Short communication: Assessment of biomarkers of inflammation in the vaginal discharge of postpartum dairy cows diagnosed with clinical metritis.

Clinical metritis, characterized by the presence of an enlarged uterus and abnormal red-brownish foul-smelling vaginal discharge (VD), is a prevalent condition that causes important economic losses to dairy operations. The accurate diagnosis and treatment of this disease can help decrease its negative effects on the well-being and performance of dairy cows. The objectives of this study were to assess (1) the concentration of haptoglobin (Hp) and neutrophil-derived haptoglobin-matrix metalloproteinase 9 (Hp-MMP 9) in the VD of postpartum cows; and (2) the correlation between Hp and Hp-MMP 9 concentrations in serum and VD. Fifty-three dairy cows from 4 farms in central Pennsylvania were enrolled in this observational study.. Postpartum cows (7 ± 3 DIM) were screened using a Metricheck device to assess VD score (VDS): 1, clear fluid (n = 4); 2, < 50% white purulent fluid (n = 14); 3, > 50% white purulent fluid (n = 8); 4, red-brownish watery fluid without fetid smell (n = 22); and 5, fetid red-brownish watery fluid (n = 5). Blood and VD samples were collected for assessment of Hp and Hp-MMP 9 concentrations. Cows with a VDS of 4 or 5 (VDS4/5) had higher serum Hp concentrations than cows with a VDS of 1, 2, or 3 (VDS1/3; 93 ± 187 µg/mL vs. 59 ± 106 µg/mL, respectively). Similarly, cows with VDS4/5 had higher VD Hp concentrations than cows with VDS1/3 (73 ± 56 µg/mL vs. 17 ± 16 µg/mL, respectively). We found a significant correlation (0.37) between Hp levels in serum and in VD. We found no difference in serum Hp-MMP 9 between VDS4/5 and VDS1/3 cows. The VD concentrations of Hp-MMP 9 were higher in VDS4/5 cows than in VDS1/3 cows (7,629 ± 9,847 ng/mL vs. 1,567 ± 2,165 ng/mL, respectively). The correlation between Hp-MMP 9 in serum and VD was 0.22; nevertheless, it was not statistically significant. Interestingly, Hp and Hp-MMP 9 concentrations were higher in VD samples than in serum, regardless of VDS. Results from this study suggest that inflammatory biomarkers may be increased in cows with a VDS of 4 or 5. Further research should be aimed at elucidating the processes involved in inflammatory biomarker production and transportation in the uterus, as well as the effect of these biomarkers on endometrial cells.

Assessment of visceral pain associated with metritis in dairy cows.

Metritis is a common disease in dairy cattle, but to our knowledge, no work has assessed pain associated with this disease. Tissue palpation is commonly used to assess pain in human and veterinary medicine. The objective of this study was to evaluate visceral pain responses during rectal palpation, with and without uterine palpation, in healthy cows and in cows diagnosed with metritis. A total of 49 Holstein dairy cows (mean ± standard deviation parity of 2.8±1.8) were subjected to systematic health checks every 3 d after parturition for 21 d, scoring for vaginal discharge (0 to 4); 13 cows showed a discharge score ≥2 during at least 1 health check and were classified as metritic, whereas 29 cows were classified as healthy and showed no sign of this or any other disease (including mastitis and lameness). Back arch and heart rate variability before examination and during palpation were recorded using video and heart rate monitors. Back arch (cm(2)) on the day of diagnosis was greater in metritic versus healthy cows (1,034±72 vs. 612±48cm(2)), and greater during rectal palpation with uterine palpation versus rectal palpation without uterine palpation (869±45 vs. 777±45cm(2)). Heart rate frequency domain analysis showed that the low-frequency portion was higher in cows with metritis versus healthy cows (16.5±1.2 vs. 12.9±1.0). Time domain analysis showed that the standard deviation between normal to normal interbeat intervals and the root mean square of successive differences both decreased during rectal palpation with uterine palpation versus rectal palpation without uterine palpation (1.9±0.1 vs. 2.5±0.1 and 1.3±0.1 vs. 1.7±0.1, respectively). Together, these results indicate that the inflammation associated with metritis is painful, and that the pain response can be detected during rectal palpation with and without uterine palpation. Rectal palpation with uterine palpation appears to be more aversive than rectal palpation without uterine palpation, suggesting that the former should be avoided when possible.

Technical note: Intraobserver, interobserver, and test-retest reliabilities of an assessment of vaginal discharge from cows with and without acute puerperal metritis.

Acute puerperal metritis (APM) in dairy cows is a common disease occurring in the first 10 d after calving. According to a widely accepted definition, the diagnosis is primarily based on body temperature and sensorial assessment of vaginal discharge. The scope of this study was to evaluate the reliability for color, smell, and viscosity of vaginal discharge from healthy cows and cows with APM. Fifteen investigators evaluated 6 vaginal discharge samples 10 times. Subsequently, the investigators rated the health status of the cows and the diagnostic value of color, smell, and viscosity. In a final questionnaire, the investigators estimated their ability to diagnose APM correctly and the influence of experience. Reliability was tested using Cohen's kappa (κ). Our study revealed slight to moderate reliabilities concerning the assessment of vaginal discharge. Overall interobserver reliability for color, smell, and viscosity was κ=0.15, 0.27, and 0.44, respectively. Overall intraobserver reliability for color, smell, and viscosity was κ=0.35, 0.39, and 0.6, respectively. By means of a questionnaire, overall personal expertise to detect cows suffering from APM correctly as such was estimated to be 59%, whereas the diagnostic value of a combination of color, smell, and viscosity to detect cows with APM correctly was estimated to be 91.1% perfect. We found a discrepancy between reliability and the personal perception of diagnostic value. Our study shows that the sensorial assessment of color, smell, and viscosity of vaginal discharge in cows postpartum is subjective.