Journal of Dairy Science最新文献

{"title":"Reducing the forage content of the ration using the undigested forage neutral detergent fiber: The effects on production, rumen environment, and digestibility.","authors":"Yoav Shaani, Jen Shpirer, Tamir Alon, Lilya Livshits, Sameer Mabjeesh, Uzi Moallem","doi":"10.3168/jds.2025-26961","DOIUrl":"https://doi.org/10.3168/jds.2025-26961","url":null,"abstract":"<p><p>Several factors influence the effectiveness of forage in ruminant rations, including NDF content and the physical nature, fragility, digestibility, and more of the forage. Recently, several studies suggested using the undigestible NDF (uNDF) fraction as a possible approach to achieve a more precise ration. The objective of the current study was to reduce the forage content of the diet by using the in vitro forage uNDF for diet formulation and to determine the effects on production, rumen environment, and digestibility. Thirty-four cows were divided into 2 groups in a crossover design study. Treatments consisted of either (1) a control (CTL) diet containing 35.8% forage (DM basis), 11.8% forage uNDF estimated through 30 h of in vitro fermentation (uNDF₃₀), and 10% forage uNDF estimated through 48 h of in vitro fermentation (uNDF₄₈) based on 20% wheat silage and 15.8% wheat hay, or (2) a low-forage (LF) diet containing 30.6% forage, 11.8% forage uNDF₃₀, and 10.4% forage uNDF₄₈ based on 20% wheat silage, 2.2% wheat hay, and 8.3% wheat straw. Each period lasted 35 d, and data collection occurred during the final 21 d. Milk yields were recorded daily, and milk samples were taken weekly. Two rumen samples were collected twice for VFA, pH, and ammonia, and 8 fecal samples were collected for total-tract digestibility measurements. No differences were observed in rumen pH, ammonia, and VFA concentrations. Apparent total-tract digestibility of DM, OM, protein, ether extracts, and NDF was higher in the CTL diet. Milk yields (52.2 and 51.7 kg/d, respectively), 4% FCM, and ECM yields were higher in the CTL than in the LF treatment. The milk fat and protein content did not differ, the milk fat tended to be higher, and the milk protein yield was higher in the CTL treatment. The DMI was 3.2% higher in the CTL than in the LF treatment (32.7 vs. 31.7 kg/d, respectively), and the milk-to-DMI ratio was higher in the LF than in the CTL treatment. In summary, reducing the forage content by balancing the diet for forage uNDF reduced the DMI, milk, fat, and protein yields and digestibility, probably due to the high inclusion rate of wheat straw in the LF diet. However, the production efficiency of milk was higher in the LF treatment. Further research is required to fine-tune the proportion of forage uNDF and to determine the optimal exchange of forage feedstuffs in the diet.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145005770","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":"Modeling feed herbage proportion and modeling of the likelihood of feeding strategies focused on grazing and herbage consumption using milk FT-MIR spectral analysis.","authors":"Killian Dichou, Charles Nickmilder, Gérard Conter, Romain Reding, Antonino Marvuglia, Hélène Soyeurt","doi":"10.3168/jds.2025-26794","DOIUrl":"https://doi.org/10.3168/jds.2025-26794","url":null,"abstract":"<p><p>Effectively evaluating and promoting pro-grazing practices necessitates the implementation of a verification system. To address this imperative, exploration of milk composition analysis as a means to assess grazing practices has garnered substantial attention. In this study, we used component predictions from milk Fourier-transform mid-infrared (FT-MIR) spectra to construct an indicator to estimate the proportion of herbage consumed by dairy cows and another indicator to validate grazing. This approach was developed and validated using 75 estimated bulk milk analyses, each associated with 3 variables related to feeding from the same day ± 3 d, totaling 526 observations. These 3 variables are based on the occupation time, harvested and conserved herbage, and other feeds from 7 farms in Luxembourg. Hierarchical clustering facilitated the effective segregation of observations into distinct groups, with one group predominantly focused on herbage and the other group on other feeds. Leveraging partial least squares discriminant analysis trained on FT-MIR predicted milk characteristics from both groups, we successfully developed an indicator-the probability of belonging to the herbage group-with a maximum accuracy of 0.93, a sensitivity of 0.94, and a specificity of 0.93 on the Luxembourg dataset. In a partial least squares regression, the cross-validation yielded results of predicting the percentage of herbage in the diet with an error of 8.77%. Notably, the indicator relied on FT-MIR predicted components expected to reflect a diet based on herbage, such as the total of C18:1 trans fatty acids and CLA. However, it also incorporated unexpected FT-MIR predicted parameters like milk acidity parameters, citrate content, and specific proteins such as lactoferrin. Finally, the developed indicators were tested on the 5,886,364 Walloon spectra collected between 2009 and 2023, as well as 23,718 Walloon spectra between 2023 and 2025 from 72 farms known to practice grazing. The annual trends were analyzed in the context of Walloon dairy production, helping to refine the selection of better indicators. These results could contribute to practical tools for monitoring and estimating days spent on pasture. Looking ahead, future research should aim to incorporate more comprehensive data, such as precise feed compositions, to further refine our understanding of the influence of specific herbage diets on milk composition and enhance the detection of associated changes.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145005777","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 close-up dietary energy content and rumen-protected lysine and methionine fed pre- and postpartum on performance and health of Holstein cows.","authors":"E S O'Meara, D M Del Olmo, J M Aguado, J K Drackley, F C Cardoso","doi":"10.3168/jds.2025-26692","DOIUrl":"https://doi.org/10.3168/jds.2025-26692","url":null,"abstract":"<p><p>This experiment was conducted to determine the effects of feeding rumen-protected Met (RPM; KESSENT M, Kemin Industries Inc., Des Moines, IA) and rumen-protected Lys (RPL; LysiGEM, Kemin Industries Inc., Des Moines, IA) prepartum at the same AA-to-ME ratio (3.21 g/Mcal of Lys and 1.21 g/Mcal of Met) with different concentrations of NEL on the performance of dairy cows. Sixty-two multiparous Holstein cows were assigned to 1 of 3 dietary treatments in a randomized, complete block design. Prepartum (-21 d to expected calving), cows were fed a controlled-energy (CE) diet (wheat straw based diet, 1.45 NEL[2.33 ME] Mcal/kg of DM] with RPL and RPM (CEAA; 0.15% RPL and 0.09% RPM of dietary DMI), CE diet without RPL and RPM (control; CENAA), or high-energy (HE) diet (corn silage-based diet, 1.71 NEL[2.70 ME], Mcal/kg of DM] with RPL and RPM (HEAA; RPL 0.22% and RPM 0.12% of dietary DMI). Postpartum, cows received the same lactation TMR (1.73 NEL[2.71 ME] Mcal/kg of DM) without RPL and RPM (CENAA, n = 19) or with RPL and RPM (CEAA, n = 21; and HEAA, n = 21; 0.38% RPL and 0.15% RPM of dietary DMI) until 70 DIM. Cows were milked twice daily, and milk samples were taken once a week from d 2 to 70 DIM. Milk yield and DMI were recorded daily. Blood samples were taken on -7 ± 4.7, 28 ± 1.6, and 70 ± 2.1 DIM. Two treatment contrasts (CENAA vs. CEAA and CEAA vs. HEAA) were compared. Cows in HEAA had higher ECM (50.5 ± 1.77 kg/d) and tended to have greater fat yield (2.04 ± 0.09 kg/d) and BCS loss (-0.71 ± 0.14) during wk 1 to 4 of lactation than cows in CEAA (45.7 kg/d, 1.82 kg/d, and -0.36, respectively). Cows in CEAA tended to have a higher protein proportion in milk (3.43% ± 0.07%) than cows in CENAA (3.26% ± 0.07%) and cows in HEAA (3.24% ± 0.07%) during wk 1 to 4 of lactation. Cows in CEAA had higher milk protein proportion (2.89% ± 0.05%) than cows in CENAA (2.72% ± 0.05%) during wk 5 to 10. Plasma Met concentrations prepartum were greater for cows in CEAA (24.7 ± 1.65 µM) than cows in CENAA (19.8 ± 1.65 µM). Cows in CEAA had higher plasma Lys (81.1 ± 3.35 µM) and Met (39.5 ± 2.04 µM) concentrations postpartum than cows in CENAA (71.5 ± 3.35 µM and 19.5 ± 2.04 µM, respectively). In conclusion, feeding a HE diet may have negatively affected the cows' body composition compared with cows fed a CE diet when both diets were formulated at 3.21 g/Mcal of Lys and 1.21 g/Mcal of Met, whereas, feeding RPL and RPM prepartum improved cows' performance compared with cows that were not fed RPL and RPM.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145005765","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":"Integrative blood transcriptomic and metabolomic profiling reveals biomarkers of natural heat tolerance in Holstein cows.","authors":"Mingxun Li, Zhiwei Wang, Liangying Zhu, Yangyang Wang, Lei Zhang, Haoran Jia, Zhangping Yang, Niel A Karrow, Yongjiang Mao","doi":"10.3168/jds.2025-26997","DOIUrl":"https://doi.org/10.3168/jds.2025-26997","url":null,"abstract":"<p><p>Heat stress poses a major threat to dairy cattle productivity, particularly in high-producing Holstein cows. To identify robust biomarkers of thermotolerance, we employed an integrative strategy combining physiological phenotyping, blood metabolite profiling, and transcriptomic analysis. A total of 120 lactating Holstein cows were evaluated under natural summer heat conditions using rectal temperature, respiratory rate, salivation index, serum HSP70, cortisol, potassium levels, and milk production. These 7 indicators were weighted via an entropy-based Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) model to classify heat-resistant (HR) and heat-sensitive (HS) individuals. Subsequent transcriptomic analysis identified 330 differentially expressed genes (DEG), with PDGFRA upregulated and TIMP3 and CCL5 downregulated in HR cows, suggesting reduced inflammation and extracellular matrix stress. Untargeted metabolomics revealed 220 differentially expressed metabolites, with HR cows exhibiting lower levels of anti-inflammatory compounds such as 6-gingerol and PIP (18:1), and higher levels of inflammatory lipids. Two plasma metabolites, 3-methoxytyramine and (3Z)-phytochromobilin, showed strong discriminative power for thermotolerance (area under the curve >0.88). Multi-omics integration uncovered 411 significant gene-metabolite correlations enriched in heat-related pathways, including sphingolipid signaling and arachidonic acid metabolism. The identified biomarkers demonstrated their utility for rapid, noninvasive screening of heat-tolerant cows. These findings provide novel insights into the molecular mechanisms of heat resilience and offer a foundation for biomarker-assisted selection in climate-resilient dairy breeding.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145005707","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":"Efficient implementation of multitrait random regression test-day models with external information for dairy cattle genomic evaluations.","authors":"A Álvarez-Múnera, M Bermann, I Aguilar, J Bauer, J Šplíchal, I Misztal, D Lourenco","doi":"10.3168/jds.2025-26387","DOIUrl":"https://doi.org/10.3168/jds.2025-26387","url":null,"abstract":"<p><p>Random regression models (RRM) combined with single-step genomic best linear unbiased prediction (ssGBLUP) are widely used for genomic evaluations in dairy cattle. This study aimed to efficiently implement RRM with ssGBLUP for national dairy cattle evaluations. Data from the Czech Holstein population were used, including 30 million test-day records for milk yield across 3 lactations. The pedigree included 2.5 million animals, of which 54,000 were genotyped. To enhance model convergence, we used a reduced number of genetic groups by combining groups with few records, and treated them as random. Additionally, the algorithm for proven and young (APY) was applied. Mixed model equations were solved by the preconditioned conjugate gradient method using iteration on data. External information from Interbull was included as deregressed proofs (DRP) of cumulative 305-d multicountry evaluation approach (MACE) breeding values and weighted by effective record contributions (ERC). Reliabilities of 305-d GEBV combined the reliability of the average of cumulative 305-d GEBV across the 3 lactations without genomic information and the reliability from a genomic BLUP model in terms of ERC. The linear regression method was used to validate EBV and genomic EBV (GEBV) of average 305-d milk yield across lactations. For that, 2 datasets for test-day records from the first 3 lactations were used: a complete dataset containing records up to 2023, and a partial dataset cut off in 2018. All models successfully achieved convergence. The validation revealed bias close to zero, with dispersion ranging from 0.97 to 0.99, correlation between complete and partial (G)EBV between 0.95 and 0.98, and validation reliability ranging from 0.77 to 0.94. Applying APY resulted in a 10-fold increase in speed compared with ssGBLUP. The correlation between MACE reliabilities and national reliabilities increased by 3% and 2% from pre-integration to post-integration for BLUP and ssGBLUP, respectively. Our results demonstrate that the application of ssGBLUP to a multitrait RRM while integrating external MACE information is feasible and results in a highly efficient genomic evaluation system, with GEBV with desirable validation statistics.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145005725","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":"Comparing carbon dioxide, oxygen, and methane exchanges, and heat production measured using GreenFeed and respiration chambers.","authors":"Ali-Reza Bayat, Päivi Mäntysaari, Tomasz Stefański, Enyew Negussie, Martin Lidauer, Pekka Huhtanen","doi":"10.3168/jds.2025-26682","DOIUrl":"https://doi.org/10.3168/jds.2025-26682","url":null,"abstract":"<p><p>The aim of this study was to evaluate the precision and accuracy of GreenFeed (GF) Emission Monitoring system in measuring O₂, CO₂, and CH₄ exchanges, and heat production (HP) when compared with respiration chambers (RC). Thirty-two lactating Nordic Red cows (634 ± 60.4 kg BW, 145 ± 63.1 DIM, 28.9 ± 6.7 kg milk/d, and parity 1.6 ± 1.16) allocated to 8 blocks based on BW, milk yield, DIM, and parity were used to compare CO₂, O₂, and CH₄ exchanges measured by GF units (n = 2) versus RC (n = 4) in a switch-back design. The experimental period for every block was 5 wk; the cows were measured by GF during 2 wk, the third wk in RC, and another 2 wk by GF. The cows were fed a grass silage-based diet with constant forage-to-concentrate ratio for each cow during the study, ranging from 42:58 to 67:33, depending on their milk production at the beginning of study. For GF data, the records outside of the range of mean ± 2.5 × SD of all measurements over 4 wk for each cow were identified as outliers. Altogether, 214 out of 3,115 data points were removed as the outliers. Average CO₂, O₂, and CH₄ exchanges, and HP in addition to their SD measured by GF during 4-wk periods (12,778 ± 1,137, 8,795 ± 773, 462 ± 57 g/d, and 131 ± 11 MJ/d) were close to those measured by RC (13,103 ± 1,421, 8,817 ± 941, and 453 ± 56 g/d, and 132 ± 14 MJ/d), respectively. Repeatability of O₂, CO₂, and CH₄ exchanges, and HP for GF was 0.88, 0.88, 0.82, and 0.88, respectively, when calculated based on the averages of 2-wk periods. Accuracy of 0.90 was achieved in 6, 8, and 12 d for O₂, CO₂, and CH₄, respectively. Based on mixed model linear regression analysis, GF (averages of 4-wk data) estimated O₂ exchanges of cows with a strong relationship with RC data (averages of 3-d; R² = 0.89, root mean square prediction error [RMSPE] = 3.1% of mean, concordance correlation coefficient [CCC] = 0.94), followed by CO₂ (R² = 0.84, RMSPE = 3.5% of mean, CCC = 0.88) and CH₄ (R² = 0.79, RMSPE = 4.6% of mean, CCC = 0.87). Heat production estimated by GF was strongly related to the estimations made by RC (R² = 0.88, RMSPE = 3.2% of mean, CCC = 0.93). The intercept and slope were not biased for O₂, CO₂, and HP, whereas for CH₄, intercept and slope were greater than 0 and less than 1, respectively. Therefore, GF can be used as an alternative to measure respiration gas exchanges and HP of dairy cows, which paves the way for large-scale measurements of energy metabolism and feed efficiency.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145005797","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":"Feeding strategies during fresh cow period in pasture-based dairy systems: Metabolic adaptation to lactation and resumption of ovarian cyclicity in primiparous and multiparous cows.","authors":"Graciana R Mendina, María de Lourdes Adrien, Catalina Rivoir, Andrés López-Radcenco, Guillermo Moyna, Pablo Chilibroste, Ana Meikle","doi":"10.3168/jds.2025-26923","DOIUrl":"https://doi.org/10.3168/jds.2025-26923","url":null,"abstract":"<p><p>The study aimed to determine whether confinement with TMR during the first 21 DIM, followed by grazing supplemented with partial mixed ration (PMR), alleviates negative energy balance, enhancing productive performance and accelerating the resumption of ovarian cyclicity in primiparous and multiparous dairy cows, relative to a control group managed on grazing supplemented with PMR after calving. Following calving, 16 primiparous and 24 multiparous Holstein dairy cows were blocked and randomly distributed into 2 treatments: one included grazing plus supplementation with PMR after calving (T0), while the other one involved confinement with TMR ad libitum during the first 21 DIM and the same feeding management of T0 from d 22 onwards until 60 DIM (T21). Primiparous cows showed no significant differences between treatments in milk production. However, T21 primiparous cows displayed lower nonesterified fatty acids (NEFA), greater glucose, and greater insulin and IGF-1 concentrations compared with T0 primiparous cows during the 21 DIM of the feeding management. In contrast, multiparous T21 cows achieved greater milk production during the first 21 DIM, with no differences in NEFA and BHB levels but greater insulin and IGF-I concentrations than multiparous T0 cows. Both parity groups in T21 underwent an extra metabolic adaptation following the management change at 22 DIM, increasing NEFA and BHB concentrations and decreasing milk production during this period. Despite the improved endocrine-metabolic profile observed in T21 during the first days postpartum, no differences were found in the resumption of ovarian cyclicity, which was shorter in multiparous than primiparous cows. Untargeted metabolomics supported evidence that primiparous cows grazing from calving had greater lipid and muscle mobilization than other groups, reflected by lower glucose and greater creatinine, dimethylglycine, and formate. Strategic feeding management during the fresh cow period affects the metabolic adaptation to lactation, but milk production responses were observed only in multiparous cows, reflecting parity-specific homeorhetic priorities.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145005736","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 dietary starch concentration and direct-fed microbial supplementation on lactation performance, total-tract nutrient digestibility, and enteric methane emissions by dairy cows.","authors":"Karissa A Juckem, Matheus R Pupo, E Cole Diepersloot, Luiz F Ferraretto","doi":"10.3168/jds.2025-26694","DOIUrl":"https://doi.org/10.3168/jds.2025-26694","url":null,"abstract":"<p><p>The objective of this experiment was to evaluate the effects of dietary starch concentration by replacing high-moisture corn with soy hulls and a direct-fed microbial (DFM) containing Bacillus subtilis 810 and Bacillus licheniformis 809 on the lactation performance, feeding behavior, total-tract nutrient digestibility, and enteric CH₄ emissions of dairy cows. Sixty-four multiparous Holstein cows (67 ± 24 DIM and 729 ± 60 kg of BW at the beginning of the covariate period) were randomly assigned to 1 of 4 treatments with a 2 × 2 factorial arrangement for a 12-wk treatment period, after a 1-wk acclimation period and 2-wk covariate period. Treatments consisted of diets with 21% starch and no DFM (RS-CON), 21% starch and DFM (RS-DFM), 27% starch and no DFM (NS-CON), and 27% starch and DFM (NS-DFM). Data were analyzed as a completely randomized design using a mixed model including a covariate and dietary starch, DFM supplementation, week, and their 2- and 3-way interactions as fixed effects. Cow within treatment was a random effect. Diets with 21% starch increased DMI and milk fat concentration but decreased feed efficiency. Cows fed DFM tended to have greater lactose concentration than those not fed DFM (CON). Milk yield and milk protein concentration did not differ. The eating rate was lower and meal length was greater for DFM than CON. Cows fed 27% starch had a lower eating time, meal length, intervals between meals, and smaller meal sizes than 21% starch diets. Meal frequency increased with greater starch. Diets with 27% starch reduced CH₄ emissions and intensity and tended to reduce CH₄ yield. Digestibility of DM, OM, CP, ether extract, and NDF was greater for DFM than CON diets. The replacement of high-moisture corn with soy hulls increased milk fat concentration but not milk yield. Diets with 27% starch decreased CH₄ production and improved feed efficiency compared with 21% starch diets. Additionally, feeding cows DFM improved total-tract nutrient digestibility compared with CON.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145005741","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":"Clostridium tyrobutyricum strains exhibit high genetic diversity and differ in their ability to cause late blowing defect in washed-curd cheese.","authors":"Aljoša Trmčić, Lucija Prinčič, Magdalena Pajor, Andre P Kalenak, Samuel J Reichler, Renato H Orsi, Nicole H Martin, Martin Wiedmann","doi":"10.3168/jds.2025-26686","DOIUrl":"https://doi.org/10.3168/jds.2025-26686","url":null,"abstract":"<p><p>Clostridium tyrobutyricum is a spore-forming bacterium and is considered to be one of the main causative agents of late blowing defect (LBD) of hard and semi-hard cheeses. However, the spoilage potential of C. tyrobutyricum appears to be strain dependent. Because previous studies have been mostly limited to laboratory liquid media or experimental food models imitating cheese matrix, we (1) characterized 6 strains of C. tyrobutyricum for their ability to cause LBD in washed-curd cheese aged at 8°C and 15°C, and (2) probed the whole-genome data for the genetic markers linked to LBD. Washed-curd cheeses were made with pasteurized cow milk individually inoculated with different C. tyrobutyricum strains. During cheese aging at 8°C, none of the 6 evaluated strains caused changes in cheese consistent with LBD (i.e., accumulation of gas, formation of cracks, and production of butyric acid). Three of the 6 tested strains were, however, able to cause LBD at 15°C; the remaining 3 C. tyrobutyricum strains showed little or no gas and butyric acid production during 160 d aging at 15°C. All 6 strains were additionally evaluated in 3 separate experiments performed in 2 different liquid media (reinforced clostridial medium and enriched milk medium) to determine germination, growth, and gas formation at temperatures between 8°C and 37°C, and pH values between 6.9 and 4.1. All 6 evaluated strains were able to grow and form gas in a liquid medium in at least one replicate at temperatures and pH values as low as 12.5°C and 5.1, respectively. Comparative genomics showed that the 6 strains exhibit high genetic diversity, without specific genetic features that would explain the observed differences in the ability to cause LBD in washed-curd cheese. Future studies would need to compare a larger set of C. tyrobutyricum strains with demonstrated ability or inability to cause LBD in cheese. This ability to cause LBD will most likely have to be determined in actual cheese experiments, as our results show that growth and gas formation in liquid medium models are not always representative of growth and gas formation in cheese.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145005784","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":"Gestation length, calf birth weight, calving difficulty, perinatal mortality, and calf health following timed artificial insemination or embryo transfer with fresh or frozen in vitro-produced embryos.","authors":"A D Crowe, R C Doyle, P Lonergan, S T Butler","doi":"10.3168/jds.2025-26958","DOIUrl":"https://doi.org/10.3168/jds.2025-26958","url":null,"abstract":"<p><p>The aim of this study was to determine the effect of embryo origin (artificial insemination [AI] vs. in vitro embryo production [IVP]), calf breed, and calf sex on gestation length (GL), birthweight (BiW), calving difficulty (CD) score and perinatal mortality. Lactating dairy cows (n = 1,106) were randomly assigned to be bred by timed AI (frozen-thawed semen) or timed embryo transfer (ET) with fresh or frozen IVP dairy (Holstein Friesian [HF] or Jersey [JE]) or beef breed (Angus, [ANG] or Limousin [LM]) embryos. Data were subsequently obtained from 442 calves derived from these breeding events. For all births, CD was scored on a scale of 1 to 4 (1 = unassisted, 2 = minor assistance, 3 = considerable difficulty or 4 = veterinary assistance or cesarean). Additional measurements were completed on subsets of calves. For 281 calves, weight was recorded immediately after birth. For 108 of these calves, blood samples were collected at birth for biochemical and hematological analysis. For 126 calves, blood samples were also collected 24 h after birth to measure serum IgG concentration to assess passive transfer of immunity. The effects of the independent variables (embryo origin, calf breed and sex) on GL, BiW, CD score and perinatal mortality, and the association between these dependent variables were examined using generalized linear mixed models. Overall, GL (mean days, 95% CI) was shorter for calves derived from AI (278.9; 277.0, 280.8) compared with calves derived from ET-fresh (281.8; 279.8, 283.7) and ET-frozen (282.0; 280.0, 284). Within the population of HF calves (n = 159), BiW (mean kg, 95% CI) was lighter for calves derived from AI (34.7 kg; 33.3, 36.2) compared with ET-fresh (39.7 kg; 37.8, 41.7) and ET-frozen (38.5 kg; 36.6, 40.6). Among calves derived from ET, breed affected GL, BiW, and CD: calves that were sired by the LM bull had a longer GL (290.9 d) than AA (282.0 d), HF (280.5 d), and JE calves (282.0 d). Angus calves were heavier (fresh: 46.3 kg; 44.5, 48.2, frozen: 43.5 kg; 41.6, 45.4) than both HF (fresh: 39.7 kg; 37.8, 41.7, frozen: 38.5 kg; 36.6, 40.6) and JE calves (fresh: 30.8 kg; 29.0, 32.7, frozen: 28.8 kg; 26.5, 31.2). Angus calves derived from ET-fresh had greater CD score than HF calves derived from both AI and ET-fresh. Results of biochemical and hematological analyses were within the normal range for healthy calves and concentrations were only affected by breed in a few of the variables measured. Embryo origin did not affect passive transfer of serum IgG from maternal colostrum to calf circulation. In conclusion, dairy breed calves derived from IVP-ET had similar incidence of CD as dairy breed calves derived from AI, but the incidence of CD was greater for beef breed calves derived from IVP-ET. In general, neonatal calf blood measurements were not affected by calf origin (AI or ET), and all treatments had comparable incidence of perinatal mortality.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144937938","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}