JDS communications最新文献

{"title":"Comparison of glucose concentration measured in samples collected with different anticoagulants and analyzed using 2 glucose quantification methods","authors":"Anay D. Ravelo ,&nbsp;Megan Ruch ,&nbsp;Isaac J. Salfer ,&nbsp;Luciano S. Caixeta","doi":"10.3168/jdsc.2024-0730","DOIUrl":"10.3168/jdsc.2024-0730","url":null,"abstract":"<div><div>Sodium fluoride (NaF), K₂-EDTA, and lithium heparin are common anticoagulants used during collection of bovine blood for glucose concentration. Whereas NaF is considered the best anticoagulant for preservation of glucose, other anticoagulants are used because of their ability to simultaneously preserve other metabolites frequently measured in dairy science experiments. To simplify sample collection and reduce the need for multiple tubes, it may be possible to use tubes with anticoagulants other than NaF, provided they yield comparable glucose concentrations. Additionally, blood glucose concentrations are commonly analyzed using a peroxidase and glucose oxidase (PGO) colorimetric assay with a standard plate reader, but the use of a semi-automated chemistry analyzer with a hexokinase (HK) enzymatic reaction method is becoming more common in dairy research because it is also available and easy to use. Thus, the objective of this study was to determine the influence of the use of NaF, dipotassium EDTA (K₂-EDTA), or lithium heparin (Li-Hep) as anticoagulants on glucose quantification, using both the PGO and HK enzymatic reaction methods. Blood samples from 20 fresh cows (7 ± 3 DIM) were collected into NaF, K₂-EDTA, or Li-Hep plasma tubes on a commercial dairy farm (n = 60 samples). All samples were analyzed using both the PGO method, performed on a 96-well plate with a colorimetric microplate reader, and the HK method, conducted on a semi-automated chemistry analyzer. It was observed that in both methods, samples collected into NaF tubes had less glucose quantified compared with samples collected into K₂-EDTA and Li-Hep tubes. Additionally, it was observed that in samples quantified with the HK method, the glucose concentrations were lower than when those samples were quantified with the PGO method. Thus, the K₂-EDTA and Li-Hep anticoagulant could be used for glucose quantification to avoid cumbersome collection of several tubes, but results must be reviewed with caution as concentrations would be higher compared with those quantified with NaF. This observation is also conserved when quantifying glucose using the PGO and HK methods.</div></div>","PeriodicalId":94061,"journal":{"name":"JDS communications","volume":"6 4","pages":"Pages 616-619"},"PeriodicalIF":0.0,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144517911","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Relationships between method used for bedding processing and presence of mastitis and nonmastitis pathogens in ready-to-use recycled manure solids bedding on Midwest dairy farms","authors":"F. Peña-Mosca ,&nbsp;S. Godden ,&nbsp;E. Royster ,&nbsp;D. Albrecht ,&nbsp;S.J. Wells ,&nbsp;B.A.C. Crooker ,&nbsp;N. Aulik","doi":"10.3168/jdsc.2025-0754","DOIUrl":"10.3168/jdsc.2025-0754","url":null,"abstract":"<div><div>Field studies have examined how processing methods affect mastitis pathogen levels in ready-to-use (RTU) recycled manure solids (RMS), but few have assessed their impact on nonmastitis pathogens. This cross-sectional study investigated associations between RMS processing methods and (1) mastitis pathogen levels and (2) the presence of <em>Mycobacterium avium</em> subspecies <em>paratuberculosis</em> (MAP), <em>Salmonella</em> (SAL), and <em>Campylobacter jejuni</em> (CAMP) in RMS from Midwest dairy herds. Twenty-seven dairies in Minnesota and Wisconsin were recruited to represent various RMS processing methods: raw or green solids (GRN; n = 6), drum composters (COM; n = 3), anaerobic digesters (DIG; n = 9), digesters with hot air dryers (DIG+DRY; n = 6), digesters with infrared dryers (DIG-IR; n = 1), and hot air dryers (DRY; n = 2). Farms were visited once in summer 2021 to collect slurry and postprocessed RMS samples before and after each processing step. Samples were tested for MAP (culture and PCR confirmation), CAMP (culture), and SAL (culture). Ready-to-use RMS samples also underwent aerobic culture to determine counts of coliforms, <em>Klebsiella</em> spp., <em>Streptococcus</em> spp., <em>Streptococcus</em> spp. and <em>Streptococcus</em>-like organisms (SSLO), and <em>Staphylococcus</em> spp. (cfu/cm³, wet basis). For analysis, dairies were grouped into 4 system types: GRN (n = 6), DIG-only (n = 9), secondary processing only (SEC; DRY or COM; n = 5), or DIG combined with SEC (DIG+SEC; n = 7). Linear regression assessed associations between processing type and mastitis pathogen counts, and logistic regression evaluated MAP and SAL presence before and after processing. No CAMP was detected. Prevalence of MAP and SAL in raw slurry was high (MAP: 68% [17/25]; SAL: 80% [21/25]). Compared with GRN, DIG-only and SEC-only systems were associated with lower mastitis pathogen counts and reduction of MAP and SAL presence, though these pathogens were still identified in RTU RMS samples. The DIG+SEC systems showed the greatest reduction in mastitis pathogen counts, and MAP and SAL were not detected in RTU RMS. Our results suggest that combining DIG with a secondary processing method (e.g., COM, DRY, or IR) most effectively reduces mastitis and nonmastitis pathogens in RMS bedding.</div></div>","PeriodicalId":94061,"journal":{"name":"JDS communications","volume":"6 4","pages":"Pages 567-572"},"PeriodicalIF":0.0,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144517987","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On-farm approaches to increase whole-milk total solids: Effects on performance and health of dairy calves","authors":"Amanda M. Cezar ,&nbsp;Ana Paula da Silva ,&nbsp;Ariany F. de Toledo ,&nbsp;Cristiane R. Tomaluski ,&nbsp;Sophia C. Dondé ,&nbsp;Gercino F. Virgínio Júnior ,&nbsp;Marcos I. Marcondes ,&nbsp;Carla M.M. Bittar","doi":"10.3168/jdsc.2024-0684","DOIUrl":"10.3168/jdsc.2024-0684","url":null,"abstract":"<div><div>This study aimed to evaluate the performance, metabolism, and health of Holstein calves fed whole milk adjusted for 15% TS by adding a commercial solids corrector (245 g/kg CP, 48 g/kg crude fat, 90 g/kg of mineral, and 3 g/kg of ADF) using 2 practical approaches: daily adjustment based on a Brix refractometer reading, or the addition of a fixed amount of the corrector based on mean milk solids content. Thirty newborn male Holstein calves were assigned to one of the 2 treatments: (1) fixed, in which whole-milk solids were adjusted using a fixed dose of 25 g/L, and (2) Brix, in which whole-milk solids were adjusted based on a daily Brix refractometer reading. Treatments were randomly assigned within blocks formed based on BW and birth date (2 calves per block). The experimental period lasted 56 d, during which calves were fed 6 L/d of the respective liquid diet and had free access to water and starter concentrate. Daily adjustments based on the Brix refractometer reading improved total liquid diet, as well as protein and lactose intake. However, calf performance and health indicators did not differ between treatments. Total serum protein concentration was greater in calves fed milk corrected using the fixed dose. Additionally, creatinine concentration was influenced by the interaction between treatment and age, with a trend toward greater concentrations in calves fed milk adjusted using the daily Brix refractometer reading at 2 wk of age. Overall, both strategies for increasing TS in whole milk (Brix refractometer and fixed dose) resulted in comparable performance and health outcomes and may serve as practical on-farm approaches for managing dairy calves.</div></div>","PeriodicalId":94061,"journal":{"name":"JDS communications","volume":"6 4","pages":"Pages 497-501"},"PeriodicalIF":0.0,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144518033","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Salivary and blood plasma oxytocin after oxytocin injection and during machine milking in dairy cows","authors":"Olga Wellnitz ,&nbsp;Benjamin Jenni ,&nbsp;Natascha Stoffel ,&nbsp;Samantha Weber ,&nbsp;Selma Aybek ,&nbsp;Rupert M. Bruckmaier","doi":"10.3168/jdsc.2025-0761","DOIUrl":"10.3168/jdsc.2025-0761","url":null,"abstract":"<div><div>Oxytocin (OT), the peptide hormone whose release from the pituitary is essential to induce milk ejection, has been measured in blood plasma of dairy cows for decades. In the present study we tested the possible use of saliva instead of blood sampling to record OT release by using a commercially available ELISA for salivary OT measurement both in saliva and blood plasma. Measurements were performed to detect the expected OT increase in response to intravenous OT injections and during machine milking. Three dairy cows were injected with increasing dosages (0.5, 1, 5, and 10 IU i.v.) of OT, and blood and saliva samples were repeatedly taken during 1 h after injection. Furthermore, 5 cows were milked and blood and saliva samples were taken during and until 20 min after milking. To verify the expected release of OT during milking, we used our established RIA for measurements in plasma in parallel to ELISA measurements. Our results showed that the commercial ELISA kit used was able to detect the OT concentrations in both saliva and plasma. The massive increase of OT concentration after OT injection and during milking could be detected in plasma with both RIA and ELISA. However, we did not observe any change of salivary OT within the duration of the experiments. Our results showed that short-term increases in blood plasma OT, such as in response to OT injection or milking, were not reflected by increasing salivary OT concentrations.</div></div>","PeriodicalId":94061,"journal":{"name":"JDS communications","volume":"6 4","pages":"Pages 620-623"},"PeriodicalIF":0.0,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144518037","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of season on birth weight, growth, and average daily gain of conventionally raised Holstein heifers in the Midwestern United States","authors":"K.N. Brost,&nbsp;J.K. Drackley","doi":"10.3168/jdsc.2025-0758","DOIUrl":"10.3168/jdsc.2025-0758","url":null,"abstract":"<div><div>The objectives of this study were to determine the effects of season on calf birth weight, growth, and ADG of Holstein heifers. This retrospective analysis included data from July 2018 to February 2022 and included 216 calves from the University of Illinois Dairy Research Unit. Calves were housed in individual hutches until weaned at 56 d. After weaning, calves moved to group housing until 175 d of age, at which time they moved to heifer dry lots. Feeding rates remained consistent throughout the year, and weaning took place from d 50 to 56. Body weight data were collected at birth, weaning, and when moved to heifer lots. Calves were assigned a season based on month of birth: winter (December, January, February), spring (March, April, May), summer (June, July, August), and fall (September, October, November). In this analysis, season was the fixed effect, and calf was a random effect and subject of the repeated effect. Data were analyzed using the MIXED and UNIVARIATE procedures in SAS. Winter-born calves had greater birth and weaning BW when compared with summer calves. Birth BW of winter calves tended to be greater and weaning BW were greater when compared with all nonwinter calves. Similarly, preweaning ADG of winter calves was greater than summer calves and all nonwinter calves. On the other hand, postweaning BW and ADG were greater for summer calves in comparison to winter calves. Likewise, summer calves were observed to have greater BW and tended to have greater ADG in contrast to all nonsummer calves. When combining the pre- and postweaning ADG through the first 175 d of life, there were no differences between winter and summer calves, winter and nonwinter calves, or summer and nonsummer calves. These results indicate calf birth BW and growth performance are greater through weaning during colder seasons. Conversely, calves born during winter do not perform as well after weaning once the seasons get warmer. Summer calves were observed to have decreased birth BW and performance through weaning, but as the seasons became cooler, they excelled postweaning to 175 d of age.</div></div>","PeriodicalId":94061,"journal":{"name":"JDS communications","volume":"6 4","pages":"Pages 518-521"},"PeriodicalIF":0.0,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144517980","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Transcriptomic changes induced by controlled cyclical heat stress in the bovine mammary gland during lactation","authors":"G. Perez-Hernandez ,&nbsp;M.D. Ellett ,&nbsp;B. Pokhrel ,&nbsp;C.L.M. Parsons ,&nbsp;B.A. Corl ,&nbsp;K.M. Daniels","doi":"10.3168/jdsc.2025-0760","DOIUrl":"10.3168/jdsc.2025-0760","url":null,"abstract":"<div><div>This study examined the effects of heat stress (HS) on mid-lactating (100 ± 14 DIM) Holstein cows. Cows were assigned to either HS (temperature-humidity index [THI] 74–80; n = 7) or thermoneutral (pair-fed PFTN; THI 64; n = 8) conditions for 4 d. Exposure to HS reduced milk (4.34 ± 1.62 kg/d), protein (0.18 ± 0.04 kg/d), and fat (0.18 ± 0.05 kg/d) yields, highlighting the negative impacts of HS on production and homeostasis. To explore main molecular responses, mammary gland tissue samples were collected for transcriptomic analysis. Transcriptomic analysis revealed 54 upregulated and 74 downregulated genes in HS conditions. Upregulated genes included heat shock proteins (<em>HSPA1A</em>, <em>HSPH1</em>) and other stress-responsive genes (<em>HSPA4L</em>, <em>SPINK4</em>, <em>ZNF772</em>). Downregulated genes involved DNA repair (<em>GADD45G</em> and <em>FEN1</em>) and mitochondrial function (<em>ND6</em> and <em>ND5</em>). Gene Ontology (GO) enrichment analysis indicated significant enrichment in protein quality control and stress response processes. Protein-protein interaction (PPI) of differentially expressed genes (DEG) analysis underscored networks of molecular chaperones and protein quality control pathways. Heat stress activates proteostasis-related pathways and molecular chaperone systems in the bovine mammary gland, reflecting cellular efforts to mitigate protein misfolding and maintain homeostasis.</div></div>","PeriodicalId":94061,"journal":{"name":"JDS communications","volume":"6 4","pages":"Pages 604-609"},"PeriodicalIF":0.0,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144517909","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Association between postpartum systemic inflammation and serum calcium in healthy multiparous dairy cows: An exploratory observational analysis","authors":"R. Couto Serrenho ,&nbsp;R.C. Neves ,&nbsp;S.J. LeBlanc","doi":"10.3168/jdsc.2024-0725","DOIUrl":"10.3168/jdsc.2024-0725","url":null,"abstract":"<div><div>Our objective was to investigate the association between serum total Ca concentration (tCa) and indicators of systemic inflammation (SI) in postpartum dairy cows. We hypothesized that the tCa-SI association varies in the first 8 d of lactation. This exploratory analysis used data from a field trial in which cows were randomly assigned to receive oral Ca supplementation after calving (OSCa), or not. Healthy multiparous cows (total n = 101; n OSCa = 51) from 2 farms in Ontario, Canada, were included. The inflammatory markers assessed were serum concentrations of albumin (a negative acute phase protein), and the positive acute phase proteins haptoglobin and serum amyloid A (SAA). Albumin, haptoglobin, and tCa were assessed at 0 (&lt;12 h after calving), 0.5 (12 h), 1, 2, 4, 6, and 8 d after parturition; SAA was assessed at d 0, 2, and 4. Linear regression models were fitted while accounting for time as a repeated measure for each analyte, and included tCa, tCa², days postpartum, parity (2 vs. ≥3), OSCa, the interactions of tCa × day postpartum, tCa² × day postpartum, tCa × parity, tCa² × parity, and farm as a random effect. A stepwise backward elimination approach was applied to improve model parsimony. The lowest albumin and greatest haptoglobin and SAA concentrations were observed at d 2. The association of albumin with tCa varied quadratically over time. At d 0, 0.5, 1, and 2, as tCa decreased, albumin increased, but at d 4, 6, and 8 as tCa decreased, albumin also decreased. At d 0, 0.5, and 1, when tCa &lt;1.7 mmol/L, tCa and haptoglobin were positively associated. Total calcium &lt;1.7 mmol/L was not observed ≥d 2. After d 1, cows with lower tCa tended to have greater haptoglobin concentrations. The greatest concentration of SAA occurred when tCa was 1.9 mmol/L. Values of tCa &lt;1.9 mmol/L were mainly observed at d 0. At d 0, and when tCa was &lt;1.9 mmol/L, lower tCa was associated with lesser SAA concentration. However, when tCa was &gt;1.9 mmol/L (93% and 99% of the values observed at d 2 and 4, respectively), lower tCa was associated with greater SAA concentration. The associations between tCa and markers of SI changed in the first 8 d of lactation in clinically healthy cows. Potential interventions to modulate hypocalcemia or SI, or both, should consider their interactions. Future studies should further explore the association of the degree and duration of hypocalcemia and SI to better understand the direction and mechanisms of this relationship.</div></div>","PeriodicalId":94061,"journal":{"name":"JDS communications","volume":"6 4","pages":"Pages 557-561"},"PeriodicalIF":0.0,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144517985","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The impact of sphingomyelin and cholesterol on ordered lipid domain formation in the bovine milk fat globule membrane using artificial giant unilamellar vesicles as a model","authors":"Haotian Zheng ,&nbsp;Rafael Jiménez-Flores ,&nbsp;David W. Everett","doi":"10.3168/jdsc.2024-0719","DOIUrl":"10.3168/jdsc.2024-0719","url":null,"abstract":"<div><div>Giant unilamellar vesicle (GUV) bilayers were constructed from polar lipids and cholesterol by electroformation as a model system to investigate the formation of ordered lipid domains (OLD) within the milk fat globule membrane (MFGM). Dark regions without fluorescent staining on the surfaces of GUV, observed by confocal laser scanning microscopy, were characterized as OLD. Lipid formulations were designed by mixing 1,2-dipalmitoyl-<em>sn</em>-glycero-3-phosphocholine; 1,2-dioleoyl-<em>sn</em>-glycero-3-phosphoethanolamine; milk sphingomyelin; and cholesterol with designated molar ratios to reveal the key components responsible for segregated OLD formation. Cholesterol, rather than milk sphingomyelin, was more responsible for OLD formation. Dark regions were observed in GUV, which contained sphingomyelin but no cholesterol. This observation revealed that at room temperature (below the melting transition temperature [<em>T_m</em>]), not only do cholesterol-mediated ordered domains contribute to lipid phase separation, but phospholipids with high <em>T_m</em> in MFGM are also segregated from the bright fluorescent liquid-disordered domains. This work provides visible evidence demonstrating the comparative roles of sphingomyelin and cholesterol in forming OLD in phospholipid bilayers.</div></div>","PeriodicalId":94061,"journal":{"name":"JDS communications","volume":"6 4","pages":"Pages 485-489"},"PeriodicalIF":0.0,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144518030","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Efficiency of genomic and phenomic selection using mid-infrared milk spectra for milk production, somatic cell count, and udder type traits in French Lacaune dairy sheep","authors":"C. Machefert ,&nbsp;H. Larroque ,&nbsp;J.M. Astruc ,&nbsp;C. Robert-Granié","doi":"10.3168/jdsc.2024-0714","DOIUrl":"10.3168/jdsc.2024-0714","url":null,"abstract":"<div><div>Genomic selection uses molecular and pedigree information to accurately estimate genomic breeding values of animals from birth for traits in selection. Recent research in phenomic selection in plant production is opening up new opportunities in animal breeding. The approach of phenomic selection has been little studied in animal production. Here, we evaluate the efficiency of phenomic selection to estimate the phenomic values of phenotype-free females using mid-infrared spectral (MIRS) data from their milk samples. The phenotypes of 1,531 first-lactation French Lacaune dairy ewes were considered for traits included classically in the breeding goals, such as milk production and functional traits (SCS and udder type traits). The inclusion of standardized raw MIRS data instead of SNPs led to very low phenomic predictive abilities for udder type traits (Pearson correlations between phenotype and phenomic values from −0.08 to 0.07). For milk production traits, the phenomic predictions were superior to the genomic ones, in particular for lactation SCS (LSCS), with a predictive ability at 0.49 instead of 0.04. Overall, random regression-BLUP and Bayesian reproducing kernel Hilbert space methods gave equivalent results on phenomic predictions across all traits, with no impact from spectral data preprocessing. Finally, the efficiency of the combination of SNPs and milk MIRS in prediction models was low (average +3.8% for milk production and LSCS traits). Phenomic predictions could open up new prospects especially for the selection of nongenotyped females.</div></div>","PeriodicalId":94061,"journal":{"name":"JDS communications","volume":"6 4","pages":"Pages 538-543"},"PeriodicalIF":0.0,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144517914","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Association of β-casein gene polymorphism with milk production characteristics in Holstein cows","authors":"Danielle de C.M. da Fonseca ,&nbsp;Alenia N. Vasconcellos ,&nbsp;Elizangela D. Marino ,&nbsp;Thais N. Chequer ,&nbsp;Luisa M.F.S. Oliveira ,&nbsp;João A. Negrão ,&nbsp;Julio C. de C. Balieiro ,&nbsp;Arlindo Saran Netto ,&nbsp;Ana M.C. Vidal","doi":"10.3168/jdsc.2025-0746","DOIUrl":"10.3168/jdsc.2025-0746","url":null,"abstract":"<div><div>The aim of this study was to analyze the association between the β-CN <em>CSN2</em> gene polymorphism, energy, enzymatic, and nitrogenous metabolites, and production, composition (fat, protein, lactose, total solids, nonfat solids), and SCC in the milk of Holstein cows submitted to the same nutritional and environmental conditions. Eighteen cows (6 A1A1 genotype, 6 A1A2 genotype, and 6 A2A2 genotype) were selected and matched for parity, calving season, and days in lactation. For the statistical analysis, a fixed linear model was applied in which genotypes were considered as a fixed effect and the dependent variables included metabolites, milk production, milk composition, and SCC. We found no statistically significant differences associating the genotype for the β-CN <em>CSN2</em> gene with milk production and composition characteristics or with energy, enzymatic, and nitrogen metabolites of blood and milk, except for variable glucose concentration (mg/dL), in which only the A2A2 genotype presented the highest means (67.78a) in relation to the other genotypes A1A1 (58.28b) and A1A2 (55.69b), where the letter a corresponds to the value of the highest mean and the letter b corresponds to the value of the lowest mean. Under the conditions in which the experiment was developed, the highest averages were numerically observed for variables milk production (kg/d), milk composition and yield (%), and urea nitrogen concentration (%) in the blood, milk, and urine of cows carrying the heterozygous genotype (A1A2) compared with both homozygous genotypes (A1A1 and A2A2), and we found that polymorphism of A1 and A2 alleles does not alter milk composition or blood and urinary metabolites.</div></div>","PeriodicalId":94061,"journal":{"name":"JDS communications","volume":"6 4","pages":"Pages 548-551"},"PeriodicalIF":0.0,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144517983","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}