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.     

Use of reagent test strips for diagnosis of endometritis in dairy cows

The use of leukocyte esterase (LE), protein, and pH tests were evaluated on widely available urinary test strips (Multistix 10 SG; Bayer Corporation, Elkart, IN, USA) on uterine lavage samples as a potential cow-side test for the diagnosis of cytologic endometritis. Uterine lavage samples of 563 lactating Holstein cows between 40 and 60 days postpartum from 28 herds were evaluated. Endometrial cytology was used as the reference for endometritis, with a cutoff point of ≥10% neutrophils. All three (LE, protein, and pH) were increased in cows with cytologic endometritis and the associations were highly significant. Optimal cutoff points determined by receiver operating characteristic analysis for LE, protein, and pH were ≥++, ≥300 mg/dL, and ≥7.0, respectively. Combining the results for LE and pH improved the performance of the test strip, but this resulted in a group of cows (20.6% of cows) which were approximately equally likely (46% with endometritis and 54% without endometritis) to have cytologic endometritis or not, and therefore could not be accurately classified. The direct relationship between reagent strip test and reproductive performance was also evaluated. Reproductive impairment due to endometritis was restricted to multiparous cows; significantly decreased reproductive performance was observed for multiparous cows with lavage fluid LE ≥+++ (154 vs. 115 median days not-pregnant), as well as cows with pH ≥ 7.0 (150.5 vs. 111.5 median days not-pregnant), but not in cows with high protein, even at the highest cutoff point. In conclusion, reagent strip test results were strongly associated with cytologic endometritis and reproductive impairment; however, in comparison with conventional cytology, the performance of reagent strip as an alternative test was relatively poor and may require further refinement.     

Evaluation of cytokine expression by blood monocytes of lactating Holstein cows with or without postpartum uterine disease

Whereas neutrophils are the main phagocytic leukocytes, monocytes and macrophages are actively involved in immunomodulation after infection. Recent studies have demonstrated that neutrophil function is impaired by the state of negative energy balance around parturition, and that cows that develop uterine disease have a greater degree of negative energy balance than healthy cows. The objectives of this study were to compare monocyte gene expression and protein secretion of selected cytokines from calving to 42 d after calving in Holstein cows that did or did not develop uterine disease. Real time quantitative RT-PCR (Tumor necrosis factor-α (TNFα), Interleukin (IL)-1β, IL-6, IL-8 and IL-10) and ELISA (TNFα, IL-1β and IL-8) were used to evaluate cytokine response following in vitro stimulation of blood-derived monocytes with irradiated E. coli. Relative to unstimulated cells, E. coli-stimulated monocytes from cows with metritis had lower gene expression of key pro-inflammatory cytokines than healthy cows from calving to 14 d after calving (TNFα at 0, 7, and 14 d after calving, IL-1β and IL-6 at 7 and 14 d after calving; P < 0.05). There were no significant differences between groups for expression of IL-8 or the anti-inflammatory cytokine IL-10. This was due, in part, to higher gene expression in unstimulated monocytes (TNFα, IL-1β, IL-6 and IL-10) in early lactation from cows with metritis. Expression of mRNA in stimulated cells (relative to housekeeping genes) was lower for TNFα (7 and 14 d postpartum) and for IL-10 (7 and 14 d postpartum) in cows with metritis. Concentration of TNFα was lower in the culture medium of E. coli-stimulated monocytes from cows with metritis than healthy cows at calving and 7 and 21 d after calving (P < 0.05). Circulating cytokine concentrations were not different between groups for IL-8 and were below the limits of detection for TNFα and IL-1β. Cytokine gene expression and production were similar between healthy cows and cows that developed endometritis, diagnosed cytologically at 42 d after calving. We concluded that altered levels of expression and production of pro-inflammatory cytokines postpartum could contribute to impaired inflammatory response and predispose cows to development of metritis.     

Evaluation of the effectiveness of intrauterine treatment with formosulphathiazole of clinical endometritis in postpartum dairy cows

In cattle, elimination of bacterial contamination from the uterine lumen after parturition is often delayed or compromised, and pathogenic bacteria can persist, causing uterine disease and infertility. The aim of this study was to compare the clinical and bacteriologic recovery following a single intrauterine administration of formosulphatiazole, cephapirin or placebo in cows with clinical endometritis. Cows (n = 80), no less than 28 days postpartum, with clinical endometritis were enrolled in the study. Endometritis was diagnosed by a complete reproductive examination, including rectal palpation, ultrasonography, vaginoscopy and uterine swab. All cows were randomly assigned to receive one of three intrauterine treatments (T0): 2500 mg of formosulphatiazole (Group A); 500 mg of cephapirin (Group B); placebo (4250 mg of propylene glycol; Group C). Cows were examined at the first estrus after treatment or no more than 30 days after (T1). Bacteria isolated were E. coli, A. pyogenes, Pasteurella spp. and Streptococcus spp. After treatment, in Group A and B only 6/30 (20.0%) and 6/24 (25.0%) cows showed a positive bacteriologic culture (P > 0.05), while in Group C the number of positive animals was significantly higher (19/26; 73.1%; P < 0.05). At T0, total clinical scores were similar between the three groups (Group A: 5.84 ± 1.07; Group B: 5.91 ± 1.0; Group C: 5.62 ± 1.17; P > 0.05) and indicative of clinical endometritis. At T1, endometritis scores were significantly lower than those reported before uterine infusion (P < 0.05); however, Group A and B score, 0.4 ± 0.9 and 1.0 ± 2.1, respectively, correspond to no and slight endometritis, while animals in Group C reported a total endometritis score significantly higher (4.6 ± 3.5; P < 0.05) corresponding to endometritis. In the present study, a commercial formosulphatiazole preparation was as effective as cephapirin and more effective than placebo for the treatment of clinical endometritis.     

Proinflammatory cytokine gene expression in endometrial cytobrush samples harvested from cows with and without subclinical endometritis

Thirty postpartum cows (28 to 41 days in milk) without signs of clinical endometritis were categorized as inflammation-negative (N = 18) or subclinical endometritis-positive (N = 12) based on endometrial cytobrush cytology (> 18% polymorphonuclear cells; PMNs). Slides for cytology were prepared before the same cytobrush was transferred to a tube containing 1 mL Trizol reagent. Total RNA was extracted from each cytobrush sample and analysis of il6, il8, tnfα, and βactin gene expression was performed using quantitative real-time polymerase chain reaction. Cytobrush sampling provided sufficient material to prepare cytosmears and extract high quality endometrial mRNA (mean = 0.96 μg RNA per sample). Cytokine expression varied between experimental groups with a 20-fold higher tnfα (P = 0.001), a 30-fold higher il6 (P = 0.01), and a greater than 50-fold higher il8 mRNA expression level (P = 0.0001) in subclinical endometritis-positive versus disease-negative cows. Regression analysis of gene expression levels (cycle threshold) versus PMN frequency showed that the frequency of PMNs in the cytosmear decreased by 3.3% (P = 0.000 01), 2.3% (P = 0.015), and 2.4% (P = 0.05) for each additional cycle threshold required to detect il8, il6, and tnfα gene expression, respectively. Expression of the individual cytokines was positively associated: il8 and il6 (P = 0.0001); il8 and tnfα (P = 0.000 01); and il6 and tnfα (P = 0.0002). In conclusion, the endometrial cytobrush technique was successfully used to obtain material for both cytology and RNA extraction, and il8 gene expression may be useful to predict endometrial inflammation.     

Exosome-derived uterine microRNAs isolated from cows with endometritis impede blastocyst development

As a common disease of cows occurring during their perinatal period, endometritis is known to affect fertility. At present, the studies on endometritis mainly focus on preventing microbial invasion. However, the mechanism that uterine inflammation affects embryo activity and implantation is unclear. Mainly containing lipids, proteins, mRNAs, and microRNAs, exosomes widely exist in various tissues and body fluids. Exosome extractions were used by commercial kits and confirmed through morphological examinations and Western blot. After exosomes’ mRNA profiles were generated using RNA sequencing, it was investigated how uterine cavity fluid exosomes affect the developmental competence of in vitro fertilization (IVF) embryos in case of endometritis. In this study, the isolated exosomes were spherical particles with a diameter of 30–150 nm according to the transmission electron microscopy. Identified with Western blotting, positive CD63 and CD9 expressions showed that the isolated exosomes could be used for the subsequent tests. We found 118 differentially expressed miRNAs in the exosomes of the uterine cavity fluid in healthy cows and those with endometritis, among which, 52 miRNAs were down regulated and 66 up regulated. Furthermore, the qRT-PCR results confirmed the up-regulation of three miRNAs and down-regulation of six miRNAs, which were consistent with the deep sequencing results. IVF embryos co-incubated with the endometritis exosomes significantly decreased the blastocyst formation rate in comparison with those co-incubated with the healthy exosomes (21.84+3.17 vs. 32.37+2.69). Therefore, exosome miRNAs may be a cause of infertility in cows with endometritis.     

Secretion of prostaglandins and leukotrienes by endometrial cells in cows with subclinical and clinical endometritis

The aims of this study were (1) to measure the secretion of prostaglandin F_2α (PGF_2α), prostaglandin E₂ (PGE₂), leukotriene B₄ (LTB₄), and leukotriene C₄ (LTC₄) by endometrial cells collected by a cytobrush from healthy cows and cows with subclinical and clinical endometritis in the fourth week postpartum, and (2) to evaluate the relationship between the mediators' levels of secretion and the number of polymorphonuclear neutrophils (PMNs) in the uterine smears of cows with subclinical endometritis. The study included cows without any signs of clinical endometritis (n = 63) and cows with clinical endometritis as a positive control (ENDOM, n = 12). Two different threshold ratios (>5% and >18% of PMNs) were used to categorize the cows without clinical signs as with or without cytologic endometritis (CE). Considering the first or second threshold, the animals with CE were included in group CE POS I or CE POS II, whereas the healthy cows were assigned to group CE NEG I or CE NEG II, respectively.     

Spontaneous recovery or persistence of postpartum endometritis and risk factors for its persistence in Holstein cows

It has been stated that postpartum endometritis in dairy cows has a tendency to cure without intervention. The objectives of this field study, therefore, were to determine the proportions of cows with spontaneous clinical recovery or persistence of postpartum endometritis and to determine some risk factors for its persistency in dairy cows (Bos taurus). Holstein-Friesian cows (n = 441 lactations) from seven dairy herds were examined monthly by vaginoscopy and transrectal palpation. A cow was considered to have “postpartum endometritis” if it had pus in the cervico-vaginal discharge at the first postpartum examination during Days 15 to 60 (Day 0 = day of calving); this was classified as mild, mucopurulent, or purulent endometritis, or endometritis with fluid in uterus. Furthermore, a cow with evidence of endometritis at least once during Days 61 to 150 was considered to have “persistence (or recurrence) of endometritis.” A total of 104 (23.6%) lactations had postpartum endometritis, of which 25.3% had persistence or recurrence of clinical endometritis. Cows with persistence or recurrence of endometritis became pregnant at a slower rate (hazard ratio [HR] = 0.28; P < 0.001) than those with no endometritis until Day 150. Calving in summer (odds ratio [OR] = 7.00; P = 0.04), early postpartum complications (OR = 6.58; P = 0.05), moderate (OR = 4.03; P = 0.08) and severe (OR = 30.99; P = 004) degrees of urovagina, and mucopurulent (OR = 9.54; P = 0.02) and purulent (OR = 5.70; P = 0.04) endometritis were risk factors for the persistence or recurrence of endometritis. Furthermore, 10.6% of cows that had not shown signs of postpartum endometritis had a new diagnosis of endometritis during Days 61 to 150. Some risk factors for the new diagnosis of endometritis beyond Day 60 were early postpartum complications (OR = 2.82; P = 0.03) and moderate (OR = 5.00; P = 0.001) or severe (OR = 12.63; P < 0.001) degrees of urovagina. In conclusion, approximately one quarter of cows with postpartum endometritis had persistence of endometritis until or beyond the breeding period. Risk factors for the persistence of clinical endometritis were summer calving, early postpartum complications, clinically relevant urovagina, and clinically relevant endometritis within 2 mo postpartum.     

Effects of body weight loss on serum progesterone concentrations of non-lactating dairy cows

The objective was to evaluate serum concentrations of nonesterified fatty acids (NEFA), cortisol, insulin, and progesterone (P4) of dairy cows maintaining or mobilizing body weight (BW). Eleven non-lactating, non-pregnant, and ovariectomized Gir × Holstein cows were stratified by BW and body condition score (BCS), and randomly assigned to: 1) BW loss (six cows; LOSS) and 2) BW maintenance (five cows; MAINT). Treatments were achieved through a grazing schedule using three pastures. From Days −7 to 1 of the study, all cows were maintained in Pasture A (12 kg of dry matter/cow daily). From Days 2 to 30, LOSS cows were maintained in Pasture B (less than 1.0 kg of dry matter/cow daily), whereas MAINT cows were maintained in Pasture C (12 kg of dry matter/cow daily). However, from Days 3 to 30 of the study, cows from both treatments were regrouped daily into Pasture A from 0600 to 1200 h to allow LOSS cows to consume, on average, 4.5 kg/d of forage dry matter. On Day −66 of the study, all cows received an intravaginal drug releasing device containing 1.9 g of P4 (replaced every 14 d and removed on Day 3). Cow BW and BCS were assessed on Day 0 and 30 and blood samples were collected daily from Days 0 to 30 at 0600 and 1200 h. Changes in BW and BCS were greater (P ≤ 0.05) in LOSS cows compared to MAINT cows. Within samples collected at 0600 h, serum NEFA concentrations were often greater (P < 0.05) in LOSS cows compared to MAINT after Day 14. Serum P4 concentrations were greater (P < 0.05) on Days 21 and 22, and tended (P < 0.10) to be greater on Days 16, 23, and 24 of the study in LOSS cows compared to MAINT. In conclusion, BW loss was associated with increased circulating concentrations of P4 in non-lactating ovariectomized dairy cows; this was mainly attributed to fat mobilization and consequent release of P4 stored in adipose tissues.     

Mycoflora of cervicovaginal fluids in dairy cows with or without reproductive disorders

Fungal infection of reproduction system of dairy cattle have not been received much more attention. The aim of this study was to determine the fungal infection of Holstein dairy cows with reproductive disorders or healthy. Fungal isolates of cervicovaginal fluids of 176 Holstein dairy cows were collected by using the double rod swabs for cervix and the sterilized cotton swabs for discharges of vagina. They were evaluated for fungal infections. The treatment group included 70 dairy cows with reproductive diseases, such as abortion, repeat breeder, endometritis, metritis, retention of fetal membrane, dystocia, cervicitis, and vaginitis. The control groups were included 42 healthy non-pregnant cows and 64 pregnant cows. Isolates of fungi were obtained from cervix and vagina of 27.1% and 28.6% of treatment group, 26.7% and 31.2% of pregnant cows, and 33.3% and 21.4% of healthy non-pregnant cows, respectively, indicating no significant differences. It is showed that the cervix and vagina of the treatment group have been infected by six different mycotic isolates. However, the cervix and vagina of pregnant and non-pregnant healthy cows in control group were infected with 5, 6 and 5, 4 different fungal agents, respectively. Penicillium and yeast were the most common isolated agents. Regarding to the result of this study, it is concluded that fungal infections can occur in cervicovaginal cavity of Holstein dairy cows with or without reproductive diseases.     

Interactions between negative energy balance,metabolic diseases,uterine health and immune response in transition dairy cows

The biological cycles of milk production and reproduction determine dairying profitability thus making management decisions dynamic and time-dependent. Diseases also negatively impact on net earnings of a dairy enterprise. Transition cows in particular face the challenge of negative energy balance (NEB) and/or disproportional energy metabolism (fatty liver, ketosis, subacute, acute ruminal acidosis); disturbed mineral utilization (milk fever, sub-clinical hypocalcemia); and perturbed immune function (retained placenta, metritis, mastitis). Consequently NEB and reduced dry matter intake are aggravated. The combined effects of all these challenges are reduced fertility and milk production resulting in diminishing profits. Risk factors such as NEB, inflammation and impairment of the immune response are highly cause-and-effect related. Thus, managing cows during the transition period should be geared toward reducing NEB or feeding specially formulated diets to improve immunity. Given that all cows experience a reduced feed intake and body condition, infection and inflammation of the uterus after calving, there is a need for further research on the immunology of transition dairy cows. Integrative approaches at the molecular, cellular and animal level may unravel the complex interactions between disturbed metabolism and immune function that predispose cows to periparturient diseases.     

Relationship between fructosamine with serum protein, albumin and glucose concentrations in dairy ewes

The aim of the study was to investigate the changes in blood fructosamine concentrations of ewes during late pregnancy and lactation. The relationship of serum fructosamine to changes in the serum glucose and blood protein and albumin concentrations were measured in 10 crossbred dairy ewes. Blood was sampled 10 days prior to lambing (D − 10), on day 10 (D + 10), day 20 (D + 20), day 90 (D + 90) and on day 130 post partum (D + 130). The concentration of serum fructosamine significantly decreased on D + 10, then significantly increased on D + 20 (p < 0.05), remaining on the same level until D + 130. The concentration of serum glucose was highest on D − 10, and gradually decreased, being significantly lower on D + 130 post partum, compared to D − 10. Similarly the serum albumin and total protein concentrations were highest on D − 10, and significantly decreased on D + 10. The concentration of both parameters increased by D + 20, but then decreased on D + 90 and D + 130. The significant decrease in fructosamine concentration observed on D + 10 probably resulted from the substantial and rapid decrease in total serum protein and albumin concentrations, also established during the same period. The results confirm that in ewes, similar to other species, the shorter serum protein life span during the transition period has an influence on the decrease in blood fructosamine concentrations. These should be considered during the interpretation of serum fructosamine concentration as part of blood biochemical findings during the pre and post partum period.     

奶牛产后感染性子宫疾病对子宫和卵巢的影响研究进展

微生物入侵是引起奶牛产后子宫疾病的主要因素,产后子宫能检出丰富的微生物种群,主要包括公认的致病菌如大肠杆菌、隐秘脓杆菌、坏死梭杆菌等,机会病原菌如产气荚膜梭菌、肺炎克雷伯菌、微球菌等和潜在致病菌如消化链球菌、金黄色葡萄球菌等。近年来,运用分子微生态技术发现子宫中的微生物属于变形菌门、梭杆菌门、厚壁菌门、拟杆菌门和软壁菌门5个已知的门和一类未被培养的种群,其中拟杆菌属、梭菌属等种群与子宫疾病密切相关。细菌侵入子宫后,以大肠杆菌为代表的革兰氏阴性菌和以化脓隐秘杆菌为代表的革兰氏阳性菌可被子宫内膜细胞上的Toll样受体识别引起炎症反应,改变子宫前列腺素分泌类型,影响卵泡发育、黄体大小,降低血清中雌激素和孕激素浓度,造成奶牛不发情、不排卵,导致产犊间隔延长、产奶量和产犊数量下降,严重影响奶业经济效益。本文从产后奶牛子宫内主要病原菌的种类及其与子宫健康状态的关系、子宫内膜对病原菌的识别与先天免疫、子宫疾病对子宫和卵巢功能的影响等方面对国内外研究进展进行了综述。     

Impact of subclinical and clinical mastitis on sensitivity to pain of dairy cows

A total of 90 cows from three commercial farms were used to evaluate the relationship between subclinical mastitis and clinical mastitis and thermal nociceptive threshold. Milk strips from all udder quarters were tested for clinical mastitis with visual inspection of milk and udder alterations and for subclinical mastitis using California Mastitis Test. Milk yield was recorded, milk was sampled and further analyzed for somatic cells count (SCC). Cows were considered healthy when SCC<200 000 cells/ml and no visual alterations in milk and/or udder, with mild subclinical mastitis when SCC>200 000 cells/ml and no visual alterations in milk and/or udder, with moderate subclinical mastitis when SCC>500 000 cells/ml and no visual alterations in milk and/or udder and with clinical mastitis when visual alterations in milk and/or udder were detected. Nociceptive threshold was evaluated with the thermal threshold meter apparatus applied to the rear legs. Thermal threshold (TT) decreased when we compared healthy cows with cows presenting clinical mastitis and tended to decrease when we compare healthy cows with those with moderate subclinical mastitis. TT was lower at the ipsilateral rear leg compared with the contralateral leg to the infected mammary gland. TT linearly decreases as _log10SCC increased and it showed sharp decrease as _log10SCC exceed the value of 6.4. Increase in one unit of _log10SCC increased the odds of low thermal threshold (lower than 55.8°C). Subclinical mastitis might be a welfare issue as it tended to decrease nociceptive thermal threshold.     

Reproductive tract defense and disease in postpartum dairy cows

This paper briefly reviews recent data and concepts on the development and mitigation of infection and inflammation in the reproductive tract of dairy cows during the first 2 mo after calving. The incidence of metritis is typically between 10 and 20%, of clinical endometritis or purulent vaginal discharge (PVD) approximately 15%, and of subclinical or cytological endometritis a further 15%. Worse postpartum negative energy balance is associated with more severe or prolonged uterine inflammation. Changes in feed intake, expression of genes for pro-inflammatory cytokines, notably interleukin (IL) 1, IL6 and IL8, circulating concentrations of beta-hydroxybutyrate (BHBA) or nonesterified fatty acids (NEFA), and innate immune function precede both metritis and endometritis by several weeks. Infections with Escherichia coli and Arcanobacterium pyogenes are associated with both metritis and PVD. There are new data to suggest that specific virulence factors in E. coli associated with adherence may be important in metritis and PVD. Cytological endometritis and PVD are overlapping but largely distinct conditions, and there are emerging data that cervicitis exists both concurrent with and separate from endometritis. Much remains to be learned about what initiates and sustains harmful inflammation of the reproductive tract. Such information is necessary to develop effective treatments for the various forms of disease and, more importantly, to develop means to prevent endometritis and cervicitis. In particular, vaccination against specific uterine pathogens and interventions to modulate innate immune response appear to be important avenues for investigation. Presently, commonly recommended best management practices for cows in the transition period are likely to be helpful to mitigate the risk of reproductive disease.     

Comparative analysis of gene expression profiles in ruminal tissue from Holstein dairy cows fed high or low concentrate diets

Cattle are often fed high concentrate (HC) diets to increase productivity, although HC diets cause changes in ruminal environment such as pH reduction. Despite those well-documented changes in cattle fed HC diets, there is currently a paucity of data describing the molecular events regulating the ruminal environment. Our objective was to gain an understanding of which genes are differentially expressed in ruminal tissue from Holstein cows fed a HC comparing to low concentrate (LC) diet using microarray analysis using a bovine 24 k microarray. A total of 5,200 differentially expressed genes (DEG) were detected for cows fed HC relative to LC. The DEG were firstly annotated with gene ontology (GO) and Kyoto encyclopedia of Genes and Genomes (KEGG), indicating that the DEG were associated with catalytic activity and MAPK pathway, respectively. Further characterization using GeneCodis identified patterns of interrelated annotations for the DEG to elucidate the relationships among annotation groups revealed that a cAMP-dependent protein kinase A catalytic subunit beta (PRKACB), may be associated with ruminal tissue maintenance. The results contributed to understanding of the regulatory mechanisms at the mRNA level for Holstein cows fed at different concentrate ratio diets.     

Risk factors for uterine diseases on small- and medium-sized dairy farms determined by clinical,bacteriological, and cytological examinations

The involution process of the postpartum bovine uterus is usually accompanied by invasion of various bacteria. The objectives of this study were to identify the relationship between the postpartum findings as risk factors for clinical endometritis (CE) and subclinical endometritis (SE). Furthermore, the effects of CE or SE on reproductive performance in small- and medium-sized dairy herds were investigated. A total of 400 cows were examined by vaginoscopy for CE at 20 to 30 days postpartum, and samples were collected for cytological examinations for SE and for bacteriology by cytobrush technique. The vaginoscopic and cytological examinations showed that 27.3% and 21.0% of the cows were found with CE and SE, respectively. The bacterial community analyses revealed a large variety of bacteria. Overall, bacteria from the order Actinomycetales, Lactobacillales, Bacillales, Burkholderiales, Caulobacteriales Enterobacteriales, Pasteurellales, and Pseudomonadales were detected, whereas in 39.5% of the samples no bacterial growth was detectable. The uterine pathogens Escherichia coli and Trueperella pyogenes were found in 16.8% and 13.0% of the samples cultivated under aerobic conditions. Other frequently isolated bacteria were Streptococcus spp. (31.3%), Staphylococcus spp. (20.0%), Corynebacterium spp. (16.5%), and Bacillus spp. (10.5%). The infection with T. pyogenes was the most important bacteriological risk factor for the occurrence of CE (odds ratio (OR) = 5.72; 95% CI = 3.07–10.83) and had a detrimental effect on the hazard of nonpregnancy by 200 days postpartum (hazard ratio = 1.66; 95% CI = 1.12–2.46). Calving assistance (OR = 1.79; 95% CI = 1.16–2.98) and farm (OR = 1.11; 95% CI = 1.02–1.20) were indicated as further risk factors for CE and SE. Effects of CE and SE on reproductive performance parameters could not be demonstrated.     

Low peripheral progesterone and late embryonic/early fetal loss in suckled beef and lactating dairy cows

Pregnancy failure during placentation in lactating dairy cows was associated with low concentrations of serum progesterone. Beef cows have greater serum progesterone and less pregnancy failure. Experiment 1 determined that reduction of serum progesterone affected late embryonic/early fetal loss in suckled beef cows. Cows (n = 40) received progesterone from two new or used controlled internal drug releasing devices, replaced every 5 d, beginning on Day 28 of gestation (mating = Day 0); CL were enucleated on Day 29. Retention of pregnancy was 77% in treated cows and 97% in 78 control cows (P < 0.05). Experiment 2 determined how pregnant, lactating dairy cows with high or low progesterone concentrations during Days 28-34 differed in luteal function or in serum progesterone during replacement therapy. Luteal tissue from such cows was assayed for progesterone and expression of mRNA for genes of endothelin and prostaglandin (PG) systems. Secretion of progesterone and prostaglandins by dispersed luteal cells was determined during incubation with LH, endothelin-1, or arachidonic acid. Neither luteal progesterone nor mRNAs for endothelin or prostaglandin systems differed. Endothelin-1 inhibited secretion of progesterone more (P < 0.05) in luteal cells from cows with low versus high serum progesterone, when incubated with arachidonic acid. Secretion of prostaglandin F₂α was increased and that of 6-keto-PGF₁α decreased by endothelin-1 in vitro. Serum progesterone during replacement was lower (P < 0.05) for cows with low than high serum progesterone at lutectomy. Thus, clearance, more than luteal production, determined peripheral progesterone in pregnant, lactating dairy cows.     

Activity of alkaline phosphatase in uterine flushings of dairy cows affected with ovarian cysts or endometritis

Both uterine horns of 14 dairy cows with ovarian follicular cysts, and four animals affected with purulent endometritis were flushed via catheter using 30 ml phosphate buffered saline, following evisceration at a local abattori. Activity in the flushing media of alkaline phosphatase (ALP) and aspartate aminotransferase (GOT) were examined. Ovaries were prepared for light microscopy. Amount and morphological integrity of luteinized tissue found on the ovaries were reflected by correspondent levels in ALP activity, which was higher in the media taken from the ipsilateral to the luteal tissue situated uterine horns (651 +/- 228 vs 244 +/- 62 u/l, n = 3). Only cows having relatively large amounts of luteal tissue on the cystic ovaries (as in luteinized follicular cysts) exhibited very high ALP activity in uterine flushings (2693 +/- 1348 u/l, n = 2). Results suggest the existence of local relationships between luteal tissue in the ovary and the ipsilateral uterine horn in cows with ovarian follicular cysts.