Journal of Dairy Science最新文献

{"title":"Optimization by an orthogonal array design of deep hydrolysis of bovine milk whey proteins and caseins to reduce allergenicity","authors":"Dayu Yang,&nbsp;Renzhi Huang,&nbsp;Ruimin Liu,&nbsp;Changlong Hao,&nbsp;Lingling Guo,&nbsp;Xinxin Xu,&nbsp;Liguang Xu,&nbsp;Hua Kuang,&nbsp;Liqiang Liu,&nbsp;Chuanlai Xu,&nbsp;Maozhong Sun","doi":"10.3168/jds.2025-27061","DOIUrl":"10.3168/jds.2025-27061","url":null,"abstract":"<div><div>Bovine milk (BM) is a common nutrient-rich food, but also a potential allergen for infants with milk allergy. In this study, a method for the preparation of deeply hydrolyzed whey proteins or caseins (DH-WP and DH-CN, respectively) was proposed and residual antigenicity was assessed. The optimal conditions for preparation of DH-WP were hydrolysis with flavorzyme for 5 h at 55°C, pH 6.5, and an enzyme–substrate ratio (E/S) of 10,000 U/g, whereas those for DH-CN were hydrolysis with neutrase for 4 h at 50°C, pH 7, and an E/S of 10,000 U/g. The relative contents of peptides (&lt;3 kDa) in the DH-WP and DH-CN products were 99.20% and 98.34%, respectively. The sensitization assessment, RBL-2H3 cell model, and peptidomics analysis indicated that the major allergens in obtained DH-WP and DH-CN were basically eliminated and the sensitization was significantly reduced. This study provides a theoretical basis and technical support for the application of DH-WP and DH-CN in hypoallergenic infant formula.</div></div>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":"108 10","pages":"Pages 10631-10644"},"PeriodicalIF":4.4,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144937850","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":"Predicting sire fertility in artificial insemination of dairy cows by the ability of spermatozoa to bind to oviduct cell aggregates.","authors":"Mateus A Silva, Paula R Cortat, Carlos E C Consentini, Sâmara C C Pinto, Eneiva C C Celeghini, José O Carvalho, Leonardo F Melo, Milo Wiltbank, Roberto Sartori","doi":"10.3168/jds.2025-27057","DOIUrl":"https://doi.org/10.3168/jds.2025-27057","url":null,"abstract":"<p><p>This study aimed to evaluate sperm morphofunctional characteristics and the ability of spermatozoa to bind to oviduct epithelial cell (OEC) aggregates as predictors of male field fertility. Based on pregnancy per artificial insemination (P/AI) data of 1,833 services in Holstein cows from a commercial dairy herd, sires were classified as of higher (HF, P/AI = 35.0% [362/1,034], n = 3) or lower (LF, P/AI = 21.4% [171/799], n = 4) fertility. Semen quality was assessed based on sperm motility (by computer-assisted sperm analysis, plasma and acrosome membrane integrity, mitochondrial membrane potential, membrane lipid peroxidation, and membrane fluidity [by flow cytometry], and OEC binding). For the analysis of OEC binding, the oviduct isthmus region from abattoir tracts was dissected, and cells were incubated for 24 h to allow OEC aggregate formation, followed by co-incubation with 1 × 10⁵ motile sperm. Bound sperm were counted at 4 time points: 0.5, 12, 24, and 36 h. Statistical analyses were conducted using the GLIMMIX procedure in SAS 9.4 (SAS Institute Inc.). Sperm motility characteristics were not different between HF and LF sires, except for greater straight-line velocity in HF (HF: 94.7 ± 3.1 μm/s vs. LF: 80.9 ± 3.1 μm/s). Flow cytometry analysis was not able to explain the difference between fertility groups (P/AI). However, in the sperm binding test to OEC, the HF sires tended to have more bound sperm per millimeter of OEC than LF sires at 0.5 h of co-incubation (59.1 vs. 54.0). At h 12 (36.5 vs. 28.6), 24 (24.0 vs. 15.3), and 36 (26.0 vs. 12.1), HF sires had more bound sperm per millimeter of OEC than LF sires. Field fertility was positively correlated (r = 0.89) with the number of sperm bound per millimeter of OEC at 36 h of co-incubation. These results suggest that LF sires may have impaired fertility due to a reduced ability to bind to oviduct cells in vivo. In addition, the result showed the potential of sperm binding test to OEC for early evaluation or prediction of bulls' fertility, although more studies are being performed to refine the procedures during these assays, as well as to better understand other potential physiological mechanisms differing between HF and LF sires.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144937825","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":"Evaluating the efficacy of maternal bovine appeasing substance in reducing stress and enhancing growth performance in dairy calves after disbudding.","authors":"J A Spencer, D Duhatschek, J Piñeiro, T Hairgrove, C Daigle, J Cleere, R F Cooke","doi":"10.3168/jds.2025-26398","DOIUrl":"https://doi.org/10.3168/jds.2025-26398","url":null,"abstract":"<p><p>The objective of this study was to investigate the effects of a maternal bovine appeasing substance (MBAS) and analgesia and anesthetics (A/A) on stress (measured via hair and serum cortisol) and performance (ADG and number of disease treatments) following caustic paste disbudding. Calves from 3 dairy farms in Texas were transported to a commercial heifer rearing ranch (d -1), weighed, and randomly assigned to 1 of 4 treatment groups (n = 30/treatment) before hutch placement: (1) receiving caustic paste only (negative control, CON); (2) receiving 5 mL of MBAS above the muzzle and 5 mL behind the poll (100 mg/mL; MBAS), (3) receiving an analgesic (transdermal flunixin meglumine, 3.3 mg/kg BW) and anesthetic (2% lidocaine, 2 mL/horn bud; A/A-CON); or (4) receiving both MBAS and A/A (A/A-MBAS). The MBAS was applied upon arrival (d -1), followed by the administration of A/A 24 h later (d 0) and the application of caustic paste within 10 min. Blood was collected via jugular vein within 1 h before disbudding (0hSERUM), 4 h after disbudding (4hSERUM), and 7 d later (d7SERUM). Tail hair samples were collected on arrival (d1HAIR) and 14 d later (d14HAIR), and BW was measured on d -1, 14, 28, and 65 and at weaning to calculate ADG. Numbers of treatments for pneumonia, bloat, fever, diarrhea, navel infection, and total treatments until weaning were recorded. Calf was considered the experimental unit for all analyses. Differences in initial BW, ADG, and cortisol concentrations (hair and serum) were analyzed for the fixed effects of MBAS, A/A, and their interactions, with random variables for calf within MBAS × A/A × farm and farm itself using the MIXED model procedure in SAS. Cortisol concentrations included covariates of 0hSERUM for 4hSERUM and d7SERUM, and d1HAIR for d14HAIR. Significance was declared at P ≤ 0.05 and tendencies at P ≤ 0.1. Cortisol concentrations increased from d1HAIR to 14dHAIR and for all calves and tended to be higher in calves not treated with A/A. Interestingly, calves that received MBAS or A/A had a numerical decrease in serum cortisol before and after disbudding, whereas calves that did not receive A/A or MBAS had an increase. For MBAS-treated calves, 4hSERUM tended to be lower than non-MBAS-treated calves. Calves treated with MBAS had a higher ADG until d 14 and tended to be greater until d 28. The only effects on the number of treatments observed were that MBAS calves tended to receive more treatments for fevers compared with non-MBAS-treated calves. These results show that administering MBAS before caustic paste disbudding positively influences ADG and may help suppress the initial cortisol rise after disbudding, thereby enhancing early calf performance.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144937895","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":"Effects of different heat treatment processes on the physicochemical properties and structural changes of casein and whey protein from bovine milk.","authors":"Fulei Xiao, Jia Shi, Yang Zou","doi":"10.3168/jds.2025-27358","DOIUrl":"https://doi.org/10.3168/jds.2025-27358","url":null,"abstract":"<p><p>To investigate the effects of different heat treatment processes, infusion technology (INF) and UHT, on the physicochemical properties and structural changes of casein and whey protein from bovine milk. Two sterilization conditions, INF (156°C to 158°C, 0.09 s) and UHT (135°C, 4 s) to treat bovine milk and isolate whey protein and casein from milk were selected. This study evaluated the particle size, milk composition, and storage stability of different milk samples, and assessed the structural and property changes of proteins. The results demonstrated that INF milk exhibited smaller average particle size, higher protein, fat, nonfat milk solids, and lactose contents compared with UHT milk. The structure stability and functional properties of casein and whey protein in INF milk were superior to those in UHT milk. In summary, this study indicated the physical properties of bovine milk under different sterilization conditions, as well as the changes in casein and whey protein in bovine milk. This can provide reference for optimizing the quality and stability of bovine milk products and help develop more functional bovine milk products.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144937923","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":"Invited Review: Manufacture and quality control of mozzarella cheese-Scientific and technological advances.","authors":"Ashutos Parhi, Anjali Verma, Pulari Krishnakutty Nair, Prateek Sharma","doi":"10.3168/jds.2024-26225","DOIUrl":"https://doi.org/10.3168/jds.2024-26225","url":null,"abstract":"<p><p>Mozzarella cheese is one of the most popular cheeses consumed on pizza worldwide. In commercial markets, mozzarella cheese is sold in a variety of formats (e.g., shreds, slices, blocks), and the functionality of mozzarella cheese is determined based on the end use. For example, for pizza applications, mozzarella cheese block is converted into shreds in the factory setting or at home. For minimizing losses during conversion, it is important to have optimum material properties in the block at low temperatures. Good-quality mozzarella cheese shreds are expected to melt, form long stretch, release right amount of free oil, and form an optimum level of brown spots when baked on a pizza. There are various factors controlling baking performance of mozzarella cheese including manufacturing process, composition, and aging. For example, during the first few weeks of refrigerated storage, the unmelted cheese becomes softer, whereas the melted cheese becomes more viscous, less elastic, and extremely stretchable due to continuous breakdown of casein matrix. Thus, the cheese achieves optimum pizza functionality during the aging process. Baking performance of mozzarella cheese can be affected by various factors such as cheese milk, composition of cheese (especially calcium, lactose, and galactose content), proteolysis, and starter cultures, therefore, making it an intriguing research domain by the food industry to deliver improved and consistent products. This review presents the status of manufacturing technology, practices, quality evaluation, and structure-function relationship in mozzarella cheese and their potential use for the cheese industry. Major findings of this review indicate use of waterless extrusion technology to improve process efficiency and performance shelf life, changing formulation to optimize baking performance and use of novel user-friendly techniques for performance evaluation.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144937877","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":"Invited review: Development of a dairy barn concept to improve animal welfare.","authors":"R Wulf, S Demba, V Röttgen, J Langbein, S Düpjan, B Weise, S Rose, A Sixt, J Harms, I Steinhöfel, H-S Bruckert, P A Guhl, M Heppelmann, S Jahn, M J Oettler, T Homeier-Bachmann, L Bachmann","doi":"10.3168/jds.2025-26627","DOIUrl":"https://doi.org/10.3168/jds.2025-26627","url":null,"abstract":"<p><p>Owing to political and societal requirements, farmers are required to produce animal-friendly and sustainable products in an economic manner. Investments have been made to improve housing conditions for farm animals such as cattle, but further improvements regarding animal welfare of dairy husbandry are needed to regain societal acceptance. In this review, we first provide a brief overview of current housing and management conditions of dairy cattle worldwide as well as their impact on animal welfare of calves, young stock, and dairy cows. This framework was the basis to develop a concept for an alternative demonstration and research barn, the \"future dairy barn\" (FDB). Crucial for this barn concept was the consideration of the natural behavior of all cattle belonging to a herd to improve animal welfare. Consequently, the FDB concept integrated a family herd that avoids regrouping and enables stable social relationships, a free lying area to allow species-typical lying behavior and pasture or paddock access to enable the cattle to stay indoors or outdoors. This alternative dairy barn concept should help answer research questions on animal welfare in a uniform social and physical environment in long-term investigations. The construction of the FDB aims to support the future of dairy farming.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144937897","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":"Effects of feeding a native rumen-native microbial live supplement during pre- and postpartum on health, performance, and blood metabolites of Holstein cows.","authors":"Emily Tabor, Anne R Guadagnin, Maverick Guenther, Lautaro R Cangiano, Faustina Panisa, Brooke Anderson, Laura Niehues, Clarisse Marotz, Mallory Embree, Jimena Laporta","doi":"10.3168/jds.2025-26677","DOIUrl":"https://doi.org/10.3168/jds.2025-26677","url":null,"abstract":"<p><p>Rumen-native microbial supplementation can improve milk production by enhancing rumen function, but its effects on immunity, health, and mammary development are less known. This study evaluated Galaxis Frontier (GF, Native Microbials, San Diego, CA) top dressed daily at 5 g/cow per day, administered either pre- and postpartum (wk -4 to 16) or postpartum only (wk 1 to 16). Microbial feed supplementation consisted of 2 × 10⁷ cfu/g of Pichia kudriavzevii, 2 × 10⁶ cfu/g of Clostridium beijerinckii, 2 × 10⁷ cfu/g of Ruminococcus bovis, and 2 × 10⁷ cfu/g of Butyrivibrio fibrisolvens. Sixty pregnant Holstein cows were assigned to treatments as follows: (1) GF supplementation for 4 wk prepartum and 16 wk postpartum (Pre+PostG, 5 g/cow per day of GF; n = 20), (2) GF supplementation for 16 wk postpartum (PostG, 5 g/cow per day of GF; n = 20), and (3) control, no supplementation of GF (CON, n = 20). Orthogonal contrasts were used to determine the effect of the inclusion of the microbial additive during the postpartum period. Cow BW, BCS, and blood metabolites (glucose, nonesterified fatty acids [NEFA], and BHB) were monitored weekly or biweekly. Milk yield was recorded daily, components weekly, and health and immune parameters evaluated through wk 4. Mammary biopsies were collected on d 14 and 60. Prepartum supplementation (27 ± 2 d) reduced BHB (8.69 vs. 6.99 mg/dL) and NEFA (0.15 vs. 0.09 mM), increased calf birth weight (+2.3 kg), and improved colostrum yield (+2.0 kg) and protein content (+0.45 kg) versus CON. During wk 1 through 4, GF-supplemented cows (average Pre+PostG and PostG) exibited a more negative energy balance (-9.08 vs. -11.65 Mcal/d) but maintained DMI and milk yield, showed improved feed efficiency (2.18 vs. 2.38 kg/kg), and slight enhancement in immune function. From wk 5 to 16, GF-supplemented cows had lower BHB and increased milk fat (+0.17%). PostG cows had greater milk protein (+0.09%) and fat (+0.24%) than Pre+PostG cows. The GF-supplemented cows had a greater number of alveolar secretory units with more epithelial cells. Supplementation with GF improved colostrum yield and quality, calf outcomes, milk components, feed efficiency, and metabolic and immune parameters. Initiating supplementation postpartum yielded similar benefits with enhanced milk protein. Further research is needed to elucidate underlying mechanisms.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144937948","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":"Role of osmotic stress in modulating antibiotic resistance and adhesion properties of Listeria monocytogenes in a dairy factory environment.","authors":"Patryk Wiśniewski, Patryk Adamski, Wioleta Chajęcka-Wierzchowska, Anna Zadernowska","doi":"10.3168/jds.2025-26971","DOIUrl":"https://doi.org/10.3168/jds.2025-26971","url":null,"abstract":"<p><p>Listeria monocytogenes is a significant foodborne pathogen capable of surviving various stress conditions encountered during food processing. The aim of this study was to evaluate the influence of osmotic pressure induced by NaCl (4% and 6%) on the phenotypic antibiotic resistance, biofilm-forming capacity, and slime production of L. monocytogenes isolates from food processing environments. A total of 10 isolates of L. monocytogenes were subjected to osmotic stress. Antimicrobial resistance was assessed using the disk diffusion method and MIC, and biofilm and slime production capacities were determined through biofilm production indices (BPI), and culture on stainless-steel 304 and polyurethane coupons and Congo red agar, respectively. Isolates were also assigned to serotypes using PCR. Genotypic variability of isolates was determined by enterobacterial repetitive intergenic consensus PCR (ERIC-PCR). All isolates tested belonged to serotype 3a. It was shown that MIC values varied depending on the antibiotics tested and NaCl concentrations. The results demonstrated that the isolates exhibited strain-specific adaptations to osmotic stress, with variable survival rates and alterations in their capacity to form biofilms. Biofilm formation remained robust under stress conditions, with certain isolates exhibiting increased capacity at 6% NaCl, particularly on polyurethane surfaces. This indicates potential adaptive responses and highlights the importance of the type of materials used in the food industry. Conversely, slime production was minimally induced by osmotic stress, with only 1 isolate exhibiting positive results. These findings highlight the resilience of L. monocytogenes to osmotic stress and its capacity to adapt to challenging conditions in food processing environments, which may complicate contamination control and sanitation efforts.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144937839","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":"Different concentrations of exopolysaccharides enhance the freeze resistance of Lactobacillus plantarum: Transcriptomics and metabolomics.","authors":"Zhou Jin, Guoguo Jin, Yating Wu, Guohua Jiang, Yifan Zhang, Xinran Wang, Baocai Xu, Lin Mei","doi":"10.3168/jds.2025-26709","DOIUrl":"https://doi.org/10.3168/jds.2025-26709","url":null,"abstract":"<p><p>The study aimed to investigate the regulatory effects of exopolysaccharides (EPS) derived from Pediococcus acidilactici S1 on the cell physiological functions of Lactobacillus plantarum FQR during the freezing process. Results demonstrated that the addition of 70 mg/mL EPS as a cryoprotectant achieved a maximum survival rate of 91.99 ± 3.52%. The EPS effectively mitigated cell wall and membrane damage, reduced membrane permeability, and stabilized membrane fluidity. Furthermore, EPS decreased the freezing point of the solution from -17.37°C ± 0.19°C to -17.08°C ± 0.20°C, thereby inhibiting ice crystal formation and maintaining post-freeze-drying stability in DNA structure, membrane structure, cell wall protein structure, and unsaturated fatty acid composition within cells. Notably, there was a significant increase in intracellular salicylic acid levels among differential metabolites observed through metabolomic analysis. Combined with transcriptomic analysis, it was revealed that purine metabolism, pyruvate metabolism, and galactose metabolism were the main metabolic pathways involved in this process.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144937900","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":"Impact of dietary supplementation of rumen native microbes on ruminal microbiome, ruminal fermentation, and total-tract digestibility in Holstein cows.","authors":"M Nehme Marinho, M C Perdomo, B Souza Simões, A Husnain, U Arshad, C C Figueiredo, P M Peixoto, H F Monteiro, B Anderson, J E P Santos","doi":"10.3168/jds.2025-26900","DOIUrl":"https://doi.org/10.3168/jds.2025-26900","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Dietary microbial additives often benefit production performance in dairy cows. The objectives were to determine the effects of microbial additives on rumen microbial diversity, total-tract digestibility, incorporation of dietary N into milk N, and serum metabolites. One-hundred and 17 cows at 61 d postpartum (31-87 d) were blocked by parity group and pretreatment ECM yield. Within block, cows were randomly assigned to receive 100 g of corn meal containing no microbial additive (CON; n = 40), 100 g of corn meal containing 5 g of a mixture of Clostridium beijerinckii and Pichia kudriavzevii (G1; 4 × 10&lt;sup&gt;7&lt;/sup&gt; cfu of C. beijerinckii and 1 × 10&lt;sup&gt;9&lt;/sup&gt; cfu of P. kudriavzevii; n = 38), or 100 g of corn meal containing 5 g of a mixture of C. beijerinckii, P. kudriavzevii, Butyrivibrio fibrisolvens, and Ruminococcus bovis (G2; 4 × 10&lt;sup&gt;7&lt;/sup&gt; cfu of C. beijerinckii, 1 × 10&lt;sup&gt;9&lt;/sup&gt; cfu of P. kudriavzevii, 1 × 10&lt;sup&gt;8&lt;/sup&gt; cfu of B. fibrisolvens, and 1 × 10&lt;sup&gt;8&lt;/sup&gt; cfu of R. bovis; n = 39). Treatments were top-dressed for 140 d. Total-tract digestibility and rumen microbial composition were evaluated on d 61 and 124 of the experiment. Orthogonal contrasts compared the effect of microbial additive (MA) and the type of microbial additive (TMA). On experimental d 61, supplementing MA did not influence rumen microbial diversity, although cows fed G2 had a less diverse microbiome than those fed G1. On d 124, both MA and TMA reduced evenness, which resulted in lesser microbial α-diversity in cows supplemented with MA than those in CON. Minor differences were observed in rumen microbial β-diversity, except for multiparous cows on d 124 in which treatment tended to affect diversity because 16 amplicon sequence variant (ASV) groups representing phylogenetically related ASV differed among treatments. Two bacteria supplemented in G2, also native to the rumen, were identified, B. fibrisolvens and R. bovis, but treatment did not affect their abundance. Cows fed MA had increased total short-chain fatty acid concentration and partition of dietary N into milk N on d 61, but not on d 124. On d 61, feeding MA increased milk N secretion by 10 g/d (187 g/d vs. 193 g/d vs. 201 g/d), and incorporation of dietary N into milk N by 1.7 percentage units (CON = 30.8% vs. G1 = 31.2% vs. G2 = 33.7%). An interaction between TMA and parity affected the estimated microbial N production on d 124 because of the differences between G1 and G2 in primiparous cows (G1 = 302 g/d vs. G2 = 264 g/d). Type of MA affected digestibility on d 124, but the effect differed with parity. Feeding G1 increased digestibility of DM, OM, and CP in primiparous cows by 2.7, 2.8, and 4.7 percentage units, but not in multiparous cows. Collectively, supplementing diets of dairy cows with MA resulted in minor effects on the composition of the ruminal microbiota, total-tract digestibility, and use of dietary N. Present findings might not fully explain differences in production performanc","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144937932","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}