Induced endometritis in early lactation compromises production and reproduction in dairy cows

The economic impact of purulent vaginal discharge in dairy herds within a single lactation

The goal of this study was to calculate the cost of purulent vaginal discharge (PVD) in dairy cows. The data set included 11,051 cows from 16 dairy herds located in 4 regions of the US. Purulent vaginal discharge was characterized as a mucopurulent, purulent, or reddish-brownish vaginal discharge collected at 28 ± 7 d in milk. Gross profit was calculated as the difference between incomes and expenses, and the cost of PVD was calculated by subtracting the gross profit of cows with PVD from the gross profit of cows without PVD. Continuous outcomes such as milk production (kg/cow), milk sales ($/cow), cow sales ($/cow), feed costs ($/cow), reproductive management cost ($/cow), replacement costs ($/cow), and gross profit ($/cow) were analyzed using linear mixed-effects models. Pregnancy and culling by 305 DIM were analyzed by generalized linear mixed-effects models using logistic regression. Models included the fixed effects of PVD, metritis, parity, region, season of calving, and morbidity in the first 60 DIM, as well as the interactions between PVD and metritis, PVD and parity group, and PVD and morbidity. Farm and the interaction between PVD and farm were considered random effects in all the statistical models. A stochastic analysis was conducted using 10,000 iterations with varying relevant inputs. Cows with PVD produced less milk (9,753.2 ± 333.6 vs. 9,994.6 ± 330.9 kg/cow), were less likely to be pregnant (70.7 ± 1.7 vs. 78.9 ± 1.2%), and were more likely to be culled by 305 DIM (34.6 ± 1.7 vs. 27.2 ± 1.3%) compared with cows without PVD. Consequently, milk sales (4,744.7 ± 162.3 vs. 4,862.1 ± 161.0 $/cow) and residual cow value (1,079.6 ± 23.0 vs. 1,179.3 ± 20.3 $/cow) were lesser for cows with PVD. Replacement (639.4 ± 26.4 vs. 526.0 ± 23.4 $/cow) and reproductive management costs (76.3 ± 2.5 vs. 69.0 ± 2.4 $/cow) were greater for cows with PVD. The mean cost of PVD was $202. The stochastic analysis also showed a mean cost of $202, ranging from $152 to $265. The robust data set and the stochastic analysis strengthen both the external and internal validity of our findings, offering a deeper understanding of the economic consequences of PVD. In conclusion, PVD resulted in large economic losses to dairy herds by being associated with decreased milk yield, impaired reproduction, and greater culling.

A20 Alleviates the Inflammatory Response in Bovine Endometrial Epithelial Cells by Promoting Autophagy

Endometritis represents a prevalent condition in perinatal dairy cows. Bovine endometrial epithelial cells (BEECs), as the primary interface between cavity and the external environment, are particularly vulnerable to infection by pathogenic bacteria following parturition. A20 is essential for regulating inflammation and modulating immune responses. Nevertheless, the exact role of A20 in the BEECs in response to inflammatory response is not fully understood. An endometritis model infected by Escherichia coli (E. coli) in vivo and a BEECs inflammation model induced with lipopolysaccharide (LPS) in vitro were built to investigate the function and governing mechanisms of A20 in endometritis. The results showed that infection with E. coli resulted in endometrial damage, inflammatory cell infiltration, and upregulation of inflammatory factors in dairy cows. Furthermore, A20 expression was upregulated in the endometrium of cows with endometritis and in BEECs following LPS stimulation. A20 overexpression attenuated the level of proinflammatory cytokines in LPS-stimulated BEECs; conversely, A20 knockdown lead to an exacerbated response to LPS stimulation. The overexpression of A20 was shown to activate autophagy and suppress the NF-κB signaling pathway in LPS-stimulated BEECs. However, blocking autophagy with chloroquine notably attenuated the anti-inflammatory effect of A20, leading to the activation of the NF-κB signaling pathway. In summary, the study demonstrated that A20's suppression of inflammation in LPS-stimulated BEECs is associated with the activation of autophagy. Therefore, the A20 protein showed potential as a novel treatment focus for managing endometritis in dairy cows.

Analysis of blood biochemistry and non-targeted metabolomics of endometritis in dairy cows

The incidence of bovine endometritis, which has a negative impact on the reproduction of dairy cows, has been recently increasing. In this study, the differential markers and metabolites of healthy cows and cows with endometritis were analyzed by measuring blood biochemical indicators and immune factors using biochemical and enzyme-linked immunosorbent assay kits combined with nontargeted metabolomics. The LC-QTOF platform was used to evaluate the serum metabolomics of healthy cows and cows with endometritis after 21-27 days of calving. The results showed that glucose, free fatty acid, calcium, sodium, albumin, and alanine aminotransferase levels were significantly lower in the serum of cows with endometritis than in healthy cows (P < 0.05). However, the serum potassium, interleukin-1, interleukin-6, and tumor necrosis factor levels were significantly higher in cows with endometritis (P < 0.05). In addition, the serum metabolome data analysis of the two groups showed that the expression of 468 metabolites was significantly different (P < 0.05), of which 291 were upregulated and 177 were downregulated. These metabolites were involved in 78 metabolic pathways, including amino acid, nucleotide, carbohydrate, lipid, and vitamin metabolism pathways; signal transduction pathways, and other biological pathways. Taken together, negative energy balance and immune activation, which are related to local abnormalities in amino acid, lipid, and carbohydrate metabolism, were the important causes of endometritis in dairy cows. Metabolites such as glucose, carnosine, dehydroascorbic acid, L-malic acid, tetrahydrofolic acid, and UDP-glucose may be used as key indicators in the hematological diagnosis and treatment of endometritis in dairy cows.

Microbial responses and changes in metabolic products in bovine uteri infected with Staphylococcus aureus

There is mounting evidence that the uterine microbiota has an important role in the pathogenesis of endometritis, with invasion of pathogenic bacteria being a main cause of uterine microbial imbalance. However, mechanisms of uterine microbiota resistance to pathogen invasion remain unclear. In this study, an intrauterine infusion of Staphylococcus aureus was used as a bovine endometritis model; it significantly increased abundance of pathogenic bacteria (Streptococcus, Helccoccus, Fusobacterium, and Escherichia-Shigella) and significantly decreased abundance of probiotics (Allstipes, Bacteroides, Phascolarctobacterium, Romboutsia, and Prevotella). In addition, the metabolite aloe-emodin was positively correlated with Prevotella and based on combined analyses of omics and probiotics, the presence of its metabolite aloe-emodin in the uterus at least partially resisted Staphylococcus aureus invasion. Therefore, Aloe-emodin has potential for regulating microbial structure and preventing endometritis.

Enhanced expression of miR-204 attenuates LPS stimulated inflammatory injury through inhibiting the Wnt/β-catenin pathway via targeting CCND2

One of the most common bacterial diseases of the reproductive system in dairy cows is endometritis, which will cause huge economic loss. Here, we investigate the mechanisms of miR-204 on LPS-stimulated endometritis in vitro and in vivo. Experiments displayed that the expression of miR-204 was lower in bovine uterine tissue samples or bovine endometrial epithelial cell line (BEND) that stimulated by LPS. Compared with the negative group, miR-204 treatment significantly suppressed the production of proinflammatory factors and the Wnt/β-catenin pathway activation. Additionally, the result of the dual luciferase assay showed that miR-204 targeted cyclin D2. More importantly, up-regulation of miR-204 alleviated LPS induced uterine injury was confirmed in vivo studies. Molecular experiments indicated that the expression level of tight junctional proteins Claudin3 and cadherin1 were both enchanced by miR-204 treatment. Accordingly, miR-204 may serve as a new measure to prevent and treat endometritis caused by LPS.