Upregulation of PD-L1 Expression by Prostaglandin E2 and the Enhancement of IFN-γ by Anti-PD-L1 Antibody Combined With a COX-2 Inhibitor in Mycoplasma bovis Infection

Bovine mycoplasmosis caused by Mycoplasma bovis results in pneumonia and mastitis in cattle. We previously demonstrated that the programmed death 1 (PD-1)/PD-ligand 1 (PD-L1) pathway is involved in immune dysfunction during M. bovis infection and that prostaglandin E₂ (PGE₂) suppressed immune responses and upregulated PD-L1 expression in Johne's disease, a bacterial infection in cattle. In this study, we investigated the role of PGE₂ in immune dysfunction and the relationship between PGE₂ and the PD-1/PD-L1 pathway in M. bovis infection. In vitro stimulation with M. bovis upregulated the expressions of PGE₂ and PD-L1 presumably via Toll-like receptor 2 in bovine peripheral blood mononuclear cells (PBMCs). PGE₂ levels of peripheral blood in infected cattle were significantly increased compared with those in uninfected cattle. Remarkably, plasma PGE₂ levels were positively correlated with the proportions of PD-L1⁺ monocytes in M. bovis-infected cattle. Additionally, plasma PGE₂ production in infected cattle was negatively correlated with M. bovis-specific interferon (IFN)-γ production from PBMCs. These results suggest that PGE₂ could be one of the inducers of PD-L1 expression and could be involved in immunosuppression during M. bovis infection. In vitro blockade assays using anti-bovine PD-L1 antibody and a cyclooxygenase 2 inhibitor significantly upregulated the M. bovis-specific IFN-γ response. Our study findings might contribute to the development of novel therapeutic strategies for bovine mycoplasmosis that target PGE₂ and the PD-1/PD-L1 pathway.

152 An effective method of inducing oestrus in superovulation-treated Japanese Black donor cows after egg collection

The objective of this study was to evaluate the effect of inducing oestrus in superovulation-treated Japanese Black donor cows after egg collection using a controlled internal drug release (CIDR) device and prostaglandin F2α treatments. The test animals were 50 biparous or triparous Japanese Black cows that had been treated for superovulation during the period of 75-110 days post-calving and from each of which 10 or more ova or embryos had been recovered using a uterine reflux method. In the 25 cows of the control group that received the conventional treatment, a CIDR was not introduced into the vagina, the number of days from egg harvesting to standing oestrus was recorded, and AI was performed using frozen semen. At the time of AI, 50µg of gonadotrophin-releasing hormone (GnRH; Consultan, Aska Animal Health) was administered intramuscularly. The cows that did not conceive in the first AI attempt were again given the same AI and GnRH treatments in the next oestrus cycle. In the 25 cows of the treatment group, a CIDR (CIDR 1900, Zoetis) device was inserted in the vagina after egg harvesting and was kept there for 12 days. At the time of insertion and removal of the CIDR, 150µg of d-cloprostenol formulation (Dalmazin, Kyoritsu Seiyaku) was administered intramuscularly. The number of days from egg harvest to standing oestrus was recorded, and GnRH was administered at the time of AI. The cows that did not conceive in the first AI attempt were given the same AI and GnRH treatments in the next oestrus cycle. The control and treatment groups were compared for the number of days from egg harvesting to oestrus (t-test) and the conception rate after AI (chi-square test). The mean number of days from egg collection to standing oestrus in the control group was 38.6±11.9, and the conception rate was 60% (15/25). Among the animals that failed to conceive in the first AI attempt, the second standing oestrus occurred 60.7±13.1 days after egg collection, and 70% (7/10) of the cows conceived after the second AI. In the treatment group, on the other hand, the mean number of days from egg collection to standing oestrus was 15.8±3.9, and 72% (18/25) of the cows conceived after the first AI. Among the cows that failed to conceive, the second standing oestrus occurred 37.4±4.7 days after egg harvest, and 71% (5/7) of the cow conceived after the second AI. There was a significant difference between the two groups in the number of days from egg collection to the first standing oestrus (P<0.05). The results described above suggest that keeping a CIDR in the vagina for 12 days and intramuscularly administering prostaglandin F2α at the time of insertion and removal of the CIDR in superovulated cows are effective for early onset of standing oestrus after egg collection and thus can reduce the number of days to conception.

Bovine milk transcriptome analysis reveals microRNAs and RNU2 involved in mastitis

Mastitis is a common inflammatory infectious disease in dairy cows. To understand the microRNA (miRNA) expression profile changes during bovine mastitis, we undertook a genome-wide miRNA study of normal milk and milk that tested positive on the California mastitis test for bovine mastitis (CMT+). Twenty-five miRNAs were differentially expressed (23 miRNAs upregulated and two downregulated) during bovine mastitis relative to their expression in normal milk. Upregulated mature miR-1246 probably derived from a U2 small nuclear RNA rather than an miR-1246 precursor. The significantly upregulated miRNA precursors and RNU2 were significantly enriched on bovine chromosome 19, which is homologous to human chromosome 17. A gene ontology analysis of the putative mRNA targets of the significantly upregulated miRNAs showed that these miRNAs were involved in binding target mRNA transcripts and regulating target gene expression, and a Kyoto Encyclopedia of Genes and Genomes pathway analysis showed that the upregulated miRNAs were predominantly related to cancer and immune system pathways. Three novel miRNAs were associated with bovine mastitis and were relatively highly expressed in milk. We confirmed that one of the novel mastitis-related miRNAs was significantly upregulated using a digital PCR system. The differentially expressed miRNAs were involved in human cancers, infections, and immune-related diseases. The genome-wide analysis of miRNA profiles in this study provides insight into bovine mastitis and inflammatory diseases. DATABASES: The miRNAseq generated for this study can be found in the Sequence Read Archive (SRA) under BioProject Number PRJNA421075 and SRA Study Number SRP126134 (https://www.ncbi.nlm.nih.gov/bioproject/PRJNA421075).

Cytokine levels of peripheral blood mononuclear cells in the clinical cases of Holstein calves infected with Mycoplasma bovis

The immune related factors of peripheral blood mononuclear cells (PBMC) were analyzed in the clinical cases with Mycoplasma (M.) bovis infection. Seventy-eight Holstein calves in one farm were used. These calves were divided into three groups; the calves with M. bovis infection of poor outcome after treatment (Non-Recovery Group), the calves with M. bovis infection recovered (Recovery Group) and clinically healthy calves (Control Group). Blood samples were collected at days of the first medical treatment and the final treatment or euthanasia. IL-17A levels in the Non-Recovery Group were higher than those in the Recovery Group on both days. Our result suggested that the IL-17A of PBMC is an important factor to affect outcome of the calves with M. bovis infection.

Effect of Mycoplasma bovis on expression of inflammatory cytokines and matrix metalloproteinases mRNA in bovine synovial cells

Mycoplasma bovis causes chronic arthritis in calves. Mycoplasma arthritis shows severe inflammatory reactions in joints that is commonly treated with antibiotics and results in significant economic losses in the calf industry. A previous study showed that inflammatory cytokines and matrix metalloproteinases (MMPs) produced by synovial cells promote progression of the pathophysiology of bacterial arthritis. However, the mechanism underlying the pathogenesis of bovine Mycoplasma arthritis has not been fully clarified. In this study, we examined the immunologic response of bovine synovial tissue to M. bovis. We observed significant increases in expression of interleukin (IL)-1β, IL-6, IL-8, MMP-1, and MMP-3 mRNA in synovial tissue from Mycoplasma arthritis calves compared with tissues from normal calves. Expression of IL-6, IL-8, and MMP-1 mRNA was also induced in cultured synovial cells stimulated with M. bovis, but not expression of IL-1β and MMP-3 mRNA. In contrast, the culture supernatant of peripheral blood mononuclear cells stimulated with M. bovis induced marked increases in the expression of IL-1β, IL-6, IL-8, MMP-1, and MMP-3 mRNA in synovial cells. Our results indicate that inflammatory cytokines and MMPs produced by synovial cells play a key role in the pathogenesis of Mycoplasma arthritis. We suggest that interactions between synovial cells and mononuclear cells in the presence of M. bovis induce expression of these cytokines and MMPs in synovial cells, resulting in severe inflammatory reactions in the joints.

Low-field magnetic resonance imaging and computed tomography of a calf with aqueductal stenosis caused by web: comparison with normal calves

A 6-day-old female Holstein displayed a dome-shaped skull and cardiac murmur on physical examination. Neurological abnormalities included progressive ataxia, decreased pupillary light reflex, and blindness soon after birth. On diagnostic imaging, CT identified expanded ventricles and thyroid hypoplasia on the left side. MRI detected expanded ventricles, especially in the rostral cerebrum at the mesencephalic aqueduct, compared with normal calves, so we suspected hydrocephalus causing stenosis of the mesencephalic aqueduct. Postmortem examination revealed a structure in the mesencephalic aqueduct resembling the “web” type of aqueductal stenosis described in humans. This case report indicates the utility of describing mesencephalic aqueductal stenosis by web and detection of other malformations on CT and MRI for antemortem diagnosis in calves.

195 Effect of feeding a licorice extract to Japanese Black cows on embryo production performance after superovulation treatment

The objective was to determine the effect of feeding a licorice extract that contains glycyrrhizic acid, which is known to have a liver function-enhancing effect, on embryo production performance after superovulation treatment in Japanese Black cows. Japanese Black breed cows (n=136) that had calved 1 to 4 times and had normal uteri as seen by ultrasonography after at least 40 days from the last calving were used as test animals. Animals in the treatment group (n=90) were continuously fed 20g head−1 d−1 of a licorice extract (Kanzou, Fabric Onishi Co. Ltd., Osaka, Japan), with at least 13% glycyrrhizic acid content) once a day, mixed with the formula feed, for 60 to 90 days starting from around the day of calving until ova/embryos were collected. The control group (n=46) received no Kanzou from the day of the last calving until ova/embryo collection. A total of 20 Armour units (AU) of FSH (Antorin R, Kyoritsu Seiyaku Corporation, Kanagawa, Japan) from porcine pituitary was given intramuscularly (IM) twice a day, morning and evening, for 3 consecutive days (decreasing dose schedule: 5 AU×2, 3 AU×2, and 2AU×2) as the superovulation treatment to the cows at 8 to 11 days post-oestrus in both groups. Prostaglandin F2α 25mg and 15mg (IM) were administered in the morning and evening, respectively, on the third day of FSH administration. Artificial insemination was done at 12 and 24h after the start of oestrus, and ova/embryos were collected using a uterine reflux method on Day 7 post-oestrus. The mean numbers of ova/embryos and transferable embryos collected and the mean embryo quality scores (according to the IETS guidelines) in the treatment and control groups were compared by t-test. A chi-squared test was used to compare the proportion of transferable embryos in the 2 groups. There was no significant difference in the mean number of ova/embryos retrieved between the treatment group (21.7±11.8) and the control group (15.8±11.3), although the former tended (P=0.07) to yield more ova/embryos. There was significant difference (P<0.05) in the mean number of transferable embryos collected in the treatment group (13.1±8.3) than in the control group (8.1±5.3). The mean embryo quality score was significantly greater (P<0.01) in the treatment group (1.6±0.4) than in the control group (2.2±0.6). The proportion of transferable embryos in the treatment group (60.3±26.4%) was also significantly higher (P<0.05) than in the control group (51.2±26.0%). In conclusion, feeding a licorice extract to Japanese Black cows for 60 days or longer improves the quality of embryos obtained after superovulation treatment and leads to an increase in the mean number of transferable embryos per cow.

Bacteriological survey of bulk tank milk from dairy farms in Montero, Santa Cruz, Bolivia

Background and Aim:

Recently, bacterial surveys for mastitis-causing pathogens in bulk tank milk (BTM) have been conducted in several countries worldwide. However, no such surveys have been reported from Bolivia. Therefore, the present study aimed to estimate the prevalence of mastitis pathogens in BTM from dairy farms in Montero, Santa Cruz, Bolivia.

Materials and Methods:

Between July 2016 and August 2017, a total of 43 BTM samples were collected from 3264 cows to determine bulk tank somatic cell counts (BTSCC) and identify mastitis-causing bacteria. BTSCC was classified as follows: <100×10³, 100-500×10³, 500-1000×10³, and >1000×10³ cells/mL.

Results:

Mastitis-causing pathogens identified by agar medium cultures included Bacillus spp., coagulase-negative staphylococci (CNS), coliforms, Staphylococcus aureus (SA), streptococci, and other species. The proportions of BTSCC of <100×10³, 200-500×10³, 500-1000×10³, and >1000×10³ cells/ml were 0%, 37%, 51%, and 12%, respectively. The proportions of coliforms, streptococci, CNS, Bacillus spp., SA, and others detected in BTM were 33%, 30%, 16%, 7%, 2%, and 16%, respectively.

Conclusion:

Although the herd prevalence of contagious mastitis-causing pathogens, such as SA, in BTM was low, increased BTSCC were identified in Montero, Santa Cruz, Bolivia.

Increase of cells expressing PD-1 and PD-L1 and enhancement of IFN-γ production via PD-1/PD-L1 blockade in bovine mycoplasmosis

Introduction

Bovine mycoplasma, chiefly Mycoplasma bovis, is a pathogen that causes pneumonia, mastitis, arthritis, and otitis media in cattle. This pathogen exerts immunosuppressive effects, such as the inhibition of interferon production. However, the mechanisms involved in bovine mycoplasmosis have not been fully elucidated. In this study, we investigated the role of the programmed death‐1 (PD‐1)/programmed death‐ligand 1 (PD‐L1) pathway in immunosuppression in bovine mycoplasmosis.

Methods

In the initial experiments, we used enzyme‐linked immunosorbent assay to measure interferon‐γ (IFN‐γ) from peripheral blood mononuclear cells (PBMCs) isolated from cattle with mycoplasmosis.

Results

Expectedly, IFN‐γ production significantly decreased in cattle with mycoplasmosis compared with that in clinically healthy cattle. Concomitantly, flow cytometric analysis revealed that the proportions of PD‐1⁺CD4⁺ and PD‐L1⁺CD14⁺ cells significantly increased in peripheral blood of the infected cattle. Interestingly, the number of PD‐1⁺CD4⁺ and PD‐1⁺CD8⁺ T cells were negatively correlated with IFN‐γ production from PBMCs in bovine mycoplasmosis. Additionally, blockade of the PD‐1/PD‐L1 pathway in vitro by anti‐bovine PD‐1‐ and anti‐bovine PD‐L1 antibodies significantly upregulated the production of IFN‐γ from anti‐mycoplasma‐specific cells.

Conclusions

These results suggest that the PD‐1/PD‐L1 pathway could be involved in immune exhaustion of bovine mycoplasma‐specific T cells. In conclusion, our study opens up a new perspective in the therapeutic strategy for bovine mycoplasmosis by targeting the immunoinhibitory receptor pathways.

Inflammation-related microRNA expression level in the bovine milk is affected by mastitis

MicroRNA (miRNA) in tissue and liquid samples have been shown to be associated with many diseases including inflammation. We aimed to identify inflammation-related miRNA expression level in the bovine mastitis milk. Expression level of inflammation-related miRNA in milk from mastitis-affected and normal cows was analyzed using qPCR. We found that expression level of miR-21, miR-146a, miR-155, miR-222, and miR-383 was significantly upregulated in California mastitis test positive (CMT+) milk. We further analyzed these miRNA using a chip-based QuantStudio Digital PCR System. The digital PCR results correlated with those of qPCR, demonstrating upregulation of miR-21, miR-146a, miR-155, miR-222, and miR-383 in CMT+ milk. In conclusion, we identified miRNA that are upregulated in CMT+ milk. These miRNA exhibited sensitivity and specificity greater than 80% for differentiating between CMT+ milk and normal milk. Our findings suggest that inflammation-related miRNA expression level in the bovine milk was affected by mastitis, and miRNA in milk have potential for use as biomarkers of bovine mastitis.

Particle-Induced X-ray Emission Analysis of Zierum Trace and Major Elements in Cattle with Acute Coliform Mastitis

The aim of the present study was to examine the applicability of the direct determination of trace and major element concentrations in serum samples collected from Holstein dairy cattle with acute coliform mastitis (n = 53) compared with a healthy control group (n = 39). Twenty-eight elements (Na, Mg, Al, Si, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ce, Ni, Cu, Zn, Ga, As, Se, Br, Rb, Sr, Y, Zr, Nb, Mo, and Pb) were detected by particle-induced X-ray emission (PIXE). Significant differences were observed in serum K, Fe, Zn, and Br concentrations, but not in those of the remaining twenty-four elements. Furthermore, serum Fe concentrations (0.751 ± 0.583 μg/ml, n = 18) were significantly lower in dairy cattle with a poor prognosis than in those with a good prognosis (0.945 ± 0.393 μg/ml, n = 35, P < 0.05) and healthy controls (1.458 ± 0.391 μg/ml, n = 39, P < 0.01). We proposed a diagnostic cut-off point for serum Fe concentrations of <0.82 μg/ml based on receiver operating characteristic (ROC) curves in order to identify cattle with a poor prognosis. The results of the present study indicated that assessing the elemental composition of serum, particularly iron, is a promising prognostic tool for determining the outcomes of cattle with severe acute coliform mastitis.

Sero-epidemiological analysis of vertical transmission relative risk of Borna disease virus infection in dairy herds

Borna disease virus (BDV) is a virus that causes a neurological disease in domestic animals, including a variety of animal species in Japan. Few studies have examined the mode of transmission of this virus in cattle, and the exact mechanisms underlying the transmission of the virus need to be elucidated. This study aimed to examine the contribution of vertical transmission of the virus, which occurs when the virus is transmitted from the mother to offspring during gestation or birth. We used an epidemiological approach. The relative risk (RR) was calculated for cattle born to BDV sero-positive cows from farms with a higher within-herd prevalence of BDV (56.8%). We tested the sera of 1,122 dairy cattle from 24 dairy herds in Hokkaido Prefecture, Japan, for BDV infection using the ELISA and western blotting method. The overall level of BDV sero-prevalence was 22.1%. Seroprevalence was significantly higher in closed-breeding herds that do not have buying in cows (39.7%) than in farms that restock cattle by buying in cows (4.4%, P<0.01). The overall RR of BDV vertical transmission from infected mothers to their daughters was 1.86 (95% confidence interval (CI): 1.54–2.56). Our results show that vertical transmission contributes significantly to BDV transmission in the farms tested in this study.

Primary ischial osteosarcoma occupying the pelvic cavity in a Japanese Black cow

A 10-year-old Japanese Black cow presented with a swelling of the right femur, and a hard, large mass occupied the pelvic cavity. The mass strongly adhered to the visceral surface of the ischium and had posteriorly invaded among the right femoral muscles. Histologically, the mass was composed of neoplastic osteoblasts and exhibited osteoid and immature trabecular bone production. In the region where the mass adhered to the ischium, neoplastic cells were continuously proliferating into the medullary cavity. Tumor emboli were observed in the small vessels of the femoral muscles and lungs. Based on these findings, the mass was diagnosed as an osteosarcoma and considered to have arisen from the ischium.

Testicular yolk sac tumor of myxomatous, reticular, and polyvesicular vitelline type in a newborn calf

Yolk sac tumors (YSTs) are rare neoplasms of germ cell origin. In humans, the tumors primarily occur in the testes or ovaries, but occasionally develop at other sites. The neoplastic cells of YSTs form many histological patterns resembling embryonal structures, and the World Health Organization classification lists 11 such patterns: reticular, macrocystic, endodermal sinus, papillary, solid, glandular-alveolar, myxomatous, sarcomatoid, polyvesicular vitelline, hepatoid, and parietal. Among domestic animals, only 2 cases of YST, which were of testicular and abdominal cavity origin, have been reported in calves. In both cases, neoplastic cells had epithelial properties and disseminated metastases in the abdomen. In the present study, the enlarged testis of a newborn calf, which was subsequently diagnosed as YST and exhibited myxomatous, reticular, and polyvesicular vitelline histological patterns, is described. There was no metastasis in this case, and histological and immunohistochemical features varied from previous cases of YST.

Changes in leukocyte populations of cows with milk fever or displaced abomasum after calving

Most of the metabolic diseases of dairy cows occur within the first 2 wk after calving, and cows with a metabolic disease are prone to infectious diseases. Although metabolic diseases are generally recognized as a risk factor for infectious diseases owing to the associated decrease in immune function, the difference in immune status between cows with milk fever (MF) or displaced abomasum (DA) during the lactation period has not been clarified. Therefore, the peripheral blood leukocyte populations in 38 multiparous Holstein cows from 1 herd were analyzed after calving. The cows were divided into 3 groups according to health: 21 cows that remained clinically healthy throughout the experimental period (control group), 9 cows that had MF on the day of calving, and 8 cows with an onset of DA within 4 wk after calving. The T- and B-cell numbers were lowest at week 0, and they increased gradually after calving. There was no significant difference between the 3 groups in the number of each subset of leukocytes on the day of calving, but the number of CD8⁺ T-cells was significantly lower in the MF and DA groups than in the control group at week 1. The numbers of CD4⁺, CD8⁺, and WC1⁺ T-cells tended to be lower in the DA group than in control group from weeks 4 to 12, a tendency not observed in the MF group. These data suggest that when cows have DA around the time of calving, their lymphocyte numbers remain lower until 12 wk after calving.

Polymeric immunoglobulin receptor expression and local immunoglobulin A production in bovine sublingual, submandibular and parotid salivary glands

The submandibular and parotid glands are the main sources of immunoglobulins A (IgAs) in human and rat saliva. These glands express the polymeric immunoglobulin receptor (pIgR), which transports IgAs into saliva. The main source of IgAs in saliva and pIgR expression in salivary glands has not been well documented in cattle. Expressions of pIgR were determined in the major bovine salivary glands (sublingual, submandibular, and parotid) by RT-PCR for mRNA and by Western blot analysis and immunohistochemistry (IHC) using an anti-human pIgR antibody for protein. The protein detected with the antibody was identified by nano-liquid chromatography-quadrupole time of flight mass spectrometry. Additionally, the distribution of Ig-producing plasma cells was analyzed by IHC. RT-PCR showed that pIgR was expressed in the sublingual and submandibular glands, but not in the parotid gland. Higher protein levels were observed in sublingual glands than in submandibular glands by Western blot. By IHC, pIgR was mainly located on the apical side of the cytoplasmic membrane in the sublingual gland, whereas it was observed only on the basal side in the submandibular gland. The highest density of plasma cells expressing IgAs was observed in the sublingual gland. These results suggest that the sublingual gland plays an important role in first-line defence of the oral cavity in cattle in contrast to humans and rats.

Short communication: effects of serum obtained from dairy cows with low or high body condition score on in vitro embryo development

The objective of the study was to determine whether the serum obtained from animals differing in body condition score (BCS) affects in vitro embryo development. After in vitro fertilization, serum obtained from dairy cows of either low (L-BCS; 2.1 ± 0.14 on a scale of 1 to 5) or high BCS (H-BCS; 4.0 ± 0.0), or commercially available bovine serum (control) was added at 5% concentration to the in vitro culture medium. Use of serum obtained from H-BCS cows increased the cleavage rates compared with control serum at both 24 and 48 h after in vitro fertilization (78.3 vs. 71.9% and 79.9 vs. 75.1%, respectively), whereas use of serum obtained from L-BCS cows increased the blastocyst rate compared with control serum at 7d (23.8 vs. 19.1%), but this difference was not evident at 8 or 9 d after in vitro fertilization. As nonesterified fatty acid concentrations were highest in control serum, followed by serum from L-BCS and H-BCS cows (621, 559, and 272 μEq/L, respectively), a high concentration of nonesterified fatty acids might adversely affect the very early stages of embryo development, and its negative effects might be greater immediately after fertilization compared with developmental stages after morula formation. Our findings also indicate that factors promoting early stage embryo development do not necessarily promote blastocyst development. Serum obtained from animals under different physiological conditions may be used for in vitro embryo culture to study the effects of nutritional management of dairy cattle on embryo development.

Analysis of trace and major elements in bronchoalveolar lavage fluid of Mycoplasma bronchopneumonia in calves

The aim of this study was to evaluate the reliability and effectiveness of direct determination of trace and major element concentrations in bronchoalveolar lavage fluid samples from Holstein calves with Mycoplasma bronchopneumonia (n = 21) and healthy controls (n = 20). The samples were obtained during bronchoscopy using a standard examination method. A total of 18 elements (aluminum, bromine, calcium, chlorine, chromium, copper, iron, potassium, magnesium, manganese, molybdenum, nickel, phosphorous, sulfur, silicon, strontium, titanium, and zinc) were detected by particle-induced X-ray emission. The average bromine, iron, potassium, magnesium, and phosphorous concentrations were higher in calves with bronchopneumonia than in controls (p < 0.05). They were found to have higher amounts of calcium and zinc, and a higher zinc-copper ratio than that in healthy calves (p < 0.001). Based on the receiver operating characteristics curves, we propose a diagnostic cutoff point for zinc-copper ratio for identification of Mycoplasma pneumonia of 8.676. Our results indicate that assessment of the elemental composition of broncholaveolar lavage fluid is a promising diagnostic tool for Mycoplasma bronchopneumonia.

The influence of Borna disease viral infection on dairy cow reproduction

We investigated the influence of Borna disease virus (BDV) infection on the clinical state of dairy cows. Sera from 149 cows were examined using enzyme-linked immunosorbent assay and western blotting detect antibodies to the BDV-nucleoprotein antigen. Among 149 investigated cows, 25 (16.8%) showed a positive reaction to BDV antigen. No significant difference existed in milk production or medical history between seropositive and seronegative cows. Although the estrus cycle appeared normal even in the seropositive cows, the frequency of artificial insemination and calving-to-conception intervals significantly increased in seropositive cows. Therefore, fertilization failure was recognized in the BDV-antibody positive cows.

Refinement of Crystallographic Parameters in Refractory Metal Disilicides

The crystallographic structures of seven refractory metal (Ti, V, Cr, Nb, Mo, Ta and W) disilicides with the C11b, C40 and C54 structures have been refined through analysis of single-crystal X-ray diffraction data. Crystallographic parameters refined are lattice constants, atomic parameters and the space group of the C40 disilicides. In most of previous studies, silicon atoms have been considered to locate at the ideal positions so that the refractory metal atoms are perfectly six-fold coordinated in RSi2 layers prevailing in all the three structures. The present analysis shows that the silicon atoms are displaced from the ideal positions. The magnitude of such displacement is found to be closely related to the interatomic distance in these pseudo-hexagonally arranged RSi2 layers. The space group of three of the four C40 disilicides, VSi2, CrSi2 and TaSi2, is determined to be P6422, which is of chirality with respect to that (P6222) assigned in the previous studies.

Genetic analysis and development of species-specific PCR assays based on ITS-1 region of rRNA in bovine Eimeria parasites

At present, morphological characteristics of oocyst is the only achievable method for the identification of bovine coccidia to the species level. In this study, the internal transcribed spacer 1 (ITS-1) region of ribosomal RNA genes of six bovine Eimeria species; E. alabamensis, E. auburnensis, E. bovis, E. cylindrica, E. ellipsoidalis and E. zuernii, were sequenced and analyzed the phylogenetic relationship among them. In pair-wise alignment, the sequences among the same species had high homology of over 90%. E. bovis and E. zuernii were closely related within the same cluster. This cluster and E. alabamensis were distant from major cluster of bovine coccidia that included E. auburnensis, E. cylindrica and E. ellipsoidalis. Species-specific PCR assays based on the amplification of the ITS-1 region were also developed to identify the 6 pathogens. The ITS-1 region of each Eimeria species had sufficient inter-specific sequence variation enough to design the primer sets that differentially amplified each target species. This PCR assay for the detection and differentiation of Eimeria parasite showed higher sensitivity when compared to the conventional oocyst-morphological examination. This is the first attempt for the identification of 6 bovine Eimeria parasites in the genomic level and may provide as useful methods for diagnosis and epidemiology of bovine coccidial infection.

Non-cytopathic bovine viral diarrhea virus infection inhibits differentiation of bovine neural stem/progenitor cells into astrocytes in vitro

Bovine viral diarrhea virus (BVDV) causes fetal brain malformations in ruminants when the fetuses are infected transplacentally in mid-pregnancy. In both cytopathic and non-cytopatic virus infections, viral lytic infection in actively replicating cells and interruption of vascular integrity have been suggested as the pathogenesis, but functional disturbance of infected neural developing cells has been unclear. In this study, we examined the effect of infection with non-cytopathic BVDV2 on the differentiation of neural stem/precursor cells isolated from the bovine fetus. In the process of differentiation to three types of neural cells, neurons, astrocytes and oligodendrocytes, virus infection significantly and selectively inhibited the differentiation of neural stem/precursor cells into the astrocytic lineage. This inhibition is possibly important for the pathogenesis of congenital brain malformations associated with non-cytopathic BVDV infection.

Hemophagocytic Histiocytic Sarcoma in a Japanese Black Cow

At necropsy, an 11-year-old Japanese Black cow with anemia, leukocytopenia, and progressive hind limb ataxia had marked diffuse splenomegaly and multiple masses in the thoracic vertebrae. Histologically, neoplastic erythrophagocytic histiocytes were in the splenic red pulp, vertebral masses, and blood vessels of the liver and lungs. The spinal cord was compressed by the vertebral masses. Clinicopathological, macroscopic, and histologic findings were consistent with hemophagocytic histiocytic sarcoma. Vertebral involvement with spinal cord compression and resultant hind limb ataxia is an unusual presentation for this tumor, which has been described mainly in dogs and cats.

Comparison of the alkalizing effects of bicarbonate precursors in calves with experimentally induced metabolic acidosis

The aims of this study were to confirm whether commercial acetated Ringer's solution, which contains 28 mM of sodium acetate, is superior to commercial lactated Ringer's solution in alkalizing effects in calves with experimentally induced metabolic acidosis. Twenty calves with experimentally induced mild acidosis were intravenously administered isotonic saline, DL-lactated, L-lactated or acetated Ringer's solution at a dose of 80 ml/kg body weight (BW). The acetated Ringer's solution induced a significantly greater increase in venous HCO(3)(-) and base excess concentrations than the other fluids during the early phases of extracellular fluid replacement in mild metabolic acidosis. Therefore, the alkalizing effect of commercial acetated Ringer's solution is superior to commercial DL- and L-lactated Ringer's solution in treatment of mild metabolic acidosis in calves.

Two cases of bovine sarcoma in clinically long-standing lesions

Histopathological examination of clinically long-standing lesions with durations of one year or more in the extremities of two cattle revealed the presence of sarcomas with distant metastases. In case 1, neoplastic cells were fusiform to pleomorphic, stained for no specific differentiation markers, and diagnosed as undifferentiated sarcoma. Neoplastic growth in case 2 was composed of spindle to histiocytoid cells and a significant number of multinucleated giant cells, both of which were immunoreactive to histiocyte markers, and diagnosed as giant cell malignant fibrous histiocytoma. Neoplastic cells of both cases were immunohistochemically positive for nitric oxide-related antigens, which were recognized as markers of inflammation-induced carcinogenesis in human and laboratory animals.

Epithelioid cells in mediastinal lymph nodes of cattle without cancer

Epithelioid cells are found in lymph nodes in cases of metastatic carcinoma; however, epithelioid cells with benign features have also been discovered incidentally in lymph nodes. Epithelioid cells were observed in mediastinal lymph nodes of cattle without cancer during routine diagnostic necropsy. To explain this finding, the authors evaluated the prevalence and histopathologic, immunohistochemical, and ultrastructural features retrospectively using mediastinal lymph nodes from 110 cattle and found that 66 of the lymph nodes contained epithelioid cells. In all 66 nodes, most of the epithelioid cells were individual or aggregated in nodal sinuses; in 21 nodes, some epithelioid cells formed tubular structures. The individual and aggregated epithelioid cells were mostly considered to be mesothelial in origin by immunohistochemical and ultrastructural examination; presumably, they entered the lymph nodes via lymphatic vessels, because they were found in afferent lymphatic vessels and nodal sinuses. Although the presence of epithelioid cells in lymph nodes prompts suspicion of metastatic carcinoma, the epithelioid cells in these bovine lymph nodes did not disrupt nodal architecture, lacked atypia or mitotic figures, and did not invade nodal parenchyma.

Feeding activated charcoal from bark containing wood vinegar liquid (nekka-rich) is effective as treatment for cryptosporidiosis in calves

The effect of activated charcoal containing wood vinegar liquid (Nekka-Rich) on Cryptosporidium parvum was evaluated in vitro and in vivo. First, the adsorption of C. parvum by the activated charcoal component of Nekka-Rich was examined. When mixed, C. parvum oo-cysts were effectively adsorbed by activated charcoal. Next, the effect of the wood vinegar liquid component of Nekka-Rich was assessed. Wood vinegar liquid had an antiprotozoan activity against C. parvum oocysts. Finally, the anticryptosporidial effect of Nekka-Rich was evaluated in calves experimentally infected with C. parvum. Six neonatal calves at 7 d of age were orally infected with 1 x 10(5) oocysts of C. parvum. When diarrhea was observed (on d 3 after the experimental infection), 3 calves received a milk replacer containing 10 g of Nekka-Rich at 8-h intervals for 4 consecutive days, and 3 control calves were given a milk replacer without Nekka-Rich at 8-h intervals for 4 consecutive days. Calves fed milk with Nekka-Rich showed recovery from diarrhea 1 d after the start of treatment. Significantly less fecal excretion of C. parvum oocysts was observed 1 d after treatment in calves fed Nekka-Rich. On d 2 from the beginning of treatment with Nekka-Rich (on d 5 after the experimental infection), oocysts were not isolated from fecal samples. On the other hand, nontreated control calves developed severe diarrhea, and fecal excretion of oocysts was consistently observed. Calves in both groups were killed for collection of samples, which were subjected to scanning electron microscopy. Scanning electron microscopy revealed adherence of C. parvum oocysts to the intestinal epithelial surface of nontreated control calves, whereas a lack of C. parvum adhesion was observed in calves fed Nekka-Rich. These results suggest that Nekka-Rich would be useful for the treatment of cryptosporidiosis in neonatal calves.

Detection of bovine torovirus in fecal specimens of calves with diarrhea in Japan

The aim of this study was to determine the prevalence of bovine torovirus (BoTV) in bovine fecal samples and to determine whether a relationship exists between BoTV and diarrhea in Japan. Ninety-nine diarrheic and 114 normal fecal samples from calves in Hokkaido Prefecture and 38 diarrheic fecal samples from calves in 10 other prefectures were examined by reverse transcription (RT)-PCR with primers designed in the spike (S) gene for the presence of BoTV. The specimens were also examined for the presence of other enteric pathogens, bovine rotavirus, coronavirus and Cryptosporidium spp. BoTV RNA was detected in 15 (15.2%) of the 99 diarrheic samples from Hokkaido and in 9 (23.7%) of the 38 diarrheic samples from the other prefectures. The incidence of BoTV in control specimens was 7.0%. In 11 of the 15 BoTV-positive specimens from Hokkaido, BoTV was the only pathogen detected among those examined, and 11 BoTV-positive specimens were obtained from calves less than 2 weeks of age. Rotavirus was confirmed to be associated with calf diarrhea, but coronavirus and Cryptosporidium spp. were not. Nucleotide sequences of 17 different BoTV RT-PCR products were determined. Phylogenetic analysis based on the sequences revealed that Japanese BoTVs could be classified into at least two groups. This study showed that BoTV is a common virus in fecal specimens of calves with diarrhea in Japan and may be an important pathogen of cattle, principally in young calves less than 2 weeks of age.

Comparison of the insulin reaction of peripheral blood T cells between healthy Holstein dairy cows and JB during the periparturient period

To compare the changes in the insulin reaction of Holstein dairy cows and Japanese Black cows (JB) during the periparturient period, the insulin resistance test in vivo and lymphocytes proliferation with insulin in vitro were performed. Ten healthy Holstein dairy cows (Holstein group) and 10 healthy JB cows (JB group) used in this study were observed on days 60, 40, and 20 before calving and days 7 and 20 after calving. In insulin resistance reaction in vivo and in vitro, a low insulin-stimulated glucose disposal rate and lymphocyte proliferation with insulin were observed in the Holstein group compared with the JB group during the experimental period. An analysis of the lymphocytes cultured with insulin showed that the percentage of CD4+CD45R- T cells in the Holstein group was significantly lower than that of the JB group before day 20. These findings indicate that T cells reaction to insulin in healthy periparturient Holstein cows is lower than that in Japanese Black.

A new method for detecting the abomasal position and characteristics of movement at the onset of the left displacement of the abomasum in cows

A new method has been developed by us to observe the movements of the abomasum by using a magnet and digital magnetometer. Four cows with left displacement of the abomasum underwent conventional correction by rolling without tacking. A doughnut-type magnet was sutured to the pyloric region in a routine operation. The same was done in three control cows. The position of the pyloric region was observed with a digital magnetometer from outside the cow's body. The magnets in the pyloric region of the control cows were located at the right side of the abdominal cavity at 10-30 cm anterior to the udder base, and moved slightly in various directions within the span of a day. On the other hand, the magnets in the pyloric region of cows with abomasal displacement moved widely in the abdominal cavity from the normal right side to the abnormal left front side. A large movement of the magnet from the normal right side to the abnormal left side of the abdominal cavity was observed within 12 h of the onset of abomasal displacement.

Dose response to vaginal administration of 1,25-dihydroxyvitamin D3 to cows

It was previously reported that intravaginal (IVAG) administration of 1,25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3)) might be protective against bovine hypocalcaemia. In the present study, various doses of exogenous 1,25(OH)(2)D(3) were administered IVAG to ovariectomised cows, and the subsequent changes in the biochemical parameters of the blood were measured to assess the characteristics of vaginal absorption. Five cows received 1,25(OH)(2)D(3) IVAG at a dose of 0.125, 0.25, 0.5, or 1.0microg/kg of body weight (BW) or intravenously at a dose of 1.0microg/kg BW. Dosing was at intervals of at least two weeks in a 5x5 Latin square design. Vaginally administered 1,25(OH)(2)D(3) was absorbed in a dose-dependent manner. There was no correlation between the IVAG dose of 1,25(OH)(2)D(3) and subsequent changes in plasma calcium concentrations. The bioavailability of 1,25(OH)(2)D(3) administered IVAG at 1.0microg/kg BW was approximately 93%.

Changes in leukocyte population after ozonated autohemoadministration in cows with inflammatory diseases

In this study, we investigated whether ozonated autohemoadministration (OAHA) influences leukocyte populations in cows with clinical inflammatory disease. Eleven cows with inflammatory disease (Inflammatory Group) and three healthy cows (Control Group) were used for this study. The CD4(+)/CD8(+) ratio in the Inflammatory Group increased significantly compared to that in the Control Group 3 to 4 days after OAHA treatment. In the Inflammatory Group, the number of CD14(+) cells decreased gradually after OAHA, but CD14(+) levels remained stable in the Control Group. The number of MHC class-II(+) cells decreased gradually in the Inflammatory Group, but increased gradually in the Control Group, and the difference between the groups was significant on day 14 after OAHA. These findings suggest a possible difference in the activation of immune response after OAHA in infected cows compared to healthy cows.

Comparison of Two Different Nutritive Conditions against the Changes in Peripheral Blood Mononuclear Cells of Periparturient Dairy Cows

To clarify the relationship between cellular immune status and nutritive condition in periparturient dairy cows, feeding content, blood profiles, and immune condition were observed in cows from two dairy herds with different types of feed content. Immunological analyses such as leukocyte population and peripheral blood mononuclear cell (PBMC) mRNA of IFN-gamma, TNF-alpha, IL-4, and IL-10, quantified by real-time RT-PCR were performed. With regard to feed content during dry periods, there were six cows in the herd with insufficient non-structural carbohydrate (NFC) intake (group I) and six cows in the herd with sufficient NFC intake (group II). Significantly lower levels of blood glucose were observed in group I between weeks -12 and 16 compared with group II. Serum cholesterol level was significantly lower in group I between weeks 2 and 10 than in group II. The numbers of CD3+ and CD4+ T cells in group I were significantly lower than those in group II in weeks 6 and 14. The numbers of CD21+ B cells were significantly lower in group I than in group II in weeks -16, -12, 2, and 10. On the other hand, the CD4+/CD8+ ratio in group II was significantly higher than group I between weeks 2 and 14. The IFNgamma/IL-4 mRNA rate in group I was significantly lower than group II in week 6. We concluded that cellular immune depression occurrs after calving in dairy cows with low nutritional status in the periparturient period.

Effect of Nutritional Conditions on Changes in Leukocyte Populations in Japanese Black Calves

To clarify the effect of nutritive conditions on changes in immune cells in Japanese Black (JB) calves during the growth period, leukocyte populations were analyzed in ten healthy JB calves managed in one herd. The calves were divided into two groups: five calves in Group 1 were given insufficient nutrition, and the other five calves in Group 2 received adequate nutrition. The levels of serum total cholesterol and glucose were significantly lower in Group 1 than in Group 2 at 1 month. The numbers of CD3+, CD4+ and CD8+ cells tended to be lower in Group 1 than in Group 2 at months 1 and 2, and the difference in CD4+ was significant at month 2. The number of MHC class-II(+high) cells was significantly lower in Group 1 than in Group 2 at months 1 and 2. These results suggest that adequate nutrition might stimulate an increase in immune cells in calves during the growth period.

Changes in peripheral leukocyte subsets in dairy cows with inflammatory diseases after calving

To clarify the cellular immune system in dairy cows with inflammatory diseases after calving, the leukocyte subsets were examined in Holstein dairy cows. Twenty Holstein cows reared in one herd, were used in this study. Nine cows (Group 1) experienced onset of mastitis or puerperal fever within 2 weeks after calving, and the other eleven cows remained healthy (Group 2) after calving. The numbers of CD3(+), CD4(+) and CD8(+) cells tended to be lower in Group 1 than in Group 2 from the day of calving through week 1. These results suggested that the cows with inflammatory diseases might have experienced a decline in T cells by the day of calving, before the onset of disease.

Technical Note: Vaginal Absorption of 1,25(OH)2D3 in Cattle

Although exogenous 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] administered via intravenous, intramuscular, and oral routes has been tested for efficacy in preventing parturient hypocalcemia in dairy cows, there are few reports concerning intravaginal administration. For this study, 1,25(OH)2D3 was administered via the bovine vaginal lumen, and subsequent changes in blood chemistry, including levels of 1,25(OH)2D3 and several minerals, were measured to confirm vaginal absorption. Each of 5 heifers received a single intravaginal dose of 1 microg of 1,25(OH)2D3/kg body weight; a single control heifer received the ethanol carrier alone. In heifers receiving 1,25(OH)2D3, the plasma 1,25(OH)2D3 levels increased markedly from baseline (88.3 +/- 20.3 pg/mL) within 2 h and reached a peak at 6 h after treatment (1967.4 +/- 1139.6 pg/mL). Plasma Ca levels increased from baseline (10.4 +/- 0.4 mg/dL) to a peak of 11.96 +/- 0.7 mg/dL at 24 h. The levels of inorganic phosphate in plasma increased over time from 7.3 +/- 0.5 to 8.1 +/- 0.8 mg/dL by 6 h and were maintained at a plateau level (9.1 +/- 0.7 to 8.6 +/- 0.6 mg/dL) from 24 to 96 h after treatment. Plasma magnesium decreased from a baseline level of 2.1 +/- 0.1 mg/dL to a plateau level of 1.8 +/- 0.1 mg/dL, which was sustained from 24 to 48 h after treatment. The present study provides evidence of the absorption of exogenous 1,25(OH)2D3 from the bovine vaginal wall, as shown by the marked elevation of plasma 1,25(OH)2D3 levels by 2 h after administration, and indicates the possible utility of intravaginal administration of 1,25(OH)2D3 for prophylaxis of hypocalcemia.

Tetralogy of Fallot in a calf: clinical, ultrasonographic, laboratory and postmortem findings

A 6-month-old female Holstein calf was referred with a history of respiratory distress, anorexia and dehydration. When first examined, a loud harsh murmur was clearly audible from both sides of the thorax. Two-dimensional echocardiography demonstrated a markedly dilated right ventricle and right atrium, hypertrophied myocardium, prominent papillary muscles and a thickened interventricular septum (IVS). A large-sized ventricular septal defect was imaged at the top of the IVS. The aorta was dextrally located and overriding both ventricles. The diagnosis was confirmed as tetralogy of fallot on postmortem examination.

Focal Fatty Liver in a Heifer: Utility of Ultrasonography in Diagnosis

A 30-month-old Holstein heifer presented with a history of decreased appetite and respiratory signs. Sonographic examination of the liver incidentally revealed an area of increased echogenicity between the portal vein and the gallbladder. The lesion was nonspherical and had no mass effect or displacement of the adjacent vessels. Its boundaries, to the liver, were geographic. The liver specimen was histologically compatible with a diagnosis of focal fatty liver change (FFLC). The sonographic features of focal fatty infiltration of the liver are characteristic. Recognition of the ultrasonographic data is important to differentiate FFLC from other lesions.

Changes in peripheral leukocyte populations of weak calf syndrome of Japanese black calves

To clarify the cellular immune condition in Japanese Black (JB) calves with a weak syndrome, peripheral leukocyte populations were analyzed by flow cytometry. Twenty JB calves were divided into two groups based on clinical observations; one group of calves was weak, because they had experienced an onset of diarrhea within 3 days after birth and needed treatment (Group 1 ;n=10), and the other group of calves was healthy (Group 2; n=10). With regard to leukocyte populations, CD8(+) cells and gamma delta T cells in Group 1 were markedly lower than those in Group 2 during the experimental periods. It is possible that immune-insufficiency might be based on T lymphocyte function in weak syndrome JB calves during the growth process.

Micromorphological characteristics of hepatic sinusoidal endothelial cells and their basal laminae in five different animal species

The micromorphological characteristics of hepatic sinusoidal endothelial cells and their basal laminae in five different animal species (cow, sheep, guinea pig, pig, and dog) were studied by electron microscopy. Using transmission electron microscopy, a prominent basal lamina was seen only in cow and sheep. In pig and guinea pig, no prominent basal lamina was evident. Basal lamina-like material was occasionally found in dog. Immunohistochemically, basal lamina was found in cow, sheep, and dog. Using scanning electron microscopy, the size of endothelial fenestrae differed between species. These results may suggest that variation of endothelia and their basal laminae of different species is related to differences in nourishment.