Stillbirth is a critical indicator of production efficiency in the beef industry and leads to substantial economic losses. Although the Japanese Black is a premier breed renowned for superior marbling, research on stillbirth risk factors specific to this breed remains limited. This study aimed to identify epidemiological and genetic factors associated with stillbirth in Japanese Black cattle in order to provide actionable insights for production sites. In total, 94,569 calving records from 24,821 cows across 1,001 farms in the Kyushu region (2009-2018) were analyzed using descriptive statistics, a single-trait threshold animal model with Bayesian inference, and mixed-effect model. The overall average stillbirth rate was 1.91%. Small-scale farms exhibited lower stillbirth rates, with more than 70% reporting no stillbirths, whereas large-scale farms showed higher risk, likely reflecting challenges in individual animal observation. Stillbirth rates varied markedly among sires, with some exceeding the overall average by more than 1%. The posterior mean (±SD) estimates for heritability and repeatability were 0.037 ± 0.024 and 0.119 ± 0.040, respectively. Environmental analyses indicated that first-parity cows (odds ratio: 1.858) and winter calving (odds ratio: 1.390) were associated with significantly increased stillbirth risk (P < 0.05). A temporary decline in stillbirth rates was also observed following the 2010 foot-and-mouth disease outbreak, suggesting that reduced herd density and improved care per animal can mitigate risk. Although heritability for stillbirth was low, the relatively high repeatability underscores the importance of managing cows with a prior history of stillbirth. Reducing stillbirth in Japanese Black cattle therefore requires a multifaceted approach, including improved calving management for heifers and winter calvings, use of sire-specific risk information in breeding decisions, and adoption of information and communication technology-based monitoring systems on larger farms. These measures have the potential to reduce economic losses and improve reproductive efficiency.

This study investigated the effect of the revision of Japan's Carcass Trading Standard for Pork (CTSP) in January 2023, which increased the optimal carcass weight (CWT) range by 3 kg, on the profitability and growth productivity of commercial pig farms. We analyzed data from 116 Japanese farrow-to-finish farms in 2022 and 2023. The study found that the mean CWT significantly increased from 76.1 to 77.1 kg (p < 0.05), with 77% of farms increasing their CWT. Statistical analysis revealed that farms that had increased their CWT by more than 2 kg saw a significantly higher increase in margin over feed cost per market pig compared with farms that had decreased their CWT (p < 0.05). This increased profit was primarily driven by higher sales revenue per market pig owing to the increased CWT, while feed cost per pig was statistically similar across all change groups. In conclusion, the CTSP revision successfully encouraged most farms to increase CWT, providing a clear economic advantage in terms of margin over feed cost.

Transboundary diseases, such as African swine fever, pose significant threats to the Japanese swine industry, making robust biosecurity essential. However, established assessment tools quantify overall biosecurity levels, and the specific practices driving performance variation among farms remain unclear. This study applied machine learning algorithms to identify key biosecurity measures distinguishing high-performing farms. Total, external, internal, and diagnostic monitoring scores from 254 records of the biosecurity assessment tool (2014-2023) were analyzed using Random Forest models coupled with Boruta feature selection, incorporating the assessment year to adjust for temporal shifts. The models demonstrated robust predictive accuracy (R2=0.83-0.93 for total, external, internal, and diagnostic monitoring scores). The analysis identified the rigorous management of high-risk external interfaces-specifically, visitor shower-in requirements, strict entry criteria, and the use of exclusive slaughter transport vehicles-as primary determinants of farm-to-farm variation. For internal biosecurity, controlling access to shared spaces like break rooms, alongside segregating production stages via clothing and boot exchanges, emerged as key differentiators. Notably, overall and diagnostic monitoring scores were strongly driven by the "software" of biosecurity-specifically, the strict maintenance of implementation records (e.g., for vermin control and disinfection) and adherence to sampling manuals. These findings suggest that biosecurity variation in Japan is defined by the integration of robust physical barriers with highly systematized, verifiable management protocols. To elevate the national biosecurity baseline, stakeholders should prioritize investments in external risk interfaces and the rigorous documentation of daily practices.

This study aimed to clarify how behavioral and physiological parameters differ among preweaning female calves with different health statuses (healthy, diarrheal, and respiratory diseases) using a multimodal tail-attached device equipped with a 3-axis accelerometer and a thermistor. We also evaluated the applicability of this device for disease detection. The device was fitted to 329 Holstein calves (mean age: 20.7 +/- 10.9 days) and recorded data for 24.2 +/- 6.2 days at 3-min intervals. During this period, calves were assessed for health status twice weekly, and only data from assessment days were analyzed (1996 days' data: 1778 healthy, 148 diarrheal, 63 respiratory, and 7 with both diseases). Five daily metrics were calculated: mean activity intensity (meanActivity), total lying time (sumLying), number of body position changes (sumPosition), standard deviation of the tail-raising index (sdTail), and maximum tail skin temperature (maxST). A linear mixed-effects model showed that diarrheal disease was negatively associated with meanActivity and sumPosition, and positively with sumLying and sdTail. Respiratory disease was negatively associated with meanActivity and positively with sumLying and maxST. However, substantial overlap in metrics was observed between the two diseases. Therefore, they were merged into a single category, and a generalized disease detection model was developed using a random forest algorithm. Model performance, evaluated using a holdout approach, showed an acceptable level of discriminative ability between healthy and diseased cases (AUC = 0.71). These findings offer insights into health monitoring strategies and support the potential utility of the tail-attached device for automated disease detection in preweaning calves.

Two studies were conducted on the relationship between ruminal mat consistency (RMC) and (1) calf mortality or (2) immunity. Assessment of RMC was by ten repeated manual compressions of the middle rumen; good-RMC showed no fluid bounce-back (FBB), while poor-RMC showed FBB. The first study examined whether RMC affected calf mortality. Monthly feeding management guidance (FMG) was implemented for 5 years on a commercial farm with Holstein-Friesian × Japanese black calves, directing increased forage consumption for poor-RMC calves aged 50-180 days. Compared to 35 control farms, the FMG period showed significantly lower total mortality (3.8% vs. 0.8%, P < 0.001, OR = 4.7) and lower respiratory mortality (2.3% vs. 0.1%, P < 0.001, OR = 18.3). The second study tested the hypothesis that RMC affects calf immunity. Peripheral blood of good-RMC (n = 6) and poor-RMC (n = 6) calves was compared. Good-RMC showed higher phagocytosis in monocytes (P = 0.05, r = 0.63) and granulocytes (P = 0.02, r = 0.78), and higher numbers of CD4 + (P = 0.07, r = 0.58), CD8 + (P = 0.07, r = 0.60), and B-cells (P = 0.03, r = 0.62). In mRNA expression, good-RMC showed lower TNF-α (P = 0.02, r = 0.70), IL-1 (P = 0.09, r = 0.49), IL-12 (P = 0.04, r = 0.59) and IL-10 (P = 0.13, r = 0.44), and higher IL-16 (P = 0.07, r = 0.53) compared to poor-RMC. These results suggest that RMC affects calf mortality and immunity, emphasizing the importance of feeding management in improving sustainability.

The calving interval (CI) is an important determinant of reproductive performance in Japanese Black cattle. The present study aimed to compare individual fertility traits among farms classified by CI. In total, 49,780 artificial insemination (AI) records for 7327 cows from 2011 to 2014 were obtained from 622 farms located in Miyazaki, Japan. The farms were classified into three groups (referred to as farm CI groups) using the lower and upper 25 percentiles of farm CI as thresholds. The mean CI of individual cows was 403.5 ± 70.9 days. The interquartile ranges of CI for individual cows were 49 days for short CI farms and 114 days for long CI farms. The interval between calving and the first AI was associated with farm CI group and parity (p < 0.05) but not with calving season and gestation length. The conception rate (CR) at the first AI in cows on long CI farms decreased as the interval from calving to the first AI decreased (p < 0.05). Additionally, no differences in CR among farm CI groups were observed for AI number ≥ 4. In long CI farms, cows with two AI treatments had longer interservice intervals than those for AI values of 3 and ≥ 4 (p < 0.05). In summary, fertility characteristics for long CI farms differed from those of farms with short or middle CI, and standard operating procedures need to be improved to decrease the CI.

Although extensively studied, the association between antimicrobial usage and the emergence of antimicrobial resistance (AMR) in livestock still has unresolved aspects. This study analyzed the genomes of 195 Escherichia coli strains from pigs, a species with high antimicrobial consumption, across five production stages on 13 farms in Japan employing diverse antimicrobial administration strategies. A total of 61 acquired AMR genes (aARGs), spanning 13 distinct antimicrobial classes, were identified. A significant correlation was found between antimicrobial usage and the number of aARGs in E. coli strains. The four farms with the highest usage administered antimicrobials orally as routine prophylaxis during fattening. These farms showed significantly higher proportions of multidrug-resistant (MDR) genotypes at all stages compared to farms without routine prophylaxis. The number of frequently detected aARGs was more strongly correlated with total antimicrobial usage than with the usage of the corresponding antimicrobial classes. Co-occurrence network analysis suggested that genetic linkages among these aARGs may promote co-selection, thereby acting as a driving force in the emergence of MDR strains under routine prophylaxis treatment.

This study investigated the effects of multiple treatments of estradiol benzoate (EB) prior to the induction of luteal regression on the efficiency of artificial lactation induction and milk yield in pseudopregnant sows. Pseudopregnant females induced by treatment with 30 mg estradiol dipropionate (EDP) were administered 2 mg (Group EB 2 mg, n = 5) or 3 mg (Group EB 3 mg, n = 6) EB on Days-10, -7, and -4 (Day 0 = the day of prostaglandin F2α [PGF2α] treatment). Six pseudopregnant sows (Group EDP) received 5 mg EDP on Day -10.5 ± 1.6. The induction efficiency of artificial lactation, collected milk volume and immunoglobulin concentrations in the milk obtained from sows after PGF2α treatment were analysed. The dosage of EB treatment before PGF2α administration had no significant effect on either the induction rate of artificial lactation or the milk yield during the experimental period. Harvested milk volumes from EB-treated pseudopregnant sows were higher than those in Group EDP. The immunoglobulin levels in harvested milk from artificial lactating sows did not differ between the EB-treated groups. In conclusion, multiple EB treatments prior to PGF2α administration increased milk production in pseudopregnant sows but did not affect the efficiency of artificial lactation induction.

Oxidative stress is a detrimental factor affecting pig reproductive performance but has rarely been evaluated in clinical fields. We evaluated the potential of diacron-reactive oxygen metabolites (d-ROMs) and biological antioxidant potential (BAP) as stable markers for assessing oxidative stress in breeding sows. The 28 sows were categorized into a low-parity group (n = 18, parity 1-2) and a high-parity group (n = 10, parity 4-6) at two commercial farms. Blood samples were collected at three stages: farrowing, weaning, and early pregnancy. At each stage, the levels of oxidative stress markers and reproductive performance parameters were statistically analyzed. The findings revealed that heightened levels of oxidative stress in sows at farrowing have negative effects on the total number of piglets at subsequent farrowing. Moreover, the farm employing a group management system demonstrated a superior total number of piglets on subsequent farrowing compared with the farm utilizing individual stall-based management. This study shows that oxidative stress can be evaluated using d-ROMs and BAP, which are associated with reproductive score. Using these parameters, the current oxidative status of sows can be evaluated, allowing for the development of countermeasures to reduce oxidative stress, which in turn may contribute to improved productivity in swine production systems.

It is well known that porcine reproductive and respiratory syndrome (PRRS) decreases herd productivity and leads to economic loss, and it is believed that biosecurity practices are effective for the control and eradication of PRRS. This study aimed to prioritize biosecurity practices useful for PRRS control and eradication by using a machine learning algorithm. Biosecurity practices on 258 Japanese breeding farms were assessed using a biosecurity assessment tool. Random forest analysis was used to assess relevant features based on feature importance. In study 1, each farm was divided into two groups (PRRS controlled or not controlled), and the most relevant biosecurity practices for PRRS control were investigated. Seven features were selected as associated with PRRS control, and results identified the prioritization of semen management and the maintenance of a controlled barn environment to be critical elements for PRRS control. In study 2, each farm was divided into two groups (PRRS-free or not free of PRRS), and the most relevant biosecurity practices for PRRS eradication were investigated. Fourteen features were identified as critically associated with PRRS eradication, and results showed that the stringent management of replacement gilts, the exclusive use of semen from PRRS-free sources, and a comprehensive awareness of farm location were essential elements for PRRS eradication. In conclusion, this research underscores the significant divergence in biosecurity strategies required for effective PRRS control compared with those for eradication.

This study aimed to determine the applicability of a tail-attached device in monitoring animal-based indicators (ABI) associated with changes in environmental conditions in calves through investigating the relationship between sensor-derived ABI and the temperature-humidity index (THI). Furthermore, to identify effective ABI indicative of heat stress status, sensor-derived ABI of calves under differing heat stress levels based on rectal temperature (RT) were compared. The tail-attached device, which is capable of measuring skin temperature (ST), activity intensity, and roll angle along the longitudinal axis of the tail at 3-min intervals, was attached to 99 preweaning female Holstein calves for an average of 4 wk (26.4 ± 6.8 d). After selecting data from mild to hot days (daily average THI of ≥55), physiological (daily maximum tail ST) and behavioral (daily average activity intensity, daily total lying time, and daily total body position change) ABI were computed, and their relationship with the daily average THI was determined using piecewise regression analysis. Additionally, during the hot season, RT of 20 randomly selected tested calves were measured thrice a week (every 2.4 ± 0.5 d), and a comparison was conducted between the ABI of calves with normal RT (<39.5°C) and those with high RT (≥39.5°C), utilizing data from days characterized by potential heat stress (daily average THI of ≥75). During the study, ambient temperature (°C) and relative humidity (%) were recorded every 10 min using an automatic digital data logger, from which the daily average THI was calculated. Piecewise regression analysis identified THI breakpoints of 73.6 for tail ST, 79.1 for average activity intensity, 72.3 for lying time, and 79.1 for position change. All the tested ABI tended to increase as THI increased, and this trend was pronounced in tail ST, activity intensity, and position change after the breakpoint. These 3 ABI were higher in calves with high RT compared with those with normal RT, whereas lying time shared similar values between the RT groups. Overall, these findings suggest that the tail-attached device can simultaneously monitor both physiological and behavioral ABI in calves, and among the ABI, tail ST, activity intensity, and position change are the effective ABI indicative of heat stress status.

We aimed to characterize the change in the incidence of stillbirth (IS) in Japanese Black cattle during and after animal movement restrictions and suspended insemination because of a foot-and-mouth disease (FMD) outbreak in Miyazaki Prefecture in 2010. Calving data from 2006 to 2018 were collected from approximately 900 farms. Post-FMD period was divided into three based on the median IS per month (1.80%): period 1 (May 2011 to February 2013), period 2 (March 2013 to August 2015), and period 3 (September 2015 to December 2018). The ISs were similar during the Pre-FMD period and Post-FMD period 1, then substantially decreased during Post-FMD period 2 (p < .05), before returning to the value before the FMD outbreak period during Post-FMD period 3. Compared with the Pre-FMD period, Post-FMD period 1 was associated with a higher proportion of calvings by primiparous cows and Post-FMD period 2 was associated with a smaller number of calvings per month (p < .05). There were high ISs in primiparous cows during the Pre-FMD period, Post-FMD period 1, and Post-FMD period 3 (p < .05), but not during Post-FMD period 2. In summary, after the animal movement restrictions and suspended insemination introduced because of the FMD outbreak, the IS temporarily decreased and consequently returned to the pre-FMD level.

This study investigated the effects of parity, season, and the previous lactation's milk yield on fertility in dairy cows. A total of 5,514 calving records for Holstein cows that calved between 2016 and 2018 on a single large dairy farm in Japan were used for analysis. The proportion of cows that get pregnant by 360 days after calving was defined as the percentage of all cows eligible for breeding that became pregnant. In the all-cow model, pregnancy probability associated with both parity and calving season (p < 0.05). Pregnancy probability decreased with an increase in parity, with hazard ratios (HRs) of 1.75 (1.58-1.94) for parity 1, 1.25 (1.13-1.39) for parity 2, 1.15 (1.04-1.29) for parity 3, and 1.13 (1.00-1.27) for parity 4, relative to parity ≥5. In terms of calving season, the lowest pregnancy probability was found in spring, and the HRs relative to spring were 1.16 (1.07-1.26) for summer, 1.35 (1.24-1.47) for autumn, and 1.17 (1.07-1.27) for winter. In the multiparous-cow model, pregnancy probability associated with the previous lactation's milk yield (p < 0.05), but not with parity or calving season. Cows with high and middle previous milk yields had lower pregnancy probabilities than those with low milk yields.

In this study, we examined whether the frequency of exogenous oestrogen treatment affects the induction of artificial lactation and milk production. Furthermore, we analysed changes in milk components obtained from artificially lactating sows. Pseudopregnant induced by treatment with 30 mg of estradiol dipropionate (EDP) on Day 10 (Day 0 = the last day of estrus) were divided into three groups: those administered 5 mg of EDP once on Day 39 (n = 5), twice on Days 32 and 39 (n = 5) and three times on Days 25, 32 and 39 (n = 6). All animals were treated with prostaglandin F2 alpha (PGF2 alpha) on Day 46 for induced lactation. Artificial lactation was induced in 66.7%-80.0% of sows, and the EDP treatment frequency before PGF2 alpha administration had no significant effect on either the induction rate of artificial lactation or the milk yield during the experimental period. The milk composition (levels of crude protein, crude fat, crude ash, lactose and immunoglobulin) did not differ among the groups. In conclusion, the number of EDP treatments prior to PGF2 alpha administration had no effect on either the efficiency of artificial lactation induction or milk production.

The objective in the present study was to assess the ventral tail base surface temperature (ST) for the early detection of Japanese Black calves with fever. This study collected data from a backgrounding operation in Miyazaki, Japan, that included 153 calves aged 3–4 months. A wearable wireless ST sensor was attached to the surface of the ventral tail base of each calf at its introduction to the farm. The ventral tail base ST was measured every 10 min for one month. The present study conducted an experiment to detect calves with fever using the estimated residual ST (rST), calculated as the estimated rST minus the mean estimated rST for the same time on the previous 3 days, which was obtained using machine learning algorithms. Fever was defined as an increase of ≥1.0 °C for the estimated rST of a calf for 4 consecutive hours. The machine learning algorithm that applied was a random forest, and 15 features were included. The variable importance scores that represented the most important predictors for the detection of calves with fever were the minimum and maximum values during the last 3 h and the difference between the current value and 24- and 48-h minimum. For this prediction model, accuracy, precision, and sensitivity were 98.8%, 72.1%, and 88.1%, respectively. The present study indicated that the early detection of calves with fever can be predicted by monitoring the ventral tail base ST using a wearable wireless sensor.

The objective of this study was to investigate the effect of herd size on stillbirth and dystocia rates; the relationships between herd size, calving season, parity, and gestation length in Japanese Black cattle were also explored. Data were collected for 41,184 calvings from 15,512 animals on 905 farms between 2006 and 2010. In this study, herds were classified into three groups based on size: small (1–10 cows), medium (11–50 cows), and large (≥51 cows). Herd size had an effect on the dystocia rate (p < 0.05) but not the stillbirth rate. Additionally, interactions between herd size and gestation length were associated with the dystocia rate (p < 0.05), and the dystocia rate was the highest in small herds, followed by medium and large herds for cows with a gestation length of 281–300 days, which is considered a pregnancy of normal duration. In summary, in Japanese Black cattle, there were different effects of herd size on the stillbirth rate and dystocia rates, as herd size was associated with the dystocia rate but not with the stillbirth rate.

We investigated the effect of both duration from vaccination to parturition in pregnant sows and colostral restriction during 6 h after birth for neonate piglets on the level of maternal antibodies for classical swine fever (CSF) vaccine in suckling piglets. In this study, piglets delivered from 3 pregnant sows vaccinated with CSF and 2 unvaccinated pregnant sows were used, and the serum CSF neutralizing antibody titeres in piglets with colostral restriction during the suckling period was significantly lower than those without the restriction. In the piglets with restricted colostrum intake, the group with a period from vaccination to parturition of 21 days had a significantly lower CSF antibody titer during the experimental period than the group of more than 161 days. The percentage of piglets testing positive for CSF antibodies was 0% at 14 and 21 days after birth in the group with short a short period (21 days) from vaccination to parturition and colostral restriction. Our results indicate that both of the timing of the initial vaccination of unimmunized pregnant sows and the restriction of colostrum have a clear effect on the level of maternal CSF antibodies in suckling piglets.

Repeat breeding (RB) has been defined as failure to conceive from three or more regularly spaced ser-vices in the absence of detectable abnormalities, and cause economic loss on the farm owing to a declining conception rate. This study aimed to evaluate the reproductive characteristics of RB in Japanese Black cattle by assessing the longitudinal effect of RB at a low parity on subsequent fertility raised in commercial cow-calf operations. Data used in this study were collected from 764 farms in Miyazaki. Data from 2005 until 2014 comprised 158,945 AI records with 80,453 parity records for 22,565 cows. The effect of RB at heifers and parities 1 and 2 cows on subsequent fertility and survival on four consecutive parities was investigated. The results showed that cows with the number of inseminations to conception (INS) of >= 4 at a low parity had a higher probability of being RB again at subsequent parities compared with cattle with INS 1 or 2. Additionally, the degree of the negative effect of an INS >= 4 on fertility and survival increased as they became older. On the other hand, cows with an INS of 2 had similar fertility and survival with those with an INS of 1. In summary, this study suggests that repeat breeders at a low parity have a higher probability of RB again at subsequent parities compared with cattle with INS 1 or 2, and the negative effect of an INS >= 4 increases as parity increases.(c) 2022 Elsevier Inc. All rights reserved.