Search

This study aimed to develop a method to evaluate the quality of bovine in vitro fertilized (IVF) embryos based on gene expression profiling via whole-transcriptome amplification. The expression of 11 developmentally important genes in individual bovine in vivo-derived (IVD) and IVF embryos were examined. Gene expression profiling was conducted by classifying the expression level of each gene in individual embryos as low, medium, or high. The IVF group had a higher (P < 0.01) proportion of embryos with low expression of SOX2, NANOG, and FGF4. In addition, a correlation analysis between the expression levels of each gene in individual embryos demonstrated that the relationship between gene expression differed with respect to IVD and IVF embryos. Our results suggest that the expression profiling of developmentally important genes using IVD embryos as normal controls could be a useful indicator for evaluating the quality of bovine IVF embryos.

To identify a biomarker for the early diagnosis of enzootic bovine leukosis (EBL) caused by bovine leukemia virus (BLV), we investigated the expression of a microRNA, bta-miR-375, in cattle serum. Using quantitative reverse-transcriptase PCR analysis, we measured bta-miR-375 levels in 27 samples from cattle with EBL (EBL cattle), 45 samples from animals infected with BLV but showing no clinical signs (NS cattle), and 30 samples from cattle uninfected with BLV (BLV negative cattle). In this study, we also compared the kinetics of bta-miR-375 with those of the conventional biomarkers of proviral load (PVL), lactate dehydrogenase (LDH), and thymidine kinase (TK) from the no-clinical-sign phase until EBL onset in three BLV-infected Japanese black (JB) cattle. Bta-miR-375 expression was higher in NS cattle than in BLV negative cattle (P < 0.05) and greater in EBL cattle than in BLV negative and NS cattle (P < 0.0001 for both comparisons). Receiver operating characteristic curves demonstrated that bta-miR-375 levels distinguished EBL cattle from NS cattle with high sensitivity and specificity. In NS cattle, bta-miR-375 expression was increased as early as at 2 months before EBL onset-earlier than the expression of PVL, TK, or LDH isoenzymes 2 and 3. These results suggest that serum miR-375 is a promising biomarker for the early diagnosis of EBL., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Murakami et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Pregnancy diagnosis during early gestation is important for cattle reproduction. The expression of interferon-stimulated genes (ISGs) in peripheral blood leukocytes (PBLs) was studied in embryo-transferred (ET) Japanese Black cattle. ISGs in PBLs- ISG15 , MX1 , MX2 , and OAS1 -were detected in multiple ovulation ET cattle using a real-time quantitative polymerase chain reaction, and receiver operating characteristic (ROC) curve analysis was performed. Gestational status was predicted using the average ISG levels during the normal estrous cycle (AVE) and the Youden index from the ROC curve analysis as cutoff values. The ISG15 , MX1 , and MX2 levels were significantly higher in pregnant cattle ( n = 10) than in non-pregnant cattle ( n = 23) on gestation day 21, whereas the levels of all ISGs were similar between non-pregnant and non-pregnant cattle with late embryonic death ( n = 7). ISG15 , MX1 , and MX2 appropriately predicted the gestational status of ET cows. The statistical evaluation of the diagnostic accuracy in ET cows on day 21 of gestation presented higher values of sensitivity, specificity, accuracy, and positive predictive values of ISG15, MX1 , and MX2 using the Youden index than using the AVE. Therefore, ISG15 , MX1 , and MX2 are excellent biomarkers of gestational status during the peri-implantation period in ET cattle.

Bovine leukemia virus (BLV) is the causative agent of enzootic bovine leukosis (EBL), a malignant B cell lymphoma. However, the mechanisms of BLV-associated lymphomagenesis remain poorly understood. Here, after deep sequencing, we performed comparative analyses of B cell microRNAs (miRNAs) in cattle infected with BLV and those without BLV. In BLV-infected cattle, BLV-derived miRNAs (blv-miRNAs) accounted for 38% of all miRNAs in B cells. Four of these blv-miRNAs (blv-miR-B1-5p, blv-miR-B2-5p, blv-miR-B4-3p, and blv-miR-B5-5p) had highly significant positive correlations with BLV proviral load (PVL). The read counts of 90 host-derived miRNAs (bta-miRNAs) were significantly down-regulated in BLV-infected cattle compared to those in uninfected cattle. Only bta-miR-375 had a positive correlation with PVL in BLV-infected cattle and was highly expressed in the B cell lymphoma tissue of EBL cattle. There were a few bta-miRNAs that correlated with BLV tax/rex gene expression; however, BLV AS1 expression had a significant negative correlation with many of the down-regulated bta-miRNAs that are important for tumor development and/or tumor suppression. These results suggest that BLV promotes lymphomagenesis via AS1 and blv-miRNAs, rather than tax/rex, by down-regulating the expression of bta-miRNAs that have a tumor-suppressing function, and this downregulation is linked to increased PVL., Competing Interests: The authors have declared that no competing interests exist.

Bovine leukemia virus (BLV) proviral load is controlled by T-cell responses, which require vitamin A (VA) derived from food. However, whether dietary VA restriction for marbling impairs the T-cell responses that control BLV proviral load in beef cattle is unknown. We assessed T-cell subsets, interferon (IFN)-γ gene expression, and BLV proviral load in naturally BLV-infected Japanese Black cattle that were fed a diet with decreased VA levels. We found that the percentage of CD4 + T cells increased over time during dietary VA restriction. In addition, BLV proviral load was negatively correlated with the percentage of CD4 + T cells and with the level of IFN-γ gene expression. These observations suggest that dietary VA restriction for marbling enhances T-cell responses that control BLV proviral load and thus does not promote leukemogenesis in fattening beef cattle., (Copyright © 2021 Elsevier B.V. All rights reserved.)

The blood luteinizing hormone (LH) surge in cows is well studied. However, little is known about urinary LH in cows. This study examined urinary LH concentrations after administration of gonadotropin-releasing hormone (GnRH) in six Japanese black cows to induce LH secretion from the pituitary gland into the bloodstream. Abrupt rises in plasma and urinary LH were observed after GnRH administration. Plasma and urinary LH peaked at 2 and 5 hr, respectively. A positive correlation was observed between plasma LH concentrations and urinary LH amounts. Ovulation was confirmed in the cows after 48 hr of GnRH administration. These data strongly suggest that urinary LH is derived from plasma LH, which triggers ovulation in cows.

A prediction method for early pregnancy status (pregnant or non-pregnant) in cattle that can be used within 3 weeks after insemination is desired. Interferon-stimulated genes (ISGs) in peripheral blood leukocytes (PBLs) have been examined as prediction molecules for determination of pregnancy status. Relative abundances of ISG15 and MX2 gene transcripts in PBLs were suitable biomarkers for the prediction of pregnancy status when there were assessments of Holstein cattle. In the present study, it was determined whether ISG biomarkers are applicable for predicting gestation in Japanese-Black (JB) cattle and evaluation of the applicability of receiver operating characteristic (ROC) analysis procedures for this purpose. There was assessment of the reliability of using average ISG values in PBLs collected during the estrous cycle (AVE) as a cutoff compared to the Youden index cutoff values. Application of AVE to assessment of pregnancy status in JB cattle indicated there was reliable predictions for pregnancy status when using ISG15 and MX2 values on day 21 after insemination, which coincided with the time of assessment in the previous study with Holstein cattle. The area under the curve values of the ROC curves confirmed the reliability of using ISGs to predict pregnancy from days 18 to 21 after insemination. Comparing AVE with Youden index values, there was confirmation of the accuracy of AVE for predicting gestation. The average mRNA transcript abundance values of ISG15 and MX2 may serve as excellent pregnancy biomarkers for cattle within 3 weeks of insemination., Competing Interests: Declaration of Competing Interest The authors declare that they have no competing interests., (Copyright © 2020 Elsevier B.V. All rights reserved.)

The effectiveness of on-farm continuous flow high-temperature short-time (HTST) pasteurization (i.e., 72°C for 15 s) for the inactivation of bovine leukemia virus (BLV) in milk was investigated with a sheep bioassay. Four sheep that had been inoculated with completely pasteurized milk containing approximately 3.4 × 10 7 BLV-infected peripheral blood mononuclear cells (PBMC) and treated by either HTST pasteurization or laboratory-scale low-temperature long-time (LTLT) pasteurization (i.e., 60°C for 30 min), remained negative for BLV for at least 17 weeks after inoculation. In contrast, all sheep inoculated with unpasteurized or inadequately pasteurized milk containing the same number of BLV-infected PBMC were tested positive for BLV and anti-BLV antibodies within 3 weeks after inoculation. These results suggest that on-farm continuous flow HTST pasteurization was equivalent value with inactivated BLV on the LTLT procedure and can effectively inactivate BLV in the milk. Therefore, on-farm HTST pasteurization of the pooled colostrum or milk used in automated feeding systems is likely to protect group-housed preweaned calves from BLV infection, thereby improving animal health on dairy farms., (© 2020 Japanese Society of Animal Science.)

The effect of bovine viral diarrhoea virus (BVDV) infection on early pregnant cows between 10 and 24 days after virus inoculation at day 26 of pregnancy was determined. Four cows were inoculated intravenously with either BVDV (treated, n=3) or growth medium (control, n=1). The treated cows were euthanized on either day 10, 17 or 24 post-infection and the control cow was euthanized on day 24 post-infection. The level of serum 2-5A synthetase increased in all of the three treated cows. Progesterone levels decreased to below 1.0 ng/ml between 10 and 22 days after inoculation in two of the three treated cows and the embryos/foetuses of two cows died. Therefore, BVDV may be a cause of early embryonic or feotal loss in early pregnant cows and serum 2-5A synthetase may be useful as an indicator of viral infection in cows., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

The aim of this study was to validate a direct time-resolved fluoroimmunoassay (TR-FIA) for quantifying progesterone concentrations in milk during the bovine oestrous cycle. Holstein-Friesian and suckled and non-suckled Japanese Black cows were used to demonstrate the relationship between milk and plasma progesterone concentrations and to monitor progesterone profiles in milk and plasma during the oestrous cycle. The minimum detection level of the assay was 1.53ng/mL. Progesterone concentrations in milk and plasma changed in a similar manner throughout the oestrous cycle in dairy and beef cows, and milk and plasma progesterone profiles were significantly correlated (P<0.001). The study confirmed that a direct TR-FIA can be used to monitor the oestrous cycle in cattle and to quantify progesterone concentrations in whole milk., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

The structure of the Y chromosome was investigated by FISH and G banding in 3 cases of bovine XY females shown by PCR to lack the SRY gene. Although 2 different repeat-DNA sequences (BC1.2 and btDYZ-1) hybridized to the short arm of the Y chromosome in a normal bull, they hybridized to both arms of the Y chromosome in the XY females. In the Y chromosome from XY females, only the centromeric region was darkly stained by G banding, in comparison with dark staining on the long arm of a normal Y chromosome. From the results obtained, it seemed that the Y chromosome from the XY females was structurally abnormal, namely an isochromosome with an identical short arm. Our results also confirm that SRY is located on the long arm of the Y chromosome in bovine.

In 6 sterile heifers which were female in appearance and in genital organs, all tissues derived from blood, skin, spleen and kidney had a single 60,XY type of metaphase plate. Although the SRY gene was detected by PCR in normal bull, it was not detected in normal cow or in 3 60,XY cases studied.