Assuming a small population of honeybee with incomplete reproductive isolation, we developed theories to predict response to selection and inbreeding coefficient. The theories were applied to a selection program with a scale applicable to beekeepers in Japan. Numerical computation showed that even under an incomplete reproductive isolation, a remarkable genetic gain could be achieved if more than 90% of drones can be isolated. It was also shown that a small amount of introgression of drones from outside populations would effectively suppress the increase of inbreeding coefficient.

The use of sex-sorted semen in dairy cows is problematic because it is associated with a low conception rate in multiparous cows. We have reported that artificial insemination (AI) using a diluent containing caffeine (Caf) in pigs can suppress the increase in the number of intrauterine polymorphonuclear leucocytes (PMNs) after AI. In this study, we investigated the effect of intrauterine infusion of Caf in the sex-sorted semen AI system using deep intrauterine insemination. The Caf-free group displayed significantly more intrauterine PMNs after AI than the non-inseminated (control) group (P<0.05). There were no significant differences between the Caf-added group and the non-inseminated (control) group. The conception rate after AI with sex-sorted semen in lactating dairy cows was 41.7% in the air injection (control) group and 47.1% in the Caf-added group. In conclusion, we demonstrate that AI with sex-sorted semen using Caf-added diluent could suppress the increase in the number of intrauterine PMNs after AI.

This study examined the relationships between mince pH and the physicochemical and textural properties of venison model sausage made from wild deer. M. longissimus thoracis from wild deer (Cervus Nippon, n＝11) was ground and the pH of the mince were analyzed. NaCl (2.0% of mince weight) was added, mixed well, and the mince mixture was then boiled to produce the model sausage. Cooking losses, color, and textural profiles in the model sausages were analyzed. Significant negative correlations were found between mince pH and the L* and b* values of the model sausage. Significant positive correlation was found between mince pH and the a* value of the model sausage. Significant negative correlations were found between mince pH and cooking loss and adhesiveness of the model sausage. Significant positive correlations were found between mince pH and the cohesiveness and load of gumminess of the model sausage. These results suggest that as mince pH increased, meat color, water holding capacity during cooking, and deformation resistance of venison model sausage increased.

The effect of muscle (M. longissimus thoracis) pH on the water holding capacity, free amino acid content, texture, color, oxidation, fatty acid composition, and antioxidant content of meat from wild boar (Sus scrofa leucomystax, n＝21) was investigated. Muscle pH did not significantly affect the moisture content, cohesiveness, adhesiveness, a* value, metmyoglobin percentage, thiobarbituric acid value, saturated fatty acid, monounsaturated fatty acid, polyunsaturated fatty acid, and α-tocopherol contents in wild boar meat. The drip loss, cooking loss, maximum load, load of gumminess, L* value, and b* value significantly decreased with the pH increased of wild boar meat. The total free amino acid content significantly increased with the pH increased of wild boar meat. These results suggest that as the pH increased, the wild boar meat color darkened, but the meat became more tender and water holding capacity and taste component increased.

We measured environmental gas emission during the composting of manure of layers from 200 to 300 days of age fed diets with 2% lower crude protein (CP) when compared with a conventional 19% CP diet. The layers fed CP 19% diet and those fed CP 17% diet showed no difference in the egg-laying rate, egg weight, feed intake, and amount of excreta. However, the layers fed CP 17% diet showed a decrease in nitrogen excretion compared with the layers fed CP 19% diet. Furthermore, environmental gas emission during the composting of manure of the layers fed CP 17% diet for 40 days was reduced as follows : 12.0% for N₂O, 49.9% for CH₄, and 34.8% for NH₃ compared with the manure of the the layers fed CP 19% diet. The concentration of nitrogen, phosphate, and potassium ; carbon-to-nitrogen ratio ; and germination percentage of Komatsuna on the manure of the layers fed CP 19% diet and the layers fed CP 17% diet were similar to those of the manure of layers in Japan. These results indicate that feeding 2% lower CP diets to layers from 200 to 300 days of age did not affect egg productivity and decreased environmental gas emission during composting of their manure

Although sex sorted sperm technology is commercially available in Japan, adoption of the technology has been limited in dairy farms due to high production cost, low conception rate and incomplete sexing accuracy. In this study, the base scenario with unsexed semen and four alternative scenarios were compared using a bio-economic and environment simulation model in dairy production and integrating dairy-beef production systems including growing and feedlot stages for beef production. Both the production systems were assumed that beef unsexed semen be inseminated with surplus cows to produce crossbred (F₁) calves. The alternative four scenarios were ① using sex sorted sperm of 90% purity with low conception rate (80% of unsexed semen) with 30% of cow. ② using sex sorted sperm of 90% purity with the same conception rate as unsexed one with 30% of cow, ③ using the same sex sorted sperm as in ① with only heifers, ④ using sex sorted sperm of 100% purity and the same conception rate as unsexed one with 30% of cow. Profit and economic efficiency were used as economic indicators and profit per emitted methane and excreted nitrogen were used as economic-environmental indicators. The number of dairy heifers for replacement was increased using sex sorted sperm, and the revenues from sale calves in dairy production systems and slaughter animals in integrating dairy and beef production systems were raised by using beef unsexed semen. The scenario ④ was the most profitable and highest economic efficiency in both production systems. The scenario ③ was comparable with scenario ② in the both systems, indicating that insemination of sex sorted sperm on only heifers has the similar effect with enhanced conception rate of sex sorted sperm. The highest economic-environmental indexes were ones obtained in both the scenario ④ in both the systems. Adoption of sex sorted sperm technology in Japan would become beneficial by improving of conception rate and sexing accuracy and by selling more high priced F₁ animals (calves, steers and heifers) in Japan.

In recent, animal industries are faced with the challenge to meet economic viability for animal production while reducing the environmental impacts. For the implementation of the environmental abatement strategies, it is important as the first step to quantify the cost-effectiveness of such strategies. This study showed the rationale of the two types of marginal abatement costs, 1) represented as a change in profit per environmental load at individual level and 2) marginal abatement cost represented by a change in profit per kg of product per environmental load intensity, and 3) the cost-effective analysis for a change in total profit calculated by considering rescaling with the number of animals under environmental restriction at farm. The present analysis provided a simple theoretical framework for both economic and environmental consideration on sustainable animal production. Finally, the policy options to mitigate environmental loads from animal industries were discussed.

Using 6,564 Japanese Black cattle slaughtered at a meat market in Hyogo prefecture, we conducted the least squares analysis of variance by assigning the carcass unit price as a dependent variable. The analytical model included carcass traits, proportion of monounsaturated fatty acids (MUFA) estimated by fiber-optic near-infrared spectrometer, and fineness index of marbling obtained by digital image analysis. All the explanatory variables, except for subcutaneous fat thickness and beef fat score, had significant effects on the carcass unit price (P < 0.05). We verified that MUFA and fineness index showed significant effects on the carcass unit price, whereas beef marbling score (BMS) had large impact on it. When the same analysis was applied to each of the four subsets of the data, generated by subdividing all the data by BMS, it was found that fineness index and MUFA significantly affected the carcasses unit price in high (10 ≤) and moderate (6 to 9) BMS categories, respectively. Partial regression coefficients of the both traits were positive in all the subsets of the data, indicating that improvements of these two traits might increase the economic values of the carcasses.

The purpose of this study is to analyse the grazing situation from the viewpoint of management development and to consider measures to solve the problems. In 2017 and 2019, questionnaires and interviews were conducted on breeding farms in A Town, Ibaraki Prefecture. The grazing rates were 40% in both years, but most of the surveyed farms seasonally graze on grazing land of less than 30a per breeding cattle. The grazing area was insufficient for the number of cattle raised, and the grazing land was often far from home and barn. In many cases, the purpose of introducing grazing system was to save labour in manure processing and to easily detect estrus. On the other hand, 40% of the respondents answered that the management of feeding and water supply is a burden. It became clear that the tasks of grazing are the burden of moving and observing livestock and transporting feed and water. As measures necessary to solve the problem, in individual grazing farms, infrastructure development of grazing land and grassland management were mentioned. The measures that the region and the government should take are considered to be the accumulation of cohesive grazing land around the grazing farms.

BMS (Beef Marbling Score) estimation using the new adaptive binarization process and BMS classification estimation method has been reported for images taken using the mirror type camera. However, since 95% of beef carcasses distributed in Japan have a narrow cross-section without cutting the thoracic spine, it is impossible to take images using the mirror type camera. Therefore, in this study, the accuracy of image analysis was examined by comparing the images taken with the MIJ camera, which can take pictures even on a narrow beef carcass cross-section and with those of the mirror type camera. In addition, the rib eye area was measured, and BMS was determined from the images taken by the MIJ camera at eight slaughterhouses around Japan. To compare the mirror type camera and the MIJ camera, we used the data obtained by capturing the cross-section of 157 beef carcasses listed on the carcass market in Hokkaido in December 2020 with both imaging devices. From October 2019 to December 2019, cross sections of 1,046 beef carcasses were photographed using MIJ cameras at eight slaughterhouses around Japan, and rib eye area was measured, and BMS was estimated. High correlations were observed between the rib eye area and the marbling characteristics in the mirror type camera and the MIJ camera. In addition, the correlation coefficient between the grading rib eye area and the MIJ camera image analysis for the rib eye area for all animals (n＝1,046) was r＝0.71, and the ratio of BMS difference (estimated BMS-grading BMS) within ±1 and ±2 were 83.6% and 97.1%. It was suggested that the measurement of the rib eye area with the MIJ camera needed to be improved because the measured values differ depending on the photographer’s technique ; however, in the BMS estimation, it depends on the carcass refrigeration period and the environment, such as the slaughterhouse. BMS estimation is possible with high accuracy, suggesting highly accurate mechanical grading of meat quality.