Journal of Dairy Science最新文献

{"title":"Genome-wide association studies of calf resilience traits derived from milk intake variability in Holstein calves.","authors":"Jason R Graham, João B Silva Neto, Masoomeh Taghipoor, Mariah C Durval, Gustavo R D Rodrigues, Artur O Rocha, Luiz F Brito","doi":"10.3168/jds.2026-28922","DOIUrl":"https://doi.org/10.3168/jds.2026-28922","url":null,"abstract":"<p><p>Understanding and genetically improving dairy calf resilience is critical for enhancing health, welfare, and productivity of dairy animals under increasing environmental and disease pressures. In this study, we conducted genome-wide association studies (GWAS) to identify genetic variants and genomic regions associated with calf resilience traits derived from automated milk feeder (AMF) records in American Holstein calves. Data from 14,749 calves, including milk intake, milk drinking behavior, and calf health records, were available for the analyses. The pedigree records included 21,630 animals, with genomic data available for 9,273 calves and 57,128 single nucleotide polymorphisms (SNP) after quality control. A range of resilience indicators were defined based on deviations from the theoretical (expected) cumulative milk intake curves, using nonlinear modeling and perturbation analyses to characterize individual calf responses to environmental and health-related stressors. The derived calf resilience traits included amplitude, perturbation time (duration), recovery time, area between observed and expected curves, recovery ratio, and autocorrelation of deviations. The genomic analyses were performed using the BLUPF90 family of programs. We identified 26 SNPs located across 5 autosomal chromosomes, which were significantly associated with 6 calf resilience traits. The genes located near these SNPs were enriched for biological functions related to immune response, mitochondrial integrity, oxidative stress regulation, and protein homeostasis, including loci harboring key candidate genes such as ABCB8 (ATP Binding Cassette Subfamily B Member 8), NOS3 (Nitric Oxide Synthase 3), AGAP3 (ArfGAP With GTPase Domain, Ankyrin Repeat And PH Domain 3), and PRKAG2 (Protein Kinase AMP-Activated Non-Catalytic Subunit Gamma 2). Functional enrichment analyses highlighted molecular functions and pathways related to nucleotide and ATP-dependent regulation, transporter and ion-channel activity, nitric oxide signaling, kinase-mediated regulation, and host-response pathways. Additionally, several significant SNPs were located within genomic regions previously associated with quantitative trait loci for economically important traits such as average daily gain and fertility, although further studies are needed to evaluate the genetic relationships between these traits and calf resilience. These findings provide foundational insights into the genetic basis of calf resilience, offering pathways for selective breeding to enhance animal adaptability and welfare in modern dairy production systems.</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":"149147402","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":"Nuclear magnetic resonance spectroscopy reveals variations in the milk metabolome associated with total and differential somatic cell count in dairy cows.","authors":"G Niero, I Sousa, S Magro, G Visentin, G Meoni, L Tenori, M Cassandro, M Penasa, M De Marchi","doi":"10.3168/jds.2026-28941","DOIUrl":"https://doi.org/10.3168/jds.2026-28941","url":null,"abstract":"<p><p>Udder health is a key determinant of milk quality, animal welfare, and economic sustainability in dairy production systems. This study evaluated the ability of proton nuclear magnetic resonance spectroscopy (¹H NMR) to discriminate milk according to udder health status and to investigate the effect of udder health on the milk metabolomic profile. Individual milk samples (n = 410) were repeatedly collected from 62 lactating cows and classified as healthy, susceptible, mastitic, and chronic based on SCC and differential somatic cell count (DSCC) thresholds. A total of 33 milk metabolites were identified through ¹H NMR. Canonical discriminant analysis based on ¹H NMR spectral data showed a higher classification performance for the binary model (healthy cows vs. the pooled susceptible, mastitic, and chronic cows) compared with the multiclass approach (healthy, susceptible, mastitic, and chronic), with overall accuracy reaching 0.85 and 0.81 in training and cross-validation, respectively. ANOVA revealed significant differences in metabolite abundance among the 4 udder health classes. In particular, chronic cows exhibited a distinctive metabolomic profile, characterized by higher concentrations of acetone, O-acetylcarnitine, acetate, lecithin, and choline, and lower concentrations of glutamate, dimethylsulfone, and glucose compared with cows in at least one of the other classes. Concentrations of mannose, galactose-1-phosphate, and orotate were higher in healthy and susceptible cows than in mastitic and chronic cows, whereas lactose concentrations decreased from the healthy to the chronic class. Overall, these findings indicate that milk metabolomic profiling by ¹H NMR is a valuable approach for characterizing udder health status and identifying potential metabolic biomarkers. The integration of metabolomic data with traditional indicators such as SCC and DSCC may contribute to the development of improved tools for monitoring udder health and enhancing milk quality in dairy production systems.</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":"149147307","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 preliminary assessment of high melting point, reduced sugar ice cream: Microstructure, consumer acceptance, nutritional impact, life cycle assessment, shelf-life, and energy consumption.","authors":"Sydney Camp, Loren Smith, Dieyckson O Freire, Stavroula N Antonopoulos, Faustina S Sekyere, Douglas T Reindl, Andrea Hicks, Richard W Hartel, Scott A Rankin","doi":"10.3168/jds.2026-29101","DOIUrl":"https://doi.org/10.3168/jds.2026-29101","url":null,"abstract":"<p><p>Ice cream and other frozen desserts such as custard, gelato, and soft serve products are popular dietary options for various purposes including nutrition and satiety. These products are generally calorie dense due to such factors as US standards of identity (e.g., minimum 10% milkfat), sensory appeal for comfort foods, and various industry conventions such as those relating to mechanical freezing, extended storage, and even acceptable rheology for scooping and consumption. Yet, there are sufficient indications, including dietary interests for reduced dietary sugar intake and potential energy savings associated with manufacturing, that warrant exploring the properties of ice cream made with less added sugar. While sugar reduction is a common approach, such adjustments are routinely coupled with the inclusion of freezing point depressants such as sugar alcohols, to match freezing properties achieved with conventional levels of sugar. In this study, we reduce the total added sucrose from 17 to 10% wt/wt with soluble corn fiber as a relatively inert filling agent while making no adjustments for freezing point depression. The resulting products were evaluated for common quality and functional parameters as well as those involving nutritional, sustainability, and energy. In general, the high melting point ice creams performed reasonably well across the assays indicated. Although average consumer panel scores for Overall Likability of the high freezing point ice creams were lower than the conventional product (6.23 vs 7.38), the overall profile of these scores as well as the collection of other assay results indicates promise for this manufacturing approach. Of particular note are the potential improvements in nutrition, energy consumption, and overall sustainability due to the reduced sugar content.</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":"149147516","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":"Decoding individual dairy cow behavioral profiles through electronic feeder and drinker data.","authors":"Kehan Sheng, Borbala Foris, Daniel M Weary, Marina A G von Keyserlingk","doi":"10.3168/jds.2026-29025","DOIUrl":"https://doi.org/10.3168/jds.2026-29025","url":null,"abstract":"<p><p>Individual animals can differ considerably in how they feed, drink, and compete for resources, yet much data analysis still relies on group-level comparisons that obscure these individual differences. Electronic feeding and drinking systems make it possible to characterize individual behavioral profiles within groups. Using 107 lactating Holstein dairy cows tracked over 207 d, we extracted 16 behavioral variables from electronic feed bin and water bin data, capturing conventional metrics (feeding and drinking intake, duration and meal frequency) alongside measures of non-nutritive visits, social competition (replacement events), and indicators of feed quality (e.g., proportion of fresh feed remaining upon arrival). Bayesian mixed-effects models quantified repeatability (between-individual variation in average behavioral expression) and predictability (between-individual variation in within-individual consistency). Variables capturing non-nutritive visits, social competition, and drinking duration showed the greatest and most consistent among-individual variation, while daily feed intake was among the least discriminating, suggesting individuals converge to similar intakes through different strategies. To identify behavioral profiles, we applied principal component analysis with varimax rotation to the 8 most repeatable and individually variable behavioral measures, then used k-means clustering on the rotated principal components. This yielded 4 distinct profiles: \"frequently replaced\" cows (the majority of the herd, frequently replaced at the bins), \"contest-winning\" cows (initiating many replacements with efficient, uninterrupted meals), \"frequent drinker visitors\" (many long drinking visits spread across the day), and \"fragmented feeders\" (many short, interrupted visits with frequent replacement events). These results illustrate how data streams from electronic feeders and drinkers can be used to build individual behavioral profiles that would not be apparent using generic group-level analyses. This framework may help researchers identify cows most susceptible to negative impacts when housed in competitive environments. To facilitate access across species and systems we developed moo4feed (https://www.skysheng.io/moo4feed/), an open-source R package designed to extract individual behavioral variables from electronic feeder and drinker data.</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":"149147026","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":"Disbudding dairy calves with caustic paste: Assessing the effect of contact duration on the healing process.","authors":"Alycia M Drwencke, Victoria S Rodas, Sarah J J Adcock, Cassandra B Tucker","doi":"10.3168/jds.2026-29403","DOIUrl":"https://doi.org/10.3168/jds.2026-29403","url":null,"abstract":"<p><p>Caustic paste disbudding has grown in popularity in North America. The methods of paste application vary across the literature and affect wound healing. Our objective was to determine whether the duration of paste contact with the horn bud affected paste disturbance by the calf, wound size, healing, and horn regrowth. At 3 d of age, 30 Holstein calves were randomly assigned to 1 of 2 treatments (n = 15 each). Calves were disbudded with a \"normal\" method, where 0.2 mL of Dr. Naylor's paste was applied to horn buds shaved with a #40 blade and left to dry, or \"wiped\" where the paste was removed after 1 h. The prevalence of paste disturbance from the calf rubbing a horn bud was observed 1 h and 4 h (normal calves only) after application. Wound diameter was measured 1 d after disbudding and 5 wk later. We evaluated the presence and absence of 8 tissue types and horn regrowth 1-2x/wk for 21 wk. Paste disturbance showed no evidence of differing by treatment (17% vs 23% of horn buds for normal and wiped, respectively, 1 h after application). Disturbance from rubbing did not affect wound size or healing time. Wound diameter was similar between application methods: wounds were (mean ± SE) 18.9 ± 0.5 and 20.1 ± 0.8 mm 1 d after disbudding and 5 wk later increased to 22.7 ± 0.6 and 23.0 ± 0.8 mm for normal and wiped treatments, respectively. There was no evidence that treatment affected the probability of reaching the 3 tissue types evaluated as stages of healing (63 vs. 73% crust, 47 vs. 57% epithelium, and 40 vs. 33% fully healed for normal vs. wiped). Calves with wiped horn buds tended to have more horn regrowth, including regrowth that required removal by a secondary procedure, compared with the normal treatment. Across both treatments, wounds took longer to heal in this study than in previous work: only 37% had fully healed by 21 wk compared with 74% of wounds created by a similar amount of paste in another study. In conclusion, wiping paste after 1 h did not appear to reduce wound size or disturbance from rubbing, or hasten healing, and tended to increase the risk of regrowth compared with letting it absorb.</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":"149147103","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":"Increasing agency in grazing dairy cows: Voluntary use of a treed area.","authors":"Gosia Zobel, Chris R Burke, Alex Crosbie, Linsday Matthews, J Paul Edwards","doi":"10.3168/jds.2026-28995","DOIUrl":"https://doi.org/10.3168/jds.2026-28995","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Pasture-based dairy systems are valued by consumers for allowing the expression of natural behaviors; however, evolving stakeholder expectations include the ability for cows to exercise agency and choice. This study examined whether dairy cows would choose to voluntarily exit their grazing paddock and walk to an independent treed area, and quantified visit patterns and their relationship to weather, paddock distance, behavior, and rumen temperature. Sixty mixed-aged Friesian-cross cows were randomly allocated to Treed (n = 2) and Reference (n = 2) herds from November 2024 to March 2025. On-animal measurement devices included collars (latitude, longitude, grazing, ruminating), leg-worn accelerometers (lying/standing), and rumen boluses (rumen temperature, drinking). Weather data included temperature, relative humidity, wind speed, rainfall, solar radiation, and a calculated grazing heat load index (GHLI). After familiarization to the treed areas, cows were monitored over 4 observation periods (the first was 23 d; remaining were 15 d) that varied in milking frequency (once/twice daily), supplementation (present/not present), and herd size (separate, 15 cows/herd; or combined, 30 cows/herd). Latitude-longitude data were used to define treed area visits (threshold of ≥ 80% of the herd present at any time &gt; 10 min). Bayesian logistic regression models (Treed area herds only) examined whether weather variables (temperature, GHLI, solar radiation, humidity; each categorized at the 75th percentile into levels: 'below-threshold', lower 75%, and 'above-threshold', upper 25%) and distance predicted treed area visit probability. Bayesian generalized additive mixed models (GAMMs; all herds) examined hourly behaviors and rumen temperature, with fixed effects for 'visit status' (Treed area herd - No Visit, Treed area herd - Visit, Reference herd), GHLI level, and their interaction. Splines captured temporal patterns. Daily behavioral and rumen temperature summaries were derived from hourly predictions. Results were reported as odds ratios (OR), and median with 95% credible intervals (CrI). Treed area herds visited treed areas 3-22 times per observation period (1.1-2.1 visits on visit days), spending 0.9-5.5 h/d there. Use peaked in the afternoons, varied by herd and observation period, and occurred in both above- and below-threshold thermal conditions. Comparing visit and non-visit days within the Treed area herds showed that paddocks ≥ 250m from the treed area reduced visit odds by 56% compared with Paddocks &lt; 250 m from the treed area (OR = 0.44, 95% CrI: 0.27-0.69). Further, above-threshold temperature (≥22°C) doubled visit odds compared with below-threshold (OR = 2.03, 95% CrI: 1.13-3.44). Comparison of Treed and Reference herds showed that during treed area visits when the GHLI was above-threshold (≥54) daily ruminating-while-standing doubled (4.7 vs 2.8 h/d, respectively), while hourly grazing (OR = 0.77, 95% CrI: 0.72-0.81), drinking (OR = 0.29, 95","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":"149147073","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":"Association between donor animal category and amino acid profiles in bovine oocytes and embryos produced in vitro.","authors":"Dorota Boruszewska, Ernestas Mockus, Ilona Kowalczyk-Zięba, Agnieszka Jończyk, Sandra Gąsiorowska, Izabela Wocławek-Potocka, Elena Bartkiene","doi":"10.3168/jds.2026-28472","DOIUrl":"https://doi.org/10.3168/jds.2026-28472","url":null,"abstract":"<p><p>In vitro embryo production (IVP) is widely used in cattle breeding, however, pregnancy outcomes remain suboptimal, primarily due to variability in oocyte and embryo quality. This study evaluated the association of donor animal category with amino acid turnover in bovine oocytes and embryos and assessed its relationship with developmental competence. Cumulus-oocyte complexes (COCs) were collected via ovum pick-up from prepubertal heifers (8.4 ± 0.5 mo of age; n = 9), pubertal heifers (16.5 ± 0.5 mo of age; n = 10), and cows (25.5 ± 0.5 mo of age; n = 10). A total of 198, 324, and 286 COCs, respectively, were subjected to in vitro maturation, fertilization, and culture. Amino acid profiles in media were quantified using gas chromatography in at least 6 independent biological replicates per experimental group, where each replicate represented a separate culture well containing pooled oocytes or embryos. Oocytes from prepubertal heifers exhibited elevated alanine and glycine levels, whereas embryos derived from these donors showed increased levels of alanine, glutamic acid, and serine, together with greater depletion of essential amino acids such as valine, isoleucine, methionine, and cystine. In contrast, oocytes and embryos from pubertal heifers and adult cows exhibited more similar amino acid profiles. These metabolic differences were associated with oocyte quality, and embryo developmental outcomes, with the highest proportion of good quality oocytes and Day 7 blastocyst formation observed in adult cows. Specific amino acids - alanine, glycine, and asparagine - showed positive associations with oocyte quality in pubertal and adult donors. These results provide insight into the developmental limitations of prepubertal oocytes and may support future efforts to refine IVM and IVC protocols. In addition, the observed amino acid profiles suggest the potential of metabolomic biomarkers for improving embryo selection and IVP efficiency in cattle, although further validation is required.</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":"149147056","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":"Effect of altering follicular dynamics on fertility of lactating dairy cows receiving artificial insemination after detected estrus.","authors":"Alisson Santos, Thaina Minela, J Richard Pursley","doi":"10.3168/jds.2026-28953","DOIUrl":"https://doi.org/10.3168/jds.2026-28953","url":null,"abstract":"<p><p>Fertility of lactating dairy cows is reduced following a naturally occurring estrus compared with fertility programs that controlled antral age of the ovulatory follicle. The aim of this study was to determine the effect of exogenous GnRH on d 5 to 8 of the estrous cycle before 1st AI on fertility of dairy cows after a subsequent estrus. We hypothesized that GnRH during the 1st follicular wave would increase the percentage of cows that ovulated a third follicular wave; and that cows ovulating a third follicular wave would have reduced antral age of the ovulatory follicle resulting in an earlier time to conceptus attachment. Lactating Holstein cows (n = 1,208) were fitted with accelerometer-based activity monitors. Cows detected in estrus during the voluntary waiting period (VWP-estrus; 45 - 67 DIM) were blocked by parity and randomly assigned to one of 2 treatments: no treatment (Control) or GnRH administration 5 to 8 d following onset of VWP-estrus. Cows that returned to estrus following treatment within the breeding period were inseminated 8 to 20 h after onset of estrus (AI-estrus; 68 to 94 DIM). Ovaries were examined on d 5 - 8, 12 or 13, 16 or 17, 20 or 21, and 24 or 25 after VWP-estrus to identify the follicular wave origin of the ovulatory follicle. Ovulation was determined 2 to 8 d post AI-estrus with ultrasound. Day of \"conceptus attachment\" was defined as an increase of ≥12.5% PSPB from an individual baseline in addition to 2 consecutive d of ≥12.5% increases. Treatment with GnRH during the 1st follicular wave altered follicular dynamics of the remainder of the estrous cycle. It caused more cows to ovulate a 1st-wave dominant follicle compared with the Control group (81 vs. 0%). It also caused more cows to develop a third follicular wave compared with the Control group (68 vs. 12%) and increased the percent of cows that ovulated a shorter antral age follicle compared with Controls. Cows that ovulated a follicle with an antral age of 7 - 9 d had a greater incidence of (53 vs. 37%) of conceptus attachment compared with cows with a greater antral age of 12 to 14 d. These cows also had a lower proportion with late conceptus attachment (11 vs. 28 percent at ≥ d 22). Ovulation of a 1st wave dominant follicle with GnRH shifted the distribution of antral ages of ovulatory follicles at time of AI-estrus. More Treated cows fell within an antral age of 7 to 9 d. More Control cows fell in the less favorable 12 to 14 d antral age group. However, extended time to estrus in cows that developed a 3rd ovulatory wave did not allow for enough cows with reduced antral age, thus, treatment did not improve the incidence or timing of conceptus attachment or reduce pregnancy losses. These outcomes support estimated antral age of the ovulatory follicle as an important fertility-associated phenotype in lactating dairy cows inseminated after detected estrus.</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":"149147185","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 a rumen-protected methionine product to improve amino acid balance and increase milk components in lactating dairy cows.","authors":"A C Benoit, P A LaPierre, T Danese, A B P Fontoura, D M Barbano, O R Drehmel, J J Albrecht, P S Yoder, M F Scott, M E Van Amburgh","doi":"10.3168/jds.2026-29010","DOIUrl":"https://doi.org/10.3168/jds.2026-29010","url":null,"abstract":"<p><p>The objective of this study was to evaluate the effect of increasing the dietary inclusion of a rumen-protected (RP) Met product (RPMet, Actus Nutrition, Eden Prairie, MN) on milk, milk components, milk fatty acids (FA), and feed efficiency in lactating dairy cows. One hundred and 44 lactating Holstein dairy cows were randomly assigned, based on milk yield, parity, and DIM, to 9 pens containing 16 cows per pen in an 84-d longitudinal study with a 14-d covariate period and 70-d experimental period. Three pens were stratified to one of 3 treatment diets based on the yields of milk and milk components and BW collected during the covariate period. The treatment diets were formulated to supply, on a metabolizable basis, 0.86g Met/Mcal of metabolizable energy (ME) (0.86-Met), 1.05g Met/Mcal ME (1.05-Met), and 1.19g Met/Mcal ME (1.19-Met). All diets were formulated to supply, on a metabolizable basis, 1.19g His/Mcal ME and 3.20g Lys/Mcal ME using the Cornell Net Carbohydrate and Protein System (v6.5.5). The statistical model included the fixed effects of treatment, week, and their interaction, and the random effect of pen nested within treatment. The treatment diets did not affect DMI or milk yield, whereas 1.05-Met and 1.19-Met increased ECM yield compared with 0.86-Met. The 1.19-Met treatment increased milk fat content compared with 0.86-Met. The 1.19-Met treatment increased milk protein content and yield compared with 0.86-Met and 1.05-Met, whereas 1.05-Met increased milk protein content and yield compared with 0.86-Met. Compared with 0.86-Met, 1.05-Met and 1.19-Met increased de novo FA content (g/100g milk), and 1.19-Met tended to increase mixed FA content. These data suggest that optimizing the supply of metabolizable Met to 1.19g/Mcal ME improved energetic use efficiency by increasing the synthesis of milk components with no effect on DMI, and that evaluations of AA should consider changes in ECM to capture all energetic and protein-synthetic pathways involved in milk component synthesis.</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":"149147210","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":"Bayesian estimation of true herd-level prevalence and spatial distribution of Salmonella Dublin-seropositive dairy herds in Alberta, Canada.","authors":"Waseem Shaukat, Diego B Nobrega, Abdul Rehman, Jessie van Heumen, Rebecca Roos, Marlinde de Pater, Chanda Liaqat, David C Hall, Guillaume Lhermie, John P Kastelic, David K Kelton, Jeroen De Buck, Herman W Barkema","doi":"10.3168/jds.2026-29221","DOIUrl":"https://doi.org/10.3168/jds.2026-29221","url":null,"abstract":"<p><p>Salmonella Dublin, a cattle-adapted serovar of Salmonella enterica ssp. enterica with zoonotic potential, has become a pathogen of increasing concern for the dairy industry in Canada and beyond. A comprehensive understanding of its epidemiology is crucial to guide effective surveillance and control. The objectives of this serial cross-sectional study were to estimate the true herd-level seroprevalence of Salmonella Dublin and to characterize the spatial distribution of Salmonella Dublin-seropositive dairy herds in Alberta, Canada. Bulk tank milk (BTM) samples were collected from all active dairy herds in Alberta, Canada, in June (n = 462) and December (n = 451) 2024, and PrioCHECK ELISA was used to detect antibodies against Salmonella Dublin. Herds were classified as positive if ≥ 1 sample had a percent positivity ≥ 35. True seroprevalence was estimated using a Bayesian latent class model accounting for imperfect sensitivity and specificity. Spatial patterns were evaluated using a Bayesian geostatistical model, and a spatial scan statistic was used to detect localized clusters. The estimated true prevalence of Salmonella Dublin-seropositive herds in Alberta was 14.9% (95% Bayesian credible interval: 7.3-28.2%), with regional estimates of 8.0% (95% BCI = 1.6-22.6%), 13.9% (95% BCI = 4.2-31.8%), and 20.9% (95% BCI = 8.5-42.5%) for the north, central, and south regions of Alberta, respectively. The continuous spatial risk surface revealed that the true herd seropositivity varied markedly across Alberta, with some areas having much higher predicted seropositivity probabilities than others. Furthermore, 2 localized clusters of higher seropositivity were detected: a prominent cluster (95-km radius) in southwestern Alberta and a relatively smaller cluster (19-km radius) in a high-density dairy corridor in the central region. These findings indicate that Salmonella Dublin exposure is moderate in Alberta, with marked regional heterogeneity and pronounced spatial gradients in herd-level seropositivity. Incorporating spatial context into surveillance and control may improve targeting of interventions aimed at reducing within-region transmission. These findings also illustrate the value of Bayesian latent class modeling for generating bias-adjusted true seroprevalence estimates in the absence of a gold-standard diagnostic test.</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":"149147274","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}