Journal of Dairy Science最新文献

{"title":"A comparative analysis of dairy production systems: Milk production tiers and their impact on dairy calf and heifer cost of production in Brazil.","authors":"L H R Silva, A L Silva, M I Marcondes, C S Bittencourt, J V C Rodrigues, W P F Amorim, E P Lima Netto, T E Silva, J H C Costa, P P Rotta","doi":"10.3168/jds.2025-26579","DOIUrl":"https://doi.org/10.3168/jds.2025-26579","url":null,"abstract":"<p><p>The objective of this study was to estimate the costs associated with raising dairy calves and heifers in Brazil during 2021. Additionally, it sought to determine the average number of lactations that heifers should remain in the herd to cover their production costs, analyzing data from 311 dairy farms in Minas Gerais. These farms were categorized into 3 milk productive tiers based on daily milk production per cow: lower production tier (LOW) 12.0 L/cow per day (7.4-14.5 L/cow per day); intermediate production tier (INT) 18.0 L/cow per day (14.6-22.5 L/cow per day), and upper production tier (UPP) 26.7 L/cow per day (22.6-32.0 L/cow per day). Mean comparisons were performed using the GLIMMIX procedure of SAS. The main cost factors were feed, labor, and machinery, which together accounted for 83.0%, 85.0%, and 83.0% of the total costs for LOW, INT, and UPP tiers, respectively. The cost of raising a heifer from birth to calving tended to be lower for INT tier ($1,821.40 ± $44.35) and higher for LOW tier ($2,006.40 ± $62.52), whereas UPP tier had a cost of $1,884.60 ± $62.52, which was similar to both LOW and INT tiers. To cover their production costs, the average number of lactations that cows should remain in the herd was 3.98 (1.33-9.33) lactations for the LOW tier, 2.64 (1.33-6.33) lactations for the INT tier, and 1.64 (0.66-3.66) lactations for the UPP tier. Dairy farms with lower production have higher costs for rearing calves and heifers due to prolonged development and delayed age at first calving, largely due to less efficient growth, feeding and reproduction methods. Feed was the main cost, followed by labor and machinery. Improving genetics and management or purchasing better genetic animals can reduce costs and increase productivity, especially on farms with limited resources.</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":"145181768","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":"Describing the decision-making process of Ontario dairy farmers when managing down dairy cattle: A qualitative focus group study.","authors":"John E Brindle, Michael W Brunt, David L Renaud, Derek B Haley, Todd F Duffield, Charlotte B Winder","doi":"10.3168/jds.2025-26939","DOIUrl":"https://doi.org/10.3168/jds.2025-26939","url":null,"abstract":"<p><p>The objective of this study was to investigate Ontario dairy farmers' attitudes and perceptions toward down dairy cows, and the barriers and motivators influencing the use of best management practices. Four focus groups were conducted in southwestern Ontario in 2024, with a total of 21 dairy producers participating. Producers were asked about current practices, thoughts on best management practices, challenges to adopting best practices, and facilities and equipment for down cow care. The focus groups were audio recorded, transcribed, and analyzed using applied thematic analysis. Five themes were identified from the data: adaptive and flexible management strategies; farm resources and facilities; veterinary relationships and communication; producer experience and emotional impact; and animal-centered decision-making. Producers emphasized a balance between proactive, long-term strategies, such as prevention, record-keeping, and research-driven improvements, and the need for flexible, real-time decision-making to address the unpredictable nature of down cows. Facility design, labor availability, financial constraints, and veterinary collaboration played important roles in the care they provided to down cows. Further, producers highlighted the emotional burden of making euthanasia decisions and discussed the balance of animal welfare and economic sustainability. Producers also expressed a need for more research, better diagnostic tools, and practical on-farm solutions to improve down cow management. Addressing these challenges requires coordinated efforts that integrate practical tools, infrastructure improvements, producer education, and veterinary support systems. The interplay of these factors underscores the need for a holistic approach to support producers in navigating the multifaceted challenges they face in their daily work. This study contributes to understanding the multidimensional factors influencing dairy producers' management practices in caring for down dairy 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":"145181742","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":"Optimizing early lactation performance in dairy cows through co-supplementation of rumen-protected methionine and omega-3-enriched calcium salts.","authors":"T L France, K S Juarez-Leon, A Javaid, M G Vogellus, D C Reyes, J W McFadden","doi":"10.3168/jds.2025-27297","DOIUrl":"https://doi.org/10.3168/jds.2025-27297","url":null,"abstract":"<p><p>Supplementing rumen-protected Met (RP-Met) during the transition period has been shown to improve DMI and increase milk production in dairy cows. Omega-3 fatty acids (FA), particularly eicosapentaenoic acid (EPA; C20:5) and docosahexaenoic acid (DHA; C22:6), are known to support immune function in nonruminants, but their effects in dairy cows remain less defined. We aimed to investigate the combined effects of RP-Met and calcium salts (CS) of FA enriched with EPA and DHA on lactation performance in periparturient Holstein cows. Seventy-nine multiparous cows were enrolled in a randomized complete block design and assigned to 1 of 4 dietary treatments (n = 18 to 19 per treatment) from 3 wk before (-21 ± 3 d) to 3 wk after calving as follows: (1) no RP-Met and CS without n-3 FA (-Met/-n3FA; CS contained 56.0% saturated FA, 35.2% oleic acid, and 8.10% linoleic acid), (2) RP-Met with CS without n-3 FA (+Met/-n3FA), (3) no RP-Met with CS enriched in n-3 FA (-Met/+n3FA; CS contained 64.5% SFA, 25.4% oleic acid, 5.10% linoleic acid, 0.60% linolenic acid, 2.60% EPA and 1.40% DHA), or 4) RP-Met and CS enriched in n-3 FA (+Met/+n3FA). All cows were fed a corn silage-based TMR pre- and postpartum. Diets were formulated to provide either ≤0.96 g Met/Mcal of ME (-Met) or ≥1.13 g Met/Mcal of ME (+Met). Calcium salts were included at 1.5% of dietary DM across all diets. Prepartum DMI, BW, and BCS were unaffected by treatment. The main effect of treatment (supplemental Met and n-3 FA) increased postpartum DMI, Met (25.2 vs. 20.1 g/d Met prepartum and 59.9 vs. 35.9 g/d Met postpartum for +Met and -Met diets, respectively) and n-3 FA intakes (1.36 vs. 0 g/d EPA and DHA prepartum and 6.61 vs. 0 g/d EPA and DHA postpartum for +n3FA and -n3FA diets, respectively). Co-supplementation increased ECM, and FCM yields, and milk fat and true protein yields, and tended to increase milk yield, relative to diets containing only RP-Met or only n-3 FA. Cows co-supplemented with RP-Met and CS enriched in n-3 FA had marginally higher plasma glucose and lower plasma triglyceride concentrations at calving, and reduced plasma total and nonessential AA concentrations during lactation. Nutrient-specific responses included increased plasma Met in cows fed +Met diets and elevated milk lactose contents and yields, along with higher n-3 FA and PUFA contents and yields in cows fed CS enriched in n-3 FA. The additive effects of co-supplementation suggest potential synergy when cows are fed Met, EPA, and DHA. Although the underlying mechanisms were not fully elucidated, the observed improvements may be linked to enhanced mammary de novo FA synthesis, altered AA utilization, and increased hepatic gluconeogenesis, collectively supporting improved metabolic function and lactation performance in early lactation dairy 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":"145181733","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":"Social housing for dairy calves: Farmer acceptance of Canadian industry-led requirements.","authors":"Katherine E Koralesky, Taylor Dyck, Christine Kuo, Marina A G von Keyserlingk, Daniel M Weary","doi":"10.3168/jds.2025-26881","DOIUrl":"https://doi.org/10.3168/jds.2025-26881","url":null,"abstract":"<p><p>Research suggests that housing milk-fed calves in pairs or small groups from a young age can provide welfare benefits, leading some policymakers to encourage dairy farmers to adopt this practice. For example, Canada's industry-led Code of Practice for the Care and Handling of Dairy Cattle requires social housing for indoor-housed calves, starting in 2031. We assessed acceptance of social housing and this new Code requirement by conducting 23 interviews with 13 farmers in Alberta and British Columbia, Canada. Interview questions were designed to evaluate 8 constructs (affective attitude, burden, ethicality, opportunity costs, perceived effectiveness, self-efficacy, and trust in the Canadian Dairy Code development process) derived from the \"Theoretical Framework of Acceptance.\" Participant acceptance varied, with some appreciating the benefits of social housing, and others citing concerns about the need for the requirement. Farmers generally thought they would be able to adopt social housing. Most participants prioritized concerns about calf health, but also considered calf socialization beneficial. However, some farmers also expressed frustration with the new Canadian Dairy Code requirement and did not feel their interests were represented in the Code development process. These findings highlight the need to address farmer concerns with new policies and practices, for example, through events that support farmers and their advisers to share successful approaches to implementation. Further research is required to better understand farmer views on representation in the development of policies that govern on-farm practices.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145102561","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":"High Fischer ratio oligopeptide-fortified goat milk: A dual efficacy study on enhancing protein nutritional value and improving functional characteristics.","authors":"Junnan Wan, Xiaoxue Fan, Haiying Tao, Kaisheng Zhang, Cunfang Wang, Yanbo Luo","doi":"10.3168/jds.2025-27291","DOIUrl":"https://doi.org/10.3168/jds.2025-27291","url":null,"abstract":"<p><p>Functional dairy products represent a substantial area of interest, but the market offers a limited variety of products enriched with oligopeptides. This study focused on the incorporation of high Fischer ratio oligopeptide (HFO) derived from whey protein into goat milk using ultrasonic-assisted pasteurization. A comprehensive examination was conducted to assess the impact of the oligopeptide on the physicochemical properties, stability, and functional characteristics of goat milk. This analysis encompassed the evaluation of protein composition and content, antioxidant capacity, and various other functional attributes. The results revealed that HFO addition significantly increased both protein and whey protein content, enhancing nutritional value. Moreover, HFO fortification notably improved antioxidant activity, foamability, and emulsification properties. Although HFO incorporation elevated viscosity and particle size and reduced the absolute zeta potential, it minimally affected the distribution of fat globules. Storage stability studies indicated that HFO supplementation contributed to extending the shelf life of pasteurized milk. This study demonstrates the dual functionality of HFO in enhancing the nutritional profile and improving the techno-functional properties of goat milk. These findings offer valuable insights for advancing the production of functional goat milk products using oligopeptides as bioactive ingredients or specialized foods for medical purposes.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145102588","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 voluntary waiting period length on milk yield, fertility, and culling in high-yielding, second-parity cows.","authors":"A Hansson, K Holtenius, R Båge, M Lindberg, C Kronqvist","doi":"10.3168/jds.2025-26348","DOIUrl":"https://doi.org/10.3168/jds.2025-26348","url":null,"abstract":"<p><p>The substantial increase in milk yield capacity in modern dairy herds has led to growing interest in extending the voluntary waiting period, the time from calving to first insemination, as a strategy to prolong the calving interval. However, the effects of an extended voluntary waiting period on fertility and milk production vary, particularly between primiparous and multiparous cows. This study evaluated the effect of an extended voluntary waiting period, compared with a conventional one, on fertility, milk production, and culling in second-parity cows from 12 high-yielding commercial herds. Cows were distributed, based on odd or even ear tag numbers, and allocated into either a 50- or 140-d voluntary waiting period. Data including calving records, fertility metrics, monthly milk yields, and culling rates were collected from the Swedish official milk recording scheme. Out of 819 cows enrolled, 590 completed a third calving. The protocol extended the interval from calving to first insemination by 60 d, which resulted in a 46-d increase in the calving interval (12.5 mo vs. 14.0 mo). Daily milk yields did not differ between groups and averaged 34 kg ECM per day between 2 consecutive calvings and 40 kg ECM per lactating day. Although average milk yield at the last test milking before dry-off tended to be lower in cows with an extended voluntary waiting period compared with those on a conventional one (LSM 32.5 ± 0.96 kg ECM vs. 33.7 ± 1.01 kg ECM), dry period length remained unaffected. Total milk yield in the first 100 d of the third lactation did not differ between treatments. Fertility outcomes were improved in the extended voluntary waiting period group compared with the conventional group, as indicated by a higher pregnancy proportion at first service (LSM 0.62 ± 0.050 vs. 0.46 ± 0.046), fewer inseminations per born calf (LSM 1.61 ± 0.131 vs. 2.02 ± 0.137), and shorter insemination period (LSM 20.8 ± 4.8 d vs. 35.6 ± 4.3 d). The voluntary waiting period did not influence culling rates. These findings indicate that a voluntary waiting period of 140 d may be a viable alternative to the conventional 50-d duration, without compromising milk production and fertility in second-parity cows from high-yielding herds.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145102619","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":"Genotype imputation accuracy of X chromosome variants in Holstein cattle based on different software and imputation strategies.","authors":"Tatiana C de Souza, Luis F B Pinto, Valdecy A R da Cruz, Tatiane S Chud, Victor B Pedrosa, Gerson A O Junior, Hinayah R de Oliveira, Henrique A Mulim, Filippo Miglior, Flávio S Schenkel, Luiz F Brito","doi":"10.3168/jds.2025-26715","DOIUrl":"https://doi.org/10.3168/jds.2025-26715","url":null,"abstract":"<p><p>The X chromosome is one of the largest in the cattle genome, but little is known about the imputation of X chromosome variants. Thus, the main objective of this study was to assess the imputation accuracy of SNPs located in the X chromosome based on different strategies. Data from 2,505 Holstein cattle were used, and the imputation was carried out in 2 steps. Step 1 consisted of imputation from 5 medium-density (MD) SNP panels to a consolidated MD SNP panel, and step 2 was based on imputation from this consolidated MD SNP panel to a high-density (HD) SNP panel. Six scenarios (S1-S6) were evaluated for imputing autosomal SNPs (S1^A, S2^A, S3^A, S4^A, S5^A, S6^A), as well as the entire X chromosome (S1^X, S2^X, S3^X, S4^X, S5^X, S6^X) and the pseudoautosomal region (PAR; S1^PAR, S2^PAR, S3^PAR, S4^PAR, S5^PAR, S6^PAR) and non-PAR (S1^non-PAR, S2^non-PAR, S3^non-PAR, S4^non-PAR, S5^non-PAR, S6^non-PAR) segments of the X chromosome. The validation population in all these scenarios had 169 females and zero (S1, S2, and S3) or 583 (S4, S5, and S6) males, whereas the reference population had 169 (S2, S5) or 392 (S1, S3, S4, S6) females and zero (S1, S4), 196 (S2, S5), or 1,361 (S3, S6) males. Two imputation software tools (Minimac and FindHap) were compared across scenarios. Step 1 provided a consolidated MD SNP panel containing 2,132 and 63,259 SNPs located on the X and autosomal chromosomes, respectively, and step 2 resulted in an HD SNP panel with 5,921 and 294,865 SNPs located on the X and autosomal chromosomes, respectively. In step 1, the lowest average allelic correlation (R) was 0.93 (S4^PAR) with Minimac and 0.79 (S4^PAR) with FindHap, whereas the lowest genotypic concordance rate (CR) was 95.0 (S4^PAR) with Minimac and 85.0 (S4^PAR) when using FindHap. In step 2, the lowest R was 0.93 (S4^PAR and S4^non-PAR) with Minimac and 0.66 (S4^X) with FindHap, whereas the lowest CR was 96.2 (S4^PAR) with Minimac and 80.3 (S4^X) with FindHap. In general, all the scenarios had high imputation accuracy of the X chromosome SNPs when using the Minimac software, whereas FindHap showed better accuracy with scenarios S3 and S6. Including both males and females in the reference and validation populations increased the imputation accuracy of X chromosome variants. These findings highlight the importance of the choice of the imputation software and the need for enlarging the reference populations to increase genotype imputation accuracy of the X chromosome variants in Holstein cattle.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145102580","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":"An observational study investigating the association of teat condition with clinical mastitis risk.","authors":"M Wieland, C O Paulrud, K Kakoulis, M E Spellman, H Somula, A Singh","doi":"10.3168/jds.2025-27316","DOIUrl":"https://doi.org/10.3168/jds.2025-27316","url":null,"abstract":"<p><p>The objectives were to investigate the association between machine milking-induced teat tissue changes and the occurrence of clinical mastitis in Holstein dairy cows. We conducted 2 separate prospective cohort studies at 1 commercial dairy farm in New York State to study the association of machine milking-induced short-term changes (STC, trial 1) and machine milking-induced long-term changes (LTC, trial 2) with clinical mastitis occurrence. Each trial consisted of four 3-wk periods. On d 1 of each period, STC and LTC were assessed through visual inspection and manual palpation. Short-term teat tissue changes were assessed based on teat discoloration, the condition of the teat base, and the consistency of the teat end and categorized into a binary variable (STC present or absent). Long-term teat tissue changes were categorized into 4 groups as follows: no callosity present (score 1), callosity ring present with no or only mild roughness (score 2); callosity ring and roughness present with keratin fronds extending 1 to 3 mm from the teat orifice (score 3); and callosity ring present with excessive keratin fronds extending ≥4 mm from the teat orifice (score 4). Data on clinical mastitis occurrence was extracted from the herd management software. We used the first clinical mastitis event of a quarter for each 3-wk trial period and applied a 14-d gap to define a new mastitis case within a quarter between 2 trial periods. In trial 1, STC was documented in 6,110 of 66,702 cases (9.2%) over the four 3-wk periods, The frequency distribution of LTC in trial 2 was as follows: score 1 in 7,348 of 61,624 cases (11.9%), score 2 in 48,553 cases (78.8%), score 3 in 5,514 cases (8.9%), and score 4 in 209 cases (0.3%). We documented 944/66,702 (1.4%) clinical mastitis cases at the quarter level during trial 1 and 866/61,624 (1.4%) cases during trial 2. Generalized linear mixed models with a logit link and a binomial distribution were used to test if machine milking-induced teat tissue changes were associated with clinical mastitis occurrence. In trial 1, we analyzed 66,702 quarter-level observations from 5,094 cows. We found no significant association between STC and clinical mastitis occurrence. Compared with a quarter with a teat without STC, the odds (95% CI) of clinical mastitis were 1.22 (0.95-1.59). In trial 2, we used 61,624 quarter-level observations from 4,998 cows. We found no significant association between LTC and clinical mastitis occurrence. Compared with a quarter with a teat with a smooth end (score 1), the odds of a clinical mastitis case were 1.02 (0.77-1.36) for score 2, 1.19 (0.84-1.69) for score 3, and 2.14 (0.80-5.71) for score 4. We concluded that in the study cohort presented here, machine milking-induced teat tissue changes were not associated with the occurrence of clinical mastitis.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145102593","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":"Abomasal infusion of docosahexaenoic acid to mid-lactation cows alters circulating leukocyte profiles and affects immune response to ex vivo bacterial stimulation.","authors":"H L Reisinger, M L Hoorman, K C Krogstad, L K Mamedova, D Vocelle, G A Contreras, A L Lock, B J Bradford","doi":"10.3168/jds.2025-26951","DOIUrl":"https://doi.org/10.3168/jds.2025-26951","url":null,"abstract":"<p><p>n-3 Fatty acids have anti-inflammatory effects across species, and within the n-3 fatty acid family, different fatty acids have unique effects on immune responses. The objective of this study was to assess circulating leukocyte phenotypes and their ex vivo immune response to challenge following abomasal infusions of the n-3 fatty acid docosahexaenoic acid (DHA; C22:6). Eight mid-lactation Holstein cows (97 ± 37 DIM) were randomly assigned to treatment sequence in a 4 × 4 Latin square design. Treatments were 0, 2, 4, and 6 g/d DHA (supplied via an enriched oil containing 65% DHA) infused into the abomasum for 11 d. Blood samples were collected on the final 2 d of each treatment period. Circulating leukocytes and phenotypes were first assessed in the absence of any challenge. Additionally, whole blood was stimulated with Escherichia coli or Staphylococcus aureus bioparticles in the presence of dihydrorhodamine 123 to assess bacterial uptake and oxidative burst of neutrophils by flow cytometry. A separate whole-blood sample was stimulated with heat-killed S. aureus and plasma was collected to quantify cytokine concentrations. Increasing DHA dose reduced circulating eosinophil concentrations in a linear manner and tended to affect lymphocyte concentrations in a quadratic manner. Cytotoxic T and helper T cell populations, along with the abundance of L-selectin on these populations, showed quadratic effects, with peak abundance in cows receiving 2 to 4 g/d DHA. The γδ T cells responded in a cubic manner, with peak concentrations in cows receiving the 4 g/d DHA dose, whereas L-selectin expression in γδ T cells linearly decreased with increasing DHA dose. Unstimulated blood samples were affected by DHA dose in a cubic manner for IL-1α and VEGF-A and a quadratic manner for TNF and IL-36RA, where highest concentrations were observed at 2 g/d DHA. During whole-blood stimulation with S. aureus, MCP-1 concentration increased linearly with increasing DHA dose and TNF responded in a cubic manner, with a nadir at the 6 g/d DHA dose. Following whole-blood stimulation, DHA dose linearly increased the proportion of neutrophils with uptake of E. coli bioparticles, whereas DHA dose did not affect the proportion of neutrophils with uptake of S. aureus. These results indicate that despite the anti-inflammatory effects of DHA, neutrophil response is not blunted following bacterial stimulation. Further studies are required to assess the effects of DHA on in vivo immune responses.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145102622","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 genetic architecture of mid-infrared-predicted energy balance, a novel energy deficiency score, and several biomarkers.","authors":"Hongqing Hu, Sébastien Franceschini, Pauline Lemal, Hadi Atashi, Clément Grelet, Yansen Chen, Katrien Wijnrocx, Soyeurt Hélène, Nicolas Gengler","doi":"10.3168/jds.2025-26876","DOIUrl":"https://doi.org/10.3168/jds.2025-26876","url":null,"abstract":"<p><p>Negative energy balance (NEB) during early lactation is a critical physiological challenge in high-producing dairy cows, affecting both their health and production performance. The objectives of this study were: (1) to compare the genetic architecture of logit-transformed predicted NEB (LPNEB), a logit-transformed novel energy deficiency score (LEDS), 15 biomarkers, and 3 production traits using SNP-based genomic correlation analysis; (2) to extend this study to a chromosomal level to identify specific genomic regions involved in the regulation of energy metabolism; and (3) to compare the independent contributions of 8 traits to the underlying genetic architecture of LPNEB and LEDS. The SNP effects estimated from single-trait models can be used to quickly calculate genomic correlations for 20 traits. The results indicate strong genomic correlations between LPNEB and LEDS, as well as with key metabolic biomarkers, particularly blood nonesterified fatty acids (NEFA), highlighting their importance in energy metabolism. Furthermore, NEFA was a strong independent contributor to both LPNEB and LEDS. Chromosome regions located on BTA19 and BTA25 were identified as potentially associated with NEB. By combining genomic correlation and contribution analyses, this study provides valuable insights into the genetic basis of NEB and related traits in dairy cows.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145102568","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}