Metritis complex in Michigan Holstein-Friesian cattle: incidence, descriptive epidemiology and estimated economic impact

Evaluating differences in milk production, reproductive performance, and survival associated with vaginal discharge characteristics and fever in postpartum dairy cows

The objective was to assess differences in productive and reproductive performance, and survival associated with vaginal discharge characteristics and fever in postpartum dairy cows located in western and southern states of the United States. This retrospective cohort study included data from 3 experiments conducted in 9 dairies. Vaginal discharge was evaluated twice within 12 DIM and scored on a 5-point scale. The highest vaginal discharge score observed for each cow was used to allocate them into 1 of 5 possible groups (VD group) as follows: VD 1 and 2 (VD 1/2; n = 1,174) = clear mucus or lochia with or without flecks of pus; VD 3 (n = 1,802) = mucopurulent with <50% pus; VD 4 (n = 1,643) = mucopurulent with ≥50% of pus or nonfetid reddish-brownish mucus, n = 1,643; VD 5 = fetid, watery, and reddish-brownish, n = 1,800. All VD 5 cows received treatment according to each herd's protocol. Rectal temperature was assessed in a subset of VD 5 cows, and subsequently divided into fever (rectal temperature ≥39.5°C; n = 334) and no fever (n = 558) groups. A smaller proportion of cows with VD 5 (67.6%) resumed ovarian cyclicity compared with VD 1/2 (76.2%) and VD 4 (72.9%) cows; however, a similar proportion of VD 5 and VD 3 (72.6%) cows resumed ovarian cyclicity. A smaller proportion of VD 5 (85.8%) cows received at least one AI compared with VD 1/2 (91.5%), VD 3 (91.0%), or VD 4 (91.6%) cows. Although we did not detect differences in pregnancy at first AI according to VD, fewer cows with VD 5 (64.4%) were pregnant at 300 DIM than cows with VD 1/2 (76.5%), VD 3 (76.2%), or VD 4 (74.7%). Hazard of pregnancy by 300 DIM was smaller for VD 5 compared with VD 1/2, VD 3, or VD 4 cows. A greater proportion of VD 5 cows were removed from the herd within 300 DIM compared with other VD groups. Milk production was 760 kg lower within 300 DIM for VD 5 compared with VD 2, VD 3, and VD 4, whereas VD 2, VD 3, and VD 4 had similar milk production. We did not detect an association between fever at diagnosis of VD 5 and reproductive performance or milk production. A greater proportion of VD 5 cows without fever were removed from the herd by 300 DIM compared with VD 5 cows with fever. Differences in productive and reproductive performance, and removal of the herd were restricted to fetid, watery, and reddish-brownish vaginal discharge, which was independent of fever.

Novel lncRNA regulatory elements in milk somatic cells of Holstein dairy cows associated with mastitis

Despite regulatory elements such as long non - coding RNAs representing most of the transcriptome, the functional understanding of long non - coding RNAs in relation to major health conditions including bovine mastitis is limited. This study examined the milk somatic cell transcriptome from udder quarters of 6 Holstein dairy cows to identify differentially expressed long non - coding RNAs using RNA - Sequencing. Ninety - four differentially expressed long non - coding RNAs are identified, 5 of which are previously annotated for gene name and length, 11 are annotated for gene name and 78 are novel, having no gene name or length previously annotated. Significant inflammatory response and regulation of immune response pathways (false discovery rate < 0.05) are associated with the differentially expressed long non - coding RNAs. QTL annotation analysis revealed 31 QTL previously annotated in the genomic regions of the 94 differentially expressed long non - coding RNAs, and the majority are associated with milk traits. This research provides a better understanding of long non - coding RNAs regulatory elements in milk somatic cells, which may enhance current breeding strategies for more adaptable or high mastitis resistant cattle.

Treatment of postpartum endometritis induced by multidrug-resistant bacterial infection in dairy cattle by green synthesized zinc oxide nanoparticles and in vivo evaluation of its broad spectrum antimicrobial activity in cow uteri

Postpartum endometritis significantly affects the health and productivity of cattle, causing significant economic loss that is speculated to exceed billions of dollars annually. Treatment of postpartum endometritis, which is linked to various bacterial infections in the uterus after delivery and has an alarmingly high risk of antibiotic treatment failure for unidentified reasons, represents a great challenge. Several studies have demonstrated that various disease complications, such as multidrug-resistant (MDR) bacterial strains, prolonged infection treatment, and increased mortality risk, have emerged as a result of the extensive use of antibiotics to treat uterine infections and other microbial-related diseases. Recent research has led to the development of zinc oxide nanoparticles (ZnO NPs) that exhibit broad-spectrum antibacterial efficacy against bacterial pathogens, including MDR bacteria, without producing mutants that are resistant to zinc oxide (ZnO). In the present work, we biologically synthesized ZnO NPs from a green natural source of Helianthus annuus seeds for the treatment of endometritis caused by MDR bacterial strains in dairy cattle. We examined ZnO's potential as a substitute antimicrobial agent to treat cow endometritis by testing its ability to sustain potent antimicrobial activity against pathogenic bacteria, including Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), in cow uteri. Among uterine bacteria, ZnO significantly decreased E. coli and S. aureus, which are known pathogenic bacteria within the uterus and achieved a high cure rate that was associated with the induction of estrous and pregnancy. Taken together, our observations of ZnO's broad range of antibacterial activity in-vivo with an animal model and subsequent evaluations of its therapeutic efficacy in cows with endometritis shed light on its potential to be used as a substitute antimicrobial agent for the treatment of uterine illness.

Use of intravaginal lactic acid bacteria prepartum as an approach for preventing uterine disease and its association with fertility of lactating dairy cows

The objective of this study was to evaluate the effects of the use of intravaginal probiotics prepartum on the incidence risk of metritis postpartum and conception risk after first artificial insemination (AI). A total of 606 Holstein cows were enrolled 3 wk before their expected calving date from 2 farms. Cows were randomly assigned to either receive a 2-mL dose of a combination of 3 lactic acid bacteria (probiotic treatment) washed with approximately 2 mL of a sterile saline solution, into the vaginal canal twice weekly until parturition, or no intervention (control). Metritis diagnoses were carried out on 6 and 12 d postpartum. Vaginal discharge and rectal temperature were assessed, and vaginal discharge was scored on a scale from 1 to 4, where 1 = clear and 4 = fetid, purulent discharge. Metritis was defined as cows having a vaginal discharge score of 4 with or without fever (rectal temperature ≥39.5°C) on either 6 or 12 d postpartum, or both. Cows were bred after a 60-d voluntary waiting period primarily via the detection of estrus using automated activity monitors; cows not found in estrus were enrolled onto timed AI protocols to receive first breeding before 100 DIM. Pregnancy diagnosis was carried out at d 35 ± 7 post-AI on both farms. Data were analyzed via ANOVA using linear mixed regression models and survival analysis using a Cox proportional hazard model. Total incidence risk of metritis was 23.7% and 34.4% on farm A and farm B, respectively. Overall, the incidence of metritis was not different between treatment groups (control: 41.6 ± 3.8%; probiotic: 38.6 ± 4.0%); however, an interaction by farm was detected, where the probiotic treatment reduced metritis on one farm but not on the other. Conception risk after first AI was not affected by treatment. However, we detected an interaction between parity and treatment, where multiparous cows receiving the probiotic treatment were more likely to become pregnant compared with multiparous cows within the control group (hazard ratio: 1.33; 95% confidence interval: 1.10-1.60); no effect of probiotic treatment was found on the hazard of pregnancy for primiparous cows. In addition, the probiotic treatment was associated with an increased proportion of cows being detected in estrus for the first AI postpartum. In conclusion, vaginal probiotic treatment applied during the 3 wk prepartum was associated with a decreased incidence of metritis on one farm but not the other, suggesting that farm management may be a key player influencing treatment efficacy. Overall, probiotic treatment was found to have only limited effects on fertility in the current study.

Relationship between Escherichia coli virulence factors, notably kpsMTII, and symptoms of clinical metritis and endometritis in dairy cows

Although Escherichia coli is a commensal bacterium of the bovine vaginal microbiota, it is an important pathogenic bacterium that causes diseases of the reproductive tract and sub-fertility. Recent studies have focused on virulence factors (VFs) of intrauterine E. coli; however, actual endometrial VFs have not been clearly identified. The purpose of this study was to identify the VFs of E. coli associated with clinical metritis and endometritis. Thirty-two strains of E. coli and four mixed Trueperella pyogenes (TP) strains were detected in the uterus of 19 Holstein dairy cows with obvious clinical signs (between 8 and 66 days postpartum). The presence of six E. coli VFs (fimH, fyuA, kpsMTII, hra1, csgA, and astA) was examined by PCR, and clinical signs and reproductive performance (mixed TP, the percentage of polymorphonuclear neutrophils [PMN%], days to uterine involution, etc.) were evaluated. Four VFs (fimH, hra1, csgA, and astA) were detected in all E. coli strains, whereas fyuA and kpsMTII were detected in 94% and 50% of strains, respectively. Cows with E. coli strains harboring kpsMTII exhibited significantly severe clinical scores (vaginal discharge score, PMN%, uterine involution), suggesting that kpsMTII is a key VF for progression of clinical metritis and endometritis. In the present study, we clearly identified six VFs associated with clinical metritis and endometritis. In addition, E. coli strains with kpsMTII probably play a crucial role in the progression of clinical metritis and endometritis.

Failure of clinical cure in dairy cows treated for metritis is associated with reduced productive and reproductive performance

Objectives were to assess reproductive and productive outcomes associated with failure of clinical cure in dairy cows diagnosed with metritis following antimicrobial therapy. This retrospective cohort study included data from 3 experiments performed in 5 dairies. Metritis was characterized by the presence of watery, fetid, reddish-brownish vaginal discharge within 21 DIM (study d 0). Cows not diagnosed with metritis (i.e., cows may have had other diseases postpartum; NoMT; n = 1,194) were paired based on lactation number and calving date. All cows with metritis received antimicrobial therapy (ampicillin or ceftiofur). Clinical cure was evaluated on d 10 based on vaginal discharge score, and cows were categorized as cured (MTC; n = 1,111) or not cured (MTnoC; n = 299). Purulent vaginal discharge (28 ± 3 or 32 ± 3 DIM), cytological endometritis (35 ± 3 or 39 ± 3 DIM), and estrous cyclicity (50 ± 3 and 64 ± 3, 36 ± 3 and 50 ± 3, or 37 ± 5 and 51 ± 5 DIM) were evaluated in subgroups of cows. Proportions of cows with purulent vaginal discharge and cytological endometritis were greatest for MTnoC (91.7 and 91.4%), intermediate for MTC (74.0 and 73.3%), and smallest for NoMT (38.1 and 36.4%). Proportion of cyclic cows was smaller for MTnoC compared with MTC and NoMT (62.0, 71.0, and 71.0%). Pregnancy per artificial insemination following first service was smaller for cows with metritis compared with their counterparts with no metritis (NoMT = 28.1, MTC = 26.1, MTnoC = 22.0%). Pregnancy loss tended to be greater for MTnoC compared with MTC (NoMT = 11.5, MTC = 11.1, MTnoC = 18.4%). Hazard of pregnancy by 300 DIM was smallest for MTnoC, intermediate for MTC, and greatest for NoMT. Death by 60 DIM (3.9, 1.1, and 0.6%) and removal from herd by 300 DIM (26.3, 17.4, and 15.4%) were greatest for MTnoC compared with MTC and NoMT, respectively. Milk production among multiparous cows was smaller for MTnoC compared with MTC and NoMT in the first 10 mo postpartum, whereas MTC produced less milk compared with NoMT only during the first 2 mo postpartum (NoMT = 42.0 ± 0.22, MTC = 40.6 ± 0.28, MTnoC = 37.7 ± 0.54 kg/d). Failure of clinical cure was not associated with milk yield in primiparous cows (NoMT = 35.2 ± 0.31, MTC = 33.9 ± 0.31, MTnoC = 35.0 ± 0.52 kg/d). Cows diagnosed with metritis that do not undergo clinical cure by 10 d of onset of antimicrobial therapy have impaired reproductive performance, reduced milk production, and increased risk of leaving the herd.

Observed and expected combined effects of metritis and other postpartum diseases on time to conception and rate of conception failure in first lactation cows in Iran

Previous observational studies have produced strong evidence that metritis alone has an impact on reproductive performance in dairy cows; but few studies have examined the combined effect of metritis and other postpartum diseases on reproduction performance in dairy cows. Information on the combined effects of postpartum diseases on fertility in dairy cows can have practical herd-health management implications. The objective of the study reported here was to examine the observed and expected combined effects of metritis and other postpartum diseases (retained fetal membranes (RFM), clinical hypocalcemia, left displaced abomasum, clinical mastitis, lameness) on time to conception and rate of conception failure in first-lactation cows up to 150 days postpartum. The study was conducted on two commercial dairy herds in Iran. Median number of days to conception was higher in 30 cows affected with metritis and RFM (90 days), compared to 287 healthy cows (57 days), 16 cows affected with RFM alone (60 days) or 44 cows affected with metritis alone (60 days), after controlling for herd and calving month (p < 0.05). In cows affected with metritis and RFM, the rate of conception failure was 3.8 times greater than that of healthy cows, after controlling for study herd and calving month (hazard ratio = 3.8; 95% CI = 2.3, 6.6; p < 0.01); this observed combined effect on conception failure was two times higher than the expected combined effect based on adding or multiplying absolute independent excesses due to metritis or RFM. In addition, we observed an interaction effect between metritis and lameness on conception failure, after controlling for herd, calving month, and RFM; but study results were inconclusive. In this study, the observed combined effect of metritis and RFM on time to conception and rate of conception failure was far in excess, compared to that in cows exposed to metritis or RFM alone. Attending veterinarians or farm managers can consider this information when making breeding and culling decisions on dairy farms.

The economic cost of metritis in dairy herds

The objective of this study was to estimate the cost of metritis in dairy herds. Data from 11,733 dairy cows from 16 different farms located in 4 different regions of the United States were compiled for up to 305 d in milk, and 11,581 cows (2,907 with and 8,674 without metritis) were used for this study. Metritis was defined as fetid, watery, red-brownish vaginal discharge that occurs ≤21 d in milk. Continuous outcomes such as 305-d milk production, milk sales ($/cow), cow sales ($/cow), metritis treatment costs ($/cow), replacement costs ($/cow), reproduction costs ($/cow), feeding costs ($/cow), and gross profit per cow ($/cow) were analyzed using mixed effect models using the MIXED procedure of SAS (SAS Institute Inc., Cary, NC). Gross profit was also compared using the Kruskal-Wallis test. Dichotomous outcomes such as pregnant and culling by 305 d in milk were analyzed using the GLIMMIX procedure of SAS. Time to pregnancy and culling were analyzed using the PHREG procedure of SAS. Models included the fixed effects of metritis, parity, and the interaction between metritis and parity, and farm as the random effect. Variables were considered significant when P ≤ 0.05. Metritis cost was calculated by subtracting the gross profit of cows with metritis from the gross profit of cows without metritis. A stochastic analysis was performed with 10,000 iterations using the observed results from each group. Milk yield and proportion of cows pregnant were lesser for cows with metritis than for cows without metritis, whereas the proportion of cows leaving the herd was greater for cows with metritis than for cows without metritis. Milk sales, feeding costs, residual cow value, and gross profit were lesser for cows with metritis than for cows without metritis. Cow sales and replacement costs were greater for cows with metritis than for cows without metritis. The mean cost of metritis from the study herds was $511 and the median was $398. The stochastic analysis showed that the mean cost of a case of metritis was $513, with 95% of the scenarios ranging from $240 to $884, and that milk price, treatment cost, replacement cost, and feed cost explained 59%, 19%, 12%, and 7%, respectively, of the total variation in cash flow differences. In conclusion, metritis caused large economic losses to dairy herds by decreasing milk production, reproduction, and survival in the herd.

Effects of metritis treatment strategies on health, behavior, reproductive, and productive responses of Holstein cows

Our objectives were to compare the effects of ceftiofur crystalline free acid (CCFA) and ampicillin trihydrate (AMP) treatments of cows diagnosed with metritis on uterine health, behavior, reproductive, and productive responses. A controlled randomized clinical trial was designed. Metritis was defined as vaginal discharge (VD) = 5 (fetid, watery, red/brown) within 21 d in milk (DIM) and rectal temperature (RT) <39.5°C, whereas VD = 5 and RT ≥39.5°C was defined as puerperal metritis. On the day of diagnosis (d 0), cows were paired by parity and severity of metritis (metritis vs. puerperal metritis) and assigned randomly to the AMP and CCFA treatments. Cows enrolled in the AMP (n = 308) treatment were moved to a nonsalable-milk pen, where they were treated once daily for 5 d, and were moved back to their original pen 72 h after the last treatment (d 7). Cows enrolled in the CCFA (n = 310) treatment remained in their original pen and received 2 treatments of CCFA, 72 h apart. Rectal temperature was measured daily from d 0 to 6 and on d 11. Vaginal discharge was evaluated on d 4, 6, and 11 to assess cure. Cure was defined as the absence of treatment with additional antimicrobial before experiment d 11, VD <5, and RT <39.5°C. Cows were examined at 28 ± 3 DIM for purulent VD (PVD) and at 35 ± 3 DIM for cytological endometritis. Pregnancy was diagnosed at 40 ± 3 and 60 ± 7 d after first and second artificial inseminations. Cure of metritis did not differ between treatments on d 11 (AMP = 64.6 ± 3.1, CCFA = 63.5 ± 3.1%). Cows treated with AMP had greater RT from experiment d 1 to 6 compared with cows treated with CCFA (AMP = 39.1 ± 0.02, CCFA = 39.0 ± 0.02°C). Cows in the AMP treatment had greater prevalence of PVD at 28 ± 3 DIM (AMP = 82.6 ± 2.3, CCFA = 74.4 ± 2.7%) and tended to have greater prevalence of cytological endometritis at 35 ± 3 DIM (AMP = 77.8 ± 6.2 vs. CCFA = 61.7 ± 7.5%) than CCFA-treated cows. Treatment did not affect the hazard of pregnancy among multiparous cows; however, among primiparous cows, CCFA treatment reduced the hazard of pregnancy and increased the median days to pregnancy (AMP = 145 vs. CCFA = 169 d). Finally, average daily milk yield up to 14 wk postpartum was not affected by treatment (AMP = 38.0 ± 0.4, CCFA = 37.5 ± 0.4 kg). We conclude from the current experiment that CCFA was more effective in reducing RT and improving uterine health of metritic cows; however, the improved hazard of pregnancy of primiparous cows treated with AMP is important and warrants further investigation.

Analysis of puerperal metritis treatment records in a grazing dairy farm in Argentina

OBJECTIVE

To assess the efficacy of antibiotic usage for the treatment of puerperal metritis (PM) and its association with reproductive performance, a retrospective cohort study including a total of 9168 records of cows from a dairy farm in Argentina was run.

MATERIAL AND METHODS

Cows having a PM3 (metricheck, scale 0-3) and treated with ceftiofur (ceftiofur crystalline free acid, 6.6 mg/kg) at 0-21 days postpartum (p. p.) (n = 2688), and cows having a PM 1-2 and not treated with an antibiotic at 0-21 days p. p. (n = 6480) were included in the study. All cows were reexamined with metricheck to assess the clinical cure (vaginal discharge [VD] score 0), partial cure (VD score similar or lower than previous), no cure (VD score higher than previous). Cows with a metricheck VD1-3 after 0-21 days p. p. were diagnosed as clinical endometritis (CE) 1-3. The occurrence of PM1-3, cure rate, calving to conception interval, the hazard of pregnancy, odds for non-pregnancy, and odds for CE were analyzed using SAS software.

RESULTS

A total of 8876 PM1-3 records were included, 2435 records of PM3 treatments with ceftiofur (27.43 %), and 6441 records of PM1-2 (72.57 %) with no treatment. Cows having PM1 and PM2 became pregnant 14 and 12 days earlier than cows with PM3 (p < 0.001). The PM3 ceftiofur treated cows had a clinical cure of 24.85 % (PM0); 53.63 % had a partially cure; and 18.52 % no cure. Conversely, cows with PM1-2 had a 51.96 %, 20.70 %, and 24.53 % cure rate, respectively (p < 0.001). Cows having complete cure became pregnant 13 and 11 days earlier than cows having partial cure and no cure (p < 0.001). Cows that had PM3 during the first 21 days p. p. had twice the chances of developing CE compared to cows having PM1-2 (41.28 % vs. 24.14 %, p < 0.001). After 21 days p. p., less than 1 % of cows with clinical cure developed CE compared to 63.32 % that developed CE with partial cure, and 38.21 % with no cure (p < 0.001).

CONCLUSION AND CLINICAL RELEVANCE

After ceftiofur treatment, 78 % of cows were cured when measured by disappearance of fetid VD but only 25 % of cows had clinical cure when measured by appearance of a clear VD. The cows that remained with clinical metritis had more chances of having CE after 21 days p. p. and had more days open than cows with clear normal VD.

GWAS and fine-mapping of livability and six disease traits in Holstein cattle

BACKGROUND

Health traits are of significant economic importance to the dairy industry due to their effects on milk production and associated treatment costs. Genome-wide association studies (GWAS) provide a means to identify associated genomic variants and thus reveal insights into the genetic architecture of complex traits and diseases. The objective of this study is to investigate the genetic basis of seven health traits in dairy cattle and to identify potential candidate genes associated with cattle health using GWAS, fine mapping, and analyses of multi-tissue transcriptome data.

RESULTS

We studied cow livability and six direct disease traits, mastitis, ketosis, hypocalcemia, displaced abomasum, metritis, and retained placenta, using de-regressed breeding values and more than three million imputed DNA sequence variants. After data edits and filtering on reliability, the number of bulls included in the analyses ranged from 11,880 (hypocalcemia) to 24,699 (livability). GWAS was performed using a mixed-model association test, and a Bayesian fine-mapping procedure was conducted to calculate a posterior probability of causality to each variant and gene in the candidate regions. The GWAS detected a total of eight genome-wide significant associations for three traits, cow livability, ketosis, and hypocalcemia, including the bovine Major Histocompatibility Complex (MHC) region associated with livability. Our fine-mapping of associated regions reported 20 candidate genes with the highest posterior probabilities of causality for cattle health. Combined with transcriptome data across multiple tissues in cattle, we further exploited these candidate genes to identify specific expression patterns in disease-related tissues and relevant biological explanations such as the expression of Group-specific Component (GC) in the liver and association with mastitis as well as the Coiled-Coil Domain Containing 88C (CCDC88C) expression in CD8 cells and association with cow livability.

CONCLUSIONS

Collectively, our analyses report six significant associations and 20 candidate genes of cattle health. With the integration of multi-tissue transcriptome data, our results provide useful information for future functional studies and better understanding of the biological relationship between genetics and disease susceptibility in cattle.

Targeted transcript analysis revealed association of suboptimal expression of certain endometrial immunity-related genes with disparate uterine diseases in zebu cows

The onset of uterine infection during postpartum period compromises uterine health, fertility, and productivity of dairy cattle. Endometrial innate immunity plays a key role in eliminating uterine infection and keeping the uterus healthy. Hence, the present study has been designed with the hypothesis that altered endometrial immune response around calving may compromise uterine health during postpartum period. Expression of interleukins (IL-1β, IL-6, IL-8, IL-10, and TNF-α), prostaglandin synthase (PGFS, PGES), and antimicrobial peptides (beta-defensins (BDEF-4, BDEF-5), lingual antimicrobial peptide (LAP), and calcium-binding proteins (S100A8, S100A9, and S100A12) in endometrial tissues on the day of calving was studied using qRT-PCR, and circulating concentrations of prostaglandin E and F metabolites (PGEM and PGFM) during peripartum period (on days - 7, - 4, - 1 (before calving), 0 (on the day of calving), + 1, + 4, and + 7 (post calving)) of normal (healthy) cows (n = 11) that did not develop postpartum uterine infection and cows that developed puerperal metritis (n = 7) and clinical endometritis (n = 6) were studied. Endometrial expression of IL-1β, TNF-α, BDEF-4, BDEF-5, S100A8, S100A12, and PGFS was higher (P < 0.05), and expression of IL-6, IL-8, IL-10, and PGES was lower (P < 0.05) in normal (healthy) cows than puerperal metritic and clinical endometritic cows. The PGFM concentration in serum was high (P < 0.05) on days 0, + 1, and + 4 of calving in puerperal metritic cows followed by normal and clinical endometritic cows. However, PGEM concentration in serum was high (P < 0.05) during peripartum period in uterine-infected (puerperal metritic and clinical endometritic) cows compared with normal cows. From the above findings, it is concluded that higher constitutive expression of IL-1β, TNF-α, PGFS, BDEF-4, BDEF-5, S100A8, and S100A12 genes in the endometrium and lower concentration of PGEM during the period immediate to calving might be beneficial for uterine health of cows.

Economic comparison of systemic antimicrobial therapies for metritis in dairy cows

Metritis is a prevalent disease with effects on production, reproduction, and survival, thereby affecting dairy farm profitability. A component of the cost of metritis is antimicrobial therapy. Some antimicrobials result in milk withhold that adds to the cost of disease. The objectives were (1) to determine cost of metritis for 2 antimicrobial treatments using a herd budget that includes costs associated with incidence of concurrent diseases, milk production and reproduction losses, and removal from the herd and (2) to apply sensitivity analysis to determine the cost of different scenarios. Cows with metritis from a previous study assigned randomly to receive ampicillin (AMP, n = 259), an antimicrobial that requires milk withhold, or ceftiofur (CEFT, n = 269), an antimicrobial with no milk withhold, were used for the economic analysis. A group of cows with no metritis (NOMET, n = 268), matched by parity and calving day, served as the baseline for comparison. The incidence of other diseases in the first 60 d postpartum, culling and death, reproductive performance, discarded milk, milk yield, total milk sold per cow, and residual cow value were used as responses. The economic analysis considered the costs associated with therapy, reproductive management, discarded milk, estimated DM consumed, income from saleable milk, and the residual cow value at 300 d postpartum or earlier if the cow was removed from the herd. Sensitivity analyses were performed considering 3 scenarios for milk and feed prices. The incidence of diseases other than metritis (NOMET, 30.4%; AMP, 45.4%; CEFT, 34.0%) and days in the hospital (NOMET, 2.7 d; AMP, 8.6 d; CEFT, 3.5 d) were greater for cows treated with AMP than CEFT. Treatment did not affect the risk of leaving the herd (NOMET, 15.5%; AMP, 15.0%; CEFT, 19.1%). The 21-d pregnancy rate was lower for cows with metritis but did not differ between AMP and CEFT (NOMET, 24.9%; AMP, 18.9%; CEFT, 17.0%). Milk yield was greater for cows without metritis than those with metritis and greater for AMP than CEFT (NOMET, 33.7 kg/d; AMP, 32.5 kg/d; CEFT, 31.2 kg/d). Cost of metritis did not differ with choice of therapy, but it increased as milk price increased. When both milk and feed prices were the average values considered ($0.44/kg and $0.26/kg, respectively), the costs of a case of metritis for AMP and CEFT were, respectively, $344 and $410 when milk was discarded and $267 and $406 when milk was fed to calves. Cost of therapy for AMP and CEFT represented 16.6 and 24.6% of the total cost of metritis when milk was discarded and 21.5 and 24.8% of the total cost of metritis when milk was fed to calves. The largest component of cost of metritis for both therapies was the reduced income from milk minus feed cost, ranging from 40.0 to 56.7%. Collectively, metritis is an expensive disease, and choice of antimicrobial therapy did not influence survival, reproduction, or cost of the disease.

Farm-specific failure costs of production disorders in European organic dairy herds

On-farm decision support in animal health management requires a tailor-made failure costs (FCs) assessment of production disorders for the individual farm. In our study we defined a generic framework to estimate the FC of production disorders in dairy cows. We converted the framework to a practical tool in which the farm-specific FC of mastitis, ketosis, lameness and metritis were estimated for 162 organic dairy farms in four European countries. Along with the structure of the framework, the FC estimation required three distinct types of model input: performance input (related to herd performance parameters), consequential input (related to the consequences of the disorders) and economic input (related to price levels). Input was derived from official herd recordings (e.g. test-day records and animal health recordings) and farmers' responses (e.g. questionnaire replies). The average FC of mastitis, ketosis, lameness and metritis amounted to € 96, € 21, € 43 and € 10 per cow per year, respectively. The variation in FC outcomes was high among farmers and countries. Overall ranking of the disorders based on absolute values was the same for all countries, with mastitis being the costliest disorder followed in order by lameness, ketosis, and metritis. Farm specific estimates can be used to rank production related disorders in terms of their associated failure costs and thus provide valuable insights for herd health management. The practical calculation tool developed in this study should be considered by farmers or herd health advisors to support their animal health practices or advice.

Cytological endometritis in dairy cows: diagnostic threshold, risk factors, and impact on reproductive performance

We determined the threshold proportion of polymorphonuclear leukocytes (PMNs) for a diagnosis of cytological endometritis (CEM), the risk factors for this condition, and its impact on reproductive performance in dairy cows. Uterine cytology was performed on 407 Holstein cows 4 weeks postpartum to determine the proportions of endometrial cells and PMNs. A receiver operator characteristics curve was used to determine the threshold above which the PMN proportion affected the likelihood of cows conceiving by 200 days postpartum. The optimal threshold was ≥ 14% PMN (sensitivity, 31.3%; specificity, 81.7%; p ＜ 0.05). The farm identity, retained placenta (odds ratio [OR] = 1.87), and septicemic metritis (OR = 3.07) were risk factors for CEM (p ＜ 0.05). Cows with CEM were less likely to resume cyclicity (OR = 0.58) and to conceive by 200 days postpartum (hazard ratio = 0.58). Cows with CEM tended (p ＜ 0.1) to be less likely to become pregnant after their first insemination (OR = 0.65) and to require a greater number of inseminations per conception (2.3 vs. 2.2). In conclusion, a PMN threshold of 14% defined the presence of CEM at 4 weeks postpartum. The farm, retained placenta, and septicemic metritis were risk factors for CEM, which reduces subsequent reproductive performance.

Effects of oxytocin and PGF2α on uterine contractility in cows with and without metritis-An in-vitro study

The aim of this study was to investigate the effects of PGF_2α and oxytocin in vitro on myometrial contractility in puerperal uteri. Thirteen puerperal uteri were removed and perfused after euthanasia of cows with (n=7) and without metritis (n=6). Measurement of uterine contractility was done using four piezoelectric crystals, which were implanted into the myometrium along the greater curvature of the uterine horn where fetal implantation occurred during the previous pregnancy. After 30min of equilibration, oxytocin (5 IU) or PGF_2α (2.5mg Dinoprost) was administered randomly into both uterine arteries, and 30min later, the second administration of either oxytocin or PGF_2α occurred. Treatment with oxytocin induced contractions in uteri with metritis and uteri without metritis (P<0.05). In uteri with metritis, greater uterine contractions occurred after stimulation with oxytocin than in uteri without metritis (P<0.05). Treatment with PGF_2α did not (P>0.05) result in increased contractions in the uteri without metrtitis, however, induced an initial decrease in contractions followed by an increase (P<0.05) in contractions in uteri with metritis. Myometrial and endometrial gene expression of PGF_2α (FPR) and oxytocin receptor (OTR) was greater (P<0.05) in uteri with metritis than in uteri without metritis. The results suggest that oxytocin, but not PGF_2α, is an effective uterotonic drug in puerperal cows. Uteri in which metritis was diagnosed contracted more strongly after treatment with oxytocin than uteri in which metritis was not diagnosed. This effect was paralleled by greater gene expression of OTR as well as FPR in uteri with metritis compared with uteri in which metritis was not diagnosed.

Estimating US dairy clinical disease costs with a stochastic simulation model

A farm-level stochastic model was used to estimate costs of 7 common clinical diseases in the United States: mastitis, lameness, metritis, retained placenta, left-displaced abomasum, ketosis, and hypocalcemia. The total disease costs were divided into 7 categories: veterinary and treatment, producer labor, milk loss, discarded milk, culling cost, extended days open, and on-farm death. A Monte Carlo simulation with 5,000 iterations was applied to the model to account for inherent system variation. Four types of market prices (milk, feed, slaughter, and replacement cow) and 3 herd-performance factors (rolling herd average, product of heat detection rate and conception rate, and age at first calving) were modeled stochastically. Sensitivity analyses were conducted to study the relationship between total disease costs and selected stochastic factors. In general, the disease costs in multiparous cows were greater than in primiparous cows. Left-displaced abomasum had the greatest estimated total costs in all parities ($432.48 in primiparous cows and $639.51 in multiparous cows). Cost category contributions varied for different diseases and parities. Milk production loss and treatment cost were the 2 greatest cost categories. The effect of market prices were consistent in all diseases and parities; higher milk and replacement prices increased total costs, whereas greater feed and slaughter prices decreased disease costs.

Transcriptional abundance of antioxidant enzymes in endometrium and their circulating levels in Zebu cows with and without uterine infection

Oxidative stress during peripartum period may compromise the uterine immunity. In the present study, we assessed the oxidative stress and antioxidant status during peripartum period and studied their relationship with postpartum uterine infection in dairy cows. Peripheral blood concentrations of total antioxidant capacity (TAC), malondialdehyde (MDA) and nitric oxide (NO) were determined (day -21, -7, on the day of calving and day +7, +21, +35) in normal (n=11), puerperal metritic (n=7) and clinical endometritic (n=6) cows. Endometrial biopsy was performed on the day of calving and expression of CAT, GPx4 and SOD2 genes was studied using qRT-PCR. Puerperal metritic cows had significantly (P<0.05) lower TAC (on day -7, day 0, day +7, +21 & +35), higher MDA (on day -21, -7 & on the day of calving) and NO (on day 0, +7 & day +35) concentrations compared to normal cows. Similarly, clinical endometritic cows had significantly (P<0.05) lower TAC (on day -7, 0, +7 & +21), higher MDA (on day -21, -7, +7 and +35) and NO (on day +7, +21 & +35) concentrations compared to normal cows. The expression of CAT and GPx4 genes was lower (P<0.05) and SOD2 gene was higher (P<0.05) in endometrial tissue of cows that developed uterine infection compared to normal cows. The relationship of peripheral levels of MDA and NO with antioxidant enzymes expression in endometrial tissue was found significant. Receiver operator characteristic analysis revealed that the concentrations of TAC on day -7 to day +35, MDA on day -21 to day +7 and NO on the day of calving to day +35 were highly correlated to the development of postpartum uterine infection in cows. It may be inferred that the low serum TAC level and high level of lipid peroxidation and NO during peripartum period influenced the endometrial expression of anitioxidative genes that compromised the uterine health during postpartum period.

Uterine Microbiota and Immune Parameters Associated with Fever in Dairy Cows with Metritis

OBJECTIVE

This study aimed to evaluate bacterial and host factors causing a fever in cows with metritis. For that, we investigated uterine microbiota using a metagenomic sequencing of the 16S rRNA gene (Study 1), and immune response parameters (Study 2) in metritic cows with and without a fever.

PRINCIPAL FINDINGS (STUDY1)

Bacterial communities were similar between the MNoFever and MFever groups based on distance metrics of relative abundance of bacteria. Metritic cows showed a greater prevalence of Bacteroidetes, and Bacteroides and Porphyromonas were the largest contributors to that difference. A comparison of relative abundance at the species level pointed to Bacteroides pyogenes as a fever-related species which was significantly abundant in the MFever than the MNoFever and Healthy groups; however, absolute abundance of Bacteroides pyogenes determined by droplet digital PCR (ddPCR) was similar between MFever and MNoFever groups, but higher than the Healthy group. The same trend was observed in the total number of bacteria.

PRINCIPAL FINDINGS (STUDY2)

The activity of polymorphonuclear leukocyte (PMN) and the production of TNFα, PGE2 metabolite, and PGE2 were evaluated in serum, before disease onset, at 0 and 3 DPP. Cows in the MNoFever had decreased proportion of PMN undergoing phagocytosis and oxidative burst compared with the MFever. The low PMN activity in the MNoFever was coupled with the low production of TNFα, but similar PGE2 metabolite and circulating PGE2.

CONCLUSION/SIGNIFICANCE

Our study is the first to show a similar microbiome between metritic cows with and without a fever, which indicates that the host response may be more important for fever development than the microbiome. Bacteroides pyogenes was identified as an important pathogen for the development of metritis but not fever. The decreased inflammatory response may explain the lack of a febrile response in the MNoFever group.

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.

Characterization of buffalo interleukin 8 (IL-8) and its expression in endometritis

River buffalo (Bubalus bubalis bubalis) with a population over 135 million heads is an important livestock. Interleukin 8 (IL-8) is a member of the chemokine family and is an important chemoattractant for neutrophils associated with a wide variety of inflammatory diseases such as endometritis. Tissue samples from the mammary gland, uterus and ovary were obtained from river buffalo (Mediterranean type) with and without endometritis. Bacteriological examination showed the presence of both gram positive and negative in all buffalo with endometritis. RNA extraction and complementary DNA (cDNA) synthesis were conducted from all tissues. Specific primer for IL8 full coding regions was designed using known cDNA sequences of Bubalus bubalis, Genbank accession number AY952930.1. IL-8 gene expression was investigated in buffalo tissues. Expression of IL-8 in buffalo with endometritis was found to increase significantly over buffalo without endometritis only in the uterus (P = 0.0159). PCR products from uterus tissues (target organs) of buffalo with and without endometritis, were purified and sequenced. No polymorphic sites were detected in the investigated samples. IL-8 cDNA nucleotide sequences of buffalo with and without endometritis were 100% identical (accession number JX413057). Buffalo IL8 cDNAs were compared with corresponding sequences of member of subfamily Bovinae (buffalo and cattle) and subfamily Caprinae (sheep and goat). IL-8 species specific differences were identified.

Hyperketonemia in early lactation dairy cattle: a deterministic estimate of component and total cost per case

The purpose of this study was to develop a deterministic economic model to estimate the costs associated with (1) the component cost per case of hyperketonemia (HYK) and (2) the total cost per case of HYK when accounting for costs related to HYK-attributed diseases. Data from current literature was used to model the incidence and risks of HYK (defined as a blood β-hydroxybutyrate concentration≥1.2 mmol/L), displaced abomasa (DA), metritis, disease associations, milk production, culling, and reproductive outcomes. The component cost of HYK was estimated based on 1,000 calvings per year; the incidence of HYK in primiparous and multiparous animals; the percent of animals receiving clinical treatment; the direct costs of diagnostics, therapeutics, labor, and death loss; and the indirect costs of future milk production losses, future culling losses, and reproduction losses. Costs attributable to DA and metritis were estimated based on the incidence of each disease in the first 30 DIM; the number of cases of each disease attributable to HYK; the direct costs of diagnostics, therapeutics, discarded milk during treatment and the withdrawal period, veterinary service (DA only), and death loss; and the indirect costs of future milk production losses, future culling losses, and reproduction losses. The component cost per case of HYK was estimated at $134 and $111 for primiparous and multiparous animals, respectively; the average component cost per case of HYK was estimated to be $117. Thirty-four percent of the component cost of HYK was due to future reproductive losses, 26% to death loss, 26% to future milk production losses, 8% to future culling losses, 3% to therapeutics, 2% to labor, and 1% to diagnostics. The total cost per case of HYK was estimated at $375 and $256 for primiparous and multiparous animals, respectively; the average total cost per case of HYK was $289. Forty-one percent of the total cost of HYK was due to the component cost of HYK, 33% to costs attributable to metritis, and 26% to costs attributable to DA. The high total cost of HYK at reported incidences of 40 to 60% highlights the importance of appropriate transition cow nutrition and management to decrease the effect of HYK.

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).

Breeding and Genetics Symposium: inferring causal effects from observational data in livestock

Data regularly recorded in commercial herds have been used extensively for estimation of disease incidence rates, for inferences regarding genetic and phenotypic associations between traits, or for developing predictive models for economically important traits. Some studies have also used field data to investigate potential causal relationships between variables. However, inferring causal effects from observational data is complex due to potential confounding effects and careful analyses using specific statistical and data mining techniques as well as different sets of assumptions are required. Nonetheless, although virtually unknown in the agricultural research community, such methods are available and have been used in many other fields. In this paper, we review and discuss the analysis of observational data using field-recorded information and its potential utility in the study of causal effects in livestock. It is our postulation that there is much to be learned from such data, which can be used either to explicitly investigate causal relationships between variables or to generate hypotheses for further investigation using controlled experiments or additional field-recorded data.

Comparison of a leukocyte esterase test with endometrial cytology for diagnosis of subclinical endometritis in postpartum dairy cows

The objective was to compare a leukocyte esterase (LE) test with endometrial cytology (EC) for diagnosis of subclinical endometritis in dairy cows. The relationship between subsequent fertility and the uterine (Ut) and cervical (Cx) leukocyte esterase activity was determined by the odds of pregnancy by 90 days in milk (DIM). Holstein cows (N = 218) without clinical endometritis and between 21 and 47 DIM from five commercial dairy herds were sampled for uterine and cervical leukocyte esterase activity and EC by cytobrush. To test the effect of time, cows were grouped into early (21-31 DIM) and late (32-47 DIM) animals. There was a slight agreement between UtLE and CxLE (weighted κ = 0.37). The percentage of neutrophils was correlated with esterase score either from the uterus (UtLE; P = 0.0001) or cervix (CxLE; P = 0.002). The percentage of neutrophils on EC (P < 0.001), the UtLE score (P < 0.0001), and the CxLE (P = 0.0009) diminished as DIM increased. Neither CxLE nor UtLE were statistically associated with pregnancy at 90 DIM. However, between 32 and 47 DIM, the percentage of neutrophils on EC and odds of pregnancy at 90 DIM were associated (P = 0.04). For the same interval, based on receiver/response operating characteristics analysis, the optimal cutoff was >6.7% neutrophils to classify cows with subclinical endometritis. In conclusion, uterine LE activity was correlated with percentage of neutrophils as determined by EC, but not with odds of pregnancy. Subclinical endometritis (>6.70% neutrophils) diagnosed by EC between 32 and 47 DIM was associated with reduced odds of pregnancy.

Therapeutic efficiency of antibiotics and prostaglandin F2α in postpartum dairy cows with clinical endometritis: an evidence-based evaluation

The occurrence of vaginal discharge in postpartum dairy cows is generally diagnosed as clinical endometritis. This uterine condition is associated with reduced fertility and economic loss for the dairy industry. Therapeutic approaches include the systemic or intrauterine application of antibiotics or the injection of prostaglandin F2α and analogues to cause luteolysis and uterine contractions to evacuate the infected content. The treatment of clinical endometritis remains a subject of considerable controversy in the literature. Better understanding of the reproductive biology of normal versus abnormal uterine involution and immune mechanisms will allow more efficient diagnostic methods and a more efficient therapeutic approach.

Experimentally induced mastitis and metritis modulate soy bean derived isoflavone biotransformation in diary cows

The present study compared the changes in isoflavone (daidzein and genistein) and their metabolite (equol and para-ethyl-phenol) concentrations in the blood plasma of cows with induced mastitis and metritis after feeding with soy bean. Sixteen cows were divided into four groups: control for mastitis group, cows with induced mastitis group, control for metritis group, and cows with induced metritis group. All cows were fed a single dose of 2.5 kg of soy bean and then blood samples were taken from the jugular vein for 8 h at predetermined intervals. The concentrations of soy bean-derived isoflavones and their active metabolites were measured in the blood plasma on HPLC system. β-Glucuronidase activity in the blood plasma of cows was measured by fluorometric method. In the blood plasma of cows with induced mastitis and metritis, we found considerably higher concentrations and time-dependent increase in isoflavone metabolites (equol and para-ethyl-phenol) with reference to cyclic cows (P < 0.05). Moreover, we noticed significant decrease of genistein in the blood plasma of the cows with induced metritis compared with control cows (P < 0.05). In addition, in the blood plasma of the cows with induced metritis, we found an increase in β-glucuronidase activity compared with control cows (P < 0.05). In conclusion, health status of the females influenced the concentrations of isoflavone metabolites in the blood plasma of the cows. Experimentally induced mastitis and metritis increased isoflavone absorption, biotransformation and metabolism. Therefore, we suggest that cows with induced mastitis and metritis are more exposed to active isoflavone metabolite actions than healthy cows.

Association between endometritis and endometrial cytokine expression in postpartum Holstein cows

The endometrium regulates the inflammatory response after infection by production and release of cytokines and chemokines. The objective was to compare gene expression of important pro-inflammatory (TNFα, IL-1β, IL-6) and anti-inflammatory (IL-10) cytokines, and the main neutrophil chemokine (IL-8), from calving to Week 7 after calving, in cows that developed endometritis and healthy control cows. Uterine biopsies were obtained at calving and at Weeks 1, 3, 5 and 7. Endometritis was evaluated at Week 5 by uterine lavage and cytology; cows with ≥ 10% neutrophils were considered to have endometritis. Real-time RT-PCR threshold values (Ct) were used to calculate the fold difference in gene expression, using the 2(-ddCt) method, normalized to GAPDH and calibrated to the average dCt for all cows at calving. Serum IL-8 concentrations were measured with ELISA. The analysis included 28 cows (11 had endometritis) for the PCR data and 44 cows (20 had endometritis) for ELISA. Expression of the TNFα gene in uterine tissue was decreased in cows with endometritis compared to control cows at calving (P = 0.09) and at Week 1 (P = 0.05). Iterleukin-1β gene expression tended to be decreased (P = 0.08) in cows with endometritis compared to control cows at Week 1, but tended to be increased (P ≤ 0.10) at Weeks 5 and 7. Cows with endometritis had increased (P < 0.05) IL-6 gene expression at calving and at Week 7 compared to control cows. Interleukin-8 gene expression was increased (P = 0.03) in endometritic cows compared to control cows at Week 7. Uterine disease was not significantly associated with IL-10 gene expression. A lower local level of expression of pro-inflammatory cytokines in the endometrium soon after calving might impair activation of inflammation and clearance of bacteria, and lead to development of endometritis.

Postpartum uterine infection in cattle

Postpartum uterine infections results from uterine contamination with bacteria during parturition. The prevalence of uterine infections varies considerably among studies. Uterine infection implies adherence of pathogenic organisms to the mucosa, colonization or penetration of the epithelium, and/or release of bacterial toxins that lead to establishment of uterine disease. The development of uterine disease depends on the immune response of the cow, as well as the species and number (load or challenge) of bacteria. The postpartum uterus has a disrupted surface epithelium in contact with fluid and tissue debris that can support bacterial growth. A variety of species of bacteria, both Gram-positive and Gram-negative aerobes and anaerobes, can be isolated from the early postpartum uterus. Most of these are environmental contaminants that are gradually eliminated during the first 6 weeks postpartum. A normal postpartum cow resolves uterine infection by rapid involution of the uterus and cervix, discharge of uterine content, and mobilization of natural host defenses, including mucus, antibodies and phagocytic cells. Clinical signs of uterine infection vary with the virulence of the causative organisms and the presence of factors that predispose to the disease. The treatment of endometritis and metritis in bovine should be directed towards improving fertility. The antibiotic should be active against the main uterine pathogens and should maintain its activity in the environment of the uterus. Also, should not inhibit the normal defense mechanisms and should be well tolerated and not induce irritation in the endometrium. Effective use of hormones in uterine infection requires knowledge of both normal reproductive endocrinology and the therapeutic characteristics of available hormonal preparations.

Risk factors for delayed conception in Korean dairy herds

Delayed conception is defined as an interval of greater than 90 days postpartum before a cow becomes pregnant again. In this study, the risk factors for delayed conception in Korean dairy herds were determined by evaluating several reproductive factors in individual cows. The following data was recorded from 1,012 pregnancies in eight dairy herds (designated A-H) from July 2001 to June 2006: herd, cow parity, repeated animal (cows included 2, 3, or more times), calving season, calving condition (abnormal partus), postpartum disorders (retained placenta, metabolic disorders, metritis and ovarian cysts) and conception. Logistic regression was used to evaluate the effects of these factors on delayed conception. A stepwise procedure was used to obtain the appropriate model (α = 0.05), which revealed the herd, metritis and ovarian cysts to be significant risk factors for delayed conception. The odds ratio showed that the likelihood of delayed conception increased by 3.3 and 2.0 fold for each incidence of metritis and ovarian cysts, respectively. Delayed conception was significantly more likely in 2 herds, in herd A by 2.0 fold and in herd B by 2.4 fold, compared with herd H. These results suggest that the prevention of postpartum metritis and ovarian cysts, as well as improved herd management, will be needed to maintain a short interval between calving and conception in Korean dairy herds.

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.

Immune responses during the peripartum period in dairy cows with postpartum endometritis

Determining the immune responses to the development of endometritis during the peripartum period may assist in the development of more efficient reproductive management regimens for dairy herds. In this study, we compared the peripartum immune responses of dairy cows that develop endometritis by 4 weeks postpartum (n = 11) to cows that did not develop this disease (n = 19). Blood samples were collected 1 week before calving, just after or during calving, and then at weeks 1, 2, 3, and 4 postpartum. Cows that developed endometriris had significantly higher total leukocyte, neutrophil, lymphocyte, and monocyte counts than the control cows (P < 0.05) at all time points. The leukocytes from cows that developed endometritis were significantly less phagocytic than those from control cows at all sampling time points (P < 0.01). The serum TNFalpha concentrations of the control cows decreased linearly from the prepartum time point (P = 0.0029), but the endometritis cows showed a different profile (P > 0.05). As a result, the serum TNFalpha concentrations were greater in the endometritis group (P < 0.01) than in the control group during the third and fourth weeks postpartum. The greater total leukocyte numbers and neutrophil, lymphocyte and monocyte counts, and the maintenance of elevated serum TNFalpha levels in the cows with endometritis may be due to infection in the postpartum period. Furthermore, the decreased phagocytic capacity of leukocytes during the peripartum period, including at the prepartum time point, makes cows more susceptible to postpartum endometritis.

Treatment of chronic endometritis in dairy cows with an intrauterine application of enzymes. A field trial

The use of proteolytic enzymes has been established in the non-antibiotic treatment of mastitis in dairy cattle. The objective of this study was to evaluate, if enzymes are efficacious in the treatment of chronic endometritis. In a controlled field trial, cows with vaginal discharge 21-27 days in milk (DIM) were randomly assigned to two treatment groups. Endometritis was classified into three categories, depending on the type of vaginal discharge: clear mucus with flakes of pus (E1), mucopurulent discharge or fluctuating contents in the uterus (E2), and purulent discharge (E3). In group ENZYMES (n=191), cows received an intrauterine treatment with a salve containing the enzymes trypsin (16 mg), chymotrypsin (16 mg), and papain (8 mg). Cows in group PGF (n=225) were treated with 0.5mg of cloprostenol. Cows that did not show any clinical signs of chronic endometritis were regarded as healthy control group (HC, n=699). In groups ENZYMES and PGF, all cows were re-examined 35-41 DIM. In group ENZYMES, cows were re-treated with enzymes if signs of endometritis were found, while in group PGF all cows received a second dose of cloprostenol, regardless of their clinical findings. Cure rate after the first treatment, defined as the absence of vaginal discharge at the re-examinations, was 59.7 and 68.0% in groups ENZYMES and PGF, respectively (P>0.05). Reproductive performance measures showed no significant differences between the two treatment groups. Service rate was significantly lower for ENZYMES and PGF, respectively, compared to HC. Conception rates to all services and percentages of cows pregnant by 250 DIM were significantly lower in group ENZYMES compared to HC, while no further differences were found between PGF and HC. In both treatment groups, cure rate and reproductive performance measures were better for cows categorized E1 or E2, than for cows categorized E3, respectively. Conception rate to all services for cows with endometritis category E1 was higher in group PGF than in group ENZYMES (P<0.05). The results of this field trial suggest that prostaglandin F(2alpha) is still the treatment of choice for chronic endometritis in dairy cattle.

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.

Uterine Involution and Fertility of Holstein Cows Subsequent to Early Postpartum PGF2α Treatment for Acute Puerperal Metritis

The objective was to evaluate the effect of 2 doses of PGF(2alpha) injected early postpartum on uterine involution, serum concentration of acute phase proteins at 12 d postpartum, and fertility in Holstein cows with acute puerperal metritis. Only cows diagnosed with retained fetal membranes and metritis and treated with ceftiofur hydrochloride for 5 d were used in the study. Two hundred cows were assigned randomly to be treated (n = 100) or to serve as controls (n = 100). Treatment consisted of 2 i.m. injections of PGF(2alpha) 8 h apart on d 8 postpartum. A subsample of 90 cows was selected randomly (45 treated cows; 45 controls) to evaluate uterine diameter using ultrasonography, uterine score, and serum concentrations of acute phase proteins at 12 d postpartum. The outcome variable for all cows was conception rate at first service. Postpartum, primiparous, treated cows had smaller uterine diameters and lower uterine scores than controls. Cows with a uterine diameter <5.1 cm at 12 d postpartum were 5.5 times more likely to conceive at first service than cows with larger uterine horn diameter. Treatment significantly reduced the concentrations of serum alpha1-acid glycoprotein. Within primiparous cows, treatment also increased conception at first service by 17%. It was concluded that 2 doses of PGF(2alpha) 8 h apart at 8 d postpartum in primiparous cows with acute puerperal metritis decreased the diameter of uterine horns and serum concentration of alpha1-acid glycoprotein at 12 d postpartum and increased the conception rate at first service.

Risk factors for postpartum endometritis and the effect of endometritis on reproductive performance in dairy cows in Korea

The objectives of this study were to determine the risk factors for postpartum endometritis by evaluating several reproductive factors in individual cows, and to determine the effect of endometritis on the subsequent reproductive performance in dairy herds in Korea. The data, including health status, parity and body condition score (BCS) of cows, and calving date, were collected from 320 cows in eight dairy herds calving from January 2001 to October 2002. We used logistic regression to evaluate the effects of these factors on endometritis. A stepwise procedure, used to obtain the appropriate model with alpha=0.05, revealed that retained placenta, metabolic disorders and parity are the important risk factors for endometritis. The mean intervals from calving to first service and conception were prolonged (P<0.01) by 23 and 36 days, respectively, in the endometritis group compared to the non-endometritis group. The first service conception rate was lower (P<0.05) in the endometritis group (47.6%) than in the non-endometritis group (62.6%). The number of services per conception was higher (P<0.05) in the endometritis group (1.9) than in the non-endometritis group (1.6). We conclude that retained placenta, metabolic disorders and cow parity are strongly correlated with the development of postpartum endometritis, which decreases reproductive performance in dairy herds in Korea.