Journal of Dairy Science最新文献

{"title":"Effects of propionic acid inclusion and ensiling time on in situ ruminal starch degradability of high-moisture flint corn grain silage.","authors":"Bernardo M Martins, Ricardo A M Vieira, Carina S Bittencourt, João V C Rodrigues, Poliana T R Salgado, Luciano S Santos, Luiz F Ferraretto, Edenio Detmann, Alex L Silva, Polyana P Rotta","doi":"10.3168/jds.2025-26841","DOIUrl":"https://doi.org/10.3168/jds.2025-26841","url":null,"abstract":"<p><p>This study evaluated the effects of propionic acid inclusion (PAI; 0, 0.25, and 0.50% of fresh matter) and ensiling time (ENT; 30, 60, 90, 120, 150, and 180 d) on the chemical composition, fermentation profile, DM losses, and in situ ruminal starch degradability of high-moisture flint corn grain silage (HMC). Rolled corn grain with 45% moisture and 80% vitreousness was ensiled in 10-L mini silos at a packing density of 1,300 kg/m³. The experimental design followed a 3 × 6 factorial arrangement with 3 replicates per treatment, totaling 54 silos. Samples were analyzed for chemical composition, ammonia-N, pH, organic acids, and ruminal starch degradability. Ruminal degradability was assessed using a nylon bag technique incubated in 3 rumen-cannulated Holstein cows, and a nonlinear modeling approach was applied to estimate starch degradation kinetics. For mycotoxin analysis and ruminal starch degradability, the 0-d (non-ensiled) sample was also included. Data analysis employed the NLMIXED procedure of SAS, with the Newton-Raphson optimization algorithm and adaptive Gaussian quadrature for likelihood integration. Contrasts were conducted to compare PAI versus control treatment (0% PAI) and between the PAI levels. An interaction between PAI and ENT was observed for DM losses, with the greatest losses (>6%) occurring in silages treated with 0.50% PAI at 60 d ENT. Silages treated with PAI had lower final pH values than the control, although PAI did not improve fermentation profile. Crude protein decreased, and ammonia-N increased with longer ENT. Ruminal starch degradability improved with ENT, but PAI reduced both the degradation rate and the maximum extent of starch degradation. At 180 d, estimated degradation rates were 100%/h for the control treatment, 80%/h for 0.25% PAI, and 70%/h for 0.50% PAI. In conclusion, under the conditions of this study, PAI did not improve silage fermentation profile and negatively affected starch degradability in the rumen. Conversely, prolonged ENT improved starch availability. Therefore, long-term ENT (180 d) is recommended to optimize the nutritional value of HMC, particularly in flint-type corn grain.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145181695","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 reducing starter feed crude protein content with different milk allowances on the performance and nitrogen balance in dairy calves.","authors":"Ana Caroline R T Silva, Anna L L Sguizzato, Mariana M Campos, Polyana P Rotta, Marcos I Marcondes, João R R Dorea, Guilherme L Menezes, Jaimison V F Vieira, Alex L Silva","doi":"10.3168/jds.2025-26714","DOIUrl":"https://doi.org/10.3168/jds.2025-26714","url":null,"abstract":"<p><p>Associate milk allowance and starter feed for dairy calves to achieve high performance and adequate nitrogen (N) balance can be challenging. Thus, this study aimed to evaluate the effects of reducing the CP content of the starter feed on the performance, mammary gland development, and N balance of dairy calves in the preweaning, weaning, and postweaning phases. The study was conducted according to a completely randomized design in a 3 × 2 factorial scheme, using 3 milk volumes (4, 6, or 8 L/d) and 2 strategies for starter feed supply (fixed or decreasing CP content). The first strategy consisted of feeding the animals a fixed starter feed with 18% CP (DM basis) throughout the preweaning phase (from 4 to 73 d), and in the second strategy, the animals were fed a starter feed with 24% CP (DM basis) from 4 to 24 d of age, 18% CP (DM basis) from 25 to 45 d of age, and 14% CP (DM basis) from 46 to 73 d of age. Therefore, 60 female crossbred calves were distributed through the 6 treatments formed: 4 L/d of milk and starter feed with fixed CP (FCP) content; 6 L/d of whole milk + FCP; 8 L/d of whole milk + FCP; 4 L/d whole milk and starter feed with decreasing CP (DCP) content; 6 L/d whole milk + DCP; 8 L/d milk + DCP. Calves receiving DCP had lower intake and fecal excretion on d 66. Moreover, younger calves (24 d old) had higher N utilization efficiency than calves at 45 and 66 d old, but when fed 8 L/d of milk, all calves had the similar N-use efficiency regardless of age. Additionally, calves receiving 8 L/d of milk had higher N intake and retention and lower N excretion. In the preweaning phase, animals fed FCP showed higher performance. In the weaning phase, higher ADG and feed efficiency were observed in animals fed 4 L/d whole milk compared with 8 L/d whole milk, and calves fed FCP had a higher BW. In the postweaning period, calves in the DCP group showed better feed efficiency, but animals fed FCP had higher ruminal ammonia-N and propionate concentrations. Moreover, calves on 4 and 6 L/d and FCP had higher blood urea N levels. Finally, for the mammary gland, age affected area, perimeter, circularity, and eccentricity, which increased in size during the 80 d of the trial. Female calves receiving 4 L/d of whole milk had a smaller area than the ones with 6 L/d, and, for perimeter, 4 L/d treatment promoted reduced parenchyma growth compared with 6 and 8 L/d treatment. To conclude, animals receiving 6 L/d of whole milk showed good performance, mammary parenchyma growth, greater N efficiency, and reduced N excretion. The FCP strategy improved performance, whereas the DCP strategy increased feed efficiency postweaning and tended to reduce fecal N excretion. However, it should be noted that this reduction was modest at the individual level, and the use of multiple starters on the farm should be carefully evaluated.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145181702","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":"Lactational performance and enteric methane emissions in dairy cows fed high-oil oats, cold-pressed rapeseed cake, and 3-nitrooxypropanol in a grass silage-based diet.","authors":"P Fant, G Mantovani, M Vadroňová, M C Sabetti, S J Krizsan, M Ramin","doi":"10.3168/jds.2025-27007","DOIUrl":"https://doi.org/10.3168/jds.2025-27007","url":null,"abstract":"&lt;p&gt;&lt;p&gt;The objective of this study was to evaluate the effects of high-oil oats and cold-pressed rapeseed cake (RSC) as dietary ingredients, along with supplementation of 3-nitrooxypropanol (3-NOP), on apparent total-tract digestibility, milk production, and enteric CH&lt;sub&gt;4&lt;/sub&gt; emissions in dairy cows fed a grass silage-based diet. Twenty-four lactating Nordic Red cows were grouped into 3 blocks. The experiment was conducted as a cyclic change-over where each treatment had 3 observations per period. The experiment consisted of 4 periods of 28 d each, including 18 d of diet adaptation and 10 d of data and sample collection. The 2 × 2 × 2 factorial design included 2 energy sources (barley or high-oil oats), 2 protein supplements (rapeseed meal [RSM] or RSC), and 3-NOP supplementation at 2 levels (0 or 68 mg/kg of DM), resulting in 8 dietary treatments. The basal diet consisted of 60% grass silage (on a DM basis). Inclusion rates of the experimental concentrates were 27% to 29% and 29% to 31% for barley and high-oil oats, respectively, and 8% to 10% and 10% to 12% for RSM and RSC, respectively. Diets were offered ad libitum as a TMR. Daily DMI, milk yield, BW, and gas emissions were recorded throughout the experiment. Gas emissions were measured using the GreenFeed system. Ether extract (EE) content across experimental diets ranged from 2.9% to 6.1% of DM. Total DMI tended to increase with high-oil oats compared with barley, but decreased with RSC compared with RSM. Digestibility of DM, OM, NDF, and EE decreased with high-oil oats versus barley, and EE digestibility increased with RSC versus RSM. Despite lower nutrient digestibility, milk and ECM yield increased by 2.4 kg/d with high-oil oats compared with barley. Milk yield decreased by 1.1 kg/d and ECM yield tended to decrease by 1.0 kg/d with 3-NOP supplementation. Milk protein concentration decreased with high-oil oats versus barley and with RSC versus RSM. Feed efficiency increased with high-oil oats compared with barley. Daily CH&lt;sub&gt;4&lt;/sub&gt; emissions (g/d), CH&lt;sub&gt;4&lt;/sub&gt; yield (g/kg of DMI), and CH&lt;sub&gt;4&lt;/sub&gt; intensity (g/kg of ECM) decreased by 11.2%, 14.2%, and 15.3%, respectively, when barley was replaced with high-oil oats in combination with RSM but were not affected in combination with RSC. Daily CH&lt;sub&gt;4&lt;/sub&gt; emissions, CH&lt;sub&gt;4&lt;/sub&gt; yield, and CH&lt;sub&gt;4&lt;/sub&gt; intensity decreased by 12.5%, 10.6%, and 12.7%, respectively, when RSM was replaced with RSC in combination with barley but not in combination with high-oil oats. Daily CH&lt;sub&gt;4&lt;/sub&gt; emissions, CH&lt;sub&gt;4&lt;/sub&gt; yield, and CH&lt;sub&gt;4&lt;/sub&gt; intensity decreased by 33.5%, 30.9%, and 31.2%, respectively, with 3-NOP supplementation, with slightly greater efficacy on CH&lt;sub&gt;4&lt;/sub&gt; intensity when barley was used as the energy source. Urinary urea concentration was greater with high-oil oats than with barley, and lower with RSC than with RSM, but only in combination with high-oil oats. In conclusion, both high-oil oats and RSC are prac","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145181759","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":"Development of genomic predictions for heat tolerance in US Holstein cattle.","authors":"N Vukasinovic, M A Sánchez-Castro, D Gonzalez-Peña, A Kulkarni","doi":"10.3168/jds.2025-26818","DOIUrl":"https://doi.org/10.3168/jds.2025-26818","url":null,"abstract":"<p><p>Heat stress (HS) represents a major threat to the overall welfare and performance of dairy cows; still, genetic evaluations for heat tolerance are not available to dairy producers in the United States. Zoetis has accumulated a large amount of data suitable for genetic and genomic evaluation for heat tolerance. Therefore, the objective of this study was to develop genomic predictions for heat tolerance in US Holstein cattle using milk yield and conception at first service based on producer-recorded data coupled with publicly available weather information. Test-day (TD) milk yields and insemination records were available from 370 herds distributed across 30 states, spanning a 20-yr period (2001-2021). Weather data were extracted from the National Oceanic and Atmospheric Administration database and used to calculate the daily temperature-humidity index (THI). Productive and reproductive records from each herd were merged with the THI data from the nearest weather station. After matching, about 83 million (M) TD milk records and over 6M inseminations were available for analysis. The effect of HS was modeled using a bivariate reaction norm linear model that assumed the negative impact of HS occurred at THI ≥70. The evaluation was conducted using the single-step genomic BLUP (ssGBLUP) methodology, applying the algorithm for proven and young animals. Over 2M genotyped animals were available. The model for conception at first service (CFS) included herd-year-season (HYS) of calving, parity, breeding type, and voluntary waiting period as fixed effects, whereas the additive genetic effect, the random regression on THI for HS genetic effect, the permanent environment, and the random regression on THI for the permanent environment effect were considered random. The model for milk yield included HYS, parity, and DIM classes as fixed effects and the same random effects as described for CFS. Heritabilities of the HS genetic components varied depending on THI, ranging from 0.17 to 0.47 for milk yield and from 0.08 to 0.55 for CFS as THI increased. Genetic correlations between additive genetic and HS-influenced genetic components were -0.29 and -0.05 for milk yield and CFS, respectively. To enable running evaluation in a commercial setting with very large number of genotypes within a reasonable time, the original threshold-linear model was changed to a bivariate linear model after performing a linear transformation of CFS. Two EBVs for heat tolerance were obtained, Milk_THI (expressed as change of daily milk yield in kg) and CFS_THI (expressed as the change of probability of conception) per unit increase of THI. Milk_THI ranged from -1.3 to 1.0 kg per day and unit of THI, and CFS_THI ranged from -6.2 to 5.3 percentage points. The range of EBV for both traits suggest potential to enhance heat tolerance in Holstein cows without negatively affecting milk production or fertility.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145181771","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":"Assessment of heat stress response of peripheral blood mononuclear cells from dairy cows' stress phenotyped using bacterial lipopolysaccharide endotoxin.","authors":"Nieve Komadan, Umesh K Shandilya, Angela Canovas, Bonnie A Mallard, Niel A Karrow","doi":"10.3168/jds.2025-26825","DOIUrl":"https://doi.org/10.3168/jds.2025-26825","url":null,"abstract":"<p><p>Heat stress (HS) can affect gut barrier integrity, leading to a leaky gut and elevated enteric bacterial LPS endotoxin levels in the circulation. This LPS can induce systemic inflammation manifesting as the acute-phase response, which includes a febrile response that may compromise heat dissipation from the body during HS. To assess the effects of HS, peripheral blood mononuclear cells (PBMC) were isolated from dairy cows that were previously stress phenotyped based on their 4-h serum cortisol response to Escherichia coli LPS (200 ng/kg administered i.m.). After stress phenotyping, a population of dairy calves (n = 260), 8 high stress responder (HSR; +1 SD from the mean, >956.0 pg/mL), 11 middle stress responder (MSR; ± SD around the mean of 573.4 pg/mL), and 11 low stress responder (LSR; -1 SD from the mean, <190.8 pg/mL) stress-responding animals were selected for the study. The PBMC were later isolated and subjected to a heat shock challenge (HSC) in vitro at 42°C for 4 h then returned to 37°C where the control plates remained. Cell viability and proliferation were assessed, culture supernatants were collected to assess cytokine and chemokine secretion, and total RNA was extracted to assess candidate gene expression. There was a significant increase in the apoptosis of PBMC from the HSR and MSR, as compared with the LSR group post-HSC. However, there was a significant increase in necrosis in the LSR PBMC as compared with other groups following HSC. Proinflammatory and anti-inflammatory cytokine and chemokine production, specifically IFN-γ, IL-8, and MCP-1, was influenced by HSC and different across treatment groups. Finally, there was a significant increase in the expression of HSP90 and HSP70 genes in HSC MSR PBMC compared with the CNT MSR PBMC. Collectively, these results demonstrate that PBMC from variable stress-responding cows respond differently to the HSC. Future research is warranted to investigate if this phenotype can be used to improve the HS resilience of dairy cattle through selective breeding.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145181717","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":"Partitioning of bromoform in dairy processing.","authors":"X Sang, S Linnenkugel, A J Fletcher","doi":"10.3168/jds.2025-27313","DOIUrl":"https://doi.org/10.3168/jds.2025-27313","url":null,"abstract":"<p><p>Bromoform is a halogenated compound of growing interest due to its potential to reduce methane emissions in dairy cows. This study investigated the partitioning behavior of bromoform during the processing of raw milk that was deliberately dosed with bromoform. Through a pilot-scale study and validated analytical methods, we quantified bromoform concentrations across various product and waste streams and calculated partition coefficients to assess its distribution. Our results showed that bromoform preferentially accumulated in fat-rich matrices, with its concentration closely correlated with the fat content of most product streams. In contrast, significant reductions in bromoform levels were observed in processes involving substantial liquid/gas mass transfer, such as evaporation during powder production. The study contributes to a better understanding of contaminant behavior in dairy processing and supports the development of safer and more sustainable production practices.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145181747","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 effect of infant formula-based powder containing milk fat globule membrane on the 4-kingdom cornerstone microbiota in the feces and the immune ability of suckling rats.","authors":"Zihan Xia, Yushi Jin, Han Sun, Congcong Guo, Haiyan Xu, Longfei Zhang, Chenchen Zhang, Chengran Guan, Hengxian Qu, Yujun Huang, Wenlong Ma, Jilong Feng, Ruixia Gu, Dawei Chen","doi":"10.3168/jds.2025-27017","DOIUrl":"https://doi.org/10.3168/jds.2025-27017","url":null,"abstract":"<p><p>Growing evidence demonstrates that the 4-kingdom intestinal microbiota (FKIM) play a critical role in improving the body's immune processes. Three batches of experiments were conducted to study the effects of infant formula-based powder (IFBP) containing milk fat globule membrane (MFGM), human milk oligosaccharides, and probiotics, respectively, on the FKIM of suckling rats, with the IFBP serving as the control. Compared with the control, 3 functional components could increase the body weight and improve the composition of FKIM. Notably, the abundance and number of cornerstone species across the FKIM in the feces of suckling rats supplemented with MFGM were significantly higher than those in the other groups, and the levels of immune factors in the serum were significantly increased. After MFGM intervention, the abundance of cornerstone species of 99 genera in the feces was significantly correlated with the levels of immune factors in the serum. Among the cornerstone species, there are 11 bacteria, 6 eukaryotes, 2 archaea, and 1 virus that serve as biomarkers to distinguish the fecal microbiota of suckling rats fed with IFBP containing and not containing MFGM. Milk fat globule membrane can improve immunity by regulating functional pathways such as NOD-like receptor signaling and primary immunodeficiency. Milk fat globule membrane can stabilize the cornerstone species in the suckling rats' feces and enhance their immune ability by modulating the intestinal cornerstone species related to serum immunity, and their functional pathways, providing a theoretical basis for developing infant formula with immune-regulating functions.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145181724","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":"Genetic parameters of mid-infrared-predicted methane production and its relationship with production traits in Walloon Holstein dairy cows.","authors":"H Atashi, Y Chen, K Wijnrocx, H Soyeurt, X Hubin, N Gengler","doi":"10.3168/jds.2025-26646","DOIUrl":"https://doi.org/10.3168/jds.2025-26646","url":null,"abstract":"<p><p>Genetic selection to reduce methane production from dairy cows may be an efficient way for reducing the impact of dairy production on climate change. In this study genetic parameters and genomic regions associated with 2 commonly used daily methane features (predicted daily methane emission [PME; g/d]), and log-transformed predicted methane intensity (LMI = log [PME/milk yield (kg)]) were investigated. The PME (g/d) data, predicted using routinely recorded milk mid-infrared spectra, collected between 2007 and 2023 on 285,530 first-parity (1,920,130 test-day records), 224,643 second-parity (1,516,843 test-day records), and 160,226 third-parity (1,072,725 test-day records) Holstein cows distributed in 1,520 herds in the Walloon region of Belgium were used. Data of 565,049 SNPs, located on 29 Bos taurus autosomes (BTA), on 7,375 animals (1,798 bulls) were used. Random regression test-day models were used to estimate genetic parameters through the Bayesian Gibbs sampling method. The SNP solutions were estimated through a single-step genomic BLUP approach. The proportion of genetic variance explained by windows of 50 consecutive SNPs (with an average size of ∼212 kb) was calculated, and regions accounting for at least 1.0% of the total additive genetic variance were used to search for positional candidate genes. Mean (SD) daily PME per cow was 324.3 (66.88) g/d, 355.0 (68.75) g/d, and 367.1 (71.42) g/d, while the mean daily LMI was 2.64 (0.36), 2.61 (0.39), and 2.58 (0.40) for the first, second, and third lactation, respectively. Mean (SD) h² estimates for PME were 0.22 (0.05), 0.20 (0.05), and 0.21 (0.05) and for LMI were 0.25 (0.05), 0.23 (0.05), and 0.22 (0.05) in the first, second and third lactation, respectively. Average genetic correlations (SD) estimated between PME and LMI were 0.53 (0.04), 0.46 (0.12), and 0.43 (0.16) in the first, second, and third lactation, respectively. The genetic correlations estimated between PME and production traits, including milk yield (MY), fat percentage (FP), protein percentage (PP), milk urea concentration (MU), and SCS, ranged from -0.12 (MY) to 0.42 (FP), -0.09 (MY) to 0.47 (FP), and -0.07 (MY) to 0.43 (FP) for the first, second, and third lactations, respectively. For LMI, the estimated genetic correlations ranged from -0.89 (MY) to 0.56 (FP), -0.91 (MY) to 0.55 (FP), and -0.90 (MY) to 0.50 (FP) for the first, second, and third lactations, respectively. Genome-wide association analyses identified 4 genomic regions (BAT1 144.38-144.47 Mb and BAT14 1.52-2.15 Mb, BAT14 2.19-2.57 Mb and BAT14 2.67 - 2.98 Mb) harboring genes including the SLC37A1 (BTA1), AHARPIN, MROH1, DGAT1, FAM83H, TIGD5, MROH6, NAPRT, GML, LYPD2, and JPK (BTA14) that were associated with the studied methane features. The findings of this study help to unravel the genomic background of methane emissions and can be used for the future implementation of genomic evaluation of methane emissions in Walloon Holstein cows.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145181766","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":"Prediction and classification of metritis and mastitis in Holstein cows using transition milk spectra under different modeling strategies.","authors":"D Lin, J A A McArt","doi":"10.3168/jds.2024-26217","DOIUrl":"https://doi.org/10.3168/jds.2024-26217","url":null,"abstract":"<p><p>Metritis and mastitis are common early-lactation diseases of dairy cows that reduce milk production. Early prediction enables timely intervention and management, yet no studies have investigated the ability of milk Fourier-transform infrared (FTIR) spectroscopy for predicting the onset and development of metritis or mastitis within the first 2 wk postpartum. Our study aimed to assess the potential of milk FTIR spectra for early detection of postpartum metritis and clinical mastitis and to describe their spectral variations as lactation advances and diseases progress. Holstein cows (n = 1,103) from a commercial dairy farm in Cayuga County, New York, were monitored through 14 DIM and classified as healthy (n = 784; no adverse health events) or as diagnosed with metritis (n = 57; diagnosis of metritis but not ketosis, displaced abomasum, or clinical mastitis within 14 DIM) or clinical mastitis (n = 72; diagnosis of clinical mastitis but not ketosis, displaced abomasum, or metritis within 14 DIM). We constructed models for predicting and classifying postpartum metritis and mastitis using pooled, multiblock, and single-day partial least squares discriminant analysis (PLS-DA) strategies, assessed with repeated leave-one-out cross-validation and permutation tests. Across all modeling strategies, metritis was more distinguishable than mastitis, a pattern that corresponded with increasing fat and decreasing protein and lactose absorbance in transition milk from cows developing metritis. In the pooled strategy, models using spectra from DIM 1 to 7 achieved average area under the receiver operating characteristic curve of 79.4% for identifying metritis from healthy cows and 79.0% for distinguishing metritis from mastitis, whereas mastitis prediction reached only 60.7%. The multiblock and single-day PLS-DA models showed similarly strong performance for metritis (up to 79.2%) but failed to detect mastitis reliably. Furthermore, the added value of FTIR spectra for metritis prediction appeared contingent on sufficient sample size, as demonstrated by down-sampling experiments in the pooled strategy (with the down-sampled ratios of 80%, 60%, 40%, 20%, 10%, 5%), where models with spectral data outperformed those without only at or above 40% sampling. We conclude that transition milk FTIR spectra within the first 7 DIM showed disease-related signatures that may support early identification, although performance varied with sample size and modeling strategy, and multiherd validation is required to confirm generality and practical value.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145181691","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 phosphorus deprivation during the periparturient period on the phospholipid composition of erythrocyte membranes in dairy cows.","authors":"Klaus Eder, Sarah M Grundmann, Jos F Brouwers, Lianne M van den Brink, Imke Cohrs, Walter Grünberg","doi":"10.3168/jds.2025-27298","DOIUrl":"https://doi.org/10.3168/jds.2025-27298","url":null,"abstract":"<p><p>Previous studies have shown that insufficient phosphorus supply in dairy cows during the transition period can lead to postparturient hemoglobinuria, which is associated with the development of anemia and is presumably a consequence of increased osmotic fragility of erythrocytes. The exact causes of this condition remain unknown. The present study investigated the hypothesis that phosphorus depletion in dairy cows during the transition phase leads to changes in the phospholipid composition of the erythrocyte membrane, which may contribute to increased osmotic fragility. To test this hypothesis, an experiment with 18 healthy, multiparous, pregnant cows was conducted, in which cows received either a control diet with adequate phosphorus content (0.28% and 0.44% phosphorus in DM during the dry period and lactation, respectively, control group) or a diet with reduced phosphorus content (0.15% and 0.20% phosphorus in DM during the dry period and lactation, respectively, phosphorus depletion group) from 4 wk before expected calving until 4 wk postpartum. Blood samples were collected 2 wk before the expected calving date, as well as 1 and 4 wk postpartum. Erythrocyte membranes were isolated, and lipids were extracted for quantitative analysis of individual phospholipid species using liquid chromatography-MS. Phospholipid class contents (sphingomyelin, phosphatidylserine, phosphatidylethanolamine [PE], phosphatidylinositol, phosphatidylcholine [PC], lyso-PC, and lyso-PE) were not affected by the treatment. Similarly, the mean carbon atom chain length and the mean number of double bonds in individual phospholipids were not affected by treatment. There were very few changes of the percentages of individual phospholipid species. The time of sampling had only minimal effect on phospholipid composition and the proportions of individual phospholipid species. In conclusion, these results indicate that moderate and transient dietary phosphorus deprivation does not alter the phospholipid composition of the erythrocyte membrane. This suggests that phosphorus deprivation-induced periparturient hemoglobinuria is not caused by alterations in erythrocyte membrane lipid composition.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145181738","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}