Relationship between bovine endometrial thickness and plasma progesterone and estradiol concentrations in natural and induced estrus.

The objective of this study was to investigate cyclical changes in endometrial thickness in relation to progesterone (P4) and estradiol-17ß (E2) concentrations during natural and induced estrus in 15 cows. In the prostaglandin (PG) F2α-induced estrus group, ultrasonography (USG) at 6-h intervals was used to determine endometrial thickness 48-24 h before the PGF2α treatment until 24 h after ovulation (ovulation = Day 0). In the natural estrus group, USG was performed every 48 h from Day 3 to Days 15-18 after the first ovulation, and then every 6 h until 24 h after ovulation. Endometrial thickness was standardized using Day 13 as a reference day. Blood was collected during every USG examination and plasma P4 and E2 concentrations were determined. Endometrial thickness of the induced estrus group (n = 11) was greater than that of the natural estrus group (n = 9) between 60 and 12 h before ovulation (P < 0.05). In the natural estrus group, prior to an increase in endometrial thickness, a decrease in P4 and an increase in E2 were detected. In the induced estrus group, based on the time of ovulation, an increase in endometrial thickness was detected at the same time of a decrease in P4 before an increase in E2. These results suggest that decreases in P4 concentrations may be a cue to changes in endometrial thickness, while increases in E2 concentrations appear to sustain and/or enhance these changes.

A transvaginal endoscopy-based technique for performing ovarian examinations in sows.

For examining pig ovaries, which have complex structures, laparoscopy is a useful technique, but requires general anesthesia; therefore, it cannot be performed repeatedly within a short period of time. We report a transvaginal endoscopy-based technique for conducting ovarian examinations without general anesthesia. Sows were sedated in pig stalls. Using a colonoscope, the vaginal wall was punctured with a trocar. To avoid the trocar being caught in the broad ligament of the uterus or the connective tissue around the vagina, the trocar was inserted close to the external uterine os and between the 2:00 and 3:00 or the 9:00 and 10:00 positions (in a clockwise direction). Then, a urethroscope was inserted into the abdomen, and an examination was carried out after the ovaries had been moved towards the urethroscope camera via rectal palpation. This less invasive procedure may allow repeated examinations and will increase our understanding of ovarian dynamics in pigs.

Changes in mammary infection status in dairy cows during the dry period using dry cow therapy approaches on three farms.

This case study evaluated the mammary infection status of dairy cows during the dry periods and explored the associated problems in their quarters with dry cow therapy (DCT). This study assessed intramammary infections, antibiotic efficacy, and antimicrobial resistance of pathogens in 464-quarter milk samples from 59 dairy cows during the dry periods after applying blanket DCT, non-DCT, and selective DCT approaches on three farms. The recovery rates of intramammary infections were 95% (19/20 quarters) with blanket DCT on farm A, 70% (14/20) with non-DCT on farm B, and 19% (4/21) with selective DCT on farm C. Analysis of mammary infections in cows with DCT revealed that mammary infections were controlled by blanket DCT, well controlled by non-DCT, and substantial problems remained in selective DCT. Lower intramammary infection prevalence in the quarters at postpartum appeared to be associated with higher recovery of mammary infections, fewer new infections, and lower uncured mammary infections within the herds. Antibacterial resistance in 14 coagulase-negative staphylococci isolated to six antimicrobial drugs was suggested to be linked to antibiotic use on the farm. Follow-up studies on the quarter-based infection status with DCT will assist in improving mastitis control in cows during the dry period.

Innate immune response of bovine mammary epithelial cells in Mycoplasma bovis mastitis using an in vitro model of bovine mammary gland infection.

Mycoplasma bovis mastitisis highly contagious and disrupts lactation, posing a significant threat to the dairy industry. While the mammary gland's defence mechanism involves epithelial cells and mononuclear cells (MNC), their interaction with M. bovis remains incompletely understood. In this study, we assessed the immunological reactivity of bovine mammary epithelial cells (bMEC) to M. bovis through co-culture with MNC. Upon co-culture with MNC, the mRNA expression levels of interleukin (IL)-1ß, IL-6, IL-8 and tumor necrosis factor (TNF)-α in bMEC stimulated by M. bovis showed a significant increase compared to monoculture. Additionally, when stimulated with M. bovis, the culture supernatant exhibited significantly higher concentrations of IL-6 and interferon (IFN)-γ, while IL-1ß concentration tended to be higher in co-culture with MNC than in monoculture. Furthermore, the mRNA expression levels of toll-like receptor (TLR) 2 in bMEC stimulated with M. bovis tended to increase, and TLR4 significantly increased when co-cultured with MNC compared to monocultures. However, the surface expression levels in bMEC did not exhibit significant changes between co-culture and monoculture. Overall, our research indicates that the inflammatory response of bMEC is increased during co-culture with MNC, suggesting that the interaction between bMEC and MNC in the mammary gland amplifies the immune response to M. bovis in cows affected by M. bovis mastitis.

Preoperative protocol for right flank laparotomy affects postoperative serum cortisol concentrations in dairy cows.

OBJECTIVE: To evaluate analgesic efficacy of 3 different preoperative protocols in cows undergoing right flank laparotomy for displaced abomasum. ANIMALS: 40 cows diagnosed with displaced abomasum. PROCEDURES: The cows were assigned by block randomization to 1 of 3 preoperative protocols: inverted L-block using 50 mL of 2% lidocaine (ILB; n = 13), ILB plus preoperative flunixin meglumine (2 mg/kg, IV; ILB-F; 13), and dorsolumbar epidural anesthesia using 2% xylazine (0.8 mL) and 2% lidocaine (4 mL; EPI; 14). Venous blood samples were collected for CBC, serum biochemistry, and cortisol preoperatively and at 0 (immediately after), 3, 17, and 48 hours postoperatively. RESULTS: The mean (95% CI) of the serum cortisol in ILB, ILB-F, and EPI were 108.7 (66.7 to 150.7), 150.7 (116.4 to 185.0), and 139.8 (93.4 to 186.3), respectively. The serum cortisol concentrations decreased over time in all groups (ILB, P = .001; ILB-F and EPI, P < .001). In the ILB group, the cortisol concentration at 17 and 48 hours postoperatively decreased (P = .026 and P = .009, respectively), compared with that preoperatively. In the ILB-F and EPI groups, the preoperative cortisol concentration was the highest and then decreased at 0, 3, 17, and 48 hours postoperatively (ILB-F, 0 hours [P = .001] and 3, 17, and 48 hours [P < .001]; EPI, all [P < .001]). CLINICAL RELEVANCE: ILB-F and EPI improved intraoperative and immediate postoperative indicators of pain-related stress when compared to standard ILB. EPI requires less anesthetic, which may be beneficial when in short supply.

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.

Characterization of Reproductive Microbiota of Primiparous Cows During Early Postpartum Periods in the Presence and Absence of Endometritis.

Endometritis has a major impact on fertility in postpartum dairy cows. Since previous studies showed an association between reproductive microbiota and perinatal disease, we monitored both bovine uterine and vaginal microbiota in primiparous cows to elucidate the effect of early postpartum microbiota on endometritis. Uterine and vaginal samples were collected at time points from pre-calving to 35 days postpartum (DPP), and analyzed by 16S rRNA sequencing, combined with ancillary bacterial culture. A total of seven healthy cows and seven cows diagnosed with endometritis on 35 DPP were used in the current study. The uterine and vaginal microbiota showed a maximum of 20.1% shared amplicon sequence variants (ASVs) at linked time points. 16S rRNA based analysis and traditional culture methods revealed that Trueperella showed a higher abundance in both uterus and vagina of the endometritis group compared to the healthy group on 21 DPP (U-test p < 0.05). Differential abundance analysis of the uterine microbiota showed that Enterococcus and six bacterial genera including Bifidobacterium were unique to the healthy group on the day of calving (0 DPP) and 28 DPP, respectively. In contrast, Histophilus and Mogibacteriaceae were characteristic bacteria in the vagina pre-calving in cows that later developed endometritis, suggesting that these bacteria could be valuable to predict clinical outcomes. Comparing the abundances of bacterial genera in the uterine microbiota, a negative correlation was observed between Trueperella and several bacteria including Lactobacillus. These results suggest that building an environment where there is an increase in bacteria that are generally recognized as beneficial, such as Lactobacillus, may be one possible solution to reduce the abundance of Trueperella and control endometritis.

Association of postpartum diseases occurring within 60 days after calving with productivity and reproductive performance in dairy cows in Fukuoka: A cow-level, retrospective cohort study.

Peripartum disorders in dairy cows negatively influence their productivity and reproductive performance. However, only a few reports have clearly indicated the influence of such disorders on the productivity and reproductive performance at a local-area or cow-level in Japan. This study aimed to elucidate the influence of diseases occurring within 60 days after calving on subsequent productivity and reproductive performance. Accordingly, a wide-area database on dairy production was used for epidemiological analysis; subsequently, multivariable analysis was performed to investigate the association of such diseases with productivity or reproductive performance in 6,545 cows from 178 farms in Fukuoka. We used 305-day energy-corrected milk (305 ECM) as an index of productivity and conception and culling as indices of reproductive performance. With regard to causality, mixed-effects model was used for analyzing the association between disease and productivity, and Cox proportional hazard model was used for analyzing the association between disease and reproductive performance. Compared to the disease absence group, the disease presence group demonstrated significantly lower 305 ECM [-154 kg; 95% confidence interval (CI), -229 to -79] and risk of pregnancy [hazard ratio (HR), 0.85; 95% CI, 0.80-0.91] and higher risk of culling (HR, 1.36; 95% CI, 1.17-1.59). These results indicate that, in Fukuoka, dairy cows affected by diseases within 60 days after calving exhibit lower productivity and reproductive performance. Therefore, proper dairy cow management during the peripartum period to prevent diseases during early lactation may maintain or improve productivity.