Artificial insemination in pigs is a crucial technique supporting efficient pig production, with implementation rates exceeding 80% in worldwide. In this process, collected semen is diluted and preserved using a diluent, and subsequently injected into sows. The diluent not only serves to protect sperm function but is also believed to assist in enhancing sperm migration within the female reproductive tract. Notably, pig diluents feature a distinctive characteristic of containing a high concentration of the nutrient substrate glucose. In light of this, we undertook a metabolic and motility analysis of pig sperm using diluents with varying glucose concentrations, aiming to unravel the role of glucose in the diluent. Our investigations revealed that within a diluent containing 30.6 mM glucose, glucose is utilized not only for energy production through glycolysis but also plays a role in suppressing reactive oxygen species (ROS) through the pentose phosphate pathway, thus supporting mitochondrial function. In this manuscript, we focus on the diluent crucial to porcine artificial insemination and the high glucose concentration therein. We summarize insights into semen extenders and the role of glucose in porcine sperm, while also presenting our emerging understanding of the role of glucose in the diluent we have been exploring.

Despite being a valuable meat resource, Japanese Black delivered cows suffer from the problem of yellowing fat color. This study aimed to investigate the effects of the parity and the fattening period on the fat color in Japanese Black delivered cows using image analysis technology. Data from 504 delivered cows that were fattened for 365 days or less at the last farmers and shipped to the carcass market in Hokkaido between September 2016 and July 2022 were analyzed. L*a*b* values were determined through image analysis for subcutaneous and intermuscular fat in three locations of the 6th-7th rib cross-section. Correlation coefficients were calculated to determine the relationship among Beef Fat Standard (BFS) No. and each trait, and the b* value of subcutaneous fat was found to have the highest correlation coefficient (r＝0.76, P<0.01). The parity and the fattening period had a significant effect on BFS No., the b* value of subcutaneous fat, the b* value of intermuscular fat surrounded by M.spinalis, M.semispinalis capitis and M.longissimus thoracis, and the average b* value of color difference between subcutaneous fat and intermuscular fat (P<0.05). At 4 months of the fattening period, BFS No. was 5.4, which decreased to 4.2 at 5 months of the fattening period (P<0.01). Similarly, the b* value of subcutaneous fat decreased from 21.2 at 4 months of the fattening period to 14.2 at 5 months of the fattening period (P<0.01). The average b* value of color difference between subcutaneous fat and intermuscular fat decreased significantly at 5 months of the fatting period(P<0.01). This study confirmed that when grading of BFS No., the color of subcutaneous fat tends to be the determining factor. The results indicated that parity and the length of the fattening period significantly affect fat color, which is yellowish until 4 months of the fattening period. Moreover, the study found that BFS No. decreased significantly after the fattening period longer than 5 months.

This study evaluated the risk of using genomically-tested, young Holstein sires (GYS) to produce progeny with a low Nippon Total Profit index (NTP). The risk was defined as the probability that the progeny had a true NTP lower than the dam’s estimated NTP. The service sires available as of August 2023 in Japan were divided into three classes : daughter-proven sires with 60 or more daughters with milk records (BULL-OLD), daughter-proven sires with fewer than 60 recorded daughters (BULL-NEW), and GYS with no daughters (BULL-GYS). Two classes of dams were considered : cows born in 2020 (COW-2020) and genomically-tested heifers born in 2022 (HEI-2022). For each class, we assumed a hypothetical animal with the average published NTP. We then used these animals as parents for mating. The true NTP of progeny was assumed to follow a normal distribution, with the mean as the parent average of estimated NTP and the variance as the sum of the prediction error variance of the parent average of estimated NTP and the Mendelian sampling variance. For COW-2020 (or HEI-2022), the risk for BULL-OLD was 14.4% (23.2%), for BULL-NEW, 10.2% (17.1%), and for BULL-GYS, 2.1% (4.1%). The result suggests that the genomically-tested young sires are more effective than daughter-proven sires in improving the average of the true NTP in dairy herds.