Journal of Dairy Science最新文献

{"title":"Navigating complexity: Salmonella Dublin risks factors in a Midwestern US calf movement system.","authors":"Sara C Sequeira, Alejandra Arevalo-Mayorga, Samantha R Locke, Greg Habing, Andréia G Arruda","doi":"10.3168/jds.2025-27055","DOIUrl":"https://doi.org/10.3168/jds.2025-27055","url":null,"abstract":"<p><p>Movement of live cattle is a known risk for pathogen spread. Understanding movement patterns, particularly at high-risk commingling facilities, is essential for targeted pathogen surveillance and disease mitigation strategies. This repeated cross-sectional study investigated calf movement patterns and detection of Salmonella spp. (including Salmonella Dublin) within a Midwestern livestock dealer facility, a critical yet underexplored component of the US cattle supply chain. From May to October 2023, records of 1,184 calf movements were analyzed alongside identification of Salmonella spp. by culture and Salmonella Dublin via PCR from environmental sampling. Weekly network metrics were assessed, including number of incoming sources, density, and source stability (Jaccard similarity indexes [JSI]). Mixed-effects logistic regression models were used to evaluate the association between movement patterns and pen-level pathogen detection. Results revealed a high number of sources and animals passing through the facility, with fluctuating connectivity over time. Environmental sampling confirmed variable Salmonella Dublin presence, with a significant decreasing trend over time, despite peak Salmonella spp. detection in late summer. Weekly movement networks showed variability in source stability, with lower JSI values (i.e., more variation in source ZIP codes) typically preceding increased detection of Salmonella Dublin, suggesting that introduction of new or shifting sources may be a risk factor. These results highlighted the need for further research into which characteristics of these new sources, such as geography, management practices, or biosecurity, might contribute to Salmonella Dublin presence and potential persistence. Findings from this study underscored the role of livestock dealer networks in pathogen occurrence and reinforced the need for targeted mitigation strategies at such facilities. Strengthening external biosecurity through accurate and accessible intra- and interstate movement records and environmental monitoring is vital for mitigating the risks of Salmonella Dublin, a pathogen of critical concern for public and animal health.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145058170","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":"Milk protein modulates antioxidant activity and metabolome stability in coffee beverages during thermal processing.","authors":"Nan Chen, Ke Xie, Zeting Jiao, Wei Zhang, Huaxiang Deng, Tolulope Joshua Ashaolu, Ken Cheng, Changhui Zhao","doi":"10.3168/jds.2025-26795","DOIUrl":"https://doi.org/10.3168/jds.2025-26795","url":null,"abstract":"<p><p>Milk is frequently added to coffee to enhance its flavor; however, its effect on antioxidant compounds and related metabolite profiles remains poorly characterized. In this study, the functional properties and free metabolites of the milk-infused coffee were analyzed under thermal conditions. Results indicated that milk addition facilitated the formation of polyphenol-protein complexes, increasing the antioxidant properties. For instance, when milk was added to achieve a protein concentration of 90 mg/mL, the 2,2-diphenyl-1-picrylhydrazyl free radical scavenging capacity of the coffee-milk system increased from 33.55% to 49.37%. Furthermore, high coffee concentration tended to increase the average particle size of the coffee-milk beverage, which made the overall system unstable, evidenced by a higher polydispersity index. An increase in milk protein concentration was observed to result in an enhanced foam expansion rate, accompanied by a slight reduction in foam stability. Meanwhile, the results of the sensory evaluation showed that the increase in milk protein concentration changed the objective sensory attributes of the coffee-milk beverages including bitterness, astringency, and sweetness, and improved the overall acceptance. When the milk protein concentration reached 90 mg/mL, the overall sensory acceptance score of coffee-milk beverages increased to 7.40 out of 10, which was significantly higher than the 3.88 score for plain black coffee. Comparative analysis by native and non-native electrophoresis revealed that there are simultaneous noncovalent and covalent interactions between the active ingredient and milk proteins. High-performance liquid chromatography quadrupole TOF MS/MS demonstrated that the addition of milk resulted in a significant change on the metabolite profile in the coffee-milk beverage in terms of both type and content, such as dicaffeoylquinic acid and feruloyl-quinolactone, which was independent of the temperature at which the coffee-milk beverage was prepared. The central factor in the binding of molecules in coffee is milk protein, which may contribute to changes in the physiochemical and nutritional properties of coffee. It is thus possible to develop milk coffee with an enhanced overall quality and optimized biofunctional properties by examining the composition ratio and processing conditions. In conclusion, milk protein acts as a key mediator in coffee molecule binding, modifying antioxidant activity and metabolite profiles. This mechanism lays the foundation for the targeted design of milk-coffee formulations with optimized biofunctional properties through precise control of composition ratios and processing parameters.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145058175","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Invited review: Fueling milk production carbon by carbon: Regulation of hepatic glucose production in dairy cattle.","authors":"Linda M Beckett, Sophia J Kendall, Theresa M Casey, Shawn S Donkin, Heather M White","doi":"10.3168/jds.2025-26987","DOIUrl":"https://doi.org/10.3168/jds.2025-26987","url":null,"abstract":"<p><p>Milk production depends on glucose supply to the mammary gland, which in ruminants is driven by the liver for gluconeogenesis (GNG). Dairy cattle rely on endogenous glucose production (EGP) via GNG for 90% of glucose needs, and the capacity for EGP depends on substrate supply, activity of GNG enzymes, and rate of flux of substrates into and through metabolic pathways like the tricarboxylic acid (TCA) cycle. Propionate serves as the primary EGP precursor, but also directly affects the activity of the rate-limiting GNG enzymes, pyruvate carboxylase (PC), and phosphoenolpyruvate carboxykinase (PEPCK). Short-chain and long-chain fatty acids, hormones, and feed restriction also regulate expression levels of PC and cytosolic PEPCK (PCK1). Herein, we review the literature regarding molecular regulation of GNG in dairy cattle and discuss the consequence of the dramatic shifts in these factors that occur around the time of calving, which mediate changes in PC and PCK1 expression, with implications for the health and nutritional management of dairy cattle. Discussion of data from studies that applied fluxomic tools to map carbon flow of stable isotope-labeled substrates through the TCA cycle and GNG pathways combined with proteome or transcriptome data in response to alterations in PC, fatty acid supply, and circadian disruption is included to tie control mechanisms with pathway flux outcomes. In the end, we advocate for greater understanding of the nuances of bovine metabolic control that are achieved through the application of multi-omic tools to deepen our understanding of the regulatory processes of hepatic GNG and to identify targets for interventions that support EGP to optimize milk production and cow health.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145058132","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":"Carvacrol alleviates endoplasmic reticulum stress and inflammation induced by lipopolysaccharide by enhancing endoplasmic reticulum autophagy in dairy mammary epithelial cells.","authors":"Yue Yang, Ming Li, Jingyi Wang, Huijing Zhang, Renxu Chang, Bichen Zhao, Ben Aernouts, Qingnian Huang, Chuang Xu","doi":"10.3168/jds.2025-26472","DOIUrl":"https://doi.org/10.3168/jds.2025-26472","url":null,"abstract":"<p><p>Mastitis is a common disease in dairy cows and has various causes. Because of its enormous negative impact on cow health, welfare, and productivity, it results in huge economic losses and threatens sustainability of the dairy industry. In dairy cows with mastitis, excessive inflammation caused by LPS is an important factor leading to mammary tissue damage. It has been reported that there is a coupling effect between endoplasmic reticulum (ER) stress (ER-stress) and inflammatory response. When ER-stress occurs, misfolded and unfolded proteins accumulate in the ER lumen and lead to ER expansion, which can be degraded by the ER autophagy (ER-phagy) pathway to maintain cell homeostasis and ER morphology and activity. Therefore, the search for effective activators that enhance ER-phagy of bovine mammary epithelial cells may be the focus of relieving ER-stress and inflammation in dairy cows with mastitis. Using in vivo experiments, we investigated ER-phagy, ER-stress, and the nuclear factor kappa-B (NF-κB) inflammatory pathway in mammary tissue of healthy cows and cows with clinical mastitis. We found that ER-stress pathways and NF-κB inflammatory pathways were activated while the ER-phagy was blocked in mammary tissue of cows with clinical mastitis compared with healthy cows. In in vitro experiments, we used LPS to stimulate the immortalized bovine mammary epithelial cell line (MAC-T cells) to produce in vitro bovine mastitis models and the effects of carvacrol (CAV) on ER-stress and inflammation were investigated. In accordance with our research, CAV was found to alleviate LPS-induced inflammation and ER-stress in MAC-T cells. In addition, by knocking down ER-phagy protein FAM134B, we demonstrated that the effect of CAV on ER-stress and inflammation disappeared after knocking down FAM134B. These outcomes suggest that CAV can relieve LPS-induced inflammation and ER-stress by enhancing ER-phagy in MAC-T cells. So the application of CAV deserves further study as a potential nonresistant treatment for dairy cows with clinical mastitis and a good alternative for antibiotics.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145058196","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 for enteric methane traits and their genetic connection with milk production in Danish Holstein cattle.","authors":"Helen Schneider, Rikke Krogh Lajevardi, Martin Bjerring, Peter L Vendahl, Mogens Sand Lund, Trine Michelle Villumsen","doi":"10.3168/jds.2025-26853","DOIUrl":"https://doi.org/10.3168/jds.2025-26853","url":null,"abstract":"<p><p>Due to their large contribution to anthropogenic GHG emissions, mitigating methane (CH₄) emissions originating from enteric fermentation of fiber in ruminants such as cattle, has become a current focus in animal breeding. This is because exploiting genetics by integrating CH₄ emissions in the breeding goal is a promising tool as it enables continuous and long-term improvement. However, a sustainable design of the selection index requires a thorough understanding of the new traits' genetic architecture and relationship with already existing breeding goal traits. This study attempted a detailed analysis of CH₄ traits, such as CH₄ and CO₂ concentrations in the cows' breath (CH₄_C and CO₂_C) as well as the ratio of these traits (CH₄:CO₂ ratio), and their genetic connection with milk production traits, using a sample of 4,019 Danish Holstein cows with 587,640 daily observations. Records of CH₄_C and CO₂_C were measured using sniffers installed on commercial Danish dairy farms. To estimate heritabilities and genetic correlations, we applied pedigree-based uni- and bivariate repeatability linear animal models while differentiating between growing (i.e., primiparous, PP) and adult (i.e., multiparous, MLP) cows. For the CH₄ traits, heritabilities were between 0.08 (se = 0.01) for the CH₄:CO₂ ratio in MLP cows and 0.19 (se = 0.03) for CH₄_C in PP cows. Repeatabilities were between 0.13 (se = 0.01) for the CH₄:CO₂ ratio and 0.42 (se = 0.01) for CO₂_C, both in MLP cows. Genetic correlations with milk production traits were in a moderate to high unfavorable direction and stronger for MLP cows, e.g., 0.44 (se = 0.09) between CH₄_C and ECM, which indicates increasing emissions with higher milk production. Our results confirm the unfavorable relationship between milk production and CH₄ emissions found in previous studies. Moreover, they raise the need for follow-up studies (1) to develop a CH₄ trait that is genetically independent from milk production to enable breeding for lower emitting cows without compromising milk production and (2) that include information on possible mediating factors of the genetic correlations found in this study (e.g., feed intake data) to further decipher the relationship between enteric CH₄ emissions and milk production.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145058199","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":"Variability of temperature exposure of dairy products during refrigerated e-commerce distribution and its impact on dairy quality.","authors":"Zoe D Wasserlauf-Pepper, Jun Su, Aljosa Trmcic, Nicole Martin","doi":"10.3168/jds.2025-27108","DOIUrl":"https://doi.org/10.3168/jds.2025-27108","url":null,"abstract":"<p><p>E-commerce food distribution has grown drastically in recent years, a trend that was accelerated by the COVID-19 pandemic. The range of perishable products purchased through e-commerce as well as the distance over which these products travel to consumers has also increased considerably. Perishable goods are commonly available through various e-commerce channels (e.g., third-party grocery shopping and delivery, direct processor-to-consumer delivery, and overnight shipment via centralized distribution centers). These e-commerce distribution methods have grown to accommodate the increasing demand for grocery delivery, which can introduce the potential for temperature abuse of these perishable goods, possibly leading to premature spoilage and quality deterioration. To determine the effect of e-commerce distribution on the shelf life of dairy products, we assessed the variability of simulated and real e-commerce time-temperature profiles of fluid milk and Greek yogurt in 3 transportation channels: (1) direct-to-consumer, (2) distributor or business-to-consumer, and (3) business-to-business-to-consumer. To further identify how real dairy products ordered through business-to-business-to-consumer (e.g., grocery delivery to consumers from retail stores through a third party) channels, containers of 1.89 L (1/2 gal) milk and 157 mL (5.3 oz) Greek yogurt were delivered to customers from local retail chains, and temperatures were measured upon delivery. Finally, the temperature profiles measured during 1.89 L milk transportation were used to conduct microbial and sensory shelf-life testing on commercial containers of milk and were also incorporated into a previously developed computational model that predicts milk spoilage based on the initial concentration of primary groups of bacterial contaminants and other relevant conditions (e.g., storage temperature). Our time-temperature profile results showed that product temperature at the time of delivery ranged from 0.2 to 10.1°C for the direct-to-consumer pathway, -0.9 to 19.2°C for the business-to-consumer pathway, and 3.1 to 18.3°C during the simulated business-to-business-to-consumer pathway. Average milk and yogurt arrival temperatures from real business-to-business-to-consumer deliveries were 7.2°C and 7.3°C, respectively, and ranged from 3.1 to 10.5°C and 3.4 to 12.7°C, respectively. Results from fluid milk shelf-life microbial testing and end of shelf-life sensory testing showed limited effect following simulated short-term temperature exposure from e-commerce conditions, although more data are needed. This is supported by our model, which also indicates that there are minimal changes to expected microbial spoilage of fluid milk at the end of shelf life. However, our models only predict microbial growth and not sensory quality, which has a larger effect on consumer acceptance and should be assessed in future studies. Overall, our study provides important information on the exposure of dairy products","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145058177","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluating the bioaccessibility of yak milk lipids in infants: Dynamic gastrointestinal simulation reveals lipidomic alterations.","authors":"Yu Yan, Lina Wang, Linlin Wang, Hailong Xing","doi":"10.3168/jds.2025-27160","DOIUrl":"https://doi.org/10.3168/jds.2025-27160","url":null,"abstract":"<p><p>Yak milk is considered an excellent dairy source for infant formula, owing to its lipid advantages including superior fatty acid composition, abundant short- and medium-chain fatty acids, and higher phospholipid content. This study compared the physical characteristics, lipidomic profiles, and fatty acid differences between human milk and yak milk digestion products through an in vitro simulation of infant digestion. The results revealed that human milk exhibited higher lipolysis rates and greater release of free fatty acids compared with yak milk. No significant differences were observed in the average particle size of fat globules or zeta potential between the 2 milk types at the same digestion stage. Distinctive differential metabolites identified during gastric digestion included TG (18:1_18:1_18:2), TG (18:0_18:2_18:3), TG (16:0_18:1_20:4), TG (O-11:0_14:0_3:0), and SM (d36:1). In the intestinal digestion phase, MG (P-21:6), MG (O-21:6), FA (22:6), FA (20:4), FA (16:0), and FA (18:0) served as characteristic differential metabolites. Palmitic acid (C16:0) and stearic acid (C18:0) served as critical discriminators of fatty acid profiles between yak milk and human milk digesta, predominantly via their enrichment in key metabolic pathways, including \"Biosynthesis of unsaturated fatty acids\" and \"Fatty acid biosynthesis.\" This could provide data support for the design of yak milk-based infant formula.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145058193","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":"Human milk oligosaccharides and infant gut microbiome in Mongolian mother-infant dyads.","authors":"Enkhtuul Davaanyam, Undarmaa Otgonbaatar, Aruto Nakajima, Mikiyasu Sakanaka, Miriam N Ojima, Tomoya Kozakai, Toshihiko Katoh, Toshitaka Odamaki, Batkhuu Javzan, Enkhmaa Dagvadorj, Davaapurev Bekh-Ochir, Takane Katayama","doi":"10.3168/jds.2025-26865","DOIUrl":"https://doi.org/10.3168/jds.2025-26865","url":null,"abstract":"<p><p>Human milk oligosaccharides (HMO) play crucial roles in establishing a healthy gut microbiota in breastfed infants. Many studies have been conducted using samples collected in different areas with varying lifestyles to examine the relationships between milk HMO, infant gut microbiota, and microbial HMO consumption in feces. The present study analyzed the tripartite relationship using samples obtained from Mongolian mothers and infants living in herder and urban environments, a population underrepresented in previous research. Breast milk and infant feces were cross-sectionally collected from 74 mothers and 57 infants, respectively, with 57 samples obtained from mother-infant dyads. Permutational multivariate ANOVA (PERMANOVA) using maternal metadata revealed significant effects of secretor status and lactation period on milk HMO profiles, while lifestyle differences may have exerted a slight influence during early lactation. Comparison of the milk HMO profiles of Mongolian mothers with those of mothers from other countries revealed compositional similarities among Asian populations. Of the 37 Mongolian infants receiving mature milk, 36 infants had gut microbiotas rich in bifidobacteria with relative abundances ranging from 43% to 98%. In contrast, 20 neonates who received immature milk had microbiotas characteristic of an underdeveloped transitional stage. The PERMANOVA using infant metadata revealed an association of gut microbiota profiles with delivery mode among infants receiving mature milk. No association was detected with the mother's secretor status and lifestyle differences. Further analysis suggested that the bifidobacteria-dominant gut microbiota of Mongolian infants is established by HMO consumption and cross-feeding mediated by fucosyllactose transporters or Bifidobacterium bifidum.</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":"145005768","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":"Transitioning toward sustainable dairy systems in Europe: A systematic literature review.","authors":"Mousaab Alrhmoun, Matthias Gauly, Thomas Zanon","doi":"10.3168/jds.2025-27018","DOIUrl":"https://doi.org/10.3168/jds.2025-27018","url":null,"abstract":"<p><p>The European Union makes a significant contribution to the global dairy industry, producing an estimated 160.8 million tons of milk in 2023, which accounts for more than 20% of the world's total milk production. However, the sector faces increasing pressure to align with sustainability goals amid economic constraints, environmental degradation, climate change, and evolving societal expectations. This systematic literature review examines the transition toward sustainable dairy systems across Europe by synthesizing peer-reviewed studies published over the past decade. It analyzes the range of agroecological practices being implemented, such as rotational grazing, breed selection, and reduced-input systems, alongside the roles played by policy frameworks, socio-economic drivers, and technological innovations. The review identifies key barriers to progress, including fragmented policy support, data limitations, and insufficient incentives for farmers. At the same time, it highlights opportunities for a just and effective transition, emphasizing the importance of multiactor collaboration and the urgent need for standardized evaluation frameworks across diverse agroecosystems. This study provides a conceptual and practical foundation to guide future research, policymaking, and on-the-ground initiatives aimed at fostering resilient and sustainable dairy systems in Europe.</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":"145005800","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 intramammary infections on mammary gland development in pregnant dairy heifers during late gestation.","authors":"M X S Oliveira, C S Gammariello, P H Baker, K M Enger, S K Jacobi, B D Enger","doi":"10.3168/jds.2025-26734","DOIUrl":"https://doi.org/10.3168/jds.2025-26734","url":null,"abstract":"<p><p>Intramammary infections are common in nonlactating dairy cattle and have been shown to disrupt mammary tissue architecture in nonpregnant heifers. However, their effect on mammary development during pregnancy remains unclear. This study assessed the effects of IMI on mammary gland development in pregnant dairy heifers during late gestation. The study used 21 pregnant Holstein heifers, divided across 3 gestational stages (∼5.75, 6.75, and 7.75 mo of gestation; corresponding to 180 ± 2, 208 ± 2, and 238 ± 2 d pregnant, respectively). Using a contralateral quarter-pair design, a single culture-negative quarter of each heifer was infused with saline (SAL), and the contralateral quarter was challenged with 5,000 cfu of Staphylococcus aureus (CHALL). Mammary secretion samples were collected at various time points until tissue harvest at 21 d postchallenge, when animals were 6.5, 7.5, and 8.5 mo pregnant. Mammary tissue samples from the center and edge parenchymal regions were collected and evaluated for immune cell infiltration and tissue morphometry. Secretions from CHALL quarters had greater SCC and a greater proportion of neutrophils compared with SAL quarters. Mammary tissues from CHALL quarters exhibited increased immune cell infiltration in both the luminal and intralobular stromal regions and lower secretion score compared with SAL, regardless of gestational stage. Additionally, tissues from animals at later gestational stages showed reduced adipose tissue area and larger lobular areas, regardless of quarter treatment. At 8.5 mo of pregnancy, luminal areas in the edge regions of CHALL quarters were nearly 50% smaller than in SAL quarters, suggesting an increased risk to restricting milk accumulation and secretion capacity in the mammary gland. Additionally, in 7.5-mo pregnant heifers, CHALL quarters showed decreased epithelial areas and increased intralobular stromal areas in the central region. Lobular, adipose, and extralobular stromal areas did not differ markedly between CHALL and SAL quarters. Overall, the results of this study indicate that IMI induces tissue damage in mammary glands of pregnant heifers, with a greater effect during late gestation, and that the IMI-induced changes in tissue architecture were not consistent across all tissue mammary gland regions or gestational ages.</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":"145005802","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}