Search Results (1,606)

Background/Objectives: DGAT1 p. K232A (rs109234250) is a well-established causal variant influencing milk fat and protein content in dairy cattle, but it is often absent from commercial genotyping arrays. PPP1R16A rs109146371 frequently appears as a top signal in genome-wide association studies (GWAS) for milk traits. This study aimed to evaluate the linkage disequilibrium (LD) between these two variants in Japanese Holsteins and assess whether rs109146371 exerts an independent effect on milk traits. Methods: A total of 256 Japanese Holstein cows were genotyped for DGAT1 p. K232A and PPP1R16A rs109146371 using TaqMan SNP assays. LD statistics (r², D′) were computed, and linear mixed-effects models were used to evaluate associations with 305-day milk yield, fat percentage, protein percentage, and solids-not-fat (SNF) percentage. Likelihood ratio tests were conducted to assess the independence of SNP effects. Results: Strong LD was observed between DGAT1 p. K232A and PPP1R16A rs109146371 (r² = 0.91, D′ = 0.9962). Both SNPs showed significant associations with all milk production traits; however, model comparisons indicated that rs109146371 did not improve model fit when K232A was included, suggesting no independent effect. Conclusions: PPP1R16A rs109146371 serves as a proxy for DGAT1 K232A rather than an independent determinant of milk traits. Full article

Over the decades, cattle have not been considered primary hosts for influenza A viruses (IAV), and their role in influenza epidemiology has been largely unrecognized. While bovines are known reservoirs for influenza D virus, the recent emergence of highly pathogenic avian influenza (HPAI) H5N1 clade 2.3.4.4b in U.S. dairy cattle marks an alarming shift in influenza ecology. Since March 2024, this virus has affected thousands of dairy cows, causing clinical signs such as fever, reduced feed intake, drastic declines in milk production, and abnormal milk appearance. Evidence suggests that the virus may be replicated within mammary tissue, raising urgent concerns about milk safety, foodborne transmission, and occupational exposure. This review highlights the unprecedented expansion of viruses into bovine populations, exploring the potential for host adaptation, and interconnected roles of pets, peridomestic animals, and human exposure within shared environments. The potential impacts on dairy production, food safety, and zoonotic spillover highlight the urgent need for integrated One Health surveillance to stay ahead of this evolving threat. Full article

The use of exogenous enzymes in the nutrition of dairy cows is an innovative and efficient strategy to maximize productivity and milk quality, with positive applications in the economic and environmental aspects of dairy farming. Therefore, the objective of this study was to evaluate whether the addition of a blend of exogenous enzymes to the diet of lactating Jersey cows has a positive effect on productive performance, milk quality, animal health, ruminal environment, and digestibility. Twenty-one primiparous Jersey cows, with 210 days in lactation (DL), were used. The exogenous enzymes used were blends containing mainly protease, in addition to cellulase, xylanase, and beta-glucanase. The animals were divided into three groups with seven replicates per group (each animal being the experimental unit), as follows: Control (T-0), basal diet without enzyme addition; Treatment (T-80), animals fed enzymes in the diet at a daily dose of 80 mg per kg of dry matter (DM); Treatment (T-160), animals fed enzymes in the diet at a daily dose of 160 mg per kg of DM. The study lasted 84 days, during which higher milk production was observed in the treated groups (T-80 and T-160) compared to the control group (p = 0.04). When calculating feed efficiency from days 1 to 84, greater efficiency was observed in both groups that received the blend compared to the control (p = 0.05). In the centesimal composition of the milk, it was observed that the percentage of protein in the milk of the T-160 group was higher compared to the control group (p = 0.03). The effect of the enzymes was verified for butyric (p = 0.05) and palmitic (p = 0.05) fatty acids. We also observed the effect of the enzyme blend on the amount of volatile fatty acids (VFAs), which were higher in the ruminal fluid of cows that received the enzymes (p = 0.01). Cows that consumed enzymes showed a higher apparent digestibility coefficient of crude protein (p = 0.01). In vitro, the main result is related to lower gas production in 24 and 48 h at T-160. We concluded that the use of a blend of exogenous enzymes in the diet of lactating Jersey cows was able to increase milk production in these animals, resulting in greater feed efficiency and also an increase in milk protein content, positively modulating the fatty acid profile in the rumen and improving the apparent digestibility of nutrients. Full article

The DHI data is crucial for monitoring the udder health of dairy cows during the breeding process. This study aimed to investigate the factors influencing milk production in dairy cows throughout this period. We analyzed DHI data from Holstein dairy cows in the Heilongjiang region, alongside the incidence of mastitis. The findings revealed that high-yielding cows demonstrated significantly higher peak milk yield days, peak milk yield, urea nitrogen levels, 305-day milk yield, and persistency (p < 0.0001) compared to their low-yielding counterparts. Conversely, high-yielding cows exhibited lower protein rates, fat-to-protein ratios, and milk fat rates (p < 0.0001). Additionally, the somatic cell count (SCC) in high-yielding cows was significantly lower than that in low-yielding cows (p < 0.0001). The multivariate linear regression analysis of the DHI data indicated that parity was the primary determinant affecting both milk yield and SCC. Statistical analysis of cows with clinical mastitis revealed that those experiencing a single episode of clinical mastitis during the lactation period were predominantly in their first and second parities, while recurrent cases were primarily observed in the second and third parities. These results suggest that as the number of lactations increases, the SCC also rises, reflecting the cumulative impact of parity on the udder health of dairy cows. Full article

Mastitis, an inflammatory disease caused by the invasion of various pathogenic microorganisms into mammary gland tissue, is a core health issue plaguing the global dairy industry. The consequences of this disease are manifold. In addition to directly compromising the health and welfare of dairy cows, it also precipitates a substantial decline in lactation function, a precipitous drop in raw milk production, and alterations in milk composition (e.g., increased somatic cell counts and imbalanced ratios of milk protein to fat). These changes result in a marked degradation of milk quality and safety, and in turn, engender significant economic losses for the livestock industry. Therefore, the establishment and implementation of a comprehensive prevention and control system is a key strategy to effectively curb the occurrence of mastitis, reduce its incidence rate, and minimise economic losses. This review systematically explores the complex etiological factors and pathogenic mechanisms of mastitis in dairy cows, and summarises various diagnostic methods, including milk apparent indicators monitoring, pathogen detection, physiological parameter monitoring, omics technologies, and emerging technologies. Furthermore, it undertakes an analysis of treatment protocols for mastitis in dairy cows, with a particular emphasis on the significance of rational antibiotic use and alternative therapies. Moreover, it delineates preventive measures encompassing both environmental and hygiene management, and dairy cow health management. The objective of this paper is to provide a comprehensive and scientific theoretical basis and practical guidance for dairy farming practices. This will help to improve the health of dairy cows, ensure a stable supply of high-quality dairy products, and promote the sustainable and healthy development of the dairy farming industry. Full article

High temperature typically decreases feed intake, milk production, and efficiency and increases metabolic disorders and health problems, greatly impacting farm economics. Supplements based on Saccharomyces cerevisiae have been suggested to benefit cows under heat stress, but effects on dairy cow performance are contradictory. This study aimed to evaluate the influence of heat stress on the effects of live yeast supplementation on the performance of dairy cows. Environmental temperature parameters were compared to two thermal humidity indices (THI1 and THI2) using wet bulb or dew point temperatures, as explanatory variables of dairy cow performance during the hot season. The experiment followed a randomized complete block design with 12 Holstein cows blocked by lactation number, days in milk, and milk production (two cows per block) and within each block, each cow was randomly assigned to a maize silage-based TMR with a concentrate mixture containing no yeast culture (Control) or 1 g/kg concentrate dry matter of a live yeast culture based on S. cerevisiae (Yeast) for 35 days. The experiment lasted for 35 d. Dry matter intake (DMI) was significantly higher for Yeast than it was for Control for all classes of temperature and THIs studied with an average increase of 2 kg DM per day, except for mean THI1 (from 54 to 60), for which the DMI was similar between treatments. Yeast promoted significantly higher milk yield than Control for all classes of daily maximum and mean temperature, averaging an increase of 4 kg of milk per day. Results suggest a more marked effect of temperature and indicate that yeast supplementation improved lactation performance of dairy cows exposed to hot weather. Full article

This study aimed to produce and evaluate artisanal garrafa ice cream made with goat milk, performing microbiological analysis and sensory evaluation, and comparing it with cow milk-based ice cream. Pasteurized goat and cow milk were used to prepare pecan and chocolate cookie-flavored ice creams. Microbiological tests confirmed the absence of total and fecal coliforms, as well as aerobic mesophiles, indicating adherence to Good Manufacturing and Hygiene Practices. All products complied with the microbiological safety limits established by Mexican Official Standards. Sensory evaluation techniques are essential for assessing how attributes such as appearance, aroma, color, flavor, and texture influence consumer preferences for dairy products. A sensory evaluation was conducted with 72 untrained panelists. Among all samples, pecan-flavored goat milk ice cream received the highest preference, particularly for its taste and texture. Panelists also noted differences in color and odor between goat and cow milk ice creams. The sensory analysis highlighted the distinctive organoleptic properties of goat milk ice cream and its potential for consumer acceptance. These findings suggest that artisanal goat milk ice cream, especially the pecan variety, can successfully compete with traditional cow milk products in the expanding market for innovative and high-quality dairy foods. Full article

Colostrum is the milk harvested during the first few hours after calving, which contains high levels of immunoglobulins, antimicrobial peptides, and growth factors essential for the health of neonates. The primary objective of this study was to investigate the genetic background of colostrum quality traits (based on Brix percentage) in Holstein cows. Using phenotypic records of 58,338 Holstein cows from 37 dairy farms, we identified significant systematic effects influencing colostrum quality measured by digital Brix refractometer, estimated genetic parameters, and performed weighted single-step genome-wide association studies (WssGWAS) to identify genomic regions and candidate genes associated with these traits. The average (±SD) Brix percentage was 23.76 ± 3.25%. With heritability values ranging from 0.21 ± 0.03 (Brix in third parity) to 0.30 ± 0.02 (Brix in second parity), colostrum quality was determined to be moderately heritable. Genetic correlations between colostrum quality across parities ranged from 0.37 ± 0.14 to 0.81 ± 0.13. For colostrum quality from cows in the first, second, and third parities, WssGWAS enabled the identification of 30, 32, and 38 genomic regions explaining 4.18%, 4.42%, and 5.58% of the total additive genetic variance, respectively. Two immune-related genes (CNR1 and ZXDC) were identified as promising candidate genes for colostrum quality traits. In summary, colostrum quality measured in first parity cows should be evaluated as a different trait from measurements in later parities in breeding programs. These findings provide useful information for dairy breeders to genetically improve colostrum quality in dairy cattle populations. Full article

Plant-based yogurts are increasingly recognized as sustainable and health-conscious alternatives to dairy-based products, driven by environmental, ethical, and nutritional motivations. Pistachio milk, derived from an efficient and resilient crop, emerges as a promising raw material for yogurt production, offering unique sensory qualities and a dense nutritional profile. Rich in unsaturated fatty acids, bioactive compounds, and essential nutrients, pistachios are ideal for fermentation with lactic acid bacteria (LAB). In this study, a novel pistachio-based yogurt analog (PBYA) was developed using lactic acid fermentation, with a yogurt commercial starter, of pistachio milk. The production process was optimized to create an additive-free, clean-label formulation without the use of stabilizers or thickeners. The physicochemical, microbiological, and sensory properties of the PBYA were evaluated over refrigerated storage. The final product exhibited high levels of protein (5.6%), fat (5.4–6.8%), and total solids (20.5–21.4%), along with desirable texture and flavor characteristics. Notably, PBYA presented significantly higher concentrations of total free amino acids (754 mg/L) compared to commercial soy (557 mg/L) and cow’s milk yogurts (390 mg/L), particularly in essential amino acids such as lysine, methionine, and tryptophan. This enhanced free amino acid profile contributes to the product’s functional and nutritional value. Sensory analysis revealed good acceptance of the product, with improvements in viscosity and firmness over time, likely due to microbial exopolysaccharide production. Overall, the findings highlight the feasibility and commercial potential of PBYA as a clean-label, plant-based fermented product that meets current consumer demands for sustainability, nutrition, and sensory quality. Full article

Mastitis is a common disease for dairy cows that exerts tremendously detrimental impacts on the productivity of cows and economic viability of pasture. Dihydromyricetin (DMY) is a flavonoid monomeric compound that possesses anti-inflammatory and antioxidant activity. This study aimed at dissecting the effects of DMY on the lactation performance, blood parameters, gut microbiota, and metabolite profiles of dairy cows with subclinical mastitis (SM). The results showed that dietary supplementation with DMY resulted in a reduction in milk somatic cell count, an increase in serum T-AOC and CAT activity, as well as a decrease in serum MDA content. DMY significantly enhanced the prevalence of Coprococcus and Roseburia and reduced the proportion of Cyanobacteria, Proteobacteria, and Dehalobacterium. The amino acid degradation, antibiotic resistance, and O-antigen building blocks biosynthesis (E. coli) capacity of gut microbes were notably diminished by DMY supplementation in cows with SM. Moreover, fecal and plasma metabolomic analysis revealed that DMY intervention reduced the abundance of pro-inflammatory metabolites including arachidonic acid analogues, ω-6 PUFA, and structural components of bacteria. Nevertheless, the levels of anti-inflammatory and antioxidant metabolites involving secondary bile acids, antioxidant vitamins, specific amino acid analogues, etc. were elevated by DMY administration. Overall, DMY might ameliorate SM via enhancing antioxidant capacity and improving the structure of the hindgut microbial community and metabolite profiles in dairy cows. These findings underscore the potential of DMY as a valuable dietary supplement for the improvement of mammary inflammatory diseases in dairy cows. Full article

MFD is a nutritional disorder in dairy cattle characterized by a reduction in milk fat content despite a normal or increased milk yield. This review synthesizes current knowledge on the biological mechanisms and nutritional factors contributing to the development of this condition. Disruptions in rumen fermentation and alterations in fatty acid biohydrogenation (particularly the formation of trans-10 fatty acids) are recognized as central contributors to MFD. Several theories have been proposed to explain its pathophysiology, including the glucogenic, volatile fatty acid, trans fatty acid, and biohydrogenation theories. MFD is most commonly associated with diets low in fiber and high in polyunsaturated fatty acids or starch, which promote the accumulation of fatty acid intermediates that inhibit mammary lipogenesis. Among these, trans-10, cis-12 conjugated linoleic acid is particularly notable for its potent suppression of de novo fatty acid synthesis in the mammary gland. While proper dietary formulation remains the most effective preventive strategy, nutritional interventions such as magnesium-based alkalinizers, sodium bicarbonate, intravenous arginine, and vitamin E have shown promise in mitigating established cases. This review underscores the importance of nutritional management in preserving milk fat synthesis and promoting overall animal health. Full article

Essential oil blends (EOBs) have been increasingly studied for their multifunctional benefits in animal nutrition and food science. This study evaluates the impact of an EOB composed of eucalyptus and peppermint oil on the physicochemical, microbiological, and sensory characteristics of dairy products—milk, cream, and colonial cheese. Forty lactating cows were assigned to two groups: control and EOB addition (3.6 mL/cow/day) on the diet. Sensory analysis showed that the addition of EOB does not significantly alter milk or cream characteristics but enhances cheese texture perception. Fatty acid analysis revealed a higher proportion of SFA and lower UFA in cheese produced from the EOB group. Additionally, the EOB reduced lipid oxidation throughout the ripening process, with significantly lower TBARS values at 45 days of maturation (0.1300), compared to those from cows without supplementation of EOB (0.1585), suggesting improved oxidative stability. Microbiome analysis indicated that the bacterial community composition remained stable, with a slight reduction in Streptococcus spp. in EOB cheeses. No drastic shifts in microbial diversity were detected, and a lower overall abundance of bacterial taxa was observed in the EOB group. Results suggest that EOBs in dairy cow diets may positively modulate dairy product characteristics and alter the microbiota without compromising sensory quality. This study highlights the technological potential of EOB supplementation in dairy production. Full article

This study evaluated the effects of reduced nitrogen fertilization and the intercropping of annual ryegrass (Lolium multiflorum Lam.) with forage legumes—common vetch (Vicia sativa L.) and red clover (Trifolium pratense L.)—on milk production and enteric methane emissions in grazing dairy cows. Twelve Holstein × Jersey cows were assigned to a crossover design involving two treatments: ryegrass monoculture (RG) or ryegrass—legume mixture (RG + Leg). Methane emissions were measured using GreenFeed systems; grazing behavior, milk yield and composition, and organic matter digestibility were also assessed. Legume inclusion contributed ~9% of the pre-grazing biomass, and cows grazing RG + Leg pastures had lower herbage mass (−214 kg DM/ha) and lower herbage allowance (−6 kg DM/cow/day) than cows on monoculture ryegrass. Energy-corrected milk (ECM), methane emissions (g/day and g/kg ECM), and grazing behavior were not significantly affected by treatment. These results suggest that, under subtropical grazing conditions, reducing nitrogen fertilization combined with the modest inclusion of vetch and red clover does not mitigate enteric methane emissions nor enhance animal performance. Enhanced strategies to increase legume proportion in mixed swards are needed to unlock their potential for sustainable intensification of pasture-based dairy systems. Full article

Trypanosoma vivax, a haemoprotozoan of African origin, has spread throughout Latin America, mainly affecting cattle through mechanical transmission by flies. This study reports an outbreak of T. vivax on a dairy farm in the midwestern region of São Paulo State, Brazil. Clinical signs included progressive weight loss, lethargy, hyporexia, reduced milk production, abortions, neurological signs, and deaths. The herd comprised 238 crossbred Holstein-Gir cattle (200 cows, 38 calves). Blood samples were collected from 104 randomly selected cows and all 38 calves to assess hematocrit (HCT) and total plasma protein (TPP), and detect trypomastigote forms using blood and buffy coat smears. PCR was performed on EDTA blood from 30 smear-negative cows. Trypanosoma sp. was identified in 51.9% (54/104) of the smear samples, with morphometric confirmation of T. vivax infection. About 66.6% (20/30) of the smear-negative cows tested positive by PCR, showing the higher sensitivity of molecular tests. Anemia was observed in 56.8% of infected cows, with significantly lower HCT and TPP values than in uninfected animals. The absence of quarantine for new animals, high fly density, and shared needles for oxytocin injections were likely contributing factors. This study underscores the crucial role of molecular diagnostics in accurately investigating outbreaks. Full article

Subclinical mastitis in dairy cows poses a significant challenge to the dairy industry, leading to reduced milk yield, altered milk composition, compromised animal health, and substantial economic losses for dairy farmers. A model based on the XGBoost algorithm, optimized with an Improved GOOSE Optimization Algorithm (IGOOSE), is presented in this work as an innovative approach for predicting subclinical mastitis in order to overcome these problems. The Dairy Herd Improvement (DHI) records of 4154 cows served as the model’s original foundation. A total of 3232 samples with 21 characteristics made up the final dataset, following extensive data cleaning and preprocessing. To overcome the shortcomings of the original GOOSE algorithm in intricate, high-dimensional problem spaces, three significant enhancements were made. First, an elite inverse strategy was implemented to improve population initialization, enhancing the algorithm’s balance between global exploration and local exploitation. Second, an adaptive nonlinear control factor was added to increase the algorithm’s stability and convergence speed. Lastly, a golden sine strategy was adopted to reduce the risk of premature convergence to suboptimal solutions. According to experimental results, the IGOOSE-XGBoost model works better than other models in predicting subclinical mastitis, especially when it comes to recognizing somatic cell scores, which are important markers of the illness. This study provides a strong predictive framework for managing the health of dairy cows, allowing for the prompt identification and treatment of subclinical mastitis, which enhances the efficiency and quality of milk supply. Full article