Journal of Dairy Science最新文献

This study aimed to identify herd management styles and measures adopted by dairy farmers to extend cow lifespan and to explore the behavioral and farm-specific factors influencing these practices. A mixed-method approach was used, including a survey of 107 dairy farmers, in-depth interviews and farm visits with 10 farmers selected from the survey, of whom 5 had cows with a relatively low average lifespan (less than 4 years and 11 mo on average) and 5 had cows with a relatively high average lifespan (8 years or more on average). Surveyed farms were categorized into 3 lifespan classes (LC) based on the average age at culling: LC_low (<5.5 years, n = 28), LC_medium (5.5-6.5 years, n = 36), and LC_high (≥6.5 years, n = 34). Survey data included herd management styles, beliefs, values, and farm characteristics. Results showed limited differences in general (e.g., quality of drinking water, fertility, claw health) and specific (i.e., retain fewer female calves for replacement, inseminate cows more often before deciding to cull, treat sick cows for a longer period before deciding to cull) measures and in scores for behavioral factors across lifespan classes. However, LC_high farms were characterized by fewer cows, fewer youngstock, and lower annual milk yield per cow compared with LC_low farms. The LC_high farmers more frequently provided pasture access for at least 6 h per grazing day compared with LC_medium farmers. Farmers' attitudes and to a lesser extent descriptive social norms (referring to the pressure that farmers might feel by the actions of other people important to them) positively influenced their intention to adopt additional measures for extending cow lifespan. Qualitative interviews highlighted key themes farmers thought contributed to lifespan, including breeding, housing systems, grazing, and animal focus. The LC_high farmers emphasized they aimed for robust, muscular, and trouble-free cows, and a frequent presence in the barn, while LC_low farmers mentioned a broad range of focus areas. The results suggest that extending cow lifespan is influenced more by farmers' attitudes and (to a lesser extent) social norms than by specific farm practices or other behavioral constructs. Encouraging positive attitudes through tailored communication and peer learning activities and addressing barriers to adopting lifespan measures might be critical for broader implementation.

Modern dairy cattle populations have been intensively selected for high milk production; therefore, cows experience significant metabolic stress after calving and during the transition period. Breeding strategies aimed at making cows more robust and resistant to diseases without compromising milk productivity exist and have been implemented in some countries. Whereas genomic investigations have been conducted on both clinical and subclinical forms of ketosis, few studies have focused on measurable features reflecting metabolic processes, such as the blood concentrations of BHB and nonesterified fatty acids (NEFA) and urea, an indicator of nitrogen metabolism. A better understanding of the coding genes and polygenic nature of blood metabolites is advisable for genomic selection and evaluation. Therefore, this study aimed to identify genomic regions associated with major hematic biomarkers of ketosis predicted from mid-infrared milk spectra in the Italian Holstein population. A single-step GWAS was performed using predicted blood phenotypes collected from 6,190 clinically healthy Holstein cows from 5 to 35 DIM, reared in 374 herds, and genotyped with arrays of different SNP density. The analyzed traits included: BHB (log-transformed), NEFA (log-transformed), urea concentration (mmol/L), and subclinical ketosis (SCK), which was identified when BHB was ≥1.20 mmol/L. Specifically, 5.51% of cows were identified as being at risk of SCK. After imputation and conventional quality control, 64,202 markers located in the autosomes were used for the association study. The genomic h² was generally low (<0.11) for all the traits investigated. Signals of BHB were scattered across several locations (BTA2, 4, 6, 7, 18, 21, 22, 25, and 28) in regions related to metabolic processes and immune system function and response. In contrast, the significant SNP for SCK were mainly concentrated in BTA1, 5, 11, and 15, confirming the combined action of multiple genes on health-related phenotypes and suggesting that the genetic control of SCK is more restricted to specific chromosomal regions than that of blood biomarker concentration. For traits such as NEFA and urea, the number of significant signals was lower, and they were mainly related to lipid metabolism. Although the results should be interpreted with caution and validated in future research, our findings provide novel insights into the genetic and molecular mechanisms underlying negative energy balance and SCK in Holstein cows, offering potential targets for future functional studies and genetic improvement strategies.

Highly pathogenic avian influenza (HPAI) A(H5N1) virus emerged in lactating dairy cattle in March 2024, causing mastitis-related disease and infections in other farm animals and workers. Recent work identified α2,6 and α2,3-linked sialic acids (SIA), which serve as influenza virus receptors, in the lactating bovine mammary gland; however, their distribution across stages of mammary growth and development remains unknown. We compared the distribution of sialylation in mammary glands of prepubertal dairy calves, primigravid dairy heifers, and lactating cows. Mammary glands at all physiological stages displayed both α2,6 SIA, the preferred receptor linkage for human influenza viruses, and α2,3 SIA, the preferred receptor linkage for avian influenza viruses. Importantly, in mammary glands of pregnant dairy heifers, α2,3 SIA was most abundant, distributed in both mammary tissue and alveolar lumens. Our results indicate that the mammary glands of pregnant dairy heifers, like those of lactating dairy cows, display receptors that could support H5N1 binding and entry. Further studies are needed to determine whether developing mammary glands can be a site of influenza virus replication.

This study evaluated how the form and fatty acid (FA) profile of dietary fat supplements influence nutrient digestibility and milk yield in mid-lactation dairy cows. Twenty multiparous Holstein cows (mean ± SD; 44.3 ± 3.00 kg/d of milk; 99 ± 23 DIM) were randomly assigned to treatment sequences in a replicated 4 × 4 Latin square design with 21-d periods. Treatments were a non-FA-supplemented control diet (CON) and 3 diets incorporating FA supplements at 2.0% DM of total FA of 1) blend of FA supplements to achieve a ratio of 70% palmitic (C16:0) + 20% oleic (cis-9 C18:1) using an FA prill and a Ca-salt of palm FA (PFAD) distillate (70FB), 2) a Ca-salt of fractionated FA containing 70% C16:0 + 20% cis-9 C18:1 (70CS), and 3) a Ca-salt of PFAD distillate containing 45% C16:0 + 35% cis-9 C18:1 (45CS). The 3 FA treatments replaced soyhulls in the CON diet. The statistical model included the random effect of cow within square and the fixed effects of treatment, period, and square. Preplanned contrasts included CON versus the average of the 3 FA treatments (FAS), the form of the FA supplement (70FB vs. 70CS), and the FA profile of the Ca-salt (70CS vs. 45CS). Compared with CON, FAS decreased DMI and NDF intake, increased intakes of 16-carbon, 18-carbon, and total FA, and increased digestibility of DM, NDF, 16-carbon, 18-carbon, and total FA. There was no difference in nutrient intake for the form of the supplement, but compared with 70CS, 70FB increased DM and 18-carbon digestibility and decreased NDF and 16-carbon digestibility, with no effect on total FA digestibility. When considering the FA profile of a Ca-salt, 70CS increased both DM and NDF intake but did not affect the digestibility of DM or NDF and decreased 16-carbon and total FA digestibility. Overall, FAS increased 3.5% FCM and milk fat yield but decreased milk protein yield. No differences were observed for production responses when comparing the form of the supplement. When comparing the FA profile of a Ca-salt, 70CS increased milk fat yield but decreased yields of milk and milk lactose. In conclusion, FAS primarily increased milk fat production by increasing FA digestibility and absorption. Digestibility varied slightly by supplement form, but production variables remained consistent regardless of form when FA profiles were similar. However, differences in FA profiles between traditional Ca-salt containing 45% C16:0 and 35% cis-9 C18:1 and 70% C16:0 and 20% cis-9 C18:1 influenced nutrient digestibility and production. These findings demonstrate that FA profile had a greater influence than supplement on nutrient digestion and production outcomes.

This paper explores stakeholder responses to policy changes under Ireland's Fifth Nitrates Action Programme (NAP), focusing on the effectiveness of a top-down, compliance-driven approach. Despite the Water Framework and the Nitrates Directives, overall biological status in Irish waterbodies has shown little improvement. Using semi-structured interviews with 16 key informants and responses to open-ended questions from surveys with 42 dairy farmers, responses to qualitative questions, the study analyzes perceptions of new measures and the broader social and ecological challenges influencing water quality outcomes. Although regulation is viewed as necessary to encourage change at the farm level, participants highlighted that it overlooks the complexities of soil, water, and grassland interactions, and provides insufficient support for farmers. Findings underscore the limitations of regulatory compliance alone, pointing factors such as collective responsibility, local ownership, societal pressure, and ecological and hydrological complexity. The article concludes that a more integrated and context-sensitive approach is needed.

The study aimed to formulate fortified dry yogurt with chamomile and saffron, making a functional, probiotic, and therapeutic food. Fortified dry yogurt was prepared in 7:2:1 ratios of dry yogurt, chamomile, and saffron powders. Flavoring of fortified dry yogurt was done at 7:3 ratios of fortified dry yogurt and each flavor (mint, cumin seeds, fennel seeds, and black pepper powder). The prepared fortified dry yogurt was acidic (pH 3-4) and the total soluble solids were 49.97% of the product concentrate. Plain yogurt (100% natural plain yogurt) had the highest sensory scores regarding appearance, texture, color, taste, aroma, flavor, consistency, mouthfeel, and overall acceptability, whereas fortified dry yogurt (FDY) had the lowest scores. Among 4 flavors of FDY, the cumin-flavored fortified dry yogurt (CFFDY) showed the highest organoleptic potential and was selected for further analysis. The CFFDY proximate profile contains a low fiber concentration but is rich in moisture (7.55%), ash (8.13%), protein (9.22%), fat (21.85%), and CHO (52.360%), and 442.73 Kcal/100 g. The mineral profile of CFFDY contains low magnesium, but calcium (397.71 mg/100 g) and sodium (776.89 mg/100 g) were high. The total phenolic content (582.78 mg of GAE/100 g), flavonoid content (204.92 mg of QE/100 g), and ferric reducing antioxidant power (2,022.82 mg Eq. of FeSO₄/100 g) show the stronger antioxidant potential of CFFDY. Pathogenic bacterial species was not detected in CFFDY, but the total plate count was 2.5 × 10³ cfu/g, indicating the presence of probiotic species. Gram staining detected small chains of gram-positive cocci cells and medium chains of gram-positive palisades that are Bacillus and Bifidobacterium species, whereas glucose fermentation and lactose fermentation tests both confirmed the presence of Lactobacillus in CFFDY. A storage study of FDY was also conducted and revealed high potential organoleptic properties at d 90. Therefore, a novel formulation of flavored FDY may be adopted in the dairy industry, serving as a functional alternative and shelf-stable dairy product.

Contamination by Cronobacter sakazakii in powdered infant formula (PIF) and the potential hazards of chemical disinfectants are pressing issues requiring urgent resolution. This study aimed to investigate the antibacterial activity and mechanism of Lonicera japonica Thunb. polyphenols (LP) against C. sakazakii and evaluate the efficacy of LP as a natural disinfectant in inhibiting C. sakazakii in biofilms on the common contact surfaces of PIF. The results showed that the minimum inhibitory concentration and minimum bactericidal concentration of LP against C. sakazakii were 4 to 8 mg/mL and 8 to 16 mg/mL, respectively. Compared with controls, LP-treated C. sakazakii showed significantly reduced intracellular ATP and reactive oxygen species levels (P < 0.05); increases in AKP, protein, and nucleic acid leakage (P < 0.05); obvious cell membrane depolarization; enhanced membrane permeability; and irreversible cell morphological damage. Untargeted metabolomics analysis identified a total of 536 differential metabolites. Among them, 67 key differential metabolites were involved in fatty acid metabolism, amino acid metabolism, energy metabolism, membrane transport metabolism, and nucleotide metabolism, thereby disrupting the structure and function of the cell wall and cell membrane, reducing the resistance to environmental stress, and inhibiting ATP and nucleic acid synthesis. Application tests demonstrated that LP can significantly inactivate C. sakazakii in biofilms on stainless steel, glass, tinplate, and polyvinyl chloride surfaces. These findings deeply reveal the antibacterial mechanism of LP against C. sakazakii, and provide a theoretical basis for the application of LP as a natural disinfectant to reduce C. sakazakii contamination of PIF.

We compared the effects of silage from a tall-stature corn (TSC) hybrid with silage from a new short-stature corn (SSC) hybrid (due to a brachytic mutation) on DMI, feeding behavior, nutrient digestibility, and performance of lactating Holstein dairy cows. A total of 24 cows (12 per group) received identical diets for 2 wk and were then stratified according to BW, parity, DIM, and average milk production and randomly assigned to the TSC group or the SSC group. Data were collected for 70 d. Data from cows were analyzed as a completely randomized design using a mixed model procedure, and week of treatment was the repeated measure. The fixed-effects model included diet (D), week (W), and their first-order interaction (D × W), and each cow was considered a random effect. During the week before administering the experimental diets, cows in the TSC group (3.3 ± 1.5 lactations; 643 ± 61 kg BW; 85 ± 34 DIM; 47.1 ± 5.5 kg milk yield [MY]) and the SSC group (3.3 ± 1.7 lactations; 621 ± 45 kg BW; 82 ± 31 DIM; 47.1 ± 6.9 kg of MY) had similar characteristics. The 2 diets had the same CP, NDF, starch, and sugar content on a DM basis. The feeding behavior, rumination time, apparent nutrient digestibility, milk yield and composition, cheese yield traits, BW, and immune-metabolic parameters were measured for 70 d. The SSC silage had greater NDFD_30h (66.7%NDF vs. 60.6%NDF) and a greater level of starch (30.3%DM vs. 28.4%DM) than the TSC silage. These 2 differences corresponded to an increased energy content of the SSC silage (1.47 vs. 1.40 Mcal/kg DM as NEL3X). Analysis of feeding behaviors demonstrated that the SSC group had a lower DMI (25.0 vs. 26.8 kg DM/cow/d), greater meal frequency (8.3 vs. 7.4 meals/cow/d), and larger meal size (3.8 vs. 3.2 kg DM/meal). Cows in the SSC group also produced more milk (44.7 vs. 42.9 kg/cow/d) compared with TSC. The 2 groups had similar cheese yield traits. These results suggest that the brachytic corn hybrid has potential as an alternative source of high-energy corn silage for dairy farmers because it satisfies the energy requirements of lactating dairy cows and leads to improved milk production.

Whey protein is commonly used to prevent sarcopenia in older adults due to its high digestibility and amino acid content. Its bioactive components may also influence the gut microbiota, which plays a growing role in healthy aging as microbial composition shifts with age. This study investigated whether daily supplementation with whey protein isolate (WPI) improves gut microbiota diversity and composition in older adults. Sixteen participants consumed 59 g of WPI (35 g of protein) daily for 3 wk. Whey protein isolate significantly increased Simpson diversity in individuals with low baseline diversity, with effects appearing by d 3 and persisting after intervention. Taxonomic analysis revealed increases in beneficial taxa (e.g., Ruminococcaceae, Faecalibacterium, and Christensenella) and reductions in potentially harmful groups (e.g., Proteobacteria, Streptococcaceae, and Colidextribacter), particularly in the low diversity group. ANCOM-BC analysis based on absolute abundance confirmed increases in probiotic genera including Lactobacillus, Lactococcus, and Christensenella. Despite these microbial shifts, no significant changes were observed in gastrointestinal symptoms or stool consistency. These findings highlight the potential of WPI supplementation as a dietary strategy to promote a healthier gut microbiome in older adults, particularly in those with low baseline diversity.

The spread of the highly pathogenic avian influenza (HPAI) H5N1 virus in dairy cattle, particularly affecting the mammary glands, highlights the adaptability of influenza A viruses (IAV) to infect nontraditional species. Mammals like pigs, sheep, goats, and camelids contribute >$30 billion annually to the US economy and are a source of meat and milk for millions, highlighting the importance of understanding viral susceptibility in these species. The zoonotic transmission of HPAI H5N1 to several dairy and poultry farm workers involved with farm operations during outbreaks is also a cause for public health concerns. Previous studies showed IAV-specific sialic acid (SA) receptors in the mammary glands of dairy cattle, but those studies did not explore their presence in pigs, sheep, goats, alpacas, and humans. The current study used lectin histochemistry staining with fluorescently labeled Sambucus nigra (SA α2,6-galactose [gal] receptors) and Maackia amurensis (SA α2,3-gal receptors) and found that the mammary glands of all of these species, including human breast, were rich in SA α2,6-gal receptors essential for mammalian-adapted IAV binding. We also found SA α2,3-gal receptors in the examined tissues of all species, although to a lesser extent. Notably, an A(H5N1) clade 2.3.4.4b virus demonstrated binding to both ruminant (cattle) and nonruminant (pigs) species' mammary tissue. These findings provide crucial insights into the potential for HPAI H5N1 to infect and spread within the mammary glands of these production animals, as well as humans.