Effect of calving season on metritis incidence and bacterial content of the vagina in dairy cows

YiMu-QingGong san alleviates lipopolysaccharide-induced endometritis in mice via inhibiting inflammation and oxidative stress through regulating macrophage polarization

ETHNOPHARMACOLOGICAL RELEVANCE

Endometritis is a common reproductive disease in dairy cattle after calving, characterized by persistent inflammation of the endometrium. YiMu-QingGong San (YMQGS), a patented Chinese medicine formulation, has demonstrated efficacy in the treatment of clinical endometritis in dairy cattle. However, the potential mechanisms by which YMQGS alleviates endometritis remain unclear.

AIM OF THE STUDY

The objective of this study is to elucidate the underlying therapeutic mechanisms of YMQGS in the context of endometritis.

MATERIALS AND METHODS

The chemical components of YMQGS were analyzed using UHPLC/MS. The anti-inflammatory capabilities of YMQGS were assessed by inducing an inflammatory response in RAW264.7 cells with lipopolysaccharide (LPS). Moreover, a clinical model of endometritis was simulated via vaginal injection of LPS into the uterine horns to investigate the therapeutic mechanisms of YMQGS.

RESULTS

YMQGS could downregulate the expression of inflammatory mediators (TNF-α, IL-6, IL-1β) by suppressing the activation of the TLRs/MyD88/TRAF6/NF-κB signaling pathway in RAW264.7 cells. Additionally, YMQGS facilitated the polarization of RAW264.7 cells towards M2-like macrophages (Mφs) while inhibiting M1-like Mφs polarization, thereby exerting anti-inflammatory effects. Further investigation revealed that YMQGS could diminish ROS production, augment cellular antioxidant capacity, preserve mitochondrial membrane potential, and reduce intracellular [Ca2+]i accumulation, thereby minimizing cellular damage. In the mouse model of endometritis, YMQGS similarly inhibited the activation of the NF-κB signaling pathway in uterine tissues and modulated Mφ polarization in the endometrium, leading to a decrease in the expression of inflammatory factors and subsidence of the inflammatory response in the endometrium. Histological staining results showed that YMQGS reduced endometrial fibrosis, increased the expression of endometrial ZO-1, Occludin and glycoprotein, protect the endometrial barrier function, and prevent the further development of endometritis.

CONCLUSION

Collectively, the present study confirms that YMQGS possesses notable anti-inflammatory and antioxidant properties. The suppression of the NF-κB signaling pathway and the modulation of Mφ polarization emerge as the pivotal mechanisms by which YMQGS alleviates endometritis.

Clinical and subclinical endometritis in dromedary camels: An overview of definition and clinical presentation, etiopathogenesis, diagnostic biomarkers, and treatment protocols

The current review collected and analyzed research on clinical endometritis (CE) and subclinical endometritis (SCE) in dromedary camels in terms of definition and clinical presentation, etiopathogenesis, diagnostic biomarkers, and treatment protocols. CE is characterized by uterine inflammation with abnormal vaginal discharges, while SCE comprises uterine inflammation with no clinical signs and is described as the infiltration of polymorphnuclear cells into the endometrium. CE is the prevalent clinical finding of barren female dromedaries (18-60 %). SCE has been detected in 9.9 % of infertile female dromedaries. CE and SCE are observed mainly in repeat breeding females. Unhygienic reproductive management, unsanitary dealings during parturition, and postpartum problems are major risk factors. Environmental stress, immunodeficiency, mucus abrasion, or the presence of other opportunistic microbes are predisposing factors. Trueperella pyogenes, Escherichia coli, Pseudomonas aeruginosa, Streptococcus spp., and Staphylococcus spp. are the major uterine isolates obtained from females with CE, while Bacillus spp., Staphylococcus spp., and Candida albicans are the most frequent isolates of SCE. CE and SCE reveal biomarker changes that could aid in the diagnosis of this common reproductive disorder. Only a few treatment protocols for CE and SCE have been tried and proven to work in camel practice. However, there is room for the new, challenging treatment programs proposed in this review. This review also provides a compilation that may be of use to future research and to those working in the field of camel reproduction.

Cow and management factors and their association with estimates of uterine size and position at the time of insemination of dairy cattle

This study examines factors affecting uterine size and position determined at 30-36 days postpartum in dairy cattle. The final study population consisted of 328 dairy cows, all calving during the warm season. Uterus position (pelvic, pelvic-abdominal, abdominal) and uterus size (small, medium, large) was measured by ultrasound on Day 30-36 postpartum. Multiparous cows had a larger uterus positioned in the abdominal cavity (p = .03) and a male newborn was associated with a larger uterus (p = .022). The number of cows with the uterus in the abdominal cavity was higher among multiparous and high producer (p < .0001) cows. High producers were 0.41 times more likely to have a small uterus in a pelvic position. The most important finding of this study was that the delivery of a male dairy, rather than beef, calf was related to the least optimal maternal uterus size and position.

Risk factors for ultrasound-diagnosed endometritis and its impact on fertility in Scottish dairy cattle herds

BACKGROUND

The aim of this study was to investigate the risk factors for and the impact of ultrasound-diagnosed endometritis (UDE) on lactating dairy cows' reproductive performance.

METHODS

Data were analysed from 1123 Holstein and Holstein-Friesian cows from two Scottish dairy farms. A reproductive ultrasound examination was conducted on two occasions, at 43 ± 3 and 50 ± 3 days in milk (DIM), to screen for hyperechoic fluid in the uterus. Statistical analyses were performed using multivariable logistic regression modelling and Cox proportional hazards models.

RESULTS

The overall incidence of UDE was 8.8% (99/1123). Risk factors for UDE included calving during autumn/winter seasons, increased parity and the presence of two or more diseases in the first 50 ± 3 days postpartum. The presence of UDE was associated with a reduced odds of pregnancy after all artificial inseminations up to 150 DIM.

LIMITATIONS

The retrospective design of this study led to some inherent limitations with the quality and quantity of data collected.

CONCLUSIONS

The findings of this study indicate which risk factors should be monitored in postpartum dairy cows to limit the impact of UDE on future reproductive performance.

Review: Reproductive consequences of whole-body adaptations of dairy cattle to heat stress

Heat stress has far-reaching ramifications for agricultural production and the severity of its impact has increased alongside the growing threats of global warming. Climate change is exacerbating the already-severe consequences of seasonal heat stress and is predicted to cause additional losses in reproductive performance, milk production and overall productivity. Estimated and predicted losses are staggering, and without advancement in production practices during heat stress, these projected losses will threaten the human food supply. This is particularly concerning as the worldwide population and, thus, demand for animal products grows. As such, there is an urgent need for the development of technologies and management strategies capable of improving animal production capacity and efficiency during periods of heat stress. Reproduction is a major component of animal productivity, and subfertility during thermal stress is ultimately the result of both reproductive and whole-body physiological responses to heat stress. Improving reproductive performance during seasonal heat stress requires a thorough understanding of its effects on the reproductive system as well as other physiological systems involved in the whole-body response to elevated ambient temperature. To that end, this review will explore the reproductive repercussions of whole-body consequences of heat stress, including elevated body temperature, altered metabolism and circulating lipopolysaccharide. A comprehensive understanding of the physiological responses to heat stress is a prerequisite for improving fertility, and thus, the overall productivity of dairy cattle experiencing heat stress.

Inflammatory responses of bovine endometrial epithelial cells are increased under in vitro heat stress conditions

Cattle exposed to heat stress have reduced fertility, reduced milk production and increased incidence of postpartum uterine infection. Heat stress is suggested to alter immune function of cattle; however, the mechanisms underlying heat stress mediated uterine infection are unknown. We hypothesized that exposure of endometrial cells to heat stress would further increase expression of inflammatory mediators in response to bacterial components due to altered heat-shock protein expression. Bovine endometrial epithelial cells (BEND) were exposed to Escherichia coli lipopolysaccharide (LPS) or a synthetic triacylated lipopeptide (Pam3CSK4) under heat stress (41.0 °C) or thermoneutral (38.5 °C) conditions for 24 h. Exposure of BEND cells to LPS or Pam3CSK4 increased the expression of the proinflammatory mediators IL1B, IL6, and CXCL8 compared to control medium. However, exposure of BEND cells to heat stress increased LPS and Pam3CSK4 induced expression of IL1B compared to cells exposed to thermoneutral conditions, and expression of LPS induced IL6 was also increased when BEND cells were exposed to heat stress. To determine if heat shock proteins increased BEND cell expression of inflammatory mediators, HSP1A1 and HSF1 were targeted by siRNA knock down. Expression of HSP1A1 and HSF1 were reduced following siRNA knockdown; however, knockdown of HSP1A1 or HSF1 further increased heat stress mediated increased expression of inflammatory mediators. These data suggest that heat stress increased BEND cell inflammatory responses to bacterial components, while heat shock proteins HSP1A1 and HSF1 help to restrain inflammatory responses. These mechanisms may contribute to the increased incidence of uterine infection observed in cows under heat stress conditions.

Prepartum heat stress in dairy cows increases postpartum inflammatory responses in blood of lactating dairy cows

Uterine diseases and heat stress (HS) are major challenges for the dairy cow. Heat stress alters host immune resilience, making cows more susceptible to the development of uterine disease. Although HS increases the incidence of uterine disease, the mechanisms by which this occurs are unclear. We hypothesize that evaporative cooling (CL) to alleviate HS in prepartum cows has carry-over effects on postpartum innate immunity. Nulliparous pregnant Holstein heifers were assigned to receive either forced CL that resulted in cool conditions (shade with water soakers and fans; n = 14) or to remain under HS conditions (barn shade only; n = 16) for 60 d prepartum. Postpartum, all cows were housed in a freestall barn equipped with shade, water soakers, and fans. Respiratory rate and rectal temperature during the prepartum period were greater in HS heifers compared with CL heifers, indicative of HS. Although milk production was decreased in HS cows compared with CL cows, the incidence of uterine disease and content of total or pathogenic bacteria in vaginal mucus on d 7 or d 21 postpartum was not affected by treatment. Whole blood was collected on d 21 and subjected to in vitro stimulation with lipopolysaccharide. Lipopolysaccharide-induced accumulation of IL-1β, IL-10, and MIP-1α was greater in blood collected from HS cows compared with CL cows. Our results imply that prepartum HS during late pregnancy has carry-over effects on postpartum innate immunity, which may contribute to the increased incidence of uterine disease observed in cows exposed to prepartum HS.

The Impact of Heat Stress on Immune Status of Dairy Cattle and Strategies to Ameliorate the Negative Effects

Heat stress (HS) is well known to influence animal health and livestock productivity negatively. Heat stress is a multi-billion-dollar global problem. It impairs animal performance during summer when animals are exposed to high ambient temperatures, direct and indirect solar radiations, and humidity. While significant developments have been achieved over the last few decades to mitigate the negative impact of HS, such as physical modification of the environment to protect the animals from direct heat, HS remains a significant challenge for the dairy industry compromising dairy cattle health and welfare. In such a scenario, it is essential to have a thorough understanding of how the immune system of dairy cattle responds to HS and identify the variable responses among the animals. This understanding could help to identify heat-resilient dairy animals for breeding and may lead to the development of climate resilient breeds in the future to support sustainable dairy cattle production. There are sufficient data demonstrating the impact of increased temperature and humidity on endocrine responses to HS in dairy cattle, especially changes in concentration of hormones like prolactin and cortisol, which also provide an indication of the likely im-pact on the immune system. In this paper, we review the recent research on the impact of HS on immunity of calves during early life to adult lactating and dry cows. Additionally, different strategies for amelioration of negative effects of HS have been presented.