Journal of Dairy Science最新文献

{"title":"Comparison of linseed oil and its ethyl esters as fat supplements in milk replacer: Impacts on physical properties, nutrient digestibility, health, and oxidative status of dairy calves.","authors":"M K Baba, J Flaga, K Dziadek, M Kasprzak, D Motyka, Z M Kowalski","doi":"10.3168/jds.2026-28505","DOIUrl":"https://doi.org/10.3168/jds.2026-28505","url":null,"abstract":"<p><p>The study aimed to examine the physical properties of milk replacer (MR) supplemented with linseed oil or ethyl esters of polyunsaturated fatty acids of linseed oil, and the subsequent impacts on nutrient and fatty acid (FA) digestibility, growth performance, health status, and some immune response and oxidative stress parameters in pre-weaned dairy calves. Eighteen Holstein calves were assigned to one of 3 treatments: a control MR with no supplemental fat added (CON), MR supplemented with 30 mL/d of linseed oil (LO), or MR supplemented with 30 mL/d of ethyl esters of polyunsaturated fatty acids of linseed oil (EELO). Physical properties of MR, including creaming index (CI), droplet size distribution, and microstructure, were evaluated after mixing/homogenizing with water. Apparent total-tract digestibility of nutrients was determined by fecal collection during 2 periods (22-25 and 50-53 d of age). Digestibility was calculated for dry matter, organic matter, crude protein, crude fat, and individual fatty acids (C16:0, C18:0, C18:1, C18:2, and C18:3). Titanium dioxide (TiO<sub>2</sub>) was included in the diet as an indigestible marker. Health parameters were recorded daily from 12 to 53 d of age, and some immune and oxidative stress indicators were measured in blood samples collected on 12, 25, 43, and 53 d of age. Performance parameters such as MR and starter mixture intake, total DMI, ADG, feed efficiency as well as nutrient intakes, nutrient digestibility coefficients, immune status, or oxidative stress parameters were analyzed as repeated measures using a linear model and the GLIMMIX procedure in SAS. Supplementation of MR with LO or EELO affected CI and droplet size characteristics, with EELO showing improved MR stability compared with LO, including a lower CI, more favorable droplet size distribution, and reduced fat globule coalescence. Fat supplementation did not affect DMI. However, final BW, ADG, and feed efficiency tended to be greater in calves receiving EEPUFALO. Digestibility of OM and CP was greater in the EELO group in both periods, whereas LO supplementation reduced C18:2 digestibility during the first experimental period. Digestibility of selected FA, including C16:0 and C18:3, was higher in calves supplemented with EELO. Irrespective of treatment, older calves exhibited greater digestibility of crude fat and PUFA, indicating an age-related improvement in lipid digestion. Fat supplementation reduced the number of days with diarrhea and the number of treatment days, with the most pronounced effects observed in the EELO group. Supplementation with EELO was associated with reduced concentrations of measured inflammatory markers, particularly TNF-α, and a tendency toward lower serum haptoglobin. In addition, EELO supplementation improved oxidative status, reflected by reduced total oxidant status, increased total antioxidant status, and a reduced oxidative stress index. In conclusion, EELO exhibited superior physical, nutritio","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.7,"publicationDate":"2026-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149147136","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Factors associated with cow- and herd-level somatic cell count patterns on organic dairy farms in the United States.","authors":"C Hernández-Gotelli, A De Vries, E K Miller-Cushon, B J Heins, R A Lynch, Q K Kolar, G M Schuenemann, V E Cabrera, E Silva, P J Pinedo","doi":"10.3168/jds.2026-28648","DOIUrl":"https://doi.org/10.3168/jds.2026-28648","url":null,"abstract":"<p><p>The objective of this study was to characterize cow- and herd-level patterns of somatic cell counts (SCC) in organic-certified cows enrolled in the DHI program, considering cow (parity, DIM, milk yield, and breed), herd (herd size), and environmental factors (geographic region, year, and season). The data set comprised 2,327,479 test-day records collected between 2018 and 2025 from 430 organic-certified dairy farms enrolled in the DHI program through the Dairy Records Management Systems, representing a total of 364,413 lactations. To evaluate potential associations at the cow-level between SCC and the variables of interest, separate linear mixed models were fitted for interactions between pairs of explanatory variables using natural log-transformed SCC (LnSCC). Additionally, relative frequencies of observations across SCC categories (≤100,000, 101,000-200,000, 201,000-500,000, 501,000-1,000,000, and >1,000,000 cells/mL) were calculated for each level of the categorical variables evaluated. For the herd-level analysis, mean herd SCC was calculated for each herd-year-season combination, and relative frequencies across SCC categories were estimated. Cumulative link mixed models for ordinal outcomes were used to assess herd-level associations between variables of interest and SCC categories, by calculating the probabilities of herds falling into higher ordinal SCC categories across explanatory variable levels. The cow-level results were back-transformed to the original SCC scale for presentation purposes, indicating that SCC increased with parity and varied throughout the lactation, peaking in early lactation (0-30 DIM), decreasing during mid-lactation (31-100 DIM), and gradually increasing again toward late lactation. Cows in the lowest quartile of relative milk yield consistently exhibited higher SCC across DIM categories compared with cows in the higher quartiles of MY. Holsteins had the lowest SCC, whereas Jersey and other breeds had higher values. Seasonal effects were evident, with SCC peaking during summer, particularly from July to September, and cows in the Midwest showing lower SCC than those in the Northeast, South, and West. SCC were highest in large herds (>500 cows) and lowest in medium-sized herds (101-500 cows). Similarly, the proportion of cows in the lowest SCC category (<100,000 cells/mL) decreased with increasing parity and was lower during early and late lactation and during the summer months. Holsteins had the highest proportion of cows in the lowest SCC category. Larger herds and farms located in the South and West showed greater proportions of cows in SCC categories above 200,000 cells/mL. Over the last 3 years of the study period, the proportion of observations in SCC >200,000 cells/mL increased in large herds and on farms in the South and West but declined in medium-sized herds (101-500 cows). At the herd-level analysis, larger herds and farms located in the South had a greater probability of being classified into high","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.7,"publicationDate":"2026-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149147391","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sample-efficient machine learning for dairy pathogen detection and origin traceability under multivariable conditions using gold nanoparticle colorimetry.","authors":"Xiaorui Han, Yiwen Tian, Junjie Li, Shu Xing, Zhenxin Wang, Xuefeng Xing, Tao Li","doi":"10.3168/jds.2026-29212","DOIUrl":"https://doi.org/10.3168/jds.2026-29212","url":null,"abstract":"<p><p>Storage temperature, humidity, and time jointly influence pathogen growth in dairy products, yet most rapid detection methods are validated under single-variable conditions that do not represent real supply chain scenarios. Testing across these combined conditions sharply increases the number of samples needed, whereas dairy safety studies usually work with small data sets, which limits the use of conventional machine learning. Here we combined gold nanoparticle colorimetric sensing, a time-temperature-humidity (TTH) framework, and a sample-efficient Random Forest model for pathogen detection and geographical origin traceability in dairy products. The colorimetric assay used aptamers as recognition elements and required no complex sample preparation, nucleic acid extraction, or cold-chain reagent storage. It achieved limits of detection of 104 cfu/mL for Staphylococcus aureus, 108 cfu/mL for Salmonella typhimurium, and 107 cfu/mL for Escherichia coli, with recoveries of 96.4-108.4% in commercially sterilized fluid milk and milk powder from 4 Chinese production regions. TTH monitoring showed that at 37°C, pathogen concentrations were estimated to reach the order of magnitude of the limits in GB 29921-2021 and GB 4789.18-2024 (10² cfu/g for S. aureus and E. coli, and zero tolerance for S. typhimurium), used here as a growth-monitoring reference, within about 4 h; at 25°C this window extended to 8-9 h, while storage at 4°C kept levels low for the first ∼12 d of the 16-17-d monitoring period. To work within the small sample sizes typical of dairy safety studies, Random Forest was optimized with a target-R²-guided hyperparameter strategy. Using 2,592 measurement records from 3 independent replicates, and evaluating the models against plate-count-calibrated concentration values and the inoculated pathogen species and region of purchase as reference labels, the optimized model reached an R² of 0.993 for pathogen concentration prediction, 94.6% accuracy for multi-class pathogen classification, and 94.2% accuracy for geographical origin discrimination among Shanghai, Yunnan, Inner Mongolia, and Xinjiang samples, with areas under the curve of at least 0.97 for both classification tasks. Region-specific growth patterns in the TTH framework enabled origin identification and could support targeted recall, origin fraud screening, and source tracing at dairy distribution checkpoints. As each region was represented by a single commercial product per type and a single production batch, these results should be regarded as a proof-of-concept. This approach provides a practical screening strategy for dairy pathogen monitoring and origin traceability under multivariable supply chain conditions.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.7,"publicationDate":"2026-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149147101","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Identification and characterization of 2 major mutations affecting sire fertility in Jersey cattle: Effects on fertilization capacity and early embryonic development.","authors":"Froylan Sosa, Hendyel A Pacheco, Briza Castro, Ethel Moreno, Everardo Anta-Galván, Byron Chasi, Fares Al-Katanani, Megan Lauber, Esmeralda Jaramillo, Emily Miller, Francisco Peñagaricano, M Sofia Ortega","doi":"10.3168/jds.2026-28893","DOIUrl":"https://doi.org/10.3168/jds.2026-28893","url":null,"abstract":"<p><p>Male fertility is a key determinant of reproductive efficiency in dairy cattle; however, some sires with normal semen parameters exhibit reduced fertility due to intrinsic sperm defects, including those arising from genetic mutations. Previous research has identified 2 genomic regions, located on BTA11 (2.6 Mb) and BTA25 (19.1 Mb), that severely affect service sire fertility in US Jersey cattle. However, the causal mutations and their impact on male fertility remain unknown. The first goal of this study was to identify the causal mutations using targeted sequencing. For each genomic region, 2 DNA pools were constructed with high- and low-fertility Jersey sires. The DNA-sequencing analysis included genome alignment, variant calling, and variant annotation. We identified a deleterious missense mutation on FER1L5 (BTA11) and a deleterious frameshift variant on ABCA16 (BTA25) carried by low-fertility sires. The second goal of this study was to determine whether these mutations affect sperm function, early embryo, and post-hatching development using frozen semen from Jersey sires homozygous for the FER1L5 and ABCA16 variants or wild-type sperm (WT). Both variants affected sperm acrosomal reaction, with lower proportions of reacted sperm in the FER1L5 and ABCA16 variants compared with WT. As a consequence, oocytes fertilized with sires carrying these variants had reduced fertilization rates (P = 0.0001), with 60.2 ± 8.8%, 76.2 ± 7.1%, and 94.2 ± 2.5% for the FER1L5, ABCA16, and WT, respectively. Cleavage rate differed among groups (P < 0.0001), with 42.0 ± 6.4%, 54.0 ± 6.5%, and 78.6 ± 4.5% for the FER1L5, ABCA16, and WT, respectively. Blastocyst formation was reduced in FER1L5 variant (11.6 ± 1.6%) and ABCA16 variant (15.4 ± 1.9%) versus WT (26.7 ± 3.3%). The proportion of cleaved embryos developing to blastocysts was lower in FER1L5 variant (26.6 ± 2.4%) than WT (35.7 ± 2.5%), while the ABCA16 variant (30.1 ± 2.2%) was intermediate. Blastocysts had similar total cell numbers, although mutations affected lineage proportions. During extended culture, mutations affected embryo survival, with reduced survival in the ABCA16 variant compared with the FER1L5 variant and WT. Embryo attachment was not different among groups, but trophectoderm outgrowth area was affected by the genotype. Overall, the candidate causal mutations identified on FER1L5 (BTA11) and ABCA16 (BTA25) impair sperm fertilization competence and early embryo development and may contribute to reduced sire fertility, highlighting the importance of identifying and managing deleterious variants in dairy cattle breeding programs.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.7,"publicationDate":"2026-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149147069","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A randomized controlled study evaluating milking performance and udder health on a New York dairy farm using a novel stimulating, cleaning, and drying device for teat preparation.","authors":"A K Vasquez, W Heuwieser, A D Ravelo, M Wieland","doi":"10.3168/jds.2026-29167","DOIUrl":"https://doi.org/10.3168/jds.2026-29167","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Development of automated ways to prepare udders before harvesting milk has allowed for more consistent application of procedures like disinfecting, stimulating, and drying, therefore replacing manual techniques. Holsteins (n = 326) at one NY dairy were enrolled in a randomized, controlled clinical trial to determine the effect of a device that uses a vortex of water, air, and disinfectant to clean and dry teats on milk yield, milk flow rates, teat end cleanliness, odds of bimodal milk flow, and udder health indices. Cows were randomized into one of 2 treatment groups and measurements were collected in a double 24 parallel parlor over 7-wk. Udder preparation for the VORTEX group consisted of using a trigger-activated vortex of water, chemical, and pressurized air to disinfect, clean, and dry teats before attachment of the milking unit. Udder preparation for the control group (TRAD) included application of disinfectant using a foamer cup, manual stripping, and a cloth towel cleaning and drying step before attachment of the milking unit. Compliance to routines, which targeted 12 s of stimulation, 120 s of preparation-lag time, and the same target disinfectant concentration for both groups, was evaluated weekly. Digital milk meters were used to determine session milk yield, duration of milking, and average and maximum milk flow rates, while bi-monthly DHIA testing captured milk yields and linear score (LS) measurements. Vacuum measurement devices were used to determine the incidence of bimodality. Percentage of dirty teat ends was evaluated using gauze impressions. Generalized mixed regression models were used to describe the effect of treatment on the outcome variables. Least squares means (95% CI) were not meaningfully different for cows that were prepared with the vortex device versus the traditional routine, respectively, for: milk yield per session [15.43 (15.10-15.76) and 15.05 (14.71-15.39) kg], test day milk yield [45.8 (45.0-46.6) and 45.3 (44.5-46.2) kg], duration [4.96 (4.80-5.13) and 4.83 (4.66-5.00) min], average flow rate [3.16 (3.14-3.19) and 3.18 (3.16-3.21) kg/min], and maximal flow rate [4.35 (4.26-4.43) and 4.24 (4.16-4.32) kg/min]. The odds of bimodal milk flow were higher for cows that were prepared using the vortex device (odds ratio = 2.4; 95% CI = 1.3 - 4.7). There was an interaction between treatment and test day for LS. Linear scores for the 1st, 2nd, and 3rd post enrollment test days [LSM (95% CI)] were 1.95 (1.69-2.21), 1.82 (1.54-2.11), and 2.51 (2.18-2.84) for the VORTEX cows and 1.25 (0.99-1.85), 1.54 (1.23-1.85), and 1.38 (1.00-1.76) for the TRAD cows, respectively. There was a higher odds of dirty teat ends in the VORTEX group (odds ratio = 1.23; 95% CI = 1.00-1.51). The odds of a subclinical infection, defined as a baseline LS graduating from &lt;4 to ≥4, favored the TRAD group (odds ratio = 3.98; 95% CI = 1.64-9.71). Although use of the vortex device did not affect milk production, milking duration, or flow rates","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.7,"publicationDate":"2026-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149147433","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dairy producers' perceptions of highly pathogenic avian influenza (HPAI) H5N1 and their influence on implementation of biosecurity changes.","authors":"Kakolee Mohanto, Catalina Picasso-Risso, Madonna Benjamin, Maria Isabel Espinoza, Annette O'Connor, Zelmar Rodriguez","doi":"10.3168/jds.2026-29246","DOIUrl":"https://doi.org/10.3168/jds.2026-29246","url":null,"abstract":"&lt;p&gt;&lt;p&gt;The emergence of highly pathogenic avian influenza (HPAI) H5N1 in dairy cattle has presented a major challenge for dairy producers in the USA, who have had to make biosecurity decisions with limited information while balancing evolving guidance, existing beliefs, and farm management constraints. This study aimed to 1) describe dairy producers' perceptions and understanding of HPAI; 2) characterize experiences and perceived impacts among producers affected by HPAI; 3) identify farm characteristics associated with implementation of biosecurity changes in response to HPAI risk; and 4) assess whether perceived biosecurity effectiveness was associated with implementation of biosecurity changes and whether concern about HPAI and perceived farm-level risk helped explain this relationship. A questionnaire mailed to Michigan dairy facilities yielded a 15.6% response rate (n = 120/766). Descriptive statistics, modified Poisson regression, logistic regression, and parallel mediation analysis using parametric g-computation were used to evaluate survey responses and associations with implementation of biosecurity changes. Overall, 18 respondents (15%) reported confirmed or suspected HPAI on their farms. Most respondents reported being moderately to very familiar with HPAI (76%) and receiving sufficient guidance about the disease (83%). The most frequently selected information sources were veterinary professionals (72%), government health agencies (52%), and industry associations (48%). Producers most frequently identified wildlife (74%) as a likely route of HPAI introduction, followed by airborne transmission (34%), cattle movement (23%), and sharing workers with other operations (12%). Among affected farms, the reported clinical phase lasted with a median of 21 d, whereas reduced productivity lasted with a median of 40 d. Median self-estimated economic loss was $152 per lactating cow. Among farms without reported confirmed or suspected HPAI, farms with ≥ 15 employees were more likely to report implementing biosecurity changes than farms with &lt; 5 employees (RR = 2.26; 95% CI: 1.24-4.10), and farms using robotic milking systems were more likely to report changes than farms using parlor or rotary systems (RR = 2.07; 95% CI: 1.21-3.55). From a mediation analysis (n = 93), the estimated probability of implementing biosecurity changes was 45.7% among producers who perceived biosecurity as effective, compared with 21.4% among those who did not, corresponding to a 24.3 percentage-point difference (95% CI: 5.4-42.4). On the odds-ratio scale, perceived biosecurity effectiveness was associated with higher odds of implementing biosecurity changes (OR = 3.17; 95% CI: 1.21-8.26), higher concern about HPAI (OR = 4.26; 95% CI: 1.58-11.51), and greater odds of perceiving the farm as lower risk than other farms in the state (OR = 2.56; 95% CI: 1.05-6.25). The indirect effect through concern about HPAI was 9.4 percentage points, accounting for approximately 39% of the to","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.7,"publicationDate":"2026-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149147267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of the relationship between residual methane emission and residual feed intake in lactating dairy cows using frequentist and Bayesian models.","authors":"V C Souza, P Niu, A Guinguina, T Yan, A R Bayat, M Kreuzer, P Lund, E Kebreab, R R White, A Schwarm, P Huhtanen","doi":"10.3168/jds.2025-28043","DOIUrl":"https://doi.org/10.3168/jds.2025-28043","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Residual methane (CH&lt;sub&gt;4&lt;/sub&gt;) emission (RCH&lt;sub&gt;4&lt;/sub&gt;) has been proposed as a promising indicator trait to identify dairy cows with inherently low enteric CH&lt;sub&gt;4&lt;/sub&gt; emissions without compromising production. We compiled a database of 1,060 individual records from 546 lactating dairy cows from 37 respiration chamber studies representing multiple breeds, diets, and production levels. Residual CH&lt;sub&gt;4&lt;/sub&gt; was calculated as the difference between observed and predicted CH&lt;sub&gt;4&lt;/sub&gt; emission (g/d) from a model including DMI and BW as predictors, whereas RFI was derived as observed minus predicted DMI using ECM, metabolic BW, and energy balance (EB) as predictors. Because EB in the present RFI implementation was derived partly from DMI, while DMI was also a predictor of RCH&lt;sub&gt;4&lt;/sub&gt;, this specific implementation introduces a shared mathematical dependency that may contribute to the observed RCH&lt;sub&gt;4&lt;/sub&gt;-RFI association. This dependency is specific to the present trait formulation and is not an inherent property of RFI methodology. Mixed-effects models indicated weak but statistically significant associations between RCH&lt;sub&gt;4&lt;/sub&gt; and RFI or residual ECM (observed minus predicted ECM). Cows classified as low RCH&lt;sub&gt;4&lt;/sub&gt; emitted less CH&lt;sub&gt;4&lt;/sub&gt; (g/d) and had lower CH&lt;sub&gt;4&lt;/sub&gt; yield (g/kg DMI) and emission intensity (g/kg ECM) than medium- and high-RCH&lt;sub&gt;4&lt;/sub&gt; cows; however, OM digestibility did not differ among groups. In contrast, cows classified as low-RFI were associated with higher apparent OM digestibility, greater production efficiency, and lower CH&lt;sub&gt;4&lt;/sub&gt; production and intensity compared with cows classified as medium- and high-RFI. Bayesian multivariate modeling indicated that the association between RCH&lt;sub&gt;4&lt;/sub&gt; and RFI resided primarily in the residual covariance rather than in structured between-study covariance. The covariance-partitioning model estimated a modest positive residual correlation (ρ = 0.27), whereas the regression-based hierarchical model estimated a smaller and uncertain residual correlation (ρ = 0.11, 95% CrI: -0.49 to +0.64). Structured between-study variation was minimal in both approaches. Collectively, these findings provide limited evidence that RCH&lt;sub&gt;4&lt;/sub&gt; represents a biologically independent efficiency trait. After accounting for hierarchical covariance, the association between RCH&lt;sub&gt;4&lt;/sub&gt; and RFI was weak, with considerable uncertainty in its estimated magnitude. In contrast, cows classified as low RFI were associated with higher apparent digestibility, lower estimated maintenance ME requirements, and lower CH&lt;sub&gt;4&lt;/sub&gt; production and intensity than cows classified as medium- and high-RFI. These results highlight the need for caution when interpreting RCH&lt;sub&gt;4&lt;/sub&gt; as an indicator of biological efficiency. Importantly, this study provides a biological and statistical evaluation of RCH&lt;sub&gt;4&lt;/sub&gt; rather than an assessment of genetic responses to selecti","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.7,"publicationDate":"2026-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149102376","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multi-scale structural regulation of Rushan cheese gels by glucono-δ-lactone toward enhanced stretchability.","authors":"Junlei Zhang, Rang Wang, Wenli Tao, Wenbin Zhang, Teng Wang, Xingying Dai, Ting Bai, Qing Liang, Luzejun Shi, Aixiang Huang, Yufang Li, Guangqiang Wei","doi":"10.3168/jds.2026-28622","DOIUrl":"https://doi.org/10.3168/jds.2026-28622","url":null,"abstract":"<p><p>The stretchability of stretched cheese is predominantly governed by the structural plasticity of casein gels. While glucono-δ-lactone (GDL)-induced milk gelation is a well-established process, its targeted application to modulate the structural plasticity of Rushan cheese and to circumvent the inherent limitations of conventional processing methods remains largely unexplored. This study systematically examined the influence of different GDL concentrations (0-0.060%, wt/wt) on the stretching behavior, microstructure, and intermolecular interactions of Rushan cheese gels. After being heated in whey maintained at approximately 70°C for 50 s, the curd was removed and manually stretched into thin sheets, during which the curd containing 0.030% GDL showed the most favorable stretching behavior. Texture profile analysis indicated that GDL significantly increased gel adhesiveness and hardness, with hardness increasing from 1,072.85 g to 2,298.02 g. Rheological measurements showed that the storage modulus (G'), loss modulus (G\"), and viscosity of the gels reached their maxima when 0.030% GDL was used. CLSM and SEM revealed that moderate GDL promoted a homogeneous, fibrous protein matrix with uniform lipid embedding, whereas excessive GDL (0.060%) led to microstructural coarsening and lipid phase separation. FTIR analysis showed that the relative β-sheet content increased from 15.7% to 21.3% at 0.030% GDL, accompanied by a decrease in β-turn content, indicating a redistribution of protein secondary-structure components within the cheese matrix. Fluorescence spectroscopy revealed GDL-dependent changes in the microenvironment of aromatic residues, consistent with reorganization of the protein matrix. Additionally, DSC analysis showed GDL-dependent changes in the thermal transition behavior of the cheese matrix, while XRD patterns indicated more compact molecular packing at 0.030% GDL. At GDL concentrations above 0.030%, the samples exhibited network coarsening, greater phase heterogeneity, and reduced stretchability, suggesting that excessive GDL addition disrupted the balance between network cohesion and structural mobility. Overall, this work provides multiscale structural evidence that moderate GDL addition can improve the stretchability of Rushan cheese and offers a plausible framework for interpreting the associated changes in the protein matrix.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.7,"publicationDate":"2026-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149101710","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Genomic evaluation of diet digestibility in US Holsteins and correlations with nationally evaluated traits.","authors":"Wasim Yousaf, Kevin J Harvatine, Chad D Dechow","doi":"10.3168/jds.2026-28934","DOIUrl":"https://doi.org/10.3168/jds.2026-28934","url":null,"abstract":"<p><p>The objectives of this study were to estimate genetic parameters for diet digestibility in Holsteins and to determine genetic correlations of digestibility with production traits. A total of 1,494 fecal samples were collected in the morning and afternoon from 1,065 lactating cows (1,314 samples) and 178 nulliparous heifers (180 samples) from 5 commercial herds and the Penn State University herd. Fecal and TMR samples were dried in a forced-air oven for 48 h at 55°C and composite fecal samples made from dried morning and afternoon samples on an equal dry-weight basis. The fecal and TMR samples were sent to a commercial laboratory to evaluate neutral detergent fiber (NDF) and indigestible NDF (iNDF) on an OM basis following a 240-h in vitro digestion. Three digestibility traits were derived including fecal potentially degradable NDF (pdNDF) concentration defined as fecal NDF - fecal iNDF, total-tract NDF digestibility (NDFD) and total-tract DM digestibility (DMD); high values for NDFD and DMD are favorable whereas a lower fecal pdNDF concentration is preferred because it indicates that there was less fiber in the feces that could have been digested. Yield data included 67,717 test-day milk yield and 67,764 test-day fat % records on 4,950 animals and genotypes were available from 947 animals with fecal samples, 2,796 cows with yield data only, and 1,838 ancestors. Digestibility traits were evaluated with single-step multi-trait animal models that considered fixed effects of lactation, contemporary group, biweekly stage of lactation, random additive genetic, random permanent environment, and error. Heritability estimates were 0.16 ± 0.04, 0.12 ± 0.02, and 0.06 ± 0.01 for fecal pdNDF, NDFD, and DMD, respectively. Additive genetic standard deviation was higher for fecal pdNDF and NDFD (1.21 ± 0.16 and 1.39 ± 0.15%, respectively) than DMD (0.67 ± 0.05%). The genetic correlation of fecal pdNDF with NDFD and DMD was -0.95 ± 0.02 and -0.34 ± 0.15, respectively, and the genetic correlation between NDFD and DMD was 0.60 ± 0.12. There was an unfavorable genetic correlation of fecal pdNDF, NDFD, and DMD with milk yield (0.63 ± 0.10, -0.77 ± 0.06, and -0.72 ± 0.05, respectively). However, the genetic correlations of fecal pdNDF and NDFD with fat % were favorable (-0.40 ± 0.10 and 0.31 ± 0.09, respectively). Correlation of EBV for fecal pdNDF, NDFD, and DMD with gPTA for milk yield were unfavorable, whereas the correlation of EBV for fecal pdNDF, and NDFD with national evaluation for fat % and protein % were favorable. In conclusion, diet digestibility is a heritable trait and can be evaluated using commercial farm animals through fecal sampling. There is genetic variation for diet digestibility among cows, and favorable genetic association with milk components, suggesting direct genetic selection for digestibility particularly NDFD is possible without compromising milk fat and protein contents.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.7,"publicationDate":"2026-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149102345","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multi-omics profiling reveals the role of gut microbiota and associated metabolites in postweaning oxidative stress in Holstein dairy calves, particularly in relation to amino acid synthesis and metabolism.","authors":"Ziwei Wang, Ye Xue, Yang Cao, Yibo Zhu, Guangning Zhang, Chongliang Zhong, Hangshu Xin","doi":"10.3168/jds.2026-29112","DOIUrl":"https://doi.org/10.3168/jds.2026-29112","url":null,"abstract":"<p><p>To investigate the relationship between post-weaning oxidative stress (OS) and gut microbiota in dairy calves, 332 Holstein calves were enrolled and weaned uniformly at 64 d of age. Based on plasma oxidative stress index (OSI) measured at 3 d post-weaning (67 d of age), 10 calves with the highest OSI (post-Hos) and 10 with the lowest OSI (post-Los) were selected for subsequent analyses. Fecal samples collected at the same time point were subjected to 16S rRNA gene sequencing, metagenomic sequencing, and LC-MS untargeted metabolomics analysis. No significant differences in fecal score (FS) were observed between groups on weaning day, although a trend toward incraeased FS was noted in post-Hos calves after weaning (P = 0.075). Microbiota analysis revealed that post-Los calves were enriched in f__Lachnospiraceae, o__Lachnospirales, and f__Barnesiellaceae, whereas post-Hos calves showed enrichment of o__Oscillospirales, f__Oscillospiraceae, and g__Ruminococcaceae_UCG-005, with the latter showing a trend of higher abundance (P = 0.064). Spearman correlation analysis identified multiple genera, particularly Barnesiella and Muribaculum, significantly associated with OSI. Metagenomic functional profiling indicated enhanced pyruvate metabolism and caprolactam degradation pathways in post-Los calves. Metabolomics detected 240 differential metabolites between the 2 groups, significantly enriched in 19 KEGG pathways, notably those related to amino acid metabolism and arginine biosynthesis. Collectively, these findings demonstrate that OS levels in post-weaning calves are associated with distinct alterations in gut microbial composition, functional capacity, and metabolic profiles, with microbiota-involved arginine biosynthesis likely playing a role in this association. This study provides correlational evidence suggesting that modulating amino acid metabolism may represent a potential strategy for alleviating weaning-induced OS.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.7,"publicationDate":"2026-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149102335","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}