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Forty-one Holstein dairy cows were categorized into two groups : 19 cows that conceived after the first postpartum insemination and 22 cows that failed to conceive. Blood composition values during the perinatal period and early lactation were compared to analyze the factors influencing the fertility of first AI. In addition, we attempted to predict the fertility of the first insemination using a discriminant equation based on early postpartum blood composition values. Alb and Ht were significantly higher in the fertility group, while Glu tended to be higher. This indicated that differences in postpartum blood properties were suggestive of subsequent fertility. In the fertility prediction of the first insemination by blood biochemical values in the first post-partum week, the discriminant equation using the three variables Alb, Glu, and PL showed the lowest misclassification rate for the conception result at 19.5%. These results indicate that a discriminant equation combining multiple blood biochemical indices as variables may be used to predict the fertility of first insemination with good accuracy. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the relationship between rumen microbiota and physiological characteristics in Japanese Black cattle during the fattening period, which are known for their distinctive physiological characteristics due to prominent intramuscular fat deposition. The experimental period was categorized into three stages: early (12 to 14 months of age; T1), middle (15 to 22 months; T2), and late fattening phases (23 to 30 months; T3). We analyzed the rumen microbiota of 21 Japanese Black cattle in each phase using 16S rRNA gene amplicon sequencing. In addition, we examined the correlation between the rumen microbiota and various physiological parameters, such as blood metabolites, hormones, and rumen fermentation characteristics. Our results showed that rumen microbial diversity was greater in T1, and the inter-group distribution of rumen microbiota in T1 was differentiated from T2 and T3. At the genus level, Flexilinea, Streptococcus, Butyrivibrio, Selenomonas and Kandleria were the most abundant in T1. Bifidobacterium, Shuttleworthia and Sharpea were the most abundant in T2. Acetitomaculum, Mycoplasma, Atopobium and Howardella were the most abundant in T3. In correlation analysis, Monoglobus and Olsenella negatively correlated with IGF-1 and positively correlated with cortisol in T1. Firmicutes/Bacteroidota ratio positively correlated with daily gain, blood total cholesterol, and lactic acid dehydrogenase in T3. Planctomycetota correlated with volatile fatty acid components during the entire period, while Verrucomicrobiota positively correlated with carcass traits in T1. Additionally, functional genetic profiles indicated that rumen microbiota related to carbohydrate metabolism and nucleotide biosynthesis was significantly enriched in T1 and T3, respectively. The composition of rumen microbial in Japanese Black cattle varied depending on fattening stages, and this variation is likely attributable to changes in feed composition. Furthermore, specific microorganisms were significantly associated with physiological parameters. Our findings could help in the development of strategies to enhance gut health and productivity by manipulating the rumen microbiota through the changes in diet compositions considering the fattening stages of Japanese Black cattle. [ABSTRACT FROM AUTHOR]

Predicting periparturient disease risk is of immense value to the dairy industry. Periparturient diseases are interrelated with each other; however, predicting the onset risk of these diseases has predominantly been based on a single blood parameter for a single disease. This study examined a new diagnostic method to predict the risk of periparturient diseases. We conducted cluster analysis of multiple blood constituents from 20 Holstein cattle at 1 week post-partum, and the cattle were divided into two groups, A or B. We then compared the periparturient and early-lactation blood constituents of these groups. Group B had significantly higher 3-hydroxybutyric acid concentrations and were suspected to have subclinical ketosis. Group B also had significantly lower calcium concentrations, with a tendency for subclinical hypocalcemia. We also performed discriminant analysis using blood parameters at 1 week post-partum, which grouped the population into the same two groups as the cluster analysis based on three variables: inorganic phosphorus, calcium, and either phospholipids or total cholesterol. We further showed that these discriminant functions could be used to predict the risk of periparturient disease even before parturition. Our results indicate that cluster analysis with multiple blood constituents is useful for predicting periparturient disease risks. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the effects of supplementing Saccharomyces cerevisiae (SC) during the pre- and post-weaning periods on growth, metabolic and hormonal responses, and rumen fermentation in calves. Three-week-old Holstein calves were assigned to either control (n = 12) or SC group (n = 12), the latter of which received 2 × 109 cfu/day of SC. The experiment was conducted over a period of 7 weeks around weaning. Daily gain (DG) in the SC group was higher (p < .05) than that in the control group. In the SC group, plasma glucose, insulin, and growth hormone (GH) concentrations were higher (p < .05) and concentrations of glucagon and insulinlike growth factor 1 (IGF-1) tended to be higher (p < .1) than in the control group. Proportion of rumen propionate and concentration of rumen ammonia nitrogen at 10 weeks of age were greater (p < .05) in the SC group than that in the control group. Supplementation of SC around weaning may improve dietary nutrient and energy availability and increase plasma GH and IGF-1 concentrations. These changes observed in SC-supplemented calves could be closely related to the improvement of DG. [ABSTRACT FROM AUTHOR]

We investigated the relationship between ruminal pH and bacteria in calves fed calf starter with and without forage during weaning transition. First, 16 Holstein bull calves were obtained from dairy farms and equipped with rumen cannulas by cannulation surgery. Then, calves (73.5 ± 4.2 kg; mean ± SE) were assigned to groups fed calf starter either with forage (HAY, n = 8) or without forage (CON, n = 8), and all calves were weaned at 8 weeks of age. Ruminal pH was measured continuously, and rumen fluid samples were collected at 7, 8, 9, and 11 weeks of age, namely −1, 0, 1, and 3 weeks after weaning, respectively, to assess volatile fatty acid concentrations and bacterial DNA. The 24-h mean ruminal pH was significantly (P < 0.05) different between the two groups. Diurnal changes in the 1-h mean ruminal pH were observed throughout the study in the HAY group; however, they were not observed at 0 and 1 weeks after weaning in the CON group. Moreover, the HAY group had significantly (P < 0.05) higher proportions of acetate and butyrate and lower proportion of propionate, and significantly (P < 0.05) lower ruminal acetate-to-propionate ratios were observed in the CON group. The ruminal bacterial diversity indices decreased after −1 week in both groups and increased at 0 and 1 weeks after weaning in the HAY and CON groups, respectively. From the 454 pyrosequencing analysis, significant differences (P < 0.05) were observed in the relative abundance of several phyla (Bacteroidetes, Actinobacteria, and Tenericutes) and one genus (Prevotella) between the two groups. From quantitative real-time PCR analysis, the HAY group had the higher copy numbers of cellulolytic bacteria (Ruminococcus flavefaciens and Ruminococcus albus) compared with the CON group. This study demonstrated that feeding of dietary forage alleviates subacute ruminal acidosis due to diurnal changes in ruminal pH. Furthermore, changes in ruminal pH affect the ruminal bacterial diversity and relative abundance, and these changes might have influenced the establishment of fermentative ruminal functions during weaning transition. [ABSTRACT FROM AUTHOR]