Plasma concentrations of progesterone in the preceding estrous cycle are associated with the intensity of estrus and fertility of Holstein cows.

The aim of this study was to determine the association between concentrations of progesterone (P4) during previous the estrous cycle with the intensity of spontaneous or estrogen-induced estrous expression and pregnancy per artificial insemination (P/AI). A total of 1,953 AI events from lactating Holstein cows were used, consisting of 1,289 timed AI events from experiment 1 (Exp. 1) and 664 AI events from experiment 2 (Exp. 2). In Exp. 1, cows were bred after a timed AI protocol based on estradiol and P4. In Exp. 2 animals were bred upon spontaneous estrus detection. In both experiments cows were continuously monitored by an automated activity monitor (AAM), in Exp.1 a relative increase of activity was calculated (i.e., percentage of increase activity at estrus compared to cow's baseline activity) and in Exp.2, activity data from each cow were computed into an index value that ranged from 0 to 100. In Exp.2 duration (hours) of estrus were calculated and defined as the total time above the threshold (35 index). The intensity of estrous expression was determined for each event and classified as either high or low intensity using the median of each experiment. Blood samples were collected for P4 analysis in Exp. 1 at -4 d, 0 d, and 7 d relative to timed AI, and in Exp. 2 immediately following estrus (0 d), 7 d, 14 d, and 21 d post-AI. Concentration of P4 was classified as greater or lower according to the median value in each experiment. Cows with lower concentrations of P4 at AI had greater estrous expression in Exp. 1 (363.6 ± 5.2 vs. 275.9 ± 8.0% relative increase) and Exp. 2 (76.7 ± 1.9 vs. 67.4 ± 4.7 index; and 12.5 ± 0.5 vs. 9.3 ± 1.8 hours). Cows with a greater intensity of estrous expression at timed AI had greater concentrations of P4 at -4 d than cows with lower intensity estrus or no estrous expression (4.6 ± 0.2 vs. 3.6 ± 0.2 vs. 3.7 ± 0.2 ng/mL). Cows with greater concentrations of P4 at -4 d had greater P/AI (32.8 ± 4.4 vs. 22.4 ± 4.5%), whereas cows with lesser concentrations of P4 at d0 for either timed AI (35.2 ± 3.4 vs. 19.6 ± 4.6%) or spontaneous estrus (31.8 ± 2.8 vs. 23.4 ± 3.2%) had greater P/AI. Cows with greater concentrations of P4 7 d post-timed AI had greater P/AI compared with cows that had lower concentration of P4 (39.1 ± 2.9 vs. 24.7 ± 2.6%). Similarly, cows that had lower concentrations of P4 at 7 d, 14 d and 21 d post-spontaneous estrus tended to have lower P/AI when compared with cows with greater concentrations of P4. Overall, concentrations of P4 prior to and at AI were associated with greater estrous intensity and P/AI at both spontaneous and timed AI events.

Transcriptional response of the bovine endometrium and embryo to endometrial polymorphonuclear neutrophil infiltration as an indicator of subclinical inflammation of the uterine environment.

The aim of the present study was to analyse the effect of subclinical endometritis on endometrial and embryonic gene expression. A total of 49 cows at either Day 0 or Day 7 of the oestrous cycle (62-83 days post partum) following superovulation were classified as having subclinical endometritis (SE-0, SE-7) or a healthy endometrium (HE-0, HE-7) on the basis of endometrial cytological evaluation. Endometrial samples and associated embryos were subjected to global transcriptome analysis using the Bovine GeneChip (Affymetrix, Santa Clara, CA, USA) and aberrant transcript profiles were observed in SE-0 and SE-7 cows. At Day 0, 10 transcripts were found to be differentially expressed in endometrial samples. Specifically, the PDZK1, PXDN, DDHD2, GPLD1 and SULT1B1 genes were downregulated, whereas the PKIB, LOC534256, BT29392, LYZ and S100A14 genes were upregulated in SE-0 cows. Similarly, 11 transcripts were found to be differentially regulated on Day 7. Of these, GNPTG, BOLA-DQA5, CHD2, LOC541226, VCAM1 and ARHGEF2 were found to be downregulated, whereas PSTPIP2, BT236441 and MGC166084 were upregulated in SE-7 cows. Accordingly, endometrial health status affected the number of flushed, transferable embryos. In all, 20 genes were differentially regulated in blastocysts derived from HE-7 and SE-7 cows. Of these, GZMK, TCEAL4, MYL7, ADD3 and THEM50B were upregulated, whereas NUDCD2, MYO1E, BZW1, EHD4 and GZMB were downregulated. In conclusion, endometrial polymorphonuclear neutrophil infiltration as an indicator of subclinical endometritis is associated with changes in endometrial gene expression patterns, including genes involved in cell adhesion and immune modulation. Consequently, subclinical endometritis affects gene expression in embryos, including the expression of genes related to membrane stability, the cell cycle and apoptosis.

Time-dependent mRNA expression of selected pro-inflammatory factors in the endometrium of primiparous cows postpartum.

BACKGROUND: Inflammatory processes and infections of the uterine wall must be accepted as a physiological event in dairy cows after calving. This might result in clinical or subclinical endometritis which is assumed to impair reproductive performance in the current lactation. Several cytokines and acute phase proteins have been discussed as local and systemic mediators of these inflammatory processes. The aim of the present study was to investigate the endometrial mRNA expression of the chemokine CXC ligand 5 (CXCL5), interleukin 1ß (IL1B), IL6, IL8, tumour necrosis factor alpha (TNF), prostaglandin-endoperoxide synthase 2 (PTGS2) and haptoglobin (HP) in the postpartum period. METHODS: Endometrial samples were obtained from primiparous cows (n = 5) on days 10, 17, 24, 31, 38 and 45 postpartum (pp) using the cytobrush technique. Cytological smears were prepared from cytobrush samples to determine the proportion of polymorphonuclear neutrophils (PMN). Total RNA was extracted from endometrial samples, and real-time RT-PCR was performed. RESULTS: A time-dependent mRNA expression of the investigated factors was found for the course of the postpartum period. In detail, a significantly higher expression of these factors was observed on day 17 pp compared to day 31 pp. Furthermore, the proportion of PMN peaked between days 10-24 pp and decreased thereafter to low percentages (< 5%) on day 31 pp and thereafter. In addition, CXCL5, IL1B, IL8 and HP mRNA expression correlated significantly with the proportion of PMN (P < 0.05). A significantly higher CXCL5, IL1B, IL6, IL8, PTGS2 and TNF mRNA content was observed in samples from cows with an inflamed endometrium compared with samples from cows with a healthy endometrium (P < 0.05). CONCLUSIONS: These results show that inflammatory cytokines and acute phase proteins are expressed in the bovine endometrium in a time-related manner during the postpartum period, with a significant expression peak on day 17 pp as a possible mucosal immune response in the uterus. The evaluation of the expression patterns of such candidate genes may reveal more information than only determining the percentage of PMN to judge the severity of an inflammation.

Selected pro-inflammatory factor transcripts in bovine endometrial epithelial cells are regulated during the oestrous cycle and elevated in case of subclinical or clinical endometritis.

Endometrial cells take part in embryo-maternal communication, as well as supporting the immune system in defending against invading pathogens. The aim of the present study was to examine the mRNA expression of factors that have been suggested to be involved in both events in the bovine endometrial epithelium, namely bovine granulocyte chemotactic protein 2 (CXCL5), interleukin-1 beta (IL1B), IL6, IL8, tumour necrosis factor (TNF), cyclooxygenase 2 (PTGS2) and haptoglobin (HP). Samples were collected in vivo from cows on Days 21-27 postpartum by the cytobrush method to evaluate the correlation between inflammatory factors and uterine health (cows with signs of clinical or subclinical endometritis and healthy cows). Bovine uteri were collected at the abattoir to investigate oestrous cycle-dependent mRNA expression patterns. Real-time reverse transcription-polymerase chain reaction revealed that the expression of CXCL5, IL1B, IL8 and TNF mRNA was significantly higher in cows with subclinical or clinical endometritis compared with healthy cows. The expression of CXCL5, IL1B and IL8 mRNA was increased around ovulation compared with the luteal phase. There was no indication of either oestrous cycle-dependent expression or a correlation with uterine health for IL6, PTGS2 and HP transcripts. These results suggest that CXCL5, IL1B, IL8 and TNF may represent potential marker genes for the detection of cows with subclinical endometritis and for monitoring new therapeutic approaches.

[Definition and diagnosis of chronic endometritis in cattle: a review]. / Einteilung und Diagnose der chronischen Endometritis beim Rind: eine Literaturstudie.

Chronic endometritis can be diagnosed after three weeks post partum. Diagnostic methods such as external inspection and transrectal palpation of the uterus are not accurate enough to find each of the affected cows. An additional vaginal examination is more successful. Manual vaginal examination with the gloved hand or the use of a speculum will be sufficient. A new diagnostic device (Metricheck) seems to be suitable for the diagnosis of endometritis. For the evaluation of a given diagnostic test false-positive and false-negative diagnoses have to be considered. Ultrasonography is established in gynaecological examination in cattle and is adequate to diagnose endometritis accurately. Further diagnostic methods are cytological, histological and bacteriological examinations. Samples can be obtained by biopsy, uteruslavage, swabs or Cytobrush. Recently, precise clinical definitions of uterine diseases were adopted by several international researchers. These definitions should be used in national languages as well. Recent papers described cytological and ultrasonographical examinations for the diagnosis of subclinical endometritis.

[Evaluation of the diagnosis of subclinical endometritis in dairy cattle using ultrasound]. / Evaluierung der Diagnostik subklinischer Endometritiden mittels Ultraschall beim Rind.

The aim of this study was to determine signs of subclinical endometritis found by ultrasound that are associated with reduced fertility in dairy cows. The maximum diameter of the uterine lumen was determined by ultrasound in 324 cows without clinical signs of endometritis after evaluation of the genital tract 21 to 27 days postpartum. Cows were classified into healthy or with subclinical endometritis by three threshold values for the maximum uterine lumen diameter of 0.2 cm, 0.5 cm or 0.8 cm. Examinations by rectal palpation and ultrasound as well as classifications were repeated 14 days later. In addition, ovaries were scanned by ultrasound to determine the stage of the estrous cycle. In a subgroup of 103 cows the echotexture of the uterus and its contents was evaluated. In these cows the diagnosis of subclinical endometritis was performed by a scoring system. The diameter of the uterine lumen was significantly affected by stage of the estrous cycle at the time of examination. However, no effects were found for the stage of the cycle at the time of examination on subsequent reproductive performance. A uterine lumen with a maximum diameter of more than 0.2 cm showed a significant negative association with conception rate and proportion of cows pregnant. Classification based on higher threshold values did not reveal an association with reproductive performance. Echogenic content in the uterus also decreased reproductive performance. A classification based on the echotexture of the uterus and its contents revealed significant differences between healthy cows and cows with subclinical endometritis regarding the proportion of cows inseminated and pregnant. The results of this study showed that the diagnostic of bovine endometritis should be broadend by ultrasonography. The definition of subclinical endometritis diagnosed by means of ultrasonography has to be evaluated in further studies.

[Postpartum reproductive failure in cattle: is the examination of gene expression in the endometrium a key to success?]. / Postpartale Fruchtbarkeitsstörungen beim Rind: Untersuchung der Genexpression im Endometrium als Schlüssel zum Erfolg?

High reproductive performance is required for successful management of dairy farms. After calving, especially endometritis is one of the main reasons for reproductive failure. However, subclinical endometritis remains undetected in many cases and causes a high financial loss. To elucidate the cellular processes in the endometrium, the acquisition of the gene expression will provide helpful information. In the literature, numerous cytokines and enzymes were discussed to play important roles in preparing the endometrium for implantation. This review gives an overview about our present understanding of the functions of cyclooxygenases 1 and 2 (COX-1/COX-2), tumor necrosis factor alpha (TNFalpha), the inducible nitric oxide synthase (iNOS), haptoglobin as well as the interleukins 1 and 6 (IL-1/IL-6). Their role is not only to regulate certain physiological processes in the bovine reproductive tract, but to act also as inflammatory mediators in infectious diseases. A better understanding of cellular processes may help to improve identification and treatment of postpartum reproductive failure.

Use of Ovsynch in dairy herds--differences between primiparous and multiparous cows.

Ovsynch protocols are used to increase service rate and decrease days open and cullings for infertility. Recent reports have indicated better results after Ovsynch in primiparous than in older cows. However, this was not observed in all investigations on the subject. The objective of the study was to evaluate differences between primiparous and multiparous cows after synchronization of ovulation with an Ovsynch protocol in six trials. A total of 1584 cows (583 primiparous and 1001 multiparous cows, respectively) on three dairy farms were synchronized with an Ovsynch protocol consisting of a GnRH-analogue at Days 0 and 9, and a prostaglandin F(2alpha) analogue on Day 7. AI was carried out in all cows 16-20 h after the last treatment. Cows were categorized into primiparous and multiparous cows for analysis. Conception rate (CR) to timed AI, to further AI, overall conception rate and proportion of cows pregnant by 200 days in milk were compared between the age groups. Finally, two logistic regression models were calculated with conception to first service and conception by 200 DIM as the outcome variables. Independent variables were trial (categorical) and age group (primiparous versus multiparous). Conception rates to TAI were higher in primiparous than in older cows (37.9% versus 31.6%, P=0.015). Likewise pregnancy rates by 200 DIM were higher in primiparous cows (81.8% versus 75.4%, P=0.003). However, the extent of the difference varied between trials. Results indicate that Ovsynch protocols are more effective in primiparous than in older cows.