Takaaki Ando

We evaluated four candidate SNPs (GC-NPFFR2 rs137147462, GC-NPFFR2 rs109452259, BRCA1 rs134817801, and DGAT1 p.K232A) previously reported in relation to mastitis or milk production traits, using 10,729 test-day phenotypic records collected over 10 years from 269 Japanese Holstein cows (Bos taurus) enrolled in the national Dairy Herd Improvement (DHI) program. Linear mixed models were used to estimate genotypic effects on somatic cell score (SCS) and to test multiple inheritance models. To assess clinical relevance, mastitis severity was further analyzed using categories defined by somatic cell counts (SCC). Among the SNPs tested, GC-NPFFR2 rs137147462 showed the clearest and most consistent association with SCS under a recessive model, with GG cows exhibiting higher SCS throughout lactation. Ordinal logistic regression confirmed a higher probability of progression to severe mastitis in GG cows. DGAT1 p.K232A showed additive effects, with the A allele increasing milk yield while lowering fat and protein percentages. AA cows also showed higher SCS under a modest recessive effect. BRCA1 rs134817801 and GC-NPFFR2 rs109452259 had minimal effects. These findings support GC-NPFFR2 rs137147462 as a promising marker for mastitis resistance and indicate the importance of considering not only additive but also recessive genetic models in genomic selection strategies.

Background/Objectives: DGAT1 p. K232A (rs109234250) is a well-established causal variant influencing milk fat and protein content in dairy cattle, but it is often absent from commercial genotyping arrays. PPP1R16A rs109146371 frequently appears as a top signal in genome-wide association studies (GWAS) for milk traits. This study aimed to evaluate the linkage disequilibrium (LD) between these two variants in Japanese Holsteins and assess whether rs109146371 exerts an independent effect on milk traits. Methods: A total of 256 Japanese Holstein cows were genotyped for DGAT1 p. K232A and PPP1R16A rs109146371 using TaqMan SNP assays. LD statistics (r², D′) were computed, and linear mixed-effects models were used to evaluate associations with 305-day milk yield, fat percentage, protein percentage, and solids-not-fat (SNF) percentage. Likelihood ratio tests were conducted to assess the independence of SNP effects. Results: Strong LD was observed between DGAT1 p. K232A and PPP1R16A rs109146371 (r² = 0.91, D′ = 0.9962). Both SNPs showed significant associations with all milk production traits; however, model comparisons indicated that rs109146371 did not improve model fit when K232A was included, suggesting no independent effect. Conclusions: PPP1R16A rs109146371 serves as a proxy for DGAT1 K232A rather than an independent determinant of milk traits.

A 36-day-old Japanese Black calf exhibited wheezing associated with dyspnea from birth. Arterial blood gas analysis revealed a low oxygen partial pressure of 51 mmHg, low oxygen saturation of 83%, and high carbon dioxide partial pressure of 58.8 mmHg. Computed tomography, endoscopy, and ultrasonography showed cyst formation under the epiglottis. When the cyst was aspirated under ultrasonic guidance to secure the airway, 30 ml of viscous white turbid content was aspirated. The cyst shrank immediately after aspiration, but the wheezing and respiratory symptoms resumed 7 days after aspiration. Therefore, the cyst was surgically removed from the ventral side of the neck. No cyst remodeling was observed 30 days after surgical removal.

This study was conducted to investigate the effects of probiotics administration on fatty acid metabolism in Japanese Black cattle as per changes in blood fatty acid concentrations and blood biochemical tests. Eighteen clinically healthy Japanese Black female fattening cattle bred on the same fattening farm were randomly classified into the probiotics administration group (n=9) or the control group (n=9). In the probiotics administration group, 50 g of probiotics were started per animal per day at the age of 18 months, and the administration period was 2 months from the start date of the study. Blood was collected twice before starting the probiotics administration and at 2 months after starting the probiotics administration. In the probiotics administration group, palmitic, linoleic, arachidonic and α-linolenic acid tended to be higher at the end of the administration compared with those before probiotics administration. Additionally, as a result of multiple comparison test, monounsaturated fatty acids at Post was significantly higher, and the ω6 / ω3 ratio was significantly lower than in the control group. Vitamin A, E and albumin were significantly higher at the end of the administration than in the control group. In this study that administering probiotics to Japanese Black cattle in the late middle stage of fattening period did not have a significant effect on fatty acid metabolism during feed digestion and absorption, but suggested that may alter some blood fatty acids concentrations.