This study was carried out as an observational study in order to determine the prevalence of postpartum subclinical ketosis (SCK) in dairy herds in Hokkaido, Japan. From April 2012 to March 2014, blood β-hydroxybutyrate (BHBA) concentration was measured once within 3–88 days in milk (DIM) in 1394 apparently healthy cows from 108 farms to diagnose SCK (≥1.2 mM). In cows within 14 DIM, this was classified as SCK II, and from 15 DIM, this was classified as SCK I. Herds with a combined percentage of SCK I and SCK II of less than 10% were classified as SCK-negative herds, those with percentages of 10–25%, were classified as alert herds, and those with one of 25% or more, we classified as positive herds. The prevalence of SCK in the entire DIM was 17.6%. The prevalence of SCK II (20.2%) tended to occur more frequently than SCK I (16.5%, p = 0.094). The frequency of SCK I was higher at the fourth parity. The number of milking cows in SCK-positive herds was significantly smaller than those of the other two types of herds (p = 0.004). The frequency of SCK-positive herds in tie stalls and with component feeding was higher than for free stall or free barn and with total mixed ration (p = 0.054 and p = 0.002). This study reveals the prevalence of SCK in Hokkaido, Japan, and shows that SCK is associated with parity and the management system.

Summary: This study evaluated the effects of lactose content in milk replacements on the growth performance, digestibility, and metabolism of calves under iso-osmotic and isocaloric conditions. Low-lactose milk replacer (MR) did not affect average daily gain and showed greater body length and growth hormone receptor messenger RNA expression in the liver. These results suggest that the difference in the energy source of the MR affects metabolism of calves.

Summary:This study evaluated the impact of diarrhea frequency on intestinal permeability, plasma glucagon-like peptide-2 (GLP-2) levels, and growth in neonatal dairy calves. Calves were classified into high- and low-diarrhea groups. Although no differences in intestinal permeability were observed, high-diarrhea group calves showed lower growth rates and GLP-2 levels. These findings suggest that recurrent diarrhea may be linked to reduced GLP-2 secretion, which could impair growth, even without detectable changes in intestinal permeability.

This study investigated IgG concentrations, bacterial contamination, and nutrient components of colostrum on dairy farms in eastern Hokkaido, Japan, to examine the factors making it possible to obtain high-quality colostrum. Colostrum samples were collected from 266 Holstein cows. The general criteria for high-quality colostrum are an IgG concentration of 50 g/L or higher and a total plate count of less than 100,000 CFU/mL. The percentage of samples with the criteria for IgG concentration was low, at 48.9%, but the percentage with the criteria for total plate count was high, at 86.5%. The colostrum Brix value was significantly correlated with the colostrum IgG concentration (r² = 0.233, p < 0.001) and provided a rough estimate of that concentration. There was no association between the colostrum IgG concentration and milk components other than protein. For colostrum milking conditions, the time from calving to milking tended to be shorter for high-IgG colostrum than for low-IgG colostrum (p < 0.01). The likelihood of high-IgG colostrum increased 1.28-fold with first parity higher and decreased 0.92-fold with a 1 L higher milking volume (p < 0.01). The results suggest that, in addition to estimating the colostrum IgG concentration via the Brix value, the likelihood of obtaining high-IgG colostrum is increased by taking into account parity, milking volume, and time from calving to milking.

Objective: Post-ruminal supplementation of glucose may contribute to subsequent milk production and health. The objective of this study was to evaluate the effects of bypass sugar (BpS) supplementation to dairy cows during the transition period on milk production and metabolic status after calving.Methods: Fifteen Holstein cows were randomly assigned into three groups considering parity and previous milk production. The three groups corresponded to the following three treatments: a BpS group supplemented with BpS, a Gly group supplemented with dietary glycerol, and a control group with no supplementation in the basal diet from 21 days pre-partum to 5 days post-partum. Cows were sampled from 21 days pre-partum to 28 days post-partum, and milk yield and blood and health statuses were determined.Results: Milk yield was higher in the BpS group than that in the other groups. The rumen fill score was highest in the BpS group from the dry period to post-partum compared with that in the other groups. Post-partum blood glucose concentrations were higher in the BpS group than in the control group. The prevalence of hyperketonemia and blood concentrations of non-esterified fatty acids, β-hydroxylbutyrate, glucagon-like peptide-2 (GLP-2) and haptoglobin were not different among the groups. In the BpS group, blood aspartate aminotransferase concentration was lower than that in the Gly group. γ-glutamyl transpeptidase was lower than that in the control group.Conclusion: From these results, feeding BpS and Gly did not affect GLP-2 secretion and alleviate inflammation after calving, but BpS increased milk production and improved liver function.

The purpose of this study was to evaluate the preventive effects of propylene glycol (PG) or sucrose (SC) in dairy cows with high levels of non-esterified fatty acids (NEFAs) during the close-up period. From July 2021 to August 2022, blood samples were collected from 193 cows between 14 and 7 days prior to the expected calving date in two farms, and 35 multiparous cows with serum NEFA ≥ 0.3 mEq/L were randomly assigned to PG (500 mL/day, n = 11), SC (1000 mL/day of 50% solution, n = 11), and untreated control (HC; n = 13) groups. Treatments were administered orally for 5 consecutive days. Compared with HC cows, the serum NEFA concentration tended to be lower in SC cows at 3 days in milk (DIM) and was significantly lower in PG cows at 14 DIM. Serum β-hydroxybutyrate concentrations tended to be lower in SC cows at 21 DIM. Blood glucose concentrations were higher in both treatment groups at 3 DIM, and the serum total bilirubin concentration remained lower until 14 DIM in PG cows and until 7 DIM in SC cows. At 7 DIM, PG cows showed significantly higher total very low-density lipoprotein levels and PG and SC cows had significantly or tendentially higher low-density lipoprotein triglyceride concentrations. Cows in both treatment groups had significantly reduced culling after calving. These results suggest that prophylactic administration of PG or SC improves energy metabolism by supporting liver function, thereby reducing postpartum culling, with the PG group showing a more consistent effect.