We aimed to compare the viability of circulating polymorphonuclear leukocyte (cPMN) and endometrial PMN (ePMN) and their function dynamics in postpartum dairy cows with subclinical (SCE) or clinical endometritis (CE). To do so, blood samples from 38 Holstein cows were collected at -7, 9, 21, and 36 d relative to calving, and endometrial cytology samples from 32 Holstein cows were harvested at 9, 21, and 36 d postpartum. Uterine health status was assessed at 36 d postpartum, and cows were classified as healthy (absence of abnormal vaginal discharge and ≤5% ePMN), SCE (absence of abnormal vaginal discharge and >5% ePMN), or CE (mucopurulent or purulent vaginal discharge and >5% ePMN). Viability (viable, apoptotic, and necrotic) and function parameters phagocytosis (PC), oxidative burst, and intracellular proteolytic degradation were evaluated for cPMN via flow cytometry. For ePMN, only viability and PC were evaluated. The association of cPMN and ePMN viability and functional parameters with reproductive tract health classification were fitted in mixed linear regression models, accounting for repeated measures, sampling day, and interactions of reproductive tract status and day. Cows with CE had a lower proportion of cPMN viability (84.5 ± 2.1%; least squares means ± standard error) and a higher proportion of apoptosis (14.4 ± 2.0%) than healthy (92.4 ± 1.3 and 6.7 ± 1.3%, respectively) or SCE (95.3 ± 2.4 and 3.8 ± 2.3%, respectively) at 9 d postpartum. Interestingly, cPMN intracellular proteolytic degradation was lower [6.2 ± 0.1 median fluorescence intensity (MFI)] in SCE compared with healthy (6.7 ± 0.08 MFI) or CE (6.8 ± 0.1 MFI) at d 9 postpartum. No other differences in cPMN function were found among experimental groups. The proportion of necrotic ePMN was higher for healthy (49.6 ± 5.1%) than SCE (27.4 ± 7.3%) and CE (27.7 ± 7.3%) cows at 36 d postpartum. Also, at 36 d postpartum, the proportion of ePMN performing PC was higher in CE (47.0 ± 8.6%) than in healthy (18.4 ± 7.6%) cows, but did not differ from SCE cows (25.9 ± 8.7%). Results of the present study suggest that cPMN viability and function at 9 d postpartum are associated with the development of uterine disease. Furthermore, ePMN at 36 d postpartum are mostly necrotic in healthy cows but viable and functional in cows with CE, probably due to active uterine inflammation. Remarkably, ePMN in cows with SCE at 36 d postpartum are also mostly viable but seem to display a numerically lower proportion of PC compared with ePMN in CE cows.

Postpartum dairy cows experience impaired peripheral polymorphonuclear leukocyte (PMN) functionality, which has been associated with reproductive tract inflammatory diseases. However, it has not been elucidated yet whether endometrial PMN functionality is (equally) impaired. We developed a method for endometrial PMN isolation and flow cytometric assessment of their viability and functionality. We also evaluated PMN immunolabeling, using a specific bovine granulocyte marker, CH138A. Blood and endometrial cytobrush samples were collected in duplicate from seventeen clinically healthy Holstein-Friesian cows between 9 and 37 days in milk. The proportion of viable, apoptotic, and necrotic PMN in endometrial samples roughly ranged from 10 to 80%, indicating highly dynamic endometrial PMN populations in the postpartum uteri. Endometrial PMN functionality testing revealed that PMN immunolabeling increased the accuracy, although this protocol might influence the median fluorescence intensity of the sample. Phagocytosis seemed the most stable and reliable endometrial PMN function and could be assessed satisfactorily without prior CH138A immunolabeling. However, the interpretation of oxidative burst and intracellular proteolysis tests remains challenging. The correlation between peripheral and endometrial PMN functionality was poor. Further research is warranted to unravel the role of uterine PMN viability and functionality in bovine uterine health.

Gastrointestinal nematodes (GIN) continue to impose substantial health and productivity losses in grazing ruminants, and the accelerating emergence of anthelmintic resistance (AR) underscores the need for SWC strategies. Although multiple SWC approaches have been validated experimentally, their implementation across European livestock systems remains inconsistent, and limited evidence exists regarding the stakeholders’ perceptions that affect decision-making. This study conducted a multilingual cross-sectional survey of 1261 respondents, including farmers, veterinarians, advisors, and other professionals, across 13 European countries to evaluate perceived worm-control cost burdens and the economic feasibility of seven SWC strategies. Descriptive and regression analyses revealed that a majority of respondents (56.7%) considered diagnostic testing to be financially reasonable, although perceptions varied significantly between countries. Sustainable anthelmintic use, quarantine and strategic screening, and grazing management were perceived as the most viable strategies, whereas biological control and bioactive compound-based approaches elicited greater uncertainty. An aggregated SWC Attitude Score demonstrated systematically higher acceptance among veterinarians compared to farmers, while male and older respondents exhibited lower levels of agreement across practices. The overall findings suggest that economic considerations may not be perceived as the primary barrier to sustainable worm control adoption, but other practical factors may potentially limit implementation.

The fetal development of the intestinal immune system is stimulated by the maternal microbiota, but it is still unclear whether viable bacteria exist in the healthy fetus. Analysis of such low microbial biomass environments are challenging due to contamination issues. The aims of the current study were to assess the bacterial load and characterize the bacterial composition of the amniotic fluid and meconium of full-term calves, leading to a better knowledge of prenatal bacterial seeding of the fetal intestine. Amniotic fluid and rectal meconium samples were collected during and immediately after elective caesarean section, performed in 25 Belgian Blue cow-calf couples. The samples were analyzed by qPCR, bacterial culture using GAM agar and 16S rRNA gene amplicon sequencing. To minimize the effects of contaminants, we included multiple technical controls and stringently filtered the 16S rRNA gene sequencing data to exclude putative contaminant sequences. The meconium samples contained a significantly higher amount of bacterial DNA than the negative controls and 5 of 24 samples contained culturable bacteria. In the amniotic fluid, the amount of bacterial DNA was not significantly different from the negative controls and all samples were culture negative. Bacterial sequences were identified in both sample types and were primarily of phyla Proteobacteria, Firmicutes, Bacteroidetes and Actinobacteria, with some individual variation. We conclude that most calves encounter in utero maternal-fetal transmission of bacterial DNA, but the amount of bacterial DNA is low and viable bacteria are rare.

Gastrointestinal nematodes (GINs) continue to impose substantial health and productivity losses in grazing ruminants, and the accelerating emergence of anthelmintic resistance (AR) underscores the need for SWC strategies. Although multiple SWC approaches have been validated experimentally, their implementation across European livestock systems remains inconsistent, and limited evidence exists regarding the stakeholder’s perceptions that affect decision-making. This study conducted a multilingual cross-sectional survey of 1,261 respondents, including farmers, veterinarians, advisors, and other professionals, across 13 European countries to evaluate perceived worm-control cost burdens and the economic feasibility of seven SWC strategies. Descriptive and regression analyses revealed that a majority of respondents (56.7%) considered diagnostic testing to be financially reasonable, although perceptions varied significantly between countries. Sustainable anthelmintic use, quarantine and strategic screening, and grazing management were perceived as the most viable strategies, whereas biological control and bioactive compound-based approaches elicited greater uncertainty. An aggregated SWC A itude Score demonstrated systematically higher acceptance among veterinarians compared to farmers, while male and older respondents exhibited lower levels of agreement across practices. Overall, the findings indicate that economic constraints may not constitute the primary barrier to SWC adoption.