Immune responses during the peripartum period in dairy cows with postpartum endometritis

Uterine Disease in Dairy Cows: A Comprehensive Review Highlighting New Research Areas

Uterine disease is an intensely studied part of dairy cattle health management as it heavily affects many commercial dairy farms and has serious economic consequences. Forms of the disease, pathophysiology, pathogens involved and the effects of uterine disease on the health and performance of cows have already been well described by various authors. Lately, researchers' attention has shifted towards the healthy microbiome of the uterus and the vagina to put emphasis on prevention rather than treatment. This aligns with the growing demand to reduce the use of antibiotics or-whenever possible-replace them with alternative treatment options in farm animal medicine. This review provides a comprehensive summary of the last 20 years of uterine disease research and highlights promising new areas for future studies.

Effect of Plant Bioactive Compounds Supplemented in Transition Dairy Cows on the Metabolic and Inflammatory Status

(1) Background: This study evaluated the effects of a plant bioactive (Phyto Ax’Cell, Phytosynthese, Mozac, France) on the inflammatory status and health of dairy cows during calving. (2) Methods: 46 Holstein crossbred cows were randomized into a control group (CON, n = 23) and the Phyto Ax’Cell group (PAC, n = 23). PAC received Phyto Ax’Cell at 25 g/cow/day, from 15 days prepartum to 7 days postpartum. Blood analyses were performed weekly from D-7 to D14 to evaluate the energy metabolism and inflammatory status; rectal temperature was measured daily within 14 days from calving day (D0). (3) Results: PAC showed lower serum haptoglobin at D7 (0.55 vs. 0.79 mg/mL; p < 0.05) and D14 (0.44 vs. 0.66 mg/mL; p < 0.05). CON had a higher number of circulating white blood cells and granulocytes on D7 (p < 0.05). Fewer cows from PAC showed hyperthermia (≥39 °C) during the first 2 weeks postpartum (−7%, p < 0.05). Energy metabolism, which was represented by the NEFA/cholesterol ratio, improved (0.21 vs. 0.36 at D0, p < 0.1; 0.19 and 0.15 vs. 0.36 and 0.32, respectively, at D+7 and D+14, p < 0.05) under the plant bioactive supplementation. (4) Conclusions: The results suggest that the anti-inflammatory plant bioactive compound with Brazilian green propolis administered during calving had a beneficial effect on the energy and inflammatory status of dairy cows.

Effect of injectable trace mineral supplementation on peripheral polymorphonuclear leukocyte function, antioxidant enzymes, health, and performance in dairy cows in semi-arid conditions

The objective of this study was to evaluate the effect of subcutaneous injections of 15 mg/mL Cu, 5 mg/mL Se, 60 mg/mL Zn, and 10 mg/mL Mn on health, performance, polymorphonuclear leukocyte (PMNL) function, circulating glutathione peroxidase (GPx) and superoxide dismutase (SOD) concentrations, and inflammation of dairy cows undergoing the transition period in high temperature-humidity index. A total of 923 multiparous cows from 2 commercial dairy farms were randomly allocated into 1 of 2 treatment groups as follows: control and injectable trace mineral supplementation (ITMS). Cows in the ITMS group received 7 mL of subcutaneous injections at dry-off (208 ± 3 d of gestation), 260 ± 3 d of gestation, and at 35 ± 3 d in milk (DIM). Data regarding health traits, reproductive performance, milk yield, and survivability were extracted from farm database software, and animals were followed-up until 300 DIM. For a subset of 142 cows from one herd, blood samples were collected at enrollment, and at 3 ± 1, 7 ± 1, 10 ± 1, and 35 ± 3 DIM to evaluate hematology, PMNL function, GPx and SOD concentrations, and circulating haptoglobin. Logistic regression was used to assess health and pregnancy per artificial insemination at first service. Cox proportional hazards models were used to evaluate hazard of pregnancy and culling. Mixed linear regression models accounting for repeated measures were used to assess all continuous variables collected over time. Parity, twinning, and previous gestation length were considered as potential confounders. Farm was included as a random effect. The ITMS cows tended to have lower incidence of metritis and stillbirth compared with control group. However, ITMS treatment did not influence the incidence of other diseases (e.g., mastitis, retained placenta), milk yield, reproductive performance, culling, and leukocyte count. Neutrophil-to-lymphocyte ratio, PMNL phagocytosis, and oxidative burst as well as intensity of the oxidative burst were greater for ITMS-treated cows in comparison to control cows. The ITMS cows had decreased expression of the adhesion molecule L-selectin on PMNL surface. The serum concentration of GPx and SOD were not affected by ITMS treatment. In conclusion, ITMS tended to reduce the incidence of metritis and stillbirth parturition, improved PMNL function, and improved the inflammatory status of dairy cows undergoing the transition period in high temperature-humidity index conditions. However, these findings did not translate into improved milk yield, reproductive performance, and survivability.

Association between phagocytic activity of monocytes and days to conception after parturition in dairy cows when considering the hormonal and metabolic milieu

The nutritional conditions and immune status of dairy cows affect reproductive performance. This study was conducted with the aim to analyze the phagocytic activity (PA) and phagocytic capacity (PC) of circulating monocytes after the period of transition from pregnancy to lactation, to evaluate possible associations with duration of time period to conception following parturition. Results indicated PA was not associated with duration of time period to conception following parturition. In contrast, cows with a lesser PC conceived earlier (98 ± 9 days in milk, DIM) than those with a greater PC (168 ± 15 DIM). Based on these results, to analyze the association of the hormonal and metabolic milieu with the PA and PC, the animals were grouped considering the days to conception following parturition. In the group with the greater number of days to conception (>168 DIM), the PA was associated with concentrations of progesterone and beta-hydroxybutyrate (BHB) at 90 DIM and glucose at 120 DIM, whereas PC was associated with the concentrations of progesterone, cortisol and glucose at 90 DIM, non-esterified fatty acids (NEFA) at 120 DIM, 17β-estradiol at 150 DIM, and 17β-estradiol and BHB at 180 DIM. Overall, these results represent a new perspective related to the reproductive performance of dairy cows. The modifications of cellular functions may be useful for predicting the onset of health complications in dairy cows and to manage cows in ways that result in an enhanced fertility during the subsequent lactational period.

Effect of clinical endometritis on physiological, hematological, biochemical and endocrinological profiles in crossbred cows under tropical island ecosystem

The present study was carried out to assess the effect of endometritis on hematological, physiological, antioxidant, oxidative and endocrinological profiles in crossbred cows under tropical island ecosystem of Andaman and Nicobar Islands. Each 12 number of cows affected with clinical endometritis was selected as group 2 and without endometritis as group 1. These cows were in same parity in same locality with similar type management. Physiological profiles, hematological profiles, antioxidant profiles and hormone profiles were estimated. The result revealed that the crossbred cows with endometritis were suffering severe anaemia. The endometritis affected animals were shown significantly low level of antioxidant profiles and higher MDA level than the unaffected animal groups. Similarly endocrinological profiles revealed that the endometritis affected animals have significantly higher level of CORT and lower level of E2, P4, FSH, LH and T4 than the unaffected crossbred cows. It was concluded that the endometritis was due to anaemia, lack of antioxidants, over production of free radicals and disturbances of endocrinological profiles in crossbred cows of Andaman and Nicobar Islands.

Peripartum changes in the activity and expression of neutrophils may predispose to the postpartum occurrence of metritis in dairy cows

Metritis is a postpartum uterine pathology that causes a huge economic loss due to increased culling risk and impaired milk yield and reproduction in cows. The present study was carried out to study the changes in the activity and expression of blood neutrophils in crossbred dairy cows with and without metritis. Collection of blood samples was done at -3, -2 and - 1 weeks before calving, at calving and during the first day of metritis diagnosis in metritis group (n = 8) or at day 8-10 post calving in healthy group (n = 8). Neutrophils were studied for its percentage (microscopically), respiratory burst (nitro blue tetrazolium assay), myeloperoxidase (MPO) concentrations (sandwich ELISA) and expression of CXCR1, CXCR2, TLR2, TLR4, GRα, CD11b, CD14, CD25, CD44, CD47 and CD62L (RT-PCR). Immunocytochemistry was used to investigate MPO concentration and CD14 activity, and western blotting was used for estimating MPO. Although most of these parameters changed in the cows that developed metritis one week before calving, MPO and CD14 got altered much earlier. Myeloperoxidase concentrations and expression of CD14 were considerably lower starting from -2 weeks before calving in cows that developed metritis compared to healthy cows. Further studies are warranted to study the possible use of MPO and CD14 to identify transition cows more vulnerable to develop metritis several weeks before disease occurrence.

Characterization of immunological, biochemical and inflammatory response of clinical and subclinical endometritis in ewes in the subtropics

Pluriparus Ossimi (n = 50) ewes were used to investigate the immune profile of the affected ewes to accurately diagnose clinical and subclinical endometritis and associations with biochemical variables. Ewes were slaughtered and animals were classified into control (no fertility problems), subclinical endometritis (SCE) and clinical endometritis (CE) groups based on pre-slaughter determinations of conception failure. Serum was collected from ewes to estimate concentrations of pro-inflammatory cytokines including interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α) and interleukin-8 (IL-8) as well as nitric oxide (NO) concentration. The results from immunological evaluations indicated there were greater (P < 0.001) serum concentrations of IL-6, IL-8, TNF-α and NO in ewes classified with SCE and CE as compared to ewes of the control group. Furthermore, values for concentrations of TNF-α were positively correlated with IL-6 and IL-8 concentrations in ewes of the SCE and CE groups. In ewes classified with CE and SCE there were greater (P < 0.01) concentrations of blood glucose, ALT, AST, urea and creatinine than in ewes of the control group. It is concluded that serum pro-inflammatory cytokines IL-6, IL-8, and TNF-α are diagnostic markers for CE and SCE in ewes and serve as a criterion for different inflammatory complications in ewes classified as having CE or SCE.

Blood metabolic profile tests at dairy cattle farms as useful tools for animal health management

Blood metabolic profile tests are simple cost-effective biochemical tests which are mostly used to identi-fy nutritional and/or management challenges in dairy cattle herds, but they also can be simply used to find animals which are clinically healthy, but really have some hidden problems like low production performance, reproductive diseases and/or long calving intervals and other sub-clinical diseases. Rou-tine metabolic profile tests commonly consist of blood glucose, urea, albumin, cholesterol, beta-hydroxybutyric acid and non-esterified fatty acids values, as well as sodium, potassium, chloride, calci-um, magnesium and inorganic phosphate levels. Briefly, the current review discusses blood metabolic profile tests, their importance, introduces an easy method for it, emphasises on the relation between blood metabolic profile parameters and many important sub-clinical diseases including ketosis, milk fever, mastitis, cystic ovaries, displaced abomasum and etc., and indicates that because of its simplicity, low cost and easy for analysis results, it can be considered as a good method for diagnosis of important diseases at dairy cattle farms.

Peripheral concentrations of metabolic and inflammatory indicators during transition period and their relationship with postpartum clinical endometritis in dairy cattle

The aim of this study was to investigate the peripheral concentration of metabolic and inflammatory indicators during transition period and their relationship in cows that developed clinical endometritis (CE) and remained nonendometritis during later postpartum period. A total of 70 cows were selected and blood was collected from 21 days before calving to 21 days after calving. After adjusting the sampling date based on the actual calving date (–21±2, –7±1, 0, 7±1, 14±1 and 21±2 days) and health status, a minimum of 8 samples each from the CE and nonendometritis cows were used at each time point of transition period for the estimation of acute phase proteins (APPs) (haptoglobin, Hp; serum amyloid A, SAA; and alpha-1 acid glycoprotein, AGP), pro-inflammatory cytokines (IL-1􀁅, TNF-􀁄, IL-6 and IL-8) and energy indicators (NEFA, BHBA, Leptin and IGF-I) using bovine specific ELISA kits. APPs (Hp, SAA and AGP), cytokines (IL-1􀁅, TNF-􀁄, IL-6) and energy indicators (NEFA, BHBA, Leptin) levels significantly increased, while IL-8 and IGF-I levels significantly decreased in transition cows that eventually developed to CE compared to the cows which remained non-endometritis during 22–47 days postpartum. It is concluded that cows that diagnosed as CE during postpartum period were experienced negative energy balance and compromised their immune status during transition period.

Bovine Endometritis and the Inflammatory Peripheral Cholinergic System

Endometritis is an inflammation of the endometrium associated with bacterial infection. The pathogenesis of endometritis in cows is still not completely understood. The combined analysis of the markers of inflammation and oxidative stress has contributed to a better understanding of disease mechanisms, but is still unexplored in uterine disorders. Moreover, research provides evidence about an important role of the vagus nerve in regulating the innate immune function through the cholinergic anti-inflammatory pathway in response to bacterial infections. This new pathway has demonstrated a critical role in controlling the inflammatory system. The aim of this study was to evaluate the activity of cholinesterase in total blood, lymphocytes, and serum of dairy cows with clinical and subclinical endometritis. Sixty-one Holstein cows, between 30 and 45 days in milk, were classified into 3 groups of animals: presenting clinical endometritis (n = 22), subclinical endometritis (n = 17), and healthy (n = 22). Mean leukocyte counts did not differ among groups, but the neutrophil number was significantly higher in cows with clinical endometritis than those in healthy animals. Also, serum concentration of interleukin-1beta (pg/mL) was significantly higher in cows with endometritis. The activity of acetylcholinesterase in blood and lymphocytes increased in both groups with endometritis. Animals with endometritis presented an increase in lipid peroxidation, but the antioxidant enzyme activity (catalase levels) was higher in endometritis groups than in normal cows. In conclusion, the inflammatory process of clinical and subclinical endometritis leads to systemic lipid peroxidation despite the compensatory increase of the antioxidant enzyme. These data also provide evidence of an important role of the cholinergic pathway in regulating dairy cows with clinical and subclinical endometritis.

Selected leukocyte subpopulations in peripheral blood and uterine washings in cows before and after intrauterine administration of cefapirin and methisoprinol

The aim of the study was to evaluate the selected lymphocyte subpopulations TCD4, TCD8, BCD21, BCD25, CD18, CD11b, and MHC II in blood and uterine flush of cows with endometritis, before and after intrauterine (i.u.) administration of cefapirin and methisoprinol. The research was carried out on 28 cows with clinical endometritis. Animals were divided into four groups, each composed of seven cows, depending on the i.u. preparation used: Group A, cefapirin; Group B, methisoprinol; Group C, cefapirin and methisoprinol simultaneously; and a control group-without medication. The study was performed using flow cytometry method. Summarizing the results of the research, i.u. infusion of cefapirin caused a weakening of the effector phase of the local uterine immune response; however, it enhanced leukocyte chemotaxis and antigen presentation. After i.u. administration of methisoprinol, the stimulation of specific uterine immunity mechanisms was mainly observed. The use of both mentioned preparations showed the strengthening of specific uterine immunological mechanisms presumably caused by methisoprinol, despite the inhibitory effect of the antibiotic. Intrauterine use of immunostimulatory substances can improve the effectiveness of the endometritis treatment in cows by improving specific local mechanisms of uterine immunity. As a consequence, it may enhance the effector function of immune competent cells and finally eliminate inflammation.

Destination of corpus luteum in postpartum clinical endometritis cows and factors affecting self-recovery

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The most cyclic clinical endometritis cows revealed new CL two weeks after clean test.

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The uterus of most of cyclic clinical endometritis cows was clean 14 days after 30 ± 3 days postpartum.

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About two third of clinical endometritis cows with persistent CL remained infected after second examination and considered as pyometric cows.

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Concentration of some metabolic or steroid hormones and production and reproduction factors influenced self-recovery of cows from clinical endometritis.

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Size and position of reproductive tract influenced self-healing from clinical endometritis.

In this study, the fate of corpus luteum was investigated in cows affected by severe clinical endometritis. Also, concentration of IL-1β, IL-6, COX-2, adiponectin, leptin, progesterone (P4), PGFM, insulin, and IGF-1 were studied in severe clinical endometritis cows at day 30 ± 3 postpartum. Eighty-seven dairy cows affected by severe clinical endometritis were selected and their reproductive tract was examined by ultrasonography at day 30 ± 3 postpartum (first examination) and 14 days later (second examination). The majority of the cows with CL and affected by clinical endometritis at first examination had new CL 14 days later, and most of these cows were clean without any treatment (self-healing). The CL of about 28.7% of all cows with clinical endometritis at first examination persisted two weeks later and the uterus of most of them remained infected as pyometric cows. Most of the anestrous cows (83.3%) were pregnant, but only 51% of cows with new CL were pregnant at the end of next six month period. There was a significant difference in the means of lactation number, uterine lumen diameter, cervical diameter, and size of uterine horn, milk production at first examination, concentrations of insulin, COX-2, P4, IL-1β, and IL-6 among persistent CL, new CL, and anestrous cows. The pregnancy rate and the discharge score were different among persistent CL, new CL, and anestrous cows. In conclusion, CL on ovary of cows and its fate could affect recovery from severe clinical endometritis. The concentration of some metabolic hormones influenced the self-recovery of cows from clinical endometritis.

Immune status during postpartum, peri-implantation and early pregnancy in cattle: An updated view

Throughout the estrous cycle the mammalian endometrium undergoes morphological and functional changes that are essential for the establishment of pregnancy and proper ovarian and uterine functions. Among these changes, the most important are alterations in both inter- and intracellular signalling molecules, many of which modulate immune processes. In the endometrial tissue there are local innate (nonspecific) and adaptive (specific/acquired) response mechanisms which vary because of the endocrine status during the estrous cycle, pregnancy and postpartum period. Endometrial cells have responses that support the immune system by producing pro-inflammatory factors such as cytokines, sensors, effector molecules and chemokines. This response is important during gestation, pregnancy, and fetal growth, as well as in preventing infection, and immuno-rejection of the semi-allogeneic embryo. In dairy cows, both before and immediately after calving, there are marked changes in the values for hormonal and metabolic variables and the immune status is impaired. Thus, in several studies there has been assessment of the physiological and/or abnormal maternal immune changes and possible effects on dairy cow reproductive performance. The objective with this review is to summarize the novel information about the immune mechanisms involved during the postpartum period, subsequent peri-implantation period and pregnancy in dairy cows, and the possible effects on reproductive performance. This information provides for an enhanced understanding of the local and systemic immune responses associated with the metabolic and hormonal status of dairy cows, and alterations in the immune system of high producing cows and the possible effects on subsequent fertility.

Changes in the blood routine, biochemical indexes and the pro-inflammatory cytokine expressions of peripheral leukocytes in postpartum dairy cows with metritis

BACKGROUND

The aim of the present study was to clarify the changes in complete blood count, blood biochemistry, and the gene expressions of pro-inflammatory cytokines of peripheral white blood cells in postpartum dairy cows with metritis.

RESULTS

The cows were assigned to the control group (n = 28) or the metritis group (n = 28), retrospectively. Blood samples were taken 7 days before the estimated parturition (- 7 d), on the day of parturition (0 d), and 7 and 30 d after parturition. There was no difference in blood indexes between the control group and the metritis group at - 7 d. The WBC, granulocytes and monocytes were generally higher at 7 and 30 d in the metritis group than the control. In comparison with the controls, all liver function parameters and triglyceride levels at 0, 7 and 30 d, and the creatinine level at 7 and 30 d were higher in cows with metritis. The concentrations of Ca and P at 0, 7 and 30 d, and of glucose at 0 d were lower for cows in the metritis group compared with cows in the control group. Among these parameters, the WBC at 30 d, the aspartate aminotransferase activity (AST) at 7 d exceeded normal ranges (WBC: 5.0 ~ 16.0 × 10⁹/L; AST: 42.5 ~ 98 U/L), whereas the concentrations of glucose and Ca from 0 to 30 d were below normal ranges (glucose: 2.5 ~ 4.5 mmol/L; Ca: 2.2 ~ 2.5 mmol/L) in the metritis group. The gene expressions of pro-inflammatory cytokines in the metritis group were higher than those in the control group, including the IL-1α at 7d, the IL-1β at - 7, 0 and 7 d, the IL-6 at - 7, 0, 7 and 30 d, the IL-8 at 0, 7 and 30 d, and the TNF-α at 7 and 30 d.

CONCLUSION

The cows with metritis experienced systemic inflammation for 4 weeks after calving, the impaired hepatic function, and the altered metabolic status with increased triglyceride level and decreased concentrations of glucose, Ca and P.

Fatty and hydroxycarboxylic acid receptors: The missing link of immune response and metabolism in cattle

Fatty and hydroxycarboxylic acids are one of the main intermediates of energy metabolism in ruminants and critical in the milk production of cattle. High production demands on a dairy farm can induce nutritional imbalances and metabolism disorders, which have been widely associated with the onset of sterile inflammatory processes and increased susceptibility to infections. The literature suggests that short-chain fatty acids (SCFA), long-chain fatty acids (LCFA) and hydroxycarboxylic acids are relevant modulators of the host innate inflammatory response. For instance, increased SCFA and lactate levels are associated with subacute ruminal acidosis (SARA) and the activation of pro-inflammatory processes mediated by diverse leukocyte and vascular endothelial cells. As such, free LCFA and the ketone body β-hydroxybutyrate are significantly increased in the plasma 1-2 weeks postpartum, coinciding with the time period in which cows are more susceptible to acquiring infectious diseases that the host innate immune system should actively oppose. Today, many of these pro-inflammatory responses can be related to the activation of specific G protein-coupled receptors, including GPR41/FFA3 and GPR43/FFA2 for SCFA; GPR40/FFA1 and GPR120/FFA4 for LCFA, GPR109A/HCA2 for ketone body β-hydroxybutyrate, and GPR81/HCA₁ for lactate, all expressed in different bovine tissues. The activation of these receptors modulates the release of intracellular granules [e.g., metalloproteinase-9 (MMP-9) and lactoferrin], radical oxygen species (ROS) production, chemotaxis, and the production of relevant pro-inflammatory mediators. The article aimed to review the role of natural ligands and receptors and the resulting impact on the host innate immune reaction of cattle and, further, to address the most recent evidence supporting a potential connection to metabolic disorders.

Concentrate supplementation of a diet based on medium-quality grass silage for 4 weeks prepartum: Effects on cow performance, health, metabolic status, and immune function

Because negative energy balance (EB) contributes to transition-period immune dysfunction in dairy cows, dietary management strategies should aim to minimize negative EB during this time. Prepartum diets that oversupply energy may exacerbate negative EB in early lactation, with detrimental effects on immune function. However, with lower body condition score (BCS) cows, it has been shown that offering concentrates in addition to a grass silage-based diet when confined during an 8-wk dry period resulted in increased neutrophil function in early lactation. The aim of this study was to examine if similar benefits occur when concentrate feeding was restricted to a 4-wk period prepartum. Twenty-six multiparous and 22 primiparous Holstein-Friesian cows were offered ad libitum access to medium-quality grass silage until 28 d before their predicted calving dates (actual mean of 32 d prepartum; standard deviation = 6.4). At this time multiparous cows had a mean BCS of 2.9 (standard deviation = 0.12) and primiparous cows a mean BCS of 3.0 (standard deviation = 0.14) on a 1 to 5 scale. Cows were then allocated in a balanced manner to 1 of 2 treatments (13 multiparous cows and 11 primiparous cows on each treatment): silage only (SO) or silage plus concentrates (S+C) until calving. Cows on SO were offered the same grass silage ad libitum. Cows on S+C were offered an ad libitum mixed ration of the same grass silage and additional concentrates in a 60:40 dry matter (DM) ratio, which provided a mean concentrate DM intake (DMI) of 4.5 kg/cow per d. After calving, all cows were offered a common mixed ration (grass silage and concentrates, 40:60 DM ratio) for 70 d postpartum. Offering concentrates in addition to grass silage during the 4 wk prepartum increased prepartum DMI (12.0 versus 10.1 kg/cow per d), EB (+40.0 versus +10.6 MJ/cow per d), and body weight (BW; 640 versus 628 kg), and tended to increase BCS (3.02 versus 2.97). However, postpartum DMI, milk yield, milk composition, BW change, BCS change, serum nonesterified fatty acid, and β-hydroxybutryrate concentrations, health, and corpus luteum measures were unaffected by treatment. The in vitro assays of neutrophil phagocytosis, neutrophil oxidative burst, and interferon gamma production, conducted on blood samples obtained at d 14 prepartum and d 3, 7, 14, and 21 postpartum, were unaffected by treatment. Primiparous cows had higher phagocytic fluorescence intensity at d 14 prepartum and d 3 and 7 postpartum; a higher percentage of neutrophils undergoing oxidative burst at d 3, 7, and 21 postpartum; and a higher oxidative burst fluorescence intensity at d 14 prepartum and d 7, 14, and 21 postpartum compared with multiparous cows. This suggests that neutrophil function of primiparous cows was less sensitive to the changes occurring during the transition period than that of multiparous cows. In conclusion, offering concentrates during the 4-wk period prepartum had no effect on postpartum DMI, milk yield, body tissue mobilization, EB, measures of neutrophil or lymphocyte function, health, or corpus luteum activity.

Potential of acute phase proteins as predictor of postpartum uterine infections during transition period and its regulatory mechanism in dairy cattle

Among the various systemic reactions against infection or injury, the acute phase response is the cascade of reaction and mostly coordinated by cytokines-mediated acute phase proteins (APPs) production. Since APPs are sensitive innate immune molecules, they are useful for early detection of inflammation in bovines and believed to be better discriminators than routine hematological parameters. Therefore, the possibility of using APPs as a diagnostic and prognostic marker of inflammation in major bovine health disorders including postpartum uterine infection has been explored by many workers. In this review, we discussed specifically importance of postpartum uterine infection, the role of energy balance in uterine infections and potential of APPs as a predictor of postpartum uterine infections during the transition period and its regulatory mechanism in dairy cattle.

Long-term impact of puerperal metritis on the profiles of peripheral blood leukocytes in peripartum dairy cows

To determine the effects of puerperal metritis on the immune response, changes in the differential peripheral blood leukocyte counts were analyzed during the peripartum period in cows with or without metritis. Multiparous Holstein cows were examined for uterine health disorders and classified into two groups: healthy (n = 11) or metritis (n = 5) cows. The lymphocyte and monocyte counts and the proportion of CD8(+) lymphocytes were higher in cows with metritis compared to healthy cows. Moreover, the effects of puerperal metritis on the lymphocyte counts and CD4(+)/CD8(+) ratio persisted weeks after the uterine inflammation had self-resolved. Taken together, the findings of the present study indicate the possible long-term alterations of systemic immune responses in cows with puerperal uterine inflammation.

Intravaginal lactic Acid bacteria modulated local and systemic immune responses and lowered the incidence of uterine infections in periparturient dairy cows

The objective of this investigation was to evaluate whether intravaginal infusion of a lactic acid bacteria (LAB) cocktail around parturition could influence the immune response, incidence rate of uterine infections, and the overall health status of periparturient dairy cows. One hundred pregnant Holstein dairy cows were assigned to 1 of the 3 experimental groups as follows: 1) one dose of LAB on wk -2 and -1, and one dose of carrier (sterile skim milk) on wk +1 relative to the expected day of parturition (TRT1); 2) one dose of LAB on wk -2, -1, and +1 (TRT2), and 3) one dose of carrier on wk -2, -1, and +1 (CTR). The LAB were a lyophilized culture mixture composed of Lactobacillus sakei FUA3089, Pediococcus acidilactici FUA3138, and Pediococcus acidilactici FUA3140 with a cell count of 10⁸-10⁹ cfu/dose. Blood samples and vaginal mucus were collected once a week from wk -2 to +3 and analyzed for content of serum total immunoglobulin G (IgG), lipopolysaccharide-binding protein (LBP), serum amyloid A (SAA), haptoglobin (Hp), tumor necrosis factor (TNF), interleukin (IL)-1, IL-6, and vaginal mucus secretory IgA (sIgA). Clinical observations including rectal temperature, vaginal discharges, retained placenta, displaced abomasum, and laminitis were monitored from wk -2 to +8 relative to calving. Results showed that intravaginal LAB lowered the incidence of metritis and total uterine infections. Intravaginal LAB also were associated with lower concentrations of systemic LBP, an overall tendency for lower SAA, and greater vaginal mucus sIgA. No differences were observed for serum concentrations of Hp, TNF, IL-1, IL-6 and total IgG among the treatment groups. Administration with LAB had no effect on the incidence rates of other transition cow diseases. Overall intravaginal LAB lowered uterine infections and improved local and systemic immune responses in the treated transition dairy cows.

Relationships among ketosis, serum metabolites, body condition, and reproductive outcomes in dairy cows

We determined the relationships among ketosis, serum metabolites, body condition, and reproductive disorders and performance in dairy cows. Blood samples from 213 dairy cows were collected at 4 and 2 weeks prepartum, just after calving, and at 1, 2, 4, 6, and 8 weeks postpartum to measure serum β-hydroxybutyrate, nonesterified fatty acids (NEFAs), glucose, total cholesterol, urea nitrogen, aspartate aminotransferase, γ-glutamyltransferase, and progesterone concentrations. Cows were grouped on the basis of the β-hydroxybutyrate concentration at 1 and/or 2 weeks postpartum into two groups: the ketotic group (≥1200 μmol/L, n = 59) and the nonketotic group (<1200 μmol/L, n = 154). The body condition score (BCS) was assessed simultaneously with blood collection. Clinical endometritis was diagnosed by observation of vaginal discharges (>50% pus), and subclinical endometritis was diagnosed by evaluation of uterine cytology (>18% neutrophils) at 4 weeks postpartum. Ovarian cysts were diagnosed by ultrasonography, and resumption of postpartum cyclicity was evaluated by progesterone concentrations (≥1 ng/mL) at 4, 6, and 8 weeks postpartum. In the ketotic group, NEFA levels were higher (P ≤ 0.0005), whereas glucose (P < 0.05-0.0005) and urea nitrogen levels (P < 0.05-0.01) were lower than those in the nonketotic group during the postpartum period. Aspartate aminotransferase levels were higher (P < 0.01) in the ketotic group than those in the nonketotic group at 2 weeks postpartum. The BCS of the ketotic group was higher than the nonketotic group during the prepartum (P < 0.001) and postpartum (P < 0.05-0.001) periods. The probabilities of clinical endometritis (odds ratio = 2.55) and ovarian cysts (odds ratio = 2.80) were higher (P < 0.05) in the ketotic group than those in the nonketotic group. The hazards of resumption of postpartum cyclicity by 8 weeks postpartum (hazard ratio = 0.67) and pregnancy by 360 days postpartum (hazard ratio = 0.68) were lower (P < 0.05) in the ketotic group. In conclusion, a higher BCS during prepartum and postpartum period and increased NEFA and aspartate aminotransferase levels, along with decreased glucose and urea nitrogen levels during postpartum, were associated with ketosis, increased reproductive disorders, and decreased reproductive performance in dairy cows.

Cytometric analysis of surface molecules of leucocytes and phagocytic activity of granulocytes and monocytes/macrophages in cows with pyometra

Pyometra is a serious problem in dairy cow herds, causing large economic losses due to infertility. The development of pyometra depends mainly on the immunological status of the cow. The aim of the study was a comparative evaluation of selected indicators involving non-specific and specific immunity in cows with pyometra and in cows without inflammation of the uterus. The study was performed in 20 cows, which were divided into two groups: pyometra group and healthy group, each comprising 10 cows, based on the results of cytological and ultrasonographic tests. A flow cytometric analysis was performed for the surface molecules CD4, CD8, CD14, CD21, CD25 and CD4(+) CD25(+) on leucocytes, and the phagocytic activity was determined from granulocytes and monocytes/macrophages in the peripheral blood and uterine washings, respectively. It was demonstrated that the percentage of phagocytic granulocytes and monocytes/macrophages in both the peripheral blood and uterine washings was significantly lower in cows with pyometra compared with the healthy group (p < 0.001). Significantly (p ≤ 0.001) lower percentage of CD4(+) , CD14(+) , CD25(+) and CD4(+) CD25(+) phenotype leucocytes was also observed in the peripheral blood of cows from the pyometra group, along with a significantly higher (p < 0.001) percentage of CD8(+) and CD21(+) lymphocytes as compared to the healthy group. The results of work indicate that disfunction of cell immunity coexisting with pyometra may be caused by a bacterial infection and the presence of blocking agents (IL-10), released by the increasing number of CD8(+) lymphocytes what leads to the advanced inflammation of uterus.

Neutrophil functions and cytokines expression profile in buffaloes with impending postpartum reproductive disorders

The study was conducted to correlate the periparturient immune status in terms of neutrophil functions and cytokine expression in peripheral blood mononuclear cell culture with impending postpartum reproductive disorders in buffaloes. Forty pregnant buffaloes were observed for occurrence of postpartum reproductive disorders (PRD), i.e., metritis, endometritis and delayed uterine involution etc., during one week prepartum to four weeks postpartum period. A representative number (n = 6) of buffaloes that did not develop any PRD were included in group I (healthy, control), while the animals which experienced PRD were assigned into group II (PRD, n = 8). The blood samples were collected at weekly interval from one week prepartum to four weeks postpartum period considering the day of calving as ‘d 0’. Differential leucocytes counts, superoxide and hydrogen peroxide production activity in isolated neutrophils and the mRNA expression profile of cytokines i.e., IL-2, IL-4 and IFN-γ in PBMC culture were studied in all the samples. A higher total leucocytes, neutrophil and band cells count along with impaired neutrophil functions i.e., lowered level of production of superoxide and hydrogen peroxide before parturition and during early postpartum period were observed in buffaloes developing PRD. Further, a lower expression of IL-2, IFN-γ and IL-4 mRNA in PBMC culture was observed at calving in buffaloes that subsequently developed PRD at later postpartum. Thus, suppression in neutrophil function and cytokine expression at prepartum to early postpartum period predisposes the buffaloes to develop postpartum reproductive disorders. Hence, monitoring of neutrophils function and cytokine expression profile would be effective to predict certain reproductive disorders at late pregnancy or immediately after parturition in buffaloes. In future, this may be a novel approach for determining suitable management and therapeutic decisions for prevention of commonly occurring reproductive disorders in farm animals.

Determination of selected parameters for non-specific and specific immunity in cows with subclinical endometritis

Endometritis in dairy cow herds is a serious economic problem all over the world due to the large economic losses. The aim of the study was a comparative evaluation of selected indicators of non-specific and specific immunity in cows with subclinical endometritis and in cows without inflammation of the uterus. The study was performed on 40 cows on day 65 after delivery. Based on the results of cytological tests, the cows were divided into two groups: experimental (subclinical endometritis) and control (20 cows in each group). A flow cytometric analysis was performed for the leukocyte surface molecules CD4, CD8, CD14, CD21, CD25. Moreover the phagocytic activity of granulocytes and monocytes/macrophages in peripheral blood and uterine washings was determined. It has been demonstrated that the percentage of phagocytic granulocytes and monocytes/macrophages in both the peripheral blood and uterine washings was significantly lower for cows with subclinical endometritis when compared to cows undergoing a normal puerperal period (p<0.001). A significant (p≤0.001) decrease in the percentage of CD4+, CD14+, CD25+ and CD4+CD25+ leukocytes was also observed in peripheral blood of the cows from the experimental group. In uterine washings a significant decrease (p<0.001) in CD21+ and increase in CD8+ lymphocytes was detected. The results indicate that dysfunction of cell immunity coexisting with subclinical endometritis may be the main factor causing advanced inflammation of the uterus. Knowledge of immunological mechanisms observed in cows with subclinical endometritis could aid in choosing the right adjuvant therapy using immunomodulating agents.

Invited review: Systematic review of diagnostic tests for reproductive-tract infection and inflammation in dairy cows

The objective of this study was to conduct a systematic and critical appraisal of the quality of previous publications and describe diagnostic methods, diagnostic criteria and definitions, repeatability, and agreement among methods for diagnosis of vaginitis, cervicitis, endometritis, salpingitis, and oophoritis in dairy cows. Publications (n=1,600) that included the words "dairy," "cows," and at least one disease of interest were located with online search engines. In total, 51 papers were selected for comprehensive review by pairs of the authors. Only 61% (n=31) of the 51 reviewed papers provided a definition or citation for the disease or diagnostic methods studied, and only 49% (n=25) of the papers provided the data or a citation to support the test cut point used for diagnosing disease. Furthermore, a large proportion of the papers did not provide sufficient detail to allow critical assessment of the quality of design or reporting. Of 11 described diagnostic methods, only one complete methodology, i.e., vaginoscopy, was assessed for both within- and between-operator repeatability (κ=0.55-0.60 and 0.44, respectively). In the absence of a gold standard, comparisons between different tests have been undertaken. Agreement between the various diagnostic methods is at a low level. These discrepancies may indicate that these diagnostic methods assess different aspects of reproductive health and underline the importance of tying diagnostic criteria to objective measures of reproductive performance. Those studies that used a reproductive outcome to select cut points and tests have the greatest clinical utility. This approach has demonstrated, for example, that presence of (muco)purulent discharge in the vagina and an increased proportion of leukocytes in cytological preparations following uterine lavage or cytobrush sampling are associated with poorer reproductive outcomes. The lack of validated, consistent definitions and outcome variables makes comparisons of the different tests difficult. The quality of design and reporting in future publications could be improved by using checklists as a guideline. Further high-quality research based on published standards to improve study design and reporting should improve cow-side diagnostic tests. Specifically, more data on intra- and interobserver agreement are needed to evaluate test variability. Also, more studies are necessary to determine optimal cut points and time postpartum of examination.

Phenotyping of leukocytes and granulocyte and monocyte phagocytic activity in the peripheral blood and uterus of cows with endometritis

This study was a comparative evaluation of selected immunological parameters in peripheral blood and uterine wash samples from cows with a normal postpartum period compared with cows with endometritis. We aimed to determine the usefulness of these parameters in monitoring the puerperium. In total, 40 cows were included in the study: 20 had endometritis (experimental group), and 20 did not have uterine inflammation (control group). Animals were chosen on the basis of cytological and bacteriological test results. The tests were conducted 5, 22, and 40 days postpartum. In both groups, flow cytometric analysis of the surface molecules CD4, CD8, CD21, CD25, and CD14 in the peripheral blood and uterine washings was performed. Granulocyte and monocyte phagocytic activity was determined using a commercial Phagotest kit that was adapted for flow cytometry. The percentage of phagocytic granulocytes and monocytes in both the peripheral blood and the uterine washings was significantly lower for cows in the experimental group compared with the control group (P < 0.01). A significant decrease (P < 0.01) in the percentage of CD4+, CD25+, CD14+, and CD4 + CD25(high) leukocyte subpopulations was also observed in the peripheral blood of cows with endometritis. A significant decrease (P < 0.01) in CD21+ lymphocytes and an increase in CD8+ lymphocytes was detected in uterine washings. The results of this work indicate that cell immunity dysfunction may be the main factor causing advanced inflammation of the uterus in endometritis. Knowledge of the immunological mechanisms observed in cows with endometritis might aid in choosing the correct immunomodulating agent-based adjuvant therapy.

Subcutaneous immunization with inactivated bacterial components and purified protein of Escherichia coli, Fusobacterium necrophorum and Trueperella pyogenes prevents puerperal metritis in Holstein dairy cows

In this study we evaluate the efficacy of five vaccine formulations containing different combinations of proteins (FimH; leukotoxin, LKT; and pyolysin, PLO) and/or inactivated whole cells (Escherichia coli, Fusobacterium necrophorum, and Trueperella pyogenes) in preventing postpartum uterine diseases. Inactivated whole cells were produced using two genetically distinct strains of each bacterial species (E. coli, F. necrophorum, and T. pyogenes). FimH and PLO subunits were produced using recombinant protein expression, and LKT was recovered from culturing a wild F. necrophorum strain. Three subcutaneous vaccines were formulated: Vaccine 1 was composed of inactivated bacterial whole cells and proteins; Vaccine 2 was composed of proteins only; and Vaccine 3 was composed of inactivated bacterial whole cells only. Two intravaginal vaccines were formulated: Vaccine 4 was composed of inactivated bacterial whole cells and proteins; and Vaccine 5 was composed of PLO and LKT. To evaluate vaccine efficacy, a randomized clinical trial was conducted at a commercial dairy farm; 371 spring heifers were allocated randomly into one of six different treatments groups: control, Vaccine 1, Vaccine 2, Vaccine 3, Vaccine 4 and Vaccine 5. Late pregnant heifers assigned to one of the vaccine groups were each vaccinated twice: at 230 and 260 days of pregnancy. When vaccines were evaluated grouped as subcutaneous and intravaginal, the subcutaneous ones were found to significantly reduce the incidence of puerperal metritis. Additionally, subcutaneous vaccination significantly reduced rectal temperature at 6±1 days in milk. Reproduction was improved for cows that received subcutaneous vaccines. In general, vaccination induced a significant increase in serum IgG titers against all antigens, with subcutaneous vaccination again being more effective. In conclusion, subcutaneous vaccination with inactivated bacterial components and/or protein subunits of E. coli, F. necrophorum and T. pyogenes can prevent puerperal metritis during the first lactation of dairy cows, leading to improved reproduction.

Peripheral blood leukocytes of cows with subclinical endometritis show an altered cellular composition and gene expression

Subclinical endometritis (SCE) is an important postpartum disease in dairy cows, but conventional cytobrush diagnosis often gives imprecise results. The aim of this study was to analyze disease-associated changes in peripheral blood as potential diagnostic parameters. Cellular subpopulations of blood leukocytes from cows with or without SCE (45-55 days postpartum) were flow-cytometrically quantified. Gene expression of whole blood leukocytes was assessed by PAXgene analysis. Subclinical endometritis cows showed significantly higher number of blood mononuclear cells and neutrophils. Among mononuclear cells, numbers of B-cells, NK-cells, and CD172a-positive monocytes were significantly elevated. Compared with non-SCE cows, blood leukocytes of SCE cows significantly expressed higher copy numbers of CXCL8, TNF, and IL12. To test whether circulating plasma factors are responsible for these changes, leukocytes, polymorphonuclear cells, and monocyte subpopulations (classical, intermediate, nonclassical) of healthy cows were stimulated with plasma of SCE and non-SCE cows. Although gene expression of whole leukocytes and polymorphonuclear cells remained unaltered, plasma from SCE animals significantly elevated expressed messenger RNA copy numbers of CXCL8, CXCL1, and IL1B in intermediate monocytes. In conclusion, elevated number of selected mononuclear subpopulations in peripheral blood and enhanced expression of distinct genes encoding for inflammatory mediators in blood leukocytes reflect the subclinical uterine inflammatory process in cows. Whether the observed changes in the periphery of SCE cows are the consequence of the uterine inflammatory process, or whether they affect the pathogenesis of the disease is currently unknown.

Interactions between negative energy balance, metabolic diseases, uterine health and immune response in transition dairy cows

The biological cycles of milk production and reproduction determine dairying profitability thus making management decisions dynamic and time-dependent. Diseases also negatively impact on net earnings of a dairy enterprise. Transition cows in particular face the challenge of negative energy balance (NEB) and/or disproportional energy metabolism (fatty liver, ketosis, subacute, acute ruminal acidosis); disturbed mineral utilization (milk fever, sub-clinical hypocalcemia); and perturbed immune function (retained placenta, metritis, mastitis). Consequently NEB and reduced dry matter intake are aggravated. The combined effects of all these challenges are reduced fertility and milk production resulting in diminishing profits. Risk factors such as NEB, inflammation and impairment of the immune response are highly cause-and-effect related. Thus, managing cows during the transition period should be geared toward reducing NEB or feeding specially formulated diets to improve immunity. Given that all cows experience a reduced feed intake and body condition, infection and inflammation of the uterus after calving, there is a need for further research on the immunology of transition dairy cows. Integrative approaches at the molecular, cellular and animal level may unravel the complex interactions between disturbed metabolism and immune function that predispose cows to periparturient diseases.

The postpartum endometrial inflammatory response: a normal physiological event with potential implications for bovine fertility

After calving, the bovine endometrium undergoes marked morphological and functional changes that are necessary for subsequent re-breeding. Regulation and integration of these key events are largely uncharacterised. Here, endometrial swabs and biopsies were taken at 15, 30 and 60 days postpartum (DPP) from 13 healthy primiparous cows, 10 of which subsequently conceived, with a view to characterising innate and inflammatory gene expression profiles. Endometrial biopsies exhibited severe inflammation (>75 leukocytes per high-power field) at 15 DPP, which had begun to resolve by 30 DPP and had completely resolved by 60 DPP. The severe inflammation at 15 DPP coincided with uterine infection in all cows and a significant increase (P < 0.05) in the expression of all of 16 genes investigated, including CD45, IL8, IL6, IL1, TNF, TAP, SAA3 and HP at 15 DPP, relative to 60 DPP. All of these parameters had begun to return to normal physiological levels at 30 DPP. Systemically, serum protein concentrations of IL-8 were elevated at 15 DPP compared with 60 DPP (78 pgmL(-1)vs 48 pgmL(-1); P = 0.02). These results indicate that endometrial inflammation, leukocyte infiltration and increased expression of pro-inflammatory, antimicrobial and acute-phase protein genes are expected features of the postpartum period, critical to bacterial clearance and uterine involution.

Determination of anti-inflammatory cytokine in periparturient cows for prediction of postpartum reproductive diseases

Forty-one pregnant cows at 240 days of gestation were selected from the cattle herd at the Indian Veterinary Research Institute, Izatnagar, Bareilly, India. The cows were critically observed daily during the periparturient period until 45 days postpartum. The prepartum sampling day was fixed on the basis of AI date supported by the external signs of the animals approaching parturition. Blood sampling was done for each experimental animal on 15 days prepartum (-15 d), calving day (0 d), 15 days (15 d), and 30 days (30 d) postpartum, and thorough gynecological examinations were performed on 0 d, 15 d, 30 d, and 45 d for diagnosis of postpartum reproductive diseases like retained placenta (ROP), clinical metritis (CM), clinical endometritis, cervicitis, and delayed involution of the uterus. The blood serum was used for estimation of the anti-inflammatory cytokine interleukin 10 (IL-10). Determintaion of IL-10 concentration in serum was done by using a commercially available bovine-specific ELISA kit. The IL-10 concentration (pg/mL) was significantly (P < 0.01) higher for ROP (1956.96 ± 325.30) and CM (2283.01 ± 326.82) than normal cows (827.19 ± 127.11) at 15 days before calving. The values for IL-10 was also significantly (P < 0.05) higher for cows with ROP and CM than for normal cows at 0 d and 15 d postpartum. However, the values for IL-10 were significantly (P < 0.05) higher for cows with clinical endometritis (1847.83 ± 539.38) than for normal cows (770.75 ± 29.22) at 30 d postpartum. The concentration of IL-10 was lower (P > 0.05) in cows with delayed involution of uterus than other groups of cows at all days of the periparturient period. The cytokine level in cows with delayed involution of the uterus was 328.906 ± 107.19, 263.08 ± 84.92, 415.26 ± 102.14, and 386.28 ± 111.11 on -15 d, 0 d, 15 d, and 30 d, respectively. According to the results of this study it can be concluded that increased serum concentration of IL-10 at 15 d prepartum was observed in cows that developed ROP and CM and remained significantly higher until 15 d postpartum. Therefore, this cytokine might be used as a prognostic marker to identify the cows that are going to develop ROP and CM.

Physiology and Endocrinology Symposium: maternal immunological adjustments to pregnancy and parturition in ruminants and possible implications for postpartum uterine health: is there a prepartum-postpartum nexus?

Establishment of microbial infections in the reproductive tract can have negative consequences for reproductive function of the postpartum female. Most periparturient cows experience bacterial contamination of the uterus after parturition, but only a fraction of these develop subclinical or clinical disease. It is not well understood why one female resolves uterine infections after parturition while another develops disease. Perhaps those that develop metritis or endometritis are exposed to a greater bacterial load at parturition than those that successfully restore the uterus to a healthy condition. A second possibility is that females that develop bacterial disease have compromised immune function, either systemically or in the reproductive tract and associated lymph nodes. Here, the possibility is raised that maternal immunological adjustments to the presence of the allogeneic conceptus may predispose some females to metritis or endometritis. Several regulatory processes ensure that adaptive immune responses against paternal antigens on the conceptus are downregulated during pregnancy. Among these are immunosuppressive effects of progesterone, local accumulation of immune cells that can inhibit inflammation and T cell responses, including M2 macrophages and γδ T cells, and differentiation of regulatory T cells to inhibit alloreactive lymphocytes. Some immunological adjustments to the conceptus also make the uterus more susceptible to bacterial infection. For example, progesterone not only depresses skin graft rejection but also reduces uterine capacity to eliminate bacterial infections. Macrophages of M2 phenotype can inhibit inflammation and facilitate persistence of some microbial infections. At parturition, immune defenses in the uterus may be further weakened by loss of the luminal epithelium of the endometrium, which is part of the innate immune system, as well as by disappearance of intraepithelial γδ T cells that produce the antibacterial proteins granulysin and perforin. It is currently not known whether molecules and cells that inhibit immune responses during pregnancy persist after parturition but, if so, they could contribute to compromised immune function in the uterus. It is hypothesized that individual variation in immune adjustments to pregnancy and parturition and the reversal of these changes in the postpartum period are important determinants of susceptibility of the uterus to infection.

Global endometrial transcriptomic profiling: transient immune activation precedes tissue proliferation and repair in healthy beef cows

BACKGROUND

All cows experience bacterial contamination and tissue injury in the uterus postpartum, instigating a local inflammatory immune response. However mechanisms that control inflammation and achieve a physiologically functioning endometrium, while avoiding disease in the postpartum cow are not succinctly defined. This study aimed to identify novel candidate genes indicative of inflammation resolution during involution in healthy beef cows. Previous histological analysis of the endometrium revealed elevated inflammation 15 days postpartum (DPP) which was significantly decreased by 30 DPP. The current study generated a genome-wide transcriptomic profile of endometrial biopsies from these cows at both time points using mRNA-Seq. The pathway analysis tool GoSeq identified KEGG pathways enriched by significantly differentially expressed genes at both time points. Novel candidate genes associated with inflammatory resolution were subsequently validated in additional postpartum animals using quantitative real-time PCR (qRT-PCR).

RESULTS

mRNA-Seq revealed 1,107 significantly differentially expressed genes, 73 of which were increased 15 DPP and 1,034 were increased 30 DPP. Early postpartum, enriched immune pathways (adjusted P < 0.1) included the T cell receptor signalling pathway, graft-versus-host disease and cytokine-cytokine receptor interaction pathways. However 30 DPP, where the majority of genes were differentially expressed, the enrichment (adjusted P < 0.1) of tissue repair and proliferative activity pathways was observed. Nineteen candidate genes selected from mRNA-Seq results, were independently assessed by qRT-PCR in additional postpartum cows (5 animals) at both time points. SAA1/2, GATA2, IGF1, SHC2, and SERPINA14 genes were significantly elevated 30 DPP and are functionally associated with tissue repair and the restoration of uterine homeostasis postpartum.

CONCLUSIONS

The results of this study reveal an early activation of the immune response which undergoes a temporal functional change toward tissue proliferation and regeneration during endometrial involution in healthy postpartum cows. These molecular changes mirror the activation and resolution of endometrial inflammation during involution previously classified by the degree of neutrophil infiltration. SAA1/2, GATA2, IGF1, SHC2, and SERPINA14 genes may become potential markers for resolution of endometrial inflammation in the postpartum cow.

Evaluation of cytokine expression by blood monocytes of lactating Holstein cows with or without postpartum uterine disease

Whereas neutrophils are the main phagocytic leukocytes, monocytes and macrophages are actively involved in immunomodulation after infection. Recent studies have demonstrated that neutrophil function is impaired by the state of negative energy balance around parturition, and that cows that develop uterine disease have a greater degree of negative energy balance than healthy cows. The objectives of this study were to compare monocyte gene expression and protein secretion of selected cytokines from calving to 42 d after calving in Holstein cows that did or did not develop uterine disease. Real time quantitative RT-PCR (Tumor necrosis factor-α (TNFα), Interleukin (IL)-1β, IL-6, IL-8 and IL-10) and ELISA (TNFα, IL-1β and IL-8) were used to evaluate cytokine response following in vitro stimulation of blood-derived monocytes with irradiated E. coli. Relative to unstimulated cells, E. coli-stimulated monocytes from cows with metritis had lower gene expression of key pro-inflammatory cytokines than healthy cows from calving to 14 d after calving (TNFα at 0, 7, and 14 d after calving, IL-1β and IL-6 at 7 and 14 d after calving; P < 0.05). There were no significant differences between groups for expression of IL-8 or the anti-inflammatory cytokine IL-10. This was due, in part, to higher gene expression in unstimulated monocytes (TNFα, IL-1β, IL-6 and IL-10) in early lactation from cows with metritis. Expression of mRNA in stimulated cells (relative to housekeeping genes) was lower for TNFα (7 and 14 d postpartum) and for IL-10 (7 and 14 d postpartum) in cows with metritis. Concentration of TNFα was lower in the culture medium of E. coli-stimulated monocytes from cows with metritis than healthy cows at calving and 7 and 21 d after calving (P < 0.05). Circulating cytokine concentrations were not different between groups for IL-8 and were below the limits of detection for TNFα and IL-1β. Cytokine gene expression and production were similar between healthy cows and cows that developed endometritis, diagnosed cytologically at 42 d after calving. We concluded that altered levels of expression and production of pro-inflammatory cytokines postpartum could contribute to impaired inflammatory response and predispose cows to development of metritis.