135 Effect of Different Bovine Breeds on Efficiency of Embryo Production by Ovum Pick-Up-IVF

Production of bovine embryos by ovum pick-up (OPU)-IVF has increased in recent years. However, numerous factors affect efficiencies of embryo production using this technology. This study was investigated the effects of different breeds on embryo production by OPU-IVF. In total, 98 OPU-IVF sessions were conducted on 41 Holstein and 27 Japanese Black cows from February 2015 to May 2017. The collected cumulus–oocyte complexes (COC) were matured for 22 h. After co-culture of COC with sperm for 6 h, the presumptive zygotes were washed and denuded by pipetting. Those zygotes were then cultured in CR1aa medium supplemented with 5% calf serum for 9 days in a micro-well culture dish. Blastocyst formation rates were analysed at 9 days post-insemination (hpi). The kinetics of embryo development was observed at 27, 31, and 55 hpi. Four factors were considered for selecting embryos to predict pregnancy competence: (1) timing of first cleavage; (2) formation of 2 blastomeres after first cleavage at 31 hpi; (3) absence of fragments after first cleavage at 31 hpi; (4) formation of 8 or more blastomeres at 55 hpi. The quality of blastocysts was compared with the proportions of embryos that were selected based on these 4 factors. Data were analysed by the Chi-squared test with Yates’ correction and Student’s t-test. Total numbers of COC from Holstein or Japanese Black cows were 1330 (n = 51) and 1543 (n = 47), respectively. However, no differences were observed in the numbers of collected and cultured COC per OPU session between Holstein (26.1 ± 20.1 and 21.7 ± 20.1) and Japanese Black (32.8 ± 24.7 and 28.7 ± 22.7) cows. The percentage of COC linked into Grade 1, 2, or 3 was 47.6, 32.1, and 10.7% for Japanese Black and 45.8, 25.6, and 12.2% for Holstein cows, respectively. The proportion of COC with expanded cumulus cells was significantly higher (P < 0.01) in Holstein (12.7%) than in Japanese Black (7.7%) cows. The number of blastocyst and transferable embryo production per OPU session in Holstein (7.5 ± 8.3 and 7.3 ± 7.7) cows was not different from that in Japanese Black (10.6 ± 9.3 and 9.8 ± 9.0) cows. Moreover, there was no difference in blastocyst formation rates between Japanese Black (36.8%) and Holstein (34.8%) cows. Percentages of embryos selected by factors 1 to 4 were 42.6, 66.8, 59.1, and 54.4% in Holstein, and 54.6, 83.2, 72.2, and 75.2% in Japanese Black cows, respectively. Proportions of blastocysts in Holstein and Japanese Black cows selected by a combination of all 4 factors were 21.6 and 36.1%, respectively. There were significant differences (P < 0.01) between the 2 breeds in terms of proportion of blastocysts selected based on individual factors as well as a combination of all 4 factors. These results suggested that the efficiency of embryo production did not differ between Japanese Black and Holstein cows. However, the quality of embryos selected by a combination of 4 factors was significantly higher in Japanese Black than in Holstein cows.

77 Monozygotic Twin Calves Production by Blastomere Separation Technique with Commercial Well-of-the-Well Culture Dish

Monozygotic twin bovine embryos can be produced by blastomere separation of 2-cell embryos and commercial well-of-the-well (WOW) culture dish (Hashiyada et al. 2016 Reprod. Fertil. Dev. 28, 178) obtaining 60% and 48% of blastocyst formation and monozygotic blastocyst pairs, respectively. The present study was conducted to evaluate the fertility of blastocysts derived from this production system in Japanese Black beef cattle. Embryos were produced using oocytes collected by ovum pick-up technique. TCM-199 supplemented with 5% calf serum (CS), Brackett-Oliphant solution supplemented with 10 mg mL−1 BSA, and CR1aa containing 5% CS, were used for each culture step: in vitro maturation, fertilization, and culture (IVM,IVF, and IVC). Two-cell stage embryos were obtained 24 to 27 h post-insemination. Zonae pellucidae were removed by exposure to 0.25% pronase. Then, embryos were separated into blastomeres by gentle pipetting in IVC medium. Each blastomere was introduced into a single conical microwell of 25 wells, each having a diameter and depth of ~287 μm and 168 μm (Dai Nippon Printing, Tokyo, Japan). Blastomeres in wells were cultured covered with a droplet of 2.5 μL of IVC medium/well. The developed blastocysts in pairs on 7 days post-insemination were used for transfer. Single embryos of monozygotic twin embryos were transferred to Japanese Black cattle with a generally small body frame to produce twin calves from a set of recipients. Twin embryos were transferred in pairs to unilateral of uterus of non-lactating Holstein cows. Pregnancy and twin pregnancy were determined at 30 days of gestation by ultrasonography and were reconfirmed at 60 days with detection of fetal loss. Statistical significance was analysed by Fisher’s exact test. There was no significant difference in pregnancy rate or twin pregnancy rate between single embryo transfer (7/14, 50% and 2/7, 28.6%) and twin embryo transfer (9/21, 42.9% and 4/21, 19%). In either transfer method, fetal loss was not observed in diagnosis carried out at 60 days by ultrasonography. To date, 2 pairs of twin calves have been obtained from twin pregnant cows by twin embryo transfer within the normal range of gestation length (286 and 288 days) and birth weight (31-40 kg). These results indicate that blastocysts developed from blastomeres separated from 2-cell embryos by culturing with commercial WOW culture dish had fertility similar to that of intact embryos derived from standard in vitro culture and further demonstrate the possibility of production of normal twin calves.

Surface force analysis of glycine adsorption on different crystal surfaces of titanium dioxide (TiO2)

Surface force analysis with atomic force microscope (AFM) in which a single amino acid residue was mounted on the tip apex of AFM probe was carried out for the first time at the molecular level on titanium dioxide (TiO₂) as a representative mineral surface for prebiotic chemical evolution reactions. The force analyses on surfaces with three different crystal orientations revealed that the TiO₂ (110) surface has unique characteristics for adsorbing glycine molecules showing different features compared to those on TiO₂ (001) and (100). To examine this difference, we investigated thermal desorption spectroscopy (TDS) and the interaction between the PEG cross-linker and the three TiO₂ surfaces. Our data suggest that the different single crystal surfaces would provide different chemical evolution field for amino acid molecules.

Evaluation of interferon-stimulated genes in peripheral blood granulocytes as sensitive responders to bovine early conceptus signals

Early detection of gestation is important in the bovine industry. New methods have been developed to detect gene expression in leucocytes induced by interferon-tau (IFNT) as gestation biomarkers. However, it is debatable which blood cell is suitable for detecting gene expression. This study was aimed at confirming whether granulocytes respond to IFNT specifically. Granulocytes and mononuclear cells (MNCs) from cows, and several types of bovine cultured cells, were treated with recombinant (r) IFNT and gene expression was analysed by quantitative real-time reverse transcriptase (RT)-PCR and microarray analysis. Expression levels of IFN receptors (R1 and R2) were approximately 30- to 900-fold higher in granulocytes than in other cultured cells, and 1.5- to 2.5-fold higher in MNCs than in granulocytes. Microarray analysis following a 2h recombinant IFNT (rIFNT) treatment revealed expression changes for 900 genes in granulocytes. Genes with expression changes included known IFN-stimulated genes (ISGs; ISG15, OAS1, MX1, and MX2). Eighteen genes were selected following granulocyte microarray analysis and their expression changes were confirmed in early gestation, which revealed that nine genes had significantly higher expression levels in pregnant than in non-pregnant animals. In conclusion, granulocytes specifically responded to rIFNT treatment and the resulting gene expression changes correlated with those in vivo. Microarray analysis indicated that various genes showed expression changes in rIFNT-treated granulocytes, which may result in the identification of alternate candidate genes for the early detection of gestation. These results strongly indicate that gene expression in granulocytes is a suitable tool to determine pregnancy status.

Frequent somatic mutations in epigenetic regulators in newly diagnosed chronic myeloid leukemia

Although tyrosine kinase inhibitors (TKIs) have significantly improved the prognosis of chronic myeloid leukemia (CML), the ability of TKIs to eradicate CML remains uncertain and patients must continue TKI therapy for indefinite periods. In this study, we performed whole-exome sequencing to identify somatic mutations in 24 patients with newly diagnosed chronic phase CML who were registered in the JALSG CML212 study. We identified 191 somatic mutations other than the BCR-ABL1 fusion gene (median 8, range 1–17). Age, hemoglobin concentration and white blood cell counts were correlated with the number of mutations. Patients with mutations ⩾6 showed higher rate of achieving major molecular response than those<6 (P=0.0381). Mutations in epigenetic regulator, ASXL1, TET2, TET3, KDM1A and MSH6 were found in 25% of patients. TET2 or TET3, AKT1 and RUNX1 were mutated in one patient each. ASXL1 was mutated within exon 12 in three cases. Mutated genes were significantly enriched with cell signaling and cell division pathways. Furthermore, DNA copy number analysis showed that 2 of 24 patients had uniparental disomy of chromosome 1p or 3q, which disappeared major molecular response was achieved. These mutations may play significant roles in CML pathogenesis in addition to the strong driver mutation BCR-ABL1.

Long-term outcomes of radiofrequency ablation combined with hepatectomy compared with hepatectomy alone for colorectal liver metastases

Background

Combining radiofrequency ablation (RFA) with hepatectomy may enable treatment with curative intent for patients with colorectal liver metastasis (CRLM). However, the oncological outcomes in comparison with resection alone remain to be clarified.

Methods

Patients who underwent a first hepatectomy between 2001 and 2012 for CRLM were enrolled. Short- and long-term outcomes of patients who underwent hepatectomy plus RFA were compared with those of patients who had hepatectomy alone using propensity score matching.

Results

Of a total of 553 patients, hepatectomy + RFA and hepatectomy alone were performed in 37 and 516 respectively. Before matching, patients in the hepatectomy + RFA group were characterized primarily by a larger tumour burden. After matching of 31 patients who underwent hepatectomy + RFA with 93 who had hepatectomy alone, background characteristics were well balanced. In the matched cohort, overall and disease-free survival in the hepatectomy + RFA group were no different from those among patients who had hepatectomy alone (5-year overall survival rate 57 versus 61 per cent, P = 0·649; 5-year disease-free survival rate 19 versus 17 per cent, P = 0·865). Local recurrence at the ablated site was observed in four of 31 patients (13 per cent). Although overall local recurrence (ablated site and/or cut surface) was more frequent in the hepatectomy + RFA group (9 of 31 (29 per cent) versus 11 of 93 (12 per cent); P = 0·032), there was no difference in intrahepatic disease-free survival between the two groups (P = 0·705).

Conclusion

Hepatectomy + RFA achieved outcomes comparable to hepatectomy alone. Combining RFA with hepatectomy should be considered as an option to achieve cure.

138 THE RELATIONSHIP BETWEEN THE NORMALITY OF FIRST CLEAVAGE, THE GENE EXPRESSION IN BLASTOMERES, AND THE ABILITY TO DEVELOP TO THE BLASTOCYST STAGE IN IVF-DERIVED BOVINE 2-CELL STAGE EMBRYOS

Early first and second cleaved embryos after IVF associated with even blastomeres without fragments or protrusions were found to be a potent criterion for the selection of embryos with high developmental competence (Sugimura et al. 2012 PLOS ONE 7, e36627). The aim of this study was to examine the relationship between an early normal first cleavage pattern, the transcript abundance, and their development to the blastocyst stage in each blastomere in 2-cell stage bovine embryos. The IVF-derived bovine embryos were cultured individually in well-of-the-well culture dishes in CR1aa medium supplemented with 5% calf serum and 0.25 mg mL−1 linoleic acid albumin at 38.5°C in 5% CO2, 5% O2, and 90% N2. The first embryonic cleavage was categorized as being either normal (occurring within 28 h after IVF with 2 even blastomeres without fragment or protrusion) or abnormal (2 uneven blastomeres, with/without fragment/protrusion and/or later than 28 h after IVF). Then, cleaved embryos were placed in 0.5% actinase-E in Ca- and Mg-free PBS and blastomeres were separated by pipetting (n = 85; 4 replicates). In each embryo, one blastomere was subjected to quantitative RT-PCR to analyse the expression of developmentally important genes. The remaining blastomere was subsequently cultured in an individually identifiable manner to verify their ability to develop to the blastocyst stage. Primers were designed for 12 target genes related to pluripotency, cell cycle, metabolism, pregnancy reorganization, placentation, and fetal growth (OCT4, ATP1A1, CCNB1, CDH1, COX1, CTNNB1, GLUT8, MNSOD-3, SOX2, DYNLL1, IGFBP3, and PMSB1) and a reference gene (PPIA). Transcript abundance of target genes in individual blastomeres was compared between embryos showing normal and abnormal cleavage. Values were normalized to the average values of the reference genes and all the means were compared by the Student t-test. Blastomeres resulted from normal cleavage developed to the blastocyst stage on Day 7 to 8 (Day 0 = IVF) at significantly higher rates than those resulted from abnormal cleavage (65.7% v. 37.5%, respectively, P < 0.05). Transcript abundance of OCT4 was significantly higher in blastomeres associated with all abnormal cleavage than in those associated with normal cleavage (P < 0.05). The expression of CCNB1, COX1, ATP1A1, GLUT8, and PMSB1 in blastomeres associated with normal cleavage and blastocyst development was higher than that in those of abnormal cleavage (P < 0.05). However, the level of OCT4, CCNB1, COX1, ATP1A1, and PMSB1 was lower in blastomeres associated with normal cleavage but failure of blastocyst development than those in blastomeres showing abnormal cleavage (P < 0.05). Our results reveal that significantly higher expression of CCNB1, COX1, ATP1A1, and PMSB1 in blastomeres at the 2-cell stage in bovine embryos with superior developmental competence compared with those showing abnormal cleavage and low competence. Research was supported by JSPS KAKENHI (26450388).

136 IMPACT OF SELECTION SYSTEM BY KINETICS ON THE EARLY EMBRYONIC DEVELOPMENT IN BOVINE OVUM PICKUP-IVF EMBRYOS

Recently, in vitro-produced (IVP) embryos have been increasingly produced using ovum pickup (OPU) and IVF in cows worldwide. However, the conception rate of IVP embryos is lower than that of in vivo-derived embryos. This study was conducted to determine the proportion of embryos that led to a high conception rate when the embryos were selected according to the 4 predicting factors. A total of 30 Holstein and 20 Japanese Black cows were used, and 81 OPU-IVF sessions were performed from October 2014 to May 2016. The collected cumulus-oocyte complexes (COC) were cultured for 22 h. Capacitated sperm (at a final concentration of 5 × 106 spermatozoa/mL) were incubated with COC for 6 h. After insemination, presumptive zygotes were separated from cumulus cells and sperm by pipetting. Then, the presumptive zygotes were cultured for 9 days in CR1aa supplemented with 5% calf serum by using a micro-well culture dish (Dai Nippon Printing, Tokyo, Japan). The kinetics of embryo development was observed at 27, 31, and 55 h post-insemination (hpi). The 4 factors used to select embryos were as follows: (1) time at which first cleavage occurred (less than 27 hpi, or less than 31 hpi, in case any of the zygotes did not cleave at 27 hpi in each culture dish); (2) 2 blastomeres after first cleavage at 31 hpi; (3) absence of fragments after first cleavage at 31 hpi; and (4) 8 or more blastomeres at 55 hpi. The number of blastocysts was analysed at 7, 8, and 9 days post IVF. Additionally, the number of produced embryos that could be used for embryo transfer (ET) was determined. The data were analysed using the chi-square test. The total numbers of blastocysts and produced embryos were 615 and 503, respectively. The numbers of blastocysts and produced embryos selected using the combination of factors 1 to 4 were 200 (32.5%) and 169 (27.5%), respectively. The numbers of blastocysts and produced embryos selected using factor 1 were 397 (64.6%) and 340 (67.6%), using factor 2 were 445 (71.3%) and 378 (75.1%), using factor 3 were 364 (81.8%) and 307 (81.2%), and using factor 4 were 374 (60.8%) and 308 (61.2%), respectively. The numbers of blastocysts and produced embryos that were rejected using a combination of factors 1 to 4 were 123 (27.5%) and 90 (17.9%), respectively. The conception rate of fresh embryo transfer was 46.6% (n = 73). We found that the conception rate of the embryos selected using factors 1 to 4 was significantly (P < 0.05) higher than that of embryos without one factor or more [60.0% (n = 35) v. 29.4% (n = 34)]. These results show the applicability and efficiency of the 4 factors for producing embryos with a high competence for conception.

137 EFFECT OF THE ADDITION OF FOLIC ACID TO MATURATION AND CULTURE MEDIA ON DEVELOPMENT OF THE BOVINE BLASTOCYST AND ITS SURVIVAL RATE AFTER FREEZE-THAWING

Reactive oxygen species (ROS) are the main causes of cell damage in bovine embryos in vitro. Folic acid (FA) is an antioxidant that protects cells from ROS. We studied the effect of the addition of FA to maturation and culture media on development of bovine blastocysts and their survival rate after freeze-thawing. Cell-oocyte complexes (COC) were allowed to mature in HEPES (25 mM)-buffered TCM199 (TCM199) supplemented with 5% calf serum (CS), 0.02 AU mL−1 of FSH, and FA (0, 2.5, 25, and 50 µM) for 20 hours (20–25 COC/100-µL droplet of the medium). After 6 hours of gamete co-culture (5 × 106 sperm/mL), presumptive zygotes were cultured in CR1aa medium supplemented with 5% CS and FA (0, 2.5, 25, and 50 μM) for 9 days (day of fertilization = Day 0). Expanded blastocysts that developed from Day 7 to 9 were frozen for further study. Each embryo was frozen in Dulbecco’s PBS (D-PBS) supplemented with 20% CS, 1.5 M ethylene glycol (EG), and 0.1 M sucrose (SUC). Embryos were equilibrated with their freezing medium for 15 min and loaded individually into a 0.25-mL straw. These straws were put into the cooling chamber of a programmable freezer precooled at −7°C. After 2 min, straws were seeded and held for 13 min at −7°C. Next, straws were cooled to −30°C at −0.3°C/min before being plunged into liquid nitrogen. Frozen embryos were thawed by allowing straws to stand in air for 7 s and warming them in a 30°C water bath for 20 s. Thawed embryos were washed twice with D-PBS supplemented with 20% fetal calf serum (FCS), which was warmed to 38°C. They were immersed into the same medium at 38°C for 10 min, and each embryo was cultured in a 20-μL droplet of TCM199 supplemented with 10% FCS and 0.1 mM β-mercaptoethanol (TCM-199-βME) for 72 h. Embryo cleavage rate was observed at 55 h post-insemination. Blastocyst rates were analysed at 9 days post-insemination. Rates of embryos developing into reexpanded, hatching, and hatched blastocyst stages were determined after 72 h of thawing. All data were analysed by the chi-square test and Fisher’s exact test. Cleavage and blastocyst rates after insemination at 55 hours and 9 days, respectively, were not significantly different among media containing 0 μM (n = 278; 74.1% and 39.9%), 2.5 μM (n = 260; 74.2% and 45.8%), 25 μM (n = 258; 75.6% and 45.7%), and 50 μM (n = 253; 76.3% and 42.7%) FA. Survival and hatching rates of frozen and thawed expanded blastocysts after 72 h in culture were 62.5% and 56.3%, respectively, in 0 μM FA (n = 16); 85.2% and 74.1% in 2.5 μM FA (n = 27); 66.7% and 62.5% in 25 μM FA (n = 24); and 68.0% and 64.0% in 50 μM FA (n = 25). Blastocysts cultured in media containing 2.5 μM FA tended to have a higher survival rate than those cultured in media containing 0 μM FA, although this difference was not significant (P = 0.09). Inclusion of FA did not appear to influence development or post-thaw survival of bovine blastocysts produced in vitro.

49 SUCCESSFUL CRYOPRESERVATION USING LOW ETHYLENE GLYCOL CONCENTRATION FOR IN VITRO-PRODUCED BOVINE EMBRYOS

In vitro-produced (IVP) bovine embryos tend to have a lower survival rate after cryopreservation than in vivo embryos do. Therefore, the freezing medium (FM) and concentration of cryoprotectant are very important factors. This study was to investigate the effect of 1.2 M ethylene glycol (EG) with 0.1 M sucrose (SUC) on survival of IVP embryos after freezing. The COC were matured in 25 mM HEPES-buffered TCM199 (TCM199) supplemented with 5% calf serum (CS) and 0.02 AU mL−1 FSH. Oocytes (20 to 25) were cultured in 100-μL droplets of maturation medium for 20 h. After 6 h of gamete co-culture (5 × 106 sperm/mL), the presumptive zygotes were cultured in CR1aa medium supplemented with 5% CS for 9 days (fertilization = Day 0). Only the expanded blastocysts from Days 7 to 9 were used in this experiment and separated into 3 treatment groups. The first and second groups were frozen in Dulbecco’s phosphate-buffered saline (D-PBS) supplemented with 20% CS, 0.1 M SUC, and 1.2 or 1.5 M EG (groups 1.2 or 1.5 M EG), respectively. The third group was D-PBS supplemented with 20% fetal calf serum (FCS), 0.25 M SUC, and 1.4 M glycerol (group GLY). In each group, embryos were equilibrated with their FM for 10 min and loaded into 0.25-mL straws individually. These straws were placed into the cooling chamber of a programmable freezer precooled to −7°C. After 2 min, the straws were seeded and then held for a further 13 min at −7°C. Then, the straws were cooled to −30°C at −0.3°C/min before being plunged into liquid nitrogen. The cryopreserved embryos were thawed by allowing the straws to stand in air for 7 s and then warming them in a 30°C water bath for 20 s. The thawed embryos were washed twice using 38°C D-PBS supplemented with 20% FCS. Subsequently, they were immersed in the same medium, held at 38°C for 10 min, and then each embryo was cultured in 20-μL droplets of TCM199 supplemented with 20% FCS and 0.1 mM β-mercaptoethanol for 72 h. The rates of embryos developing to the re-expanded and hatching blastocyst stages were determined 72 h after thawing. All data were analysed by the chi-squared test with Yates’ correction. The re-expanded and hatching rates of frozen-thawed embryos after 72 h in culture were not significantly different between 1.2 M EG (n = 39: 71.8% and 69.2%), 1.5 M EG (n = 38: 76.3% and 63.2%), and 1.4 M GLY (n = 37: 75.7% and 64.9%) groups (P > 0.05). Survival and hatching rates according to embryo quality were also not significantly different between 1.2 M EG (good n = 18: 88.9% and 88.9%; fair n = 21: 57.1% and 52.4%), 1.5 M EG (good n = 19: 89.5% and 84.2%; fair n = 19: 63.2% and 42.1%), and 1.4 M GLY (good n = 18: 77.8% and 66.7%; fair n = 19: 73.7% and 63.2%) (P > 0.05). In conclusion, cryoprotectant type and concentration did not affect embryo survival or development after cryopreservation in this study. Therefore, the ethylene glycol concentration used for the cryopreservation of IVP embryos can be reduced.

10 PREDICTION OF CALVING TIME USING BODY-SURFACE TEMPERATURE SENSORS AND PEDOMETERS IN BEEF CATTLE

Predicting the onset of calving is important for the prevention of stillbirths. This study aimed to investigate whether using body-surface temperature and number of steps at the time of calving could be used to predict calving time. Three heifers and 4 cows of the beef cattle variety were used in this study. All animals were housed in calving pens measuring 4.2 × 3.6 m each. Body-surface temperature was recorded using a sensor that was fixed ventrally to the body of the tail head (NIAH, NARO, Tsukuba, Japan). The number of steps the beef cattle took was measured using pedometers (Gyuho, Comtec, Miyazaki, Japan), where each 10 steps resulted in 1 count. The temperature sensors and pedometers were placed on the animals for at least 10 days before the estimated date of delivery. Body-surface temperature and pedometer readings were automatically collected every 2 min and every hour. The data used to predict calving were the means of the body-surface temperature and steps taken, which were recorded from the day the sensors were mounted until 1 day after calving. All data were statistically analysed using t-tests. The mean body-surface temperature before calving was 35.4°C (10 h), which was significantly lower than that recorded 3 days before calving (36.2°C; P < 0.05). The mean body-surface temperature of beef cattle 10 to 6 h before calving (36.0°C) was not significantly different from the mean temperature 3 days before calving. However, from 5 to 1 h before calving, the mean body-surface temperature (34.8°C) was significantly lower than that 3 days before calving (P < 0.05). The mean step number of 101.4 counts, taken 10 h before calving, was significantly increased compared with the mean step number of 44.7 counts 3 days before calving (P < 0.05). The mean step number of 59.7 counts from 10 to 6 h before calving was not significantly different from readings taken 3 days before calving. The mean step number count from 5 to 1 h before calving was 143.1 counts, which increased significantly from readings taken 3 days before calving (P < 0.05). In conclusion, ventral tailhead body-temperature sensors and pedometers can be used to predict the onset of calving in beef cattle. Their body-surface temperature, along with the number of steps taken before calving, decreased and increased, respectively, in the 5 h leading up to calving. This study was supported by the Council for Science, Technology and Innovation (CSTI), Cross-ministerial Strategic Innovation Promotion Program (SIP), and the Technologies for creating next-generation agriculture, forestry and fisheries (funding agency: Bio-oriented Technology Research Advancement Institution, NARO).