61.8 %) AB treatment. For a beef cow with RFM without fever, 21.5 % of vets prefer no AB treatment, while others prefer an intrauterine (24.2 %), systemic (24.8 %), combined (29.5 %) AB treatment. Beef cows with RFM and fever receive AB from the large majority of vets, by systemic (34.9 %) or combined (56.3 %) administration. In case of a parenteral treatment, benzylpenicillin, amoxicillin and ampicillin are by far the most frequently used molecules; only a minority of vets use cephalosporins. Manual placental removal is attempted by 93.9 % of the respondents. These results demonstrate that there is room for improvement when considering the treatment protocols of RFM. Many veterinarians use AB in RFM cows not presenting symptoms of general illness, or administer intrauterine AB in cows with or without clinical signs of illness. Concerning the molecules of choice, practical routines are largely in line with national AB recommendations. Beef cows suffering from RFM are treated more rigorously than dairy cows, regardless of their rectal temperature.

Reproductive Tract Infections in Dairy Cows: Can Probiotics Curb Down the Incidence Rate?

Postpartum uterine diseases are common in dairy cows and are a great concern for the dairy industry as they are associated with various consequences, including lower fertility, lower milk yield, and an overall negative impact on the host health. An infected uterus is a source of bacterial compounds and cytokines that spill into the systemic circulation, spreading inflammation to other organs. In this review article, we discuss a short overview of the anatomy of the reproductive tract of dairy cows and several infectious diseases of the uterus including metritis, endometritis, and pyometra. Additionally, we discuss the microbiome of the reproductive tract in health and during uterine diseases. As well, diagnostic criteria for metritis and endometritis and contributing factors for increased susceptibility to metritis infection are important topics of this review. To better understand how the uterus and reproductive tract respond to bacterial pathogens, a section of this review is dedicated to immunity of the reproductive tract. Both the innate and adaptive immunity systems are also discussed. We conclude the review with a factual discussion about the current treatments of uterine diseases and the new developments in the area of application of probiotics for uterine health. Mechanisms of actions of probiotics are discussed in detail and also some applications to prevent uterine infections in dairy cows are discussed.

Therapy of retained fetal membranes in cattle: Comparison of two treatment protocols

This prospective study was conducted to compare two treatment protocols for retained foetal membranes (RFM) in cattle. The routine therapy consisting of intrauterine tetracycline boluses was compared with the administration of ozone foam, both intrauterine therapies without attempts to manually remove the placenta. Cows undergoing caesarean section, suffering from uterine torsion or prolapse of the uterus, and other illnesses than RFM on the first day post-partum were excluded. Values for baseline variables as age, breed, yearly milk yield, parity, pregnancy duration, calving season and number of routine intrauterine treatments were not different between the groups. Number of days with rectal temperature >39.7 °C within the first 10 days in milk (DIM) were greater in the ozone group. Number of escape therapies were recorded when there was imposing of this therapy as a result of cows having a fever (based on rectal temperature >39.7 °C) and a significant reduced food intake. Escape therapies consisted of parenteral administration of tetracyclines and NSAIDS during the first 10 DIM. Number of escape therapies, however, was not different between the groups. Results from use of a logistic regression model with fever as a dichotomous variable indicated there was no effect of breed, studbook, type of stall, pasture, business and no effect of age or milk yield. In a second assessment, cows were evaluated until 200 DIM. Results from a survival analysis indicated group (Te/Oz) did not affect rate of culling from the herd.

Management of Reproductive Disease in Dairy Cows

Postpartum diseases are common in dairy cows, and their incidence contributes to reduced fertility and increased risk of culling, making their prevention and management extremely important. Reproductive efficiency has a major impact on economic success of any dairy production unit. Optimizing reproductive efficiency contributes to overall efficiency of production units, minimizing environmental impacts and contributing to sustainability of food production. Additionally, control of reproductive diseases is important for maintenance of health and welfare of dairy cows; for minimizing use of antibiotics; and ensuring a wholesome, safe, and nutritious product.

Relationship between Escherichia coli virulence factors and postpartum metritis in dairy cows

The objectives of this study were to report the prevalence of Escherichia coli and Trueperella pyogenes in the uterus of postpartum dairy cows before the onset of postpartum metritis (PPM) and to quantify their association with subsequent occurrence of PPM, to quantify the association between the presence of genes encoding E. coli virulence factors (VF) and PPM, and to determine the accuracy of using early postpartum uterine bacteriology results (bacteria and VF) to identify cows at risk of PPM. A prospective cohort study was conducted on 3 commercial dairy farms. Uterine swabs were collected from 371 Holstein dairy cows (3 commercial herds) at 1 to 7d in milk and submitted to the laboratory for identification of E. coli, T. pyogenes, and E. coli VF. A total of 40 VF were tested using the radioactive probe hybridization method. Postpartum metritis was defined as the presence of a fetid watery red-brown uterine discharge, associated with fever (rectal temperature >39.5°C), and systemic signs of illness (dullness, reduced appetite, and milk production). Surveillance of PPM was done by trained farmers blinded to laboratory results and cows were followed until 21d in milk. Statistical analyses were conducted using 2×2 tables and mixed logistical regression models. Prevalences of E. coli, T. pyogenes, and PPM were 42, 34, and 15%, respectively. A total of 32 VF were found in E. coli isolates. Most prevalent VF were extraintestinal pathogenic genes such as fimH (89%), hlyE (87%), and iss (70%). Cows positive for intrauterine E. coli were 3.2 times more likely to have subsequent PPM compared with bacteriologically negative cows. Cows with VF hra1 in their uterus were 2.7 times more likely to have PPM than cows positive for E. coli and negative for hra1 and 5.9 times more likely than bacteriologically negative cows. Cows with VF kpsMTII in their uterus were 3.2 times more likely to have PPM than cows positive for E. coli and negative for kpsMTII and 6.2 times more likely than bacteriologically negative cows. Using E. coli, hra1, and kpsMTII as predictors for subsequent PPM, positive predictive values were 23, 31, and 42%, respectively, whereas the negative predictive values were 91, 80, and 78%, respectively. Overall, these results showed that E. coli and some VF were associated with PPM.

Effect of puerperal metritis on reproductive and productive performance in dairy cows in Argentina

The objectives of this study were to evaluate the reproductive and productive performance of dairy cows with and without puerperal metritis and to evaluate the effectiveness of using a long-acting ceftiofur preparation. Dairy cows in one dairy farm, calving from July 2009 to January 2010, were examined between 3 and 14 days postpartum and classified on the basis of vaginal discharge into three groups: cows with normal discharge (control; C); cows with a bloody mucus purulent or pathologic nonfetid discharge (PnFD), and cows with bloody mucopurulent or purulent fetid discharge (PFD). Cows in C and PnFD groups were not treated, whereas those in the PFD group were randomly allocated to receive 2.2 mg/kg of ceftiofur subcutaneously behind the ear (PFD-T) or remain untreated (PFD-No T). From the 640 cows examined, 58.2% formed the C group, 13.4% formed the PnFD group, and 28.4% formed the PFD group. Survival curves differed between cows in the C group and PFD-No T group (P = 0.0013) and between PFD-No T versus PFD-T group (P = 0.0006). Survival curves of PnFD were intermediate and did not differ from those in the C group (P = 0.2) and PFD-T group (P = 0.1) but tended to be different from the PFD-No T group (P = 0.056). The postpartum interval to achieve a 25% pregnancy rate was 72 days for cows in the C group, 73 days for the PFD-T group, 83 days for PnFD group, and 95 days for the PFD-No T group. The chance of pregnancy in a cow in the C group was 1.98 times higher (95% confidence interval = 1.33, 3.08) and in cows in the PFD-T group was 2.16 times higher (95% confidence interval = 1.37, 3.50) than that in the PFD-No T group. Finally, the chance of pregnancy in cows in the PnFD group tended to be higher (P = 0.08) than that in the PFD-No T group but did not differ from the other two groups. Cumulative 305-day milk production was higher (P < 0.0001) in C group than those with vaginal discharge, regardless of fetidness and regardless of treatment. It is concluded that puerperal metritis affects the reproductive and productive performance of dairy cows and the treatment with ceftiofur was effective in reducing the adverse effects on reproductive performance but not on milk production.

Strategies for the treatment of dairy cows at high risk for postpartum metritis and for the treatment of clinical endometritis in Argentina

The objectives of this study were to evaluate the efficacy of (1) administering ceftiofur hydrochloride in dairy cows with calving-related disorders to prevent metritis and (2) a combination of GnRH and PGF2α for the treatment of clinical endometritis, under Argentinean dairy farming conditions. Cows at high risk (HRC) for metritis (dystocia, RFM >12 h postpartum, hypocalcaemia, twins, or stillbirth) were randomly assigned to receive either 1.1 mg/Kg of ceftiofur hydrochloride on three consecutive days (HRC treated group HRCT, n = 110) or remained untreated (HRC control group HRCC, n = 126). Cows with low risk (LRC, no calving-related disorders, n = 868) did not receive any treatment (LRC group, n = 868). All cows were examined for metritis between days 4 and 10 and for clinical endometritis between 24 and 30 days postpartum. The body condition score (BCS) was recorded at both examinations. Cows with endometritis at days 24 to 30 postpartum received either 1.5 mg of D-cloprostenol (PGF; n = 129) or 100 μg of GnRH followed by D-cloprostenol after 7 days (GnRH+PGF, n = 119). There was no overall effect of treatment on the incidence of metritis or on time to pregnancy. Treatment, however, reduced the incidence of metritis in cows with high BCS (HRCT = 24.0 %, HRCC = 38.5 %) but had no effect in cows with low BCS (HRCT = 38.7 %, HRCC = 37.5 %). The proportion of pregnant cows by days in milk was greater (P < 0.01) in LRC group compared with that of the HRCT and HRCC groups. No significant differences were found between groups PG and PG+GNRH. GnRH+PGF treatment, however, tended (P = 0.06) to increase pregnancy rate in cows with a moderate loss of BCS (76.5 vs 65.2 %) but tended to reduce pregnancy rate (54.5 vs 76.0 %) in cows with a more pronounced loss in BCS (>0.75 points).

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

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

Nitric oxide synthase expression in foetal placentas of cows with retained fetal membranes

The objectives of this study were to investigate relationship of retained fetal membranes (RFM) to expression of NOS and NOS mRNA and to analyze pathohistological changes and the distribution of nitric oxide synthase (NOS) in foetal placentas of cows with RFM. Twenty cows were assigned to two groups, a control group (no retained fetal membranes, NRFM, n = 10) and a diseased group (RFM, n = 10). The endpoint method was used to detect the nitric oxide (NO) content and nitric oxide synthase (NOS) activity in foetal placental tissue fluid and the fluorescent quantitation PCR was used to measure the expression of NOS mRNA. Immunohistochemistry and hematoxylin-eosin staining were used to observe pathohistological changes. Tissue from RFM cows showed fibronecrosis of the chorionic villi, and a decreased number of trophoblastic cells. The majority of trophoblastic cells displayed vacuolar degeneration. Interstitium vessels were distended and congested. Expression of induced nitric oxide synthase (iNOS) protein and iNOS mRNA was significantly higher (P < 0.05) in the cytoplasm of placental villus trophoblastic cells in the RFM group. But expression of endothelial nitric oxide synthase (eNOS) protein and eNOS mRNA was significantly lower (P<0.05) in the RFM group. The NO content and NOS activity of cows with RFM were significantly higher (P < 0.05). A high expression of iNOS protein and iNOS mRNA in the cow foetal placenta could produce high content of NO, which might inhibit uterine contraction. So over expression of iNOS protein and iNOS mRNA might be an important agent of retained fetal membranes in cows, and it may be a potential diagnosis biomarker.

Evaluation of breed-dependent differences in the innate immune responses of Holstein and Jersey cows toStaphylococcus aureusintramammary infection

Mastitis is one of the most prevalent diseases of cattle. Various studies have reported breed-dependent differences in the risk for developing this disease. Among two major breeds, Jersey cows have been identified as having a lower prevalence of mastitis than Holstein cows. It is well established that the nature of the initial innate immune response to infection influences the ability of the host to clear harmful bacterial pathogens. Whether differences in the innate immune response to intramammary infections explain, in part, the differential prevalence of mastitis in Holstein and Jersey cows remains unknown. The objective of the current study was to evaluate several parameters of the innate immune response of Holstein and Jersey cows to intramammary infection withStaphylococcus aureus, a common mastitis-inducing pathogen. To control for non-breed related factors that could influence these parameters, all cows were of the same parity, in similar stages of milk production, housed and managed under identical conditions, and experimentally infected and sampled in parallel. The following parameters of the innate immune response were evaluated: acute phase protein synthesis of serum amyloid A and lipopolysaccharide-binding protein; total and differential circulating white blood cell counts; milk somatic cell counts; mammary vascular permeability; milk N-acetyl-beta-d-glucosaminidase (NAGase) activity; and production of the cytokines, interferon (IFN)-γ, interleukin (IL)-12, tumour growth factor(TGF)-α, and TGF-β1. The temporal response of all of these parameters following infection was similar between Holstein and Jersey cows. Further, with the exception of changes in circulating neutrophils and NAGase activity, the overall magnitude of these parameters were also comparable. Together, these data demonstrate that the innate immune response of Holstein and Jersey cows toStaph. aureusintramammary infection remains highly conserved despite previously reported differences in mastitis prevalence, as well as genotypic and phenotypic traits, that exist between the two breeds.

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.

Innate Immune Response to Intramammary Mycoplasma bovis Infection

The objective of the current study was to characterize the systemic and local innate immune response of dairy cows to IMI with Mycoplasma bovis, a pathogen of growing concern to the dairy industry. Ten Holstein cows were each infused in 1 quarter with M. bovis and studied for a 10-d period. Acute phase protein synthesis, which reflects 1 parameter of the systemic response to infection, was induced within 108 h of infection, as evidenced by increased circulating concentrations of lipopolysaccharide binding protein and serum amyloid A. Transient neutropenia was observed from 84 to 168 h postinfection, whereas a constant state of lymphopenia and thrombocytopenia was observed from 84 h until the end of the study. Milk somatic cell counts initially increased within 66 h of M. bovis infusion and remained elevated, relative to control (time 0) concentrations, for the remainder of study. Increased milk concentrations of BSA, which reflect increased permeability of the mammary epithelial-endothelial barrier, were evident within 78 h of infection and were sustained from 90 h until the end of the study. Milk concentrations of several cytokines, including IFN-gamma, IL-1beta, IL-10, IL-12, tumor growth factor-alpha, and tumor necrosis factor-alpha, were elevated in response to infection over a period of several days, whereas increases in milk IL-8 were of a more limited duration. Complement activation, reflected by increased milk concentrations of complement factor 5a, was also observed over several days. Despite the indication by these observed changes that the cows mounted a prolonged inflammatory response to M. bovis intramammary infection, all quarters remained infected throughout the study with persistently high concentrations of this bacterium. Thus, a sustained inflammatory response is not sufficient to eradicate M. bovis from the mammary gland and may reflect the ongoing struggle of the host to clear this persistent pathogen.

Ceftiofur Derivatives in Serum, Uterine Tissues, Cotyledons, and Lochia after Fetal Membrane Retention

The objective of the study was to determine concentrations of ceftiofur derivatives after subcutaneous application of ceftiofur hydrochloride in cows with retained fetal membranes. Concentrations of ceftiofur derivatives detected as desfuroylceftiofuracetamide were determined in blood serum, endometrium, caruncles, cotyledons, and lochia during 72 h. After induction of parturition, 2 primiparous and 4 multiparous cows having retained fetal membranes for at least 12 h were studied. All cows received 3 consecutive injections (C1 to C3; 24 h apart) of 1-mg ceftiofur equivalents per kilogram of body weight as ceftiofur hydrochloride sterile suspension. Samples of blood, endometrium, caruncles, cotyledons, and lochia were collected immediately before each injection (0 h) and again at 4, 12, and 24 h after C1, C2, and C3. Blood samples were collected from coccygeal vessels. Caruncles were removed from the uterine lumen by manual extirpation and separated from cotyledons. Endometrial tissue (0.5 g) was collected by using Kenny's biopsy apparatus. For all samples, concentrations of potentially active ceftiofur derivatives were quantified using an HPLC assay. Within 2 h (serum), 4 h (endometrium), and 12 h (caruncles, cotyledons, lochia) after C1 and during the entire study period, mean concentration of ceftiofur derivatives exceeded the reported minimum drug concentrations required to inhibit the growth of 90% of isolates for relevant bacteria such as Escherichia coli, Fusobacterium necrophorum, and Arcanobacterium pyogenes. Only in single samples did concentrations decrease temporarily below the reported minimum drug concentrations required to inhibit the growth of 90% of isolates.