Journal of Dairy Science最新文献

{"title":"A novel controlled wood smoke exposure model to evaluate physiological responses to smoke-derived air pollution in dairy calves.","authors":"M Kamyabi, A Pace, J R Kok, A M S Smith, D Sarantopulos, L Christensen, A S Marquez-Acevedo, L De Moura Pereira, M Larson, A Ahmadzadeh, D Konetchy, P Rezamand, A L Skibiel","doi":"10.3168/jds.2026-29100","DOIUrl":"https://doi.org/10.3168/jds.2026-29100","url":null,"abstract":"<p><p>Fine particulate matter (PM<sub>2.5</sub>) from wildfire smoke is a major air pollutant in dairy-producing regions of the United States. However, knowledge of direct causative effects of wildfire-derived pollutants on calf health is lacking because of a reliance on observational studies from natural wildfire smoke exposures. Calves represent an important population in a dairy herd and improving their health is especially critical during the vulnerable pre-weaning window, as respiratory diseases during this period can affect performance later in life. The objective of this study was to evaluate the acute effects of controlled short-term wood smoke exposure on respiratory function, immune responses, and clinical health measures in pre-weaned dairy calves using novel smoke enclosures we developed. Intact male Holstein calves (n = 24; 37 ± 2 d of age [mean ± SD]) were randomly assigned to control (CON; n = 12) or wood smoke (WS; n = 12) treatments. Calves were kept for 6 h in the experimental smoke enclosures where they were either exposed to wood combustion smoke (WS; smoke inlet open) or not exposed (CON; smoke inlet closed). Environmental conditions within the enclosures including PM<sub>2.5</sub>, carbon dioxide, carbon monoxide, ambient air temperature, and relative humidity were recorded during the experiment trials. Fine particulate matter concentrations (mean ± SD) were 9.94 ± 4.50 µg/m<sup>3</sup> for CON and 238.44 ± 62.97 µg/m<sup>3</sup> for WS. All other environmental conditions were similar between CON and WS groups. Immediately after treatment, pulmonary function and health scores were evaluated, and blood samples were collected. Calves were humanely euthanized, and bronchoalveolar lavage was performed. Wood smoke exposure altered pulmonary function, as WS calves had a lower respiratory rate (17.50 vs. 21.52 breaths/min) and higher tidal volume (0.90 vs. 0.75 L) compared with CON calves, while minute ventilation did not differ between groups. Bronchoalveolar lavage fluid (BALF) immunophenotyping revealed increased proportions of granulocytes, CD68-positive macrophages, and natural killer cells in WS compared with CON calves, suggesting activation of pulmonary innate immune responses. Circulating neutrophil counts were reduced in WS calves, whereas total white blood cell counts, and other hematological variables did not differ between groups. Plasma concentrations of acute phase proteins, including serum amyloid A, haptoglobin, and albumin, did not differ statistically between treatments. Phagocytosing granulocytes (%) in whole blood was greater in the WS group compared with CON (97.03 vs. 93.89%). Oxidative stress, assessed by concentrations of thiobarbituric acid reactive substances (TBARS) in BALF and plasma, was not affected by treatment. These findings demonstrate that short-term wood smoke exposure at concentrations reflective of natural wildfire conditions induces an acute pulmonary inflammatory response and alters respirat","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.7,"publicationDate":"2026-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149073011","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":"The effects of a clay mineral-based feed additive on metabolism and inflammation in heat-stressed lactating dairy cows.","authors":"S Rodriguez-Jimenez, J Opgenorth, E J Mayorga, M A Abeyta, B M Goetz, N Reisinger, J Faas, R Palme, L H Baumgard","doi":"10.3168/jds.2026-28578","DOIUrl":"https://doi.org/10.3168/jds.2026-28578","url":null,"abstract":"<p><p>Study objectives were to determine the effects of a dietary clay mineral-based feed additive on performance, metabolism, inflammation, and liver and gastrointestinal health in acutely heat-stressed lactating dairy cows. Primiparous Holstein cows (148 ± 25 DIM; 600 ± 50 kg BW; n = 12) were balanced by DIM and milk yield and assigned to 1 of 2 ad libitum fed treatments: 1) control (CON; 500 g ground corn/d; n = 6), or 2) clay mineral-based mycotoxin binder (CM; 500 g ground corn and 50 g of Biofix®/d; n = 6). Respective treatments were top-dressed into the individually fed TMR and the mycotoxin quantities naturally found in the TMR were considered low. Following 3 d of acclimation to individual pens, cows were enrolled in 2 experimental periods (P). During P1 (10 d), cows were housed in thermoneutral (TN) conditions and fed their respective dietary treatments. During P2 (7 d), heat stress (HS) was induced using individual electric heat blankets (EHB, Thermotex Therapy Systems Ltd., Calgary, AB, Canada). Regardless of diet, HS increased rectal temperature and respiration rate (1.9°C and 54 breaths/min, respectively), and decreased DMI and milk yield (45 and 35%, respectively) relative to P1. Heat stress decreased circulating glucose and glucagon similarly in both treatments (6 and 21%, respectively). Overall, circulating insulin tended to be increased in CM-fed cows (36 and 54%, in P1 and P2, respectively). Plasma NEFA and BUN concentrations increased (70 and 41%, respectively) during HS, but neither metabolite was affected by dietary treatment. Although circulating cortisol was unaffected by HS, fecal cortisol metabolites increased (3.4-fold) similarly between diets. Circulating lipopolysaccharide binding protein and haptoglobin increased on d 1 of HS relative to P1 (1.4- and 27.8-fold, respectively), but no dietary differences were observed. Relative to P1, HS increased circulating serum amyloid A (SAA) in CM-fed cows (7.0-fold) on d 1, while it was unaffected by HS in CON, which suggests CM might have immunomodulatory effects. Following d 1 of HS, SAA returned to P1 levels in CM-fed cows, and both treatments had similar SAA levels for the remainder of P2. In summary, HS markedly reduced milk production and caused an acute phase protein response, and while feeding CM did not ameliorate the production responses, it did influence insulin and SAA. Further investigation on the potential role of clay mineral-based feed additive(s) during a longer and less severe HS and when cows are fed a more mycotoxin-contaminated TMR is warranted.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.7,"publicationDate":"2026-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149073110","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 feed restriction on dynamics of feed intake, milk yield, and energy balance in dairy cows.","authors":"Y Huang, L Delaby","doi":"10.3168/jds.2026-28854","DOIUrl":"https://doi.org/10.3168/jds.2026-28854","url":null,"abstract":"<p><p>Due to climate change, forage shortages may become more frequent, potentially leading to underfeeding in dairy cows. Limited knowledge exists on how milk yield and energy balance evolve during and, in particular, after the underfeeding phase. This study aimed to assess the impact of 2 feed restriction durations (4 and 6 weeks) on the changes in feed intake, milk yield, and energy balance in dairy cows. A total of 42 cows were first fed ad libitum for 3 weeks and then divided into 3 groups of 14 cows. Two groups were underfed by 5 kg of DM per day for 4 or 6 weeks (R4 and R6). After the restriction phase, cows were again fed ad libitum for 5 weeks. The control group was fed ad libitum throughout the trial. During the restriction phase, ECM yield dropped by 4.7 and 5.0 kg in the R4 and R6 groups, respectively, compared with the control group. During the refeeding phase, previously restricted cows exhibited higher DMI than the control group (+1.1 kg DM for R4; +0.80 kg DM for R6), while ECM yield remained similar across all groups. The energy balance during refeeding phase was higher in the restricted cows compared with the control group, suggesting a greater rate of body reserve reconstitution. The increase in feed intake during refeeding appeared primarily driven by the need to restore body reserves. Cows experiencing a more negative cumulative energy balance during restriction exhibited a greater proportional increase in intake during refeeding. Extending the duration of restriction from 4 to 6 weeks did not exacerbate milk yield losses nor enhance compensatory responses during refeeding, largely because cows progressively adapted their energy partitioning. During restriction, cows with initially high energy partitioning toward milk decreased the proportion of net energy secreted in milk relative to dietary energy supply, whereas those with lower partitioning increased it (e.g., from 0.60 to 0.66). During refeeding, this proportion continued to decrease in high-partitioning cows (e.g., from 0.80 to 0.71) but remained stable in low-partitioning cows (e.g., from 0.60 to 0.58), highlighting greater yield stability in these low-partitioning cows. Overall, the findings of present study provide useful perspectives for improving feeding system models by incorporating dynamic components, and highlight the need to consider different levels of restriction intensity in future studies.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.7,"publicationDate":"2026-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149073120","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":"Investigation of laparoscopic ovum-pickup in juvenile heifers followed by in vitro embryo production and embryo transfer in dairy cattle.","authors":"E M Murphy, L Thompson, M McDonald, R C Doyle, T V Silva, L Bell, S Chaubal, M Creek, M M Herlihy, E Parra, X Torruella, V Huuskonen, J Furlong, F Randi, P Lonergan, S T Butler","doi":"10.3168/jds.2026-28802","DOIUrl":"https://doi.org/10.3168/jds.2026-28802","url":null,"abstract":"<p><p>The objectives of this pilot study were (1) to investigate the potential application of juvenile in vitro fertilization and embryo transfer (JIVET) in seasonal pasture based dairy systems and (2) to provide insights into donor and recipient management that might be useful in designing future studies. Oocytes were collected from the ovaries of elite Holstein Friesian donor calves (n = 49) by laparoscopic ovum pickup. Following in vitro maturation, oocytes were fertilized with frozen-thawed X-sorted semen from a panel of proven fertility Holstein Friesian sires (n = 8) and cultured for 7 d. A total of 87 embryos were transferred fresh to Holstein Friesian heifers or lactating dairy cows that had been synchronized using a progesterone-Ovsynch protocol. Pregnancy diagnosis was carried out using transrectal ultrasound at d 35 after synchronized estrus and was confirmed at d 63. Pregnancy loss was characterized as loss between d 35 and d 63. Gestation length (GL), birthweight (BiW), calving difficulty (CD) and vitality scores were recorded from the resulting calves (n = 21) and a contemporaneous cohort of calves derived from artificial insemination (AI; n = 44). Blood samples were collected from a subset (n = 35) of these calves for hematological analysis on d 0 and biochemical analysis on d 0 and d 14. There was evidence that the number of blastocysts produced (0.3 vs 2.1), and blastocyst yield (percentage of presumptive zygotes that formed blastocysts; 0.8% vs 15.1%) were both less for donors that had experienced a health event before LOPU than for those that had not. Fewer oocytes were recovered from donors that were in the bottom 25% category for plasma anti-Müllerian hormone (AMH) compared with those in the middle 50% category, and these in turn had lower oocyte recovery compared with donors in the top 25% category (3.9, 8.1 and 26.9, respectively). Fewer transferrable embryos were produced from donors that were in the bottom 25% category for plasma AMH compared with those in the middle 50% and the top 25% category (0.6, 1.1 and 4.4, respectively). Mean serum concentration of pregnancy specific protein-B (PSPB) on d 21 was lowest in recipients that were diagnosed not pregnant on d 35 (0.16 ng/mL) and was greatest in recipients that maintained the pregnancy to term (0.96 ng/mL). Gestation length and BiW were similar for calves derived from AI and JIVET. Calving difficulty and calf vigour scores were not affected by calf origin. In conclusion, donor calf health before LOPU and plasma AMH concentration were associated with subsequent embryo yield, and calves derived from JIVET had similar GL, BiW, CD and calf vigour scores to AI-derived calves.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.7,"publicationDate":"2026-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149015158","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":"Supply of a histidine-rich bypass protein source improves productive performance and N efficiency independently of metabolizable Met and Lys.","authors":"M Killerby, K Ruh-Etteldorf, A Hoppmann, V Pszczolkowski, A Larsen, E Cohan, A Benn, D N Sherlock, S I Arriola Apelo","doi":"10.3168/jds.2026-28843","DOIUrl":"https://doi.org/10.3168/jds.2026-28843","url":null,"abstract":"<p><p>The milk protein equation of the Nutrient Requirements of Dairy Cattle 8th Revised Edition includes additive effects of the metabolizable (m-) supply of Met, Lys, Leu, Ile, and His. However, additive effects of those AA in dietary studies have not been reported. This study aimed to evaluate the relationship between dietary level of mHis and of mMet, mLys, and mLeu as a group (MKL) on lactation performance, N efficiency, and metabolism, with a 2 × 2 factorial arrangement of treatments. The 4 diets consisted of low (L) or high (H) mHis (HIS; 2.2 vs 2.7% MP) and L or H levels of mMet (2.4 vs 2.8% MP) and mLys (8.0 vs. 9.0% MP). Although mLeu was aimed to increase along with Met and Lys, higher than expected Leu content in the HIS diet resulted in similar increase for both factors. Thirty-two multiparous lactating Holstein cows (77 ± 17 DIM) were enrolled by DIM and parity in a 4 × 4 Latin square study replicated 8 times with 4 periods of 28 d. The 4 experimental diets contained the same inclusion level of corn silage, alfalfa silage, cottonseed, dry corn grain, fat supplement, urea, and vitamins and minerals, while varying inclusion levels of corn gluten meal, a blood meal-based protein mix, and rumen-protected Met and Lys to increase the metabolizable supply of targeted AA. The L-HIS/L-MKL diet was 15% MP deficient while meeting requirements for NEL. Data were analyzed with a mixed model containing fixed effects of HIS, MKL, HIS × MKL interaction, period, and square, and the random effect of cow within square. Both factors increased DMI to a similar extent (+1 kg/d), but no further increase was observed when combined, indicating antagonistic effects between factors. Accounting for DMI, H-HIS increased the supply of mHis and mLeu by 17 and 21 g/d, respectively, compared with L-HIS. Meanwhile, compared with L-MKL, H-MKL increased the supply of mMet, mLys, and mLeu by 15, 44, and 20 g/d, respectively. Both factors increased circulating concentrations of their respective AA in plasma, except for Leu, and decreased glucose to a similar extent (-2.7 mg/dL), without affecting the concentrations of insulin, nonesterified fatty acids, or triglycerides. The yields of milk, lactose, and > 16C fatty acids were increased only by HIS. The yields of ECM (HIS 1.7 kg/d, MKL 0.9 kg/d), true protein (HIS 74 g/d, MKL 45 g/d), fat (HIS 46 g/d, MKL a trend of 31 g/d), and < 16C and = 16C (a trend for HIS) fatty acids were additively increased by the 2 factors. Plasma and milk urea N concentrations, urinary urea N, and total urinary N outputs were increased by MKL. Meanwhile, HIS only increased MUN and tended to increase urinary urea N output. Under L-MKL, HIS maintained gross N use efficiency, while it recovered the drop induced by H-MKL. Despite non-additive effects on DMI, increasing mHis supply, in addition to mMet, mLys, and mLeu, increased milk protein yield and improved N use efficiency, contradicting the limiting AA theory.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.7,"publicationDate":"2026-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149015152","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":"Fusing heterogeneous sensor data using artificial intelligence hybrid models for dairy cattle health anomaly detection.","authors":"Arnas Nakrošis, Mahammad Ismayilov, Gurban Shukurov, Adhithiyan Arul Mani, Sanjaykrishna Ravali Srinivas, Joris Vėžys, Vytautas Ostaševičius, Agnė Paulauskaitė","doi":"10.3168/jds.2026-28889","DOIUrl":"https://doi.org/10.3168/jds.2026-28889","url":null,"abstract":"<p><p>This observational study evaluated a hybrid artificial intelligence framework for same day anomaly detection in dairy cows using multimodal sensor data collected under commercial farm conditions. The framework integrated thermal video recorded during routine milking, milking-system measurements, and rumen bolus sensor data from 88 cows. Thermal recordings were processed to extract region-level temperature statistics and deep visual-temporal features using residual convolutional networks and Transformer-based temporal modeling. These thermal features were temporally aligned with production and physiological variables, including somatic cell count, milk yield, electrical conductivity, blood indicators, milk flow, internal body temperature, activity, rumination, and bolus event flags. The fused feature sets were evaluated using several machine-learning classifiers under different modality configurations to assess the contribution of thermal, milking, and bolus data. Model performance depended strongly on modality selection and decision-threshold optimization. The best selected configuration achieved a receiver operating characteristic area under the curve of 0.934 and an F1-score of 0.890, indicating strong discrimination between normal and anomalous health states. Results suggest that production and physiological sensor variables provide strong predictive information, whereas thermal imaging adds complementary value when combined with structured farm data. The proposed framework demonstrates the potential of multimodal artificial intelligence systems to support same day health anomaly detection and decision-support tools for dairy cow health monitoring in real farm environments.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.7,"publicationDate":"2026-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149015043","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":"Climate-smart dairy practices and perceptions across 2 global dairy producing countries.","authors":"Meredith T Niles, Rebecca C Mitchell, Lauren Hunt, Lisa McPherson, Phillip Stahlmann-Brown","doi":"10.3168/jds.2026-28492","DOIUrl":"https://doi.org/10.3168/jds.2026-28492","url":null,"abstract":"<p><p>Both in the United States and internationally, the dairy sector has set ambitious targets to reduce greenhouse gas emissions and implement climate-smart agriculture practices. Despite this, little research has explored dairy producer perceptions or adoption of climate-smart practices, especially across contexts. This study presents the first comparison study of dairy producer adoption and perceptions around climate-smart practices across 2 major dairy-producing countries, New Zealand and the United States. Data were collected through 2 online surveys (deployed in 2023 US and 2025 in New Zealand), which were developed to reflect contextual differences for each respective country and included current and anticipated adoption of climate adaptation and mitigation practices, beliefs around climate change and anticipated climate impacts on the dairy industry, herd information, and producer demographics. We find that while dairy producers are adopting climate-smart practices relevant to the production systems in both countries, NZ producers (n = 306) displayed higher likelihood of adoption of emerging enteric mitigation strategies such as feed additives, selective breeding, and methane-inhibiting vaccines, as well as a higher proportion of anthropogenic climate change belief, compared with US producers (n = 920, approximately 700 full responses). Across both countries, cow welfare, farm profitability, and ensuring a viable farming operation for future generations were the top considerations when adopting new practices, suggesting these are critical to support farmers' climate-related strategy adoption. Despite having greater policy support and incentive programs for climate-smart practices, US producers were more likely to perceive initial cost and equipment barriers, to adopting climate-smart practices, while NZ producers were more likely to perceive information and technical assistance barriers. Finally, producers in both countries had high levels of uncertainty about how climate change may impact their operations, indicating that local and regionally appropriate climate risk extension and outreach engagement is important. These results provide key insights for stakeholders who seek to increase adoption of climate-smart dairy practices to meet industry and government expectations.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.7,"publicationDate":"2026-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149015066","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 phytogenic supplementation at different dietary protein concentrations on performance, rumen fermentation, and nutrient digestibility in lactating dairy diets.","authors":"N Alfaro-Diaz, M Siregar, A Osorio, S Saikumar, G Salas-Solis, K Arriola, J A Davidson, T Aubert, D Vyas","doi":"10.3168/jds.2026-28978","DOIUrl":"https://doi.org/10.3168/jds.2026-28978","url":null,"abstract":"<p><p>We aimed to evaluate the effects of phytogenic supplementation at different dietary protein concentrations in lactating dairy cattle diets. We hypothesized that phytogenic supplementation with a blend of several plant-based ingredients providing saponins, encapsulated cinnamaldehyde, curcumin, capsaicin, and piperine would act synergistically with dietary protein supply to maintain or enhance lactational performance when CP is adequate. Twenty-four lactating Holstein dairy cows were used in a 4 × 4 Latin Square design with 4 28-d experimental periods (21 d adaptation + 7 d collection) and 4 treatments in a 2 × 2 factorial arrangement (CP concentrations and phytogenic supplementation): 16.5% without or with phytogenic and reduced CP concentration at 14.5% without or with phytogenic supplementation. Phytogenic supplement was top-dressed (7 g/d) on the TMR. Intake and milk yield were recorded daily, and milk samples were collected during the last week of the experimental period for milk components and FA analysis. Data were analyzed using PROC GLIMMIX of SAS 9.4 and the statistical model included the main effects of protein, phytogenic supplement and their interaction and period as a fixed effect, and cow nested in square as a random effect. Significance was declared at P ≤ 0.05 and tendencies were discussed at 0.05 <P ≤ 0.10. Milk yield (MY) and feed efficiency (MY/DMI) were greater with adequate protein diets whereas phytogenic supplementation had no main effect on these variables; however, DMI increased with phytogenic supplementation in reduced CP diets. Phytogenic supplementation increased milk fat concentration and yield, 3.5% FCM, ECM, and the proportions of de novo and preformed FA, while mixed FA tended to increase. In summary, phytogenic supplementation, irrespective of dietary CP concentration, enhanced FCM, milk fat concentration and yield, as well as the proportion of de novo and preformed FA. Additionally, adequate protein diets, regardless of phytogenic supplementation, increased milk yield and improved feed efficiency.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.7,"publicationDate":"2026-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149015082","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":"Indoor-housed dairy heifers' motivation to access an additional space.","authors":"Malina Suchon, Sarah Kappel, Daniel M Weary, Marina A G von Keyserlingk","doi":"10.3168/jds.2026-29307","DOIUrl":"https://doi.org/10.3168/jds.2026-29307","url":null,"abstract":"<p><p>Dairy heifers are often housed in confined environments that can limit the range of behaviors they express. Previous studies have assessed the motivation of indoor-housed dairy cows for specific resources, such as pasture or brushes, by comparing the weight animals are willing to push to access these resources relative to an empty space. However, little is known about how much confined cattle value access to additional space itself. We assessed the use of, and motivation to access, additional space in dairy heifers housed in a freestall barn. Holstein heifers (n = 48; mean age: 7.1 ± 0.74 mo; mean BW: 279.8 ± 32.57 kg) were housed in 4 groups of 12 in pens (7 m x 12 m) containing 13 lying stalls, a waterer and 35 cm of feed bunk space per animal. Groups were given 3h/d access to an additional space (23 × 2 m, sand-bedded) adjacent to the home pen under both a free access phase (i.e., with no restriction) and a weighted gate phase (i.e., requiring heifers to push a progressively heavier weight). All heifers used the additional space when provided free access, but the number of animals entering the space declined when access was restricted via a weighted gate. Variation among groups and individuals was observed in both how much time heifers spent in the space and expressed motivation, with maximum weight pushed ranging from 1.5 to 22.5 kg. Heifers willing to push the most weight actually spent less time using the space when access was free. Additionally, heifers' use of the additional space appeared to be influenced by the movements of herd mates. These findings indicate that dairy heifers housed in freestall barns are motivated to access additional space, suggesting that greater opportunities for movement should be considered in housing design and that \"empty space\" may not represent an appropriate negative control in motivation studies.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.7,"publicationDate":"2026-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149015093","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":"Assessing the potential of UV-C as a nonthermal alternative to pasteurization in milk powder processing at pilot-scale for the retention of nutrients.","authors":"Loreto Alonso-Miravalles, Christoph Widmer, Alessandro Gianfrancesco, Nicholas B Johnson, Hoang Du Le","doi":"10.3168/jds.2026-28906","DOIUrl":"https://doi.org/10.3168/jds.2026-28906","url":null,"abstract":"<p><p>This study evaluated UV-C (UV-C) treatment as a non-thermal alternative to pasteurization for cow's milk, with a focus on the retention of nutritionally relevant components during liquid and powder processing. The milk was thermized and subsequently processed either by conventional pasteurization (72°C, 15 s) or UV-C irradiation (3,900 J/m² at 4°C), followed by evaporation and spray drying. Microbial inactivation, lipase activity, protein denaturation, amino acid profile, in vitro protein digestibility, immunoglobulin A (IgA) and G (IgG), and vitamin stability were assessed. UV-treated milk showed no significant changes in protein denaturation, amino acid profile and in vitro digestibility compared with raw milk. In contrast to pasteurization, UV-C treatment preserved lipase activity in liquid milk, although no residual activity was detected after evaporation and spray drying. Retention of IgA and IgG was significantly higher in UV-treated liquid milk and milk powder than in pasteurized counterparts. UV-C treatment increased vitamin D₃ concentration in milk preserving its bio-accessibility. Overall, UV-C processing preserved key nutritional and bioactive milk components supporting its potential application in dairy processing.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.7,"publicationDate":"2026-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149015106","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}