Animal Science Journal最新文献

The performance of multi-trait genomic prediction was assessed by simulating phenotypic data with the publicly available information on the genomic relationship matrix for 9850 Japanese Black cattle utilizing eigen decomposition. Variance component estimation and genomic breeding value prediction were performed by analyzing simulated phenotypic data of two different traits with four simulation settings of varied heritability (0.1, 0.4, and 0.7), genetic correlation (0.6 and 0.95), and phenotypic correlation (0.4 and 0.8). A total of 1000, 3000, and 5000 animals were selected as training populations. The performance of the algorithm for proven and young was also examined using simulated and real phenotypic data. Core animals were chosen from the 9850 animals to minimize the genetic variance of non-core animals conditional on the core animals using the genomic relationship matrix. Five sets of core animals were provided, and those explaining 25%, 50%, 75%, 90%, and 99% of the genetic variance were first explained. The multi-trait model gave greater prediction accuracy than the single-trait model for both traits, and not only heritability and genetic correlation but phenotypic correlation affected the accuracy in the current settings. Core animals explaining 90% and 99% variance could yield results similar to those obtained by using the original genomic relationship matrix.

A feeding trial was conducted with lactating cows to evaluate the feed value of domestic dry-crushed corn grain. The corn grains were treated using a feed rice grain-crushing machine with a roll clearance of 0.2 mm. Six lactating cows were assigned to diets ensiled into a total mixed ration containing either steam-flaked (SF) or dry-crushed corn (DC). Group DC tended to have increased milk protein concentration and nitrogen secretion in milk, and decreased blood non-esterified fatty acid concentrations (p = 0.05, 0.06, and 0.08). Whereas, this group showed significantly higher dry matter intake per kg body weight, non-fiber carbohydrate, and starch digestibility (p = 0.04, 0.03, and < 0.001). No significant differences were found between the treatments in terms of lactation performance, nitrogen balance, rumen fluid profile, or total tract digestibility, suggesting that in lactating cows, the feeding value of dry-crushed corn was equal to or greater than that of steam-flaked corn. This finding suggests that crushing is an effective and practical method for processing domestic corn grain in dairy diets and that dry-crushed domestic corn grain can serve as an effective alternative to imported steam-flaked corn, potentially enhancing nutrient utilization in lactating cows.

The effects of pen relocation at dam-calf separation on behavioral changes and stress were examined in Japanese Black calves. Male and female calves were randomly assigned at 4 months of age to one of two groups: a non-relocation group, in which the dam was moved to a separate pen while the calf remained in its original pen; and a relocation group, in which the calf was moved while the dam remained in place. Calves were observed for step counts per 24 h and vocalizing counts per 12 h and per hour, and for time spent feeding, lying, and ruminating over 12-h periods around weaning. Blood samples were collected for hematological analysis and serum cortisol assay just before and after weaning. Calves in the non-relocation group had significantly fewer steps and less vocalization than those in the relocation group after weaning. Postweaning lying, feeding, and ruminating times were significantly longer in the non-relocation group than in the relocation group. Neutrophil-to-lymphocyte ratio and serum cortisol concentrations were also significantly lower in the non-relocation group after weaning. These findings suggest that avoiding pen relocation of calves during weaning may alleviate behavioral disturbances and reduce stress associated with maternal separation in Japanese Black cattle.

The high lactation performance or parity in dairy cows may affect intrauterine oxidative stress (OS) status. This study aimed to investigate the effects of milk yield, blood β-hydroxybutyrate (BHBA) concentrations, and parity on oxidative stress (diacron-reactive oxygen metabolites [d-ROMs]) or antioxidant activity (biological antioxidant potential [BAP]) in the uterine flush fluid of lactating Holstein Friesian dairy cows. Uterine flush fluid samples were collected at 4, 5, 6, and 8 weeks postpartum (n = 43), and d-ROMs and BAP were measured. d-ROMs, BAP, and oxidative stress index (OSI) were investigated in relation to the correlation between milk yield and BHBA concentrations. Cows were classified into primiparous cow groups (P group, n = 11), biparous cow group (B group, n = 5), and the third or more calving groups (M group, n = 27); d-ROMs, BAP, and OSI changes were evaluated across the groups. No significant correlations were noted between milk yield, blood BHBA concentrations, and d-ROMs, BAP, or OSI. The M group exhibited higher d-ROMs and OSI than the P group at 5 weeks, and the M group had a higher OSI than the B group at 6 weeks. Therefore, parity may influence uterine OS and antioxidant activity.

This study aimed to compare the growth of goats grazed in abandoned paddy fields with those raised in confined systems for meat production and to clarify the relationship between plasma metabolites including phytol derivatives and botanical conditions of the field. Eight Saanen goats at 4 months of age were allocated to the grazing and confined groups. Goats in the grazing group were grazed in an abandoned field with a concentrate supplement at 1.2% body weight (BW) from the end of May to early November. Grass silage and concentrate supplement at 1.0% BW were provided to the confined goats. Imperata cylindrica and Boehmeria nivea were the dominant plants in the grazing field. Plant biomass and its utilization reached a maximum in August and then decreased thereafter. Although the BW of goats in both groups was almost comparable until the end of September, the grazing goats showed a lower final BW than those in the confined group. Plasma concentrations of urea, total cholesterol, nonesterified fatty acids, lactate, amino acids, and phytanic acid in grazing goats fluctuated throughout the experimental period. These plasma metabolites can be used to monitor the nutritional condition of goats and botanical conditions of grazing fields.