Dairy, Volume 7, Issue 1 (February 2026) – 18 articles

Enterococci are ubiquitous lactic acid bacteria frequently detected in dairy environments, where they represent an important component of the non-starter lactic acid bacteria community, particularly in artisanal cheeses produced from raw milk. Due to their metabolic versatility, enterococci may contribute to cheese ripening and the development of characteristic sensory attributes; however, their technological relevance is accompanied by growing concern regarding their role as opportunistic pathogens and reservoirs of antimicrobial resistance. This review critically summarizes current knowledge on antimicrobial resistance in enterococci isolated from milk and dairy products, with emphasis on both intrinsic and acquired resistance traits and their reported prevalence across different dairy matrices and geographical regions. Particular attention is given to artisanal cheeses, in which heterogeneous and region-specific resistance patterns have been described. Advances in whole-genome sequencing have substantially improved understanding of the genetic basis of antimicrobial resistance in dairy enterococci and have largely corroborated earlier findings obtained through phenotypic antimicrobial susceptibility testing combined with targeted resistance gene detection. Nevertheless, available data remain fragmented due to variability in study design, analytical approaches, and reporting practices. Overall, the evidence highlights the need for harmonized surveillance strategies integrating phenotypic and genomic data within a One Health framework to improve risk assessment and to better understand the role of dairy enterococci in the dissemination of antimicrobial resistance along the food chain. Full article

This study examined the effects of average daily gain (ADG) during gestation on growth, nutrient digestibility, metabolic response, and subsequent milk yield and composition in dairy heifers. Twenty pregnant Holstein × Gyr heifers (450 ± 5.0 kg; 18 ± 1.1 months) were randomly assigned to moderate (MOD; target 0.35 kg/day) or high (HIG; target 0.70 kg/day) ADG groups, and received a total mixed ration from day 70 of gestation until calving. Body growth, blood metabolites, and lactation performance after birth were measured. At calving, HIG heifers had greater body weight (p < 0.01) and thoracic perimeter (p = 0.02). Nutrient digestibility and most blood metabolites were not affected by ADG (p > 0.05), except for triiodothyronine concentrations, which differed between treatments over time (p < 0.01). Milk yield and energy-corrected milk were not affected by gestational ADG (p > 0.10), while milk fat and total solids showed numerical treatment × week interactions (p ≤ 0.10). These results indicate that higher ADG during gestation increases body reserves at calving but does not affect milk yield. The moderate ADG for Holstein × Gyr heifers during gestation may improve milk quality through higher fat and solids content, emphasizing the importance of tailoring growth strategies for heifers during gestation. Full article

Historically, methods to detect subclinical mastitis have been used to aid treatment decisions. The limitations of these tests have led to the exploration of the use of differential somatic cell count (DSCC). The objective of this study was to evaluate the relationship between DSCC and antibiotic success in subclinically infected cows. Cows were pre-screened to confirm an SCC ≥ 200,000 cells/mL and a positive bacterial culture. At enrollment, aseptic quarter milk samples were collected for culturing and evaluated using SCC, DSCC, the California Mastitis Test (CMT), and electrical conductivity. Enrolled quarters were treated with an intramammary antibiotic and resampled 7-, 14-, 28-, and 35-days post-treatment and retrospectively classified as “Cured” or failed to cure (Failed) based on a bacteriological cure. The overall cure rate was 51.5%. Pre-treatment SCC, total leukocyte count (TLC), neutrophils, and CMT were lower in Cured quarters compared to Failed. Meanwhile, macrophage percentage was greater in Cured quarters compared to Failed. No difference was found between lymphocyte percentage and conductivity. When evaluating the use of multiple threshold optimizations to predict cure outcome, TLC tended to have the highest ranking for the metric of interest; however, SCC tended to numerically perform as well in sensitivity and specificity outside of the optimized parameter. Full article

The transition period, spanning approximately three weeks before and after parturition, represents one of the most critical physiological windows in dairy production. Profound metabolic, endocrine, and immune adaptations occur as the cow shifts from gestation to lactation, predisposing high-yielding cows to oxidative stress, inflammation, and metabolic imbalance. Negative energy and metabolisable protein balances stimulate extensive lipolysis and the accumulation of non-esterified fatty acids (NEFAs) and β-hydroxybutyrate (BHBA), which can impair hepatic function and postpartum performance. This review integrates recent advances in the understanding of metabolic and immunometabolic regulation during transition, emphasising the interplay among energy metabolism, oxidative stress, and immune dysregulation. It critically re-evaluates current nutritional interventions including controlled-energy and negative DCAD diets, rumen-protected polyunsaturated fatty acids, and methyl donor amino acids while highlighting the emerging potential of injectable trace minerals as adjunct strategies to improve metabolic resilience. The review concludes by outlining remaining knowledge gaps and proposing a framework linking physiological mechanisms with targeted nutritional management. Full article

Colonial cheese production represents a valuable cultural and economic activity in southern Brazil. This study evaluated the effect of oral supplementation of dairy cows with an essential oil blend (EOB)—a combination of eucalyptus oil, peppermint oil, and menthol crystals—on the chemical composition and quality parameters of Colonial cheese during 21 days of ripening. Nine dairy cows were randomly assigned to three groups: control, EOB3.6 (3.6 g/cow/day), and EOB7.2 (7.2 g/cow/day). Milk from each treatment was used to produce Colonial cheeses, which were analyzed for physicochemical composition, texture, color, lipid profile, thiobarbituric acid reactive substances (TBARS), and microbiological quality at different ripening stages. Data were analyzed by analysis of variance (ANOVA) using SAS^® software, following verification of normality and homogeneity of variances. When assumptions were met, repeated-measures ANOVA was applied, and means were compared using Tukey’s test (p < 0.05). Sensory data were evaluated by ANOVA using XLSTAT^® (Addinsoft, Paris, France). EOB supplementation maintained the physicochemical integrity of the cheeses, with a gradual increase in fat content during maturation (40 g/100 g at 21 days, p < 0.05). At seven days, the EOB7.2 treatment showed lower lipid oxidation (TBARS = 0.063, p < 0.05), indicating antioxidant potential. Significant interactions between treatment and maturation were observed for color parameters and polyunsaturated fatty acids (PUFA) (p < 0.05). Cheeses from EOB7.2 presented higher saturated fatty acids (SFA) and lower unsaturated fatty acids (UFA) compared with the control (p < 0.05). No Salmonella spp. or Staphylococcal enterotoxins were detected. Counts of coagulase-positive Staphylococcus, molds, and yeasts remained stable, while Escherichia coli counts were lower in EOB-supplemented cheeses throughout ripening. Overall, EOB supplementation improved oxidative stability and microbiological safety without compromising the technological or compositional quality of Colonial cheese. Full article

The study analyzes the long-term development prospects of the Latvian dairy sector until 2032, using an integrated modeling approach that combines the AGMEMOD partial equilibrium model with the TOPSIS multi-criteria evaluation method. The study addresses the main challenge facing the sector—how to maintain productivity in the context of structural consolidation and increasing environmental requirements. The AGMEMOD model was recalibrated using updated data for Latvia for 2015–2023. Two scenarios were developed: A1 “Targeted and intensive farm modernization” and A2 “Limited farm modernization”. Scenario A1 is characterized by gradual technological adoption, leading to higher productivity while keeping total milk production almost unchanged relative to the Baseline scenario, whereas scenario A2 reflects slower modernization and reduced productivity growth. The TOPSIS evaluation identified scenario A1 as the most attractive alternative, as it combines productivity gains and greater adaptability to policy and environmental requirements. The results confirm that technological modernization and flexible policy mechanisms are essential to maintain the competitiveness and productivity performance of Latvia’s dairy sector. The integrated AGMEMOD–TOPSIS approach provides a methodological tool for evidence-based policy analysis and strategic planning in agricultural market management. Full article

The polymorphism of the bovine β-casein gene (CSN2) is of increasing interest due to its relevance for A2 milk production. This study genotyped 2773 Holstein-Friesian cows for five CSN2 alleles (A1, A2, A3, B, I) using both conventional DNA-based PCR and a newly evaluated direct PCR protocol. Eleven genotypes were detected, with A2/A2 (33.9%) and A1/A2 (30.3%) being the most common, resulting in an A2 allele frequency of 59.0%. Genetic diversity indices indicated moderate polymorphism and a significant deviation from Hardy–Weinberg equilibrium, consistent with ongoing selection for the A2 allele. Associations between CSN2 genotype and milk traits (305-day milk, fat, and protein yield; fat% and protein%) were evaluated using linear mixed-effects models including lactation number, age at calving, and calving year as covariates, and cow ID as a random intercept. Several genotype effects reached statistical significance (p < 0.05); however, all effect sizes were very small (partial η² < 0.01), indicating that any influence of CSN2 on production traits is negligible within this population and management context. These findings suggest that A2-oriented selection is unlikely to compromise productivity. The direct PCR genotyping method achieved 96–100% success and enabled substantially faster and more cost-efficient processing (approximately 80–90% reduction in reagent costs), providing a rapid and scalable approach for large herds. Full article

Kefir grains, originating from the Caucasus, are irregularly shaped, semi-solid granules resembling popcorn or cauliflower (0.3 to 3.5 cm), composed of bacteria and fungi embedded in extracellular polysaccharides such as kefiran. In this study, kefir samples were produced using different ratios of goat’s and cow’s milk (100:0, 75:25, 50:50, 25:75, and 0:100) to examine microbial populations, physicochemical and volatile properties, rheological behaviour, antioxidant capacity, and organic acid content. The type of milk used significantly affected the chemical composition and pH (p < 0.05), although titratable acidity remained stable during storage. Increasing the proportion of goat’s milk decreased viscosity but enhanced the total free amino acid (FAA) content. Goat milk kefir exhibited stronger antioxidant activity than cow milk kefir due to the formation of bioactive peptides and FAAs through proteolysis, with the highest values observed in samples with a higher proportion of goat’s milk and the lowest in 100% cow’s milk kefir. Organic acid levels increased during fermentation and, in 100% goat milk kefir, lactic, acetic, propionic, hippuric, butanoic, and citric acids reached their highest concentrations. The diversity and intensity of volatile compounds also increased proportionally with the goat milk ratio. In conclusion, considering antioxidant activity, volatile aroma components, organic acid content, sensory properties, and viscosity values, sample D, which is 75% goat milk kefir, is recommended for consumers. Full article

Colostrum is crucial for the survival, development, and the future productivity of newborns. In this study, we evaluated the immunological and microbiological quality of colostrum in 28 Rasa Aragonesa ewes and its relationship with offspring growth during the first 48 h postpartum. Colostrum samples were collected by hand milking immediately after parturition. Immunoglobulin concentration was assessed using Brix refractometry and the samples were categorised according to their immunoglobulin content: high (>24 Brix value), medium (19–23 Brix value), and low (<19 Brix value). Bacterial counts of aerobes and coliforms were determined with the 3M Petrifilm™ system and the weight of the lambs was recorded using a digital suspension scale. The mean aerobic count (AC) was 3.63 ± 0.69 log₁₀ CFU/mL after 24 h of incubation and the mean coliform count (CC) was 1.59 ± 0.82 log₁₀ CFU/mL after 24 h of incubation. Colostrum with a high immunoglobulin concentration had lower aerobic count after 48 h of incubation than that with poor immunological quality. In relation to coliform counts, similar values were found in all groups. No significant differences were observed in terms of lamb weight gain according to colostrum quality. In conclusion, the immunological quality of colostrum affected the AC determined, but it did not affect CC or early postnatal lamb weight. These findings offer preliminary insights into the usefulness of the Petrifilm™ system in microbiological quality determination of colostrum and its relationship with immunological quality determined in vitro. Full article

Lactoferrin (LF) is an iron-binding immunoprotein of the mammary gland whose levels increase during mastitis and may be influenced by the metabolic status of the cow. During early lactation, dairy cows are exposed to a negative energy balance (NEB) and the associated increase in susceptibility to mastitis. However, the extent to which the metabolic profile influences LF secretion in milk during the postpartum period remains unclear. The objective of this study was to assess the associations between metabolic status and milk LF contents in Holstein cows (n = 122) in the first twenty days of lactation. Based on the milk LF contents, the cows were categorized into two groups: LF-LOW (≤123 mg/L; n = 81) and LF-HIGH (>123 mg/L; n = 41). Serum indicators of energy and nitrogen metabolism, hepatic function, and selected macro-/microelements were measured; urine electrolytes and net acid–base excretion (U-ABB) were assessed; and milk composition, including somatic cell count (SCC), was determined. LF-HIGH cows showed higher SCC (p = 0.0516) and serum glucose (p < 0.001), together with lower serum triglycerides (p = 0.0101) versus LF-LOW cows. Milk beta-hydroxybutyric acid (BHB) content was lower in the LF-HIGH group (trend, p ≈ 0.062). LF-HIGH also exhibited significantly greater natriuresis (p = 0.0078) and a more negative U-ABB (p < 0.001), indicating higher acid–base load. In conclusion, elevated LF contents during the postpartum period were associated with the activation of local mammary gland immune defence and concurrent compensatory metabolic processes related to NEB, rather than with pronounced alterations in basic milk composition. Milk LF content may therefore be considered as a specific indicator of immunometabolic compensation during the early postpartum period, rather than as a general marker of overall cow health. Full article

Kargı Tulum cheese differs from other Tulum cheeses with its unique production and ripening method. No systematic study has yet explored the change in the volatile compounds and fatty acids during the ripening process of Kargı Tulum cheese. The objective of this study was to monitor the change in the fatty acids and volatile compounds of Kargı Tulum cheese at different time points during the production and ripening stages. Fatty acid profile, lipid quality parameters and volatile compound profiles were determined. A principal component analysis (PCA) was performed to determine how the volatile profiles differed across production and ripening stages. During the ripening, short- and medium-chain fatty acids (FAs) increased with notably high levels of butyric acid. Lipid quality parameters, including total saturated FAs (SFAs), atherogenicity index (AI), and thrombogenicity index (TI), remained unchanged throughout ripening. A total of 62 volatile compounds (VOC) were detected. Esters and ketones were the most abundant groups in fresh curds, while carboxylic acids became the dominant group by the end of the ripening process. The total concentration of most VOC increased over time. Butyric acid, hexanoic acid, ethyl hexanoate and acetic acid were the dominant compounds contributing the flavor of the Kargı Tulum cheese. This study presents data on what flavor compounds form and how they change during ripening and can be useful for comparative purposes in future studies on ripened raw milk cheeses. Full article

This study aimed to evaluate the effect of the supplementation with rumen-protected fat from soybean or palm and thermally processed soybean on the feed intake, digestibility of nutrients, milk production, and milk content of ewes. Twenty-five Pantaneiras ewes, 3–6 years old, 39.8 ± 3.51 kg body weight, and 65 ± 4 days in milk, were distributed into five treatments (5 ewes in each) in a completely randomized design continuous trial, over 56 days. The treatments consisted of daily supplementation with soybean-based rumen-protected fat (SPF; 30 g/d), palm-based rumen-protected fat (PPF; 30 g/d), a blend of soybean and palm rumen-protected fats (Blend; 30 g/d), thermally processed soybean (TPS; 124 g/d), and a control without supplementation. We performed a daily evaluation of feed intake and milk production, and every 14 days, we evaluated the nutrient digestibility, milk composition, and fatty acid profile. The protein and casein content were lower in the SPF treatment. Supplementation with PPF resulted in a higher saturated fatty acid content, while supplementation with TPS resulted in higher monounsaturated and polyunsaturated fatty acid contents. The supplementation with SPF resulted in higher milk fatty acid functionality. Feeding ewes SPF or TPS enhanced nutrient intake and digestibility, leading to increased milk production and an improved milk fatty acid profile. In contrast, supplementation with PPF resulted in a less favorable fatty acid composition. Full article

Iodine deficiency is the leading preventable cause of neurological damage worldwide. Dairy foods represent an important dietary iodine source. This study aimed to assess iodine concentration in milk, ricotta cheese, and yogurt, and to evaluate their contribution toward the recommended daily iodine intake. Whole pasteurized milk (WM; n = 12), partially skimmed pasteurized milk (PM; n = 21), skimmed pasteurized milk (SM; n = 7), ricotta cheese (RC; n = 26), whole yogurt (WY; n = 13), and low-fat yogurt (LY; n = 15) were purchased in local stores. Samples were analyzed through inductively coupled plasma mass spectrometry for iodine quantification. After removing outliers, the final dataset comprised 11 WM, 19 PM, 7 SM, 26 RC, 13 WY and 15 LY samples. Data were investigated through a mixed model with iodine concentration as the dependent variable, product type as fixed effect, and brand as random effect. Low-fat yogurt exhibited the greatest estimated iodine concentration (293.76 µg/kg), while SM and WM exhibited the lowest (211.92 and 197.63 µg/kg, respectively). Based on these results, a serving of milk (250 g) would provide 31.82–39.08% of the average daily iodine requirement, a serving of ricotta (125 g) 21.66%, and a yogurt jar (125 g) 21.54–24.11%. These findings confirm the nutritional relevance of dairy products as primary iodine sources. Full article

An elevated somatic cell count (SCC) affects the physicochemical characteristics of milk, altering its renneting ability and ultimately impacting the yield and quality of the cheese produced. This study aims to analyse the variations in the composition of Latvian goat milk and its technological properties in relation to SCC. Individual goat milk samples (n = 240) were collected from one of the largest goat farms in Latvia during 2019 and 2020. Latvian, Saanen, and cross-breed goat milk samples from different lactations were tested for their chemical composition (fat, protein, lactose, dry matter, and SCC), fat-to-protein ratio, freezing point, and curd firmness. Samples were collected during different lactation periods in order to analyse the seasonal effect on milk quality. The results demonstrated that milk samples from goats with lower SCCs (Group I) exhibited the highest fat (3.34%), lactose (4.56%), and dry matter (11.28%) concentrations and fat-to-protein ratios (1.02). Curd firmness decreased progressively from Group I to Group IV, fluctuating between Latvian Native (1.96–1.47 N), Saanen (1.91–1.59 N), and cross-breed (1.66–1.58 N) goat milk samples. A significantly lower (p = 0.030) curd firmness (1.56 N) was determined in the Group IV goat milk samples. Seasonal fluctuations in milk composition were observed in relation to curd firmness, which peaked in late lactation milk (3.85 N), although minor fluctuations were observed in protein concentrations (3.23% to 3.30%) across the sampling periods (2019 and 2020). These findings highlight the necessity of SCC monitoring in Latvian goat milk to ensure appropriate quality for milk processing. Full article

Using raw milk in cheesemaking poses several risks and often requires higher salt levels. Gel brine is a promising brining method to reduce salt and to prevent excessive softening, yet it was not employed to raw milk cheese before. In this study, the impact of ripening in gel brine—prepared by adding selected thickeners (gelatin and carrageenan) to a 12% salt brine—on the composition, proteolysis, texture, and microbiological properties of raw milk cheese was examined over 120 days. The aim was to assess the potential of gel brine to shorten the ripening time of raw milk cheese at a relatively low salt concentration while maintaining acceptable quality parameters. Response surface methodology was used to determine the optimum ripening time and thickener concentrations required to achieve target microbial counts, proteolysis, and moisture levels. The addition of stabilizers did not significantly influence the overall composition of the cheese, except for salt in dry matter. Stabilizers also limited the increase in trichloroacetic acid-soluble nitrogen (TCA-SN) during storage and led to a marked reduction in Escherichia coli counts. Texture profile analysis results were significantly affected (p < 0.05). The optimum conditions were estimated as 0.9% carrageenan, 0.8% gelatin, and 35 days of ripening. Full article

Although best known as a major parasite of sheep and goats, the blood-feeding abomasal nematode Haemonchus contortus can also infect cattle and buffaloes under the mixed-grazing Mediterranean conditions prevalent in Greece. The objectives of this study were as follows: (i) to determine the prevalence of H. contortus infections in dairy and beef cattle and buffaloes in Greece through an abattoir survey, (ii) to evaluate potential host- and farm-related risk factors including age, sex, management system, cattle productive orientation, and the co-existence of cattle and buffaloes on the occurrence of haemonchosis, and (iii) to assess the likelihood of detecting homozygous benzimidazole (BZ)-resistant H. contortus in large ruminant populations in relation to these determinants. A total of 213 abomasa (115, 55, and 43 from dairy, beef cattle, and buffaloes, respectively) were examined. A structured questionnaire provided additional animal- and farm-level information. Haemonchus-like helminths were collected and molecularly identified at the species level by amplifying a 321 bp fragment of the internal transcribed spacer 2 region of nuclear DNA. An allele-specific multiplex PCR, targeting codon 200 of the β-tubulin gene, was applied to detect BZ-resistant alleles. The prevalence of H. contortus infection was 21.2% in cattle and 69.8% in buffaloes. In cattle, multivariable analysis revealed that mixed-species farming (i.e., farms where cattle were the primary species and buffaloes were kept in smaller numbers), productive orientation, and slaughter age were significant predictors of increased H. contortus infection. Controversially, none of these factors were significantly associated with infection in buffaloes. Finally, multivariable modelling suggested that resistance patterns varied by host species, being more prevalent in intensively managed, older cattle, yet less common among older buffaloes and in herds where both species coexisted. Full article

Hyperketonemia (HYK), defined by blood beta-hydroxybutyrate (BHB) ≥ 1.2 mmol/L, is described as a significant risk factor for cows developing postpartum (pp) diseases and impaired reproductive performance. The goal of the present study was to observe metabolic challenges in transition cows and to identify systemic markers reflecting HYK associated with lessened reproductivity. Fifty-four Simmental cows were monitored, revealing approximately 30% prevalence of HYK at the early pp period on 7, 14, or 28 days in milk (DIM). We assessed the dry matter intake, rumination time (RT), serum liver activity index, non-esterified fatty acids (NEFAs), acute phase proteins, and uterine and oviductal health. Elevated NEFA and reduced RT 14 days antepartum were a good predictor for HYK at 7 DIM. Hyperketonemia at 14 DIM resulted in higher milk yield compared with controls. We could neither detect differences in uterine health nor in reproductive key performance parameters between hyperketonemic and control cows, whereby the proportion of polymorphonuclear neutrophils in oviductal epithelia was significantly lower in hyperketonemic cows 14 DIM. We conclude that elevated concentrations of BHB in HYK 7, 14, or 28 DIM indicated energy supply to support physiological metabolic adaptations and lactation and that, in the absence of excessive inflammation during the transition period, HYK was not a risk factor for impaired fertility. Full article

We evaluated the effects of rapeseed oil (RSO, rich in oleic, linoleic, and linolenic acids) and a commercial fat source (BOVI-LM, rich in palmitic and stearic acids) on the growth performance and blood biochemical parameters of dairy calves during the pre- and post-weaning phases. Eighteen crossbred bull calves were randomly allocated in a randomized complete block design to three dietary treatments (Control, RSO, and BOVI-LM) during the milk-replacer phase (Phase 1, days 0–28). Due to technical issues, BOVI-LM supplementation was discontinued in Phase 2 (starter-feed phase, days 35–77), leaving only Control (n = 12) and RSO (n = 6). Energy supply was calculated to support target average daily gains of 0.6 (Phase 1) and 1.0 kg (Phase 2). Body weight, clinical health, and blood samples for biochemical analysis were monitored throughout the trial. No treatment effect on body weight or blood biochemical parameters was detected (main effect of treatment: p ≥ 0.18 for all analytes). In contrast, phase and time effects were significant for most biochemical parameters (p < 0.05), reflecting the metabolic transition from a milk-based to a solid-feed diet. Aspartate aminotransferase activity increased over time (p < 0.001), whereas glucose concentrations decreased post-weaning (time × phase: p = 0.020). The treatment × phase interaction was non-significant for all variables (p ≥ 0.13), supporting the absence of detectable carry-over effects and justifying the pooling of former BOVI-LM calves into the Control group in Phase 2. Full article