Cow-level risk factors for reproductive tract disease diagnosed by 2 methods in pasture-grazed dairy cattle in Ireland

The cow-side diagnosis of reproductive tract disease (RTD) involves identifying the presence of purulent vaginal discharge (PVD) and ultrasonographic endometritis (UE). The objectives of our study were to obtain prevalence estimates for RTD diagnosed by 2 methods (PVD and UE scoring) and to investigate the risk factors for increased probability of RTD if these methods are used in isolation or in combination. Our retrospective observational cohort study tested the hypothesis that RTD assessed by 2 methods would have similar risk factors, and that those would be mainly cow- and calving-related factors. We analyzed data from 5,049 pre-breeding examinations (PBE) from 2,460 spring-calved cows on 8 farms between 2014 and 2018. Cow-related details assessed were days in milk at PBE, breed, lactation number, dry period length, body condition score at calving and PBE, 305-d milk yield, predicted transmitting ability for production and fertility, the presence of a corpus luteum at PBE, and positive diagnosis the previous year. Calving details assessed were type of sire, calf sex, twinning, stillbirth, calving difficulty score, and retained fetal membranes. We conducted statistical analyses using 4 multivariable logistic regression models to identify the risk of RTD diagnosed by (1) PVD in isolation, (2) UE in isolation, (3) the presence of either PVD or UE; and (4) the presence of both PVD and UE. We accounted for herd, cow, and year as random effects in all 4 models. The overall prevalence of RTD in models 1, 2, 3, and 4 were 7.5, 6.7, 11.6, and 2.6%, respectively. Days in milk at PBE, the interaction between days in milk and retained fetal membranes, twinning, and the predicted transmitting ability for calving interval were consistently significant risk factors for positive scores in all 4 models. Considerable calving difficulty [adjusted odds ratio (AOR) = 13.64], Holstein Friesian dam breed (AOR = 2.58), first lactation (AOR = 2.39), and body condition score at PBE (AOR = 1.64) were risk factors for a positive PVD score but not for a positive UE score. Fifth lactation (AOR = 1.69), a beef-sired calf (AOR = 1.46), and the absence of a corpus luteum at PBE (AOR = 1.57) were risk factors for a positive UE score but not for a positive PVD score. These results support the hypothesis that most of the risk factors for PVD and UE are the same but some are distinctly different, implying that in some instances the 2 methods diagnose separate components of the RTD complex.

Efficiency of uterine fluid cytology in the diagnosis of subclinical endometritis in the water buffalo (Bubalus bubalis)

This study compared endometrial cytology vis-a-vis uterine fluid cytology for assessment of uterine health in clinically normal and subclinical endometritis (SE)-affected buffaloes. Uterine fluid samples and endometrial samples were collected from the buffaloes (n = 38) at oestrus using blue sheath and cytobrush, respectively. The smears were stained with Field stain for 3 minutes, and a minimum of 400 cells were counted in each smear for determination of the percentage of polymorphonuclear (PMN) leucocyte. The incidence of subclinical endometritis, based on the cytobrush cytology, was 23.08%. The correlation between cytobrush cytology with uterine fluid cytology was positive and significant (r = .37; p = .02). The ratio of PMN leucocyte in cytobrush cytology to uterine fluid cytology was 1:2.4. ROC analysis revealed that the threshold value of 6.16% PMN leucocyte in uterine fluid cytology showed a diagnostic sensitivity and specificity of 100% in differentiating normal from SE-affected buffaloes. In conclusion, collection of uterine fluid was easier compared to collection of endometrial samples using cytobrush and the percentage of PMN leucocyte in uterine fluid cytology can be used as a tool for diagnosis of subclinical endometritis in buffaloes.

Clinical endometritis in an Argentinean herd of dairy cows: risk factors and reproductive efficiency

The objectives of this study were to assess the clinical and metabolic risk factors for clinical endometritis, the likelihood for having a normal vaginal discharge during postpartum, and the effects of endometritis on milk yield, reproductive efficiency, and metabolic status in Holstein cows. The study was conducted in a commercial dairy herd (Cordoba, Argentina) where 303 Holstein cows were enrolled. Cows were body condition scored (1 to 5) and tail bled on -14, 7, 21, 31, 41, and 50 d relative to parturition. Cows having a vaginal discharge with presence of pus between 21 and 41 d postpartum (dpp) were diagnosed as having clinical endometritis. Plasma blood samples were analyzed for nonesterified fatty acids (NEFA), β-hydroxybutyrate (BHBA), and blood urea nitrogen using commercial kits and insulin-like growth factor 1, insulin, and leptin by RIA. Data were analyzed with PROC MIXED, PROC GENMOD, and PROC PHREG of SAS (SAS Institute Inc., Cary, NC). Abnormal calving and puerperal metritis increased the risk for endometritis [adjusted odds ratio (AOR)=2.21 for both]. High prepartum NEFA and high postpartum BHBA increased the risk for endometritis (AOR=1.003 and 1.001, respectively), whereas high prepartum blood urea nitrogen reduced it (AOR=0.853). Cut-offs of 456.6 μM NEFA and 402.5 μM BHBA had sensitivities of 0.69 and 0.58, and specificities of 0.88 and 0.86, respectively. The likelihood for having normal vaginal discharge increased with time (∼1% × dpp) and with normal calving. Cows with endometritis had higher milk yield than normal herdmates (27.8±0.9 vs. 25.7±0.4 kg/d), lower risk for pregnancy by 100 dpp (AOR=0.10), higher nonpregnancy risk by 200 dpp (AOR=2.87), and higher risk for culling than normal cows (AOR=2.28). Cows with endometritis had a lower hazard rate (0.44) for pregnancy and had approximately 70 d longer calving-to-conception intervals. Finally, endometritis had no effect on metabolic hormones. In conclusion, the risk for clinical endometritis increases with abnormal calving and puerperal metritis, as prepartum NEFA and postpartum BHBA concentrations increase. Prepartum NEFA and postpartum BHBA could be useful for the prediction of endometritis. Last, clinical endometritis has detrimental effects on reproductive efficiency, as affected cows take longer to get pregnant and are at higher risk for culling.

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.