Milk Production Research Articles

Genetic score omics regression and multi-trait meta-analysis detect widespread cis-regulatory effects shaping bovine complex traits

Abstract To complete the genome-to-phenome map, transcriptome-wide association studies (TWAS) are performed to correlate genetically predicted gene expression with observed phenotypic measurements. However, the relatively small training population assayed with gene expression could limit the accuracy of TWAS. We propose Genetic Score Omics Regression (GSOR) correlating observed gene expression with genetically predicted phenotype, i.e., Estimated Breeding Values (EBV) in agriculture or polygenic score (PGS) in medicine. The score, calculated using variants near genes with assayed expression (cis-EBV or cis-PGS), provides a powerful association test between cis-effects on gene expression and the trait. In simulated and real data, GSOR outperforms TWAS in detecting causal/informative genes. We applied GSOR to transcriptomes of 16 tissues (N∼5000) and 37 traits in ∼120,000 cattle and conducted multi-trait meta-analyses of omics-associations (MTAO). We found that, on average, each significant gene expression and splicing mediates cis-genetic effects on 8∼10 traits. Many prioritised genes by GSOR and MTAO can be verified by Mendelian Randomisation analysis and show significantly reduced dN/dS, suggesting elevated evolutionary constraint for these genes. Using multiple methods, we detect expression levels of genes and/or RNA splicing events underlying previously thought single-gene loci to influence multiple traits. For example, the expression and RNA splicing of DGAT1 from multiple tissues regulated milk production, mastitis, gestation length, temperament and stature. Also, gene expression and splicing of ABO (Histo-blood group) and ACHE (acetylcholinesterase, Cartwright blood group) affected protein concentration and mastitis, respectively. Taken together, our work provides new methods and biological insights for prioritising informative omics-phenotype associations in mammals.

«Сырная проблема»: попытка объективного количественного анализа в региональном аспекте

Milk and dairy products are traditional components of Russian diet. In difficult economic conditions, dairy import tends to decrease, and the national dairy industry tries to compensate for it. Today, the cheese consumption in Russia is below the rational standard, which makes it necessary to boost the domestic cheese production. The authors studied the cheese segment of the domestic dairy industry to analyze the possibilities of increasing cheese production. The research relied on the leadership criteria and the main industrial indicators in the regions, e.g., raw materials and production infrastructure, which were subjected to statistical and mathematical processing. The data were systematized by a set of indicators with precalculated statistical characteristics, which made it possible to rank the national cheese leaders. The organic index of cheese products was measured based on the protocol proposed by the authors. The correlation analysis revealed the links between the gross cheese production in the regions and their raw material supply. The Russian Federation produces more than 900,000 tons of cheese and cheese products and imports 300,000 tons. The current per capita consumption of cheese is 6.5 kg per year, but domestic companies provide only 4.2 kg, i.e., 60% of the rational consumption rate. The list of the cheese leaders includes 38 regions, 20 of which provide more than 78% of the total national production, with the Altai Region leading the way. However, some of these cheese-making regions are currently experiencing an acute shortage of dairy raw materials, while some milk-producing regions have a poor processing infrastructure that cannot support cheese production. The national dairy industry has not enough raw materials as a result of a long-term dairy cattle decrease over the past two decades. A sustainable raw material base for cheese making needs 1.2 million more cows to increase the gross milk production by 9.8 million tons (29.6% of the data for 2022). “The cheese issue” can be resolved by increasing the population of pedigree dairy cattle and encouraging farmers to start cheese dairy businesses. Both measures require strong federal and regional support.

Nicotinic acetylcholine receptors modulate casein secretion and claudin expression in mammary epithelial cells by regulating STAT5 and Akt pathways.

Nicotinic acetylcholine receptors modulate casein secretion and claudin expression in mammary epithelial cells by regulating STAT5 and Akt pathways.

Effects of corn silage, alfalfa hay, and oat-vetch mixed silage combinations on milk production, rumen fermentation, and nutrient digestibility in high-producing dairy cows.

The objective of this study was to explore the effects of corn silage, alfalfa hay, and oat-vetch mixed silage combinations on milk production, rumen fermentation, nutrient digestibility, and feeding cost in dairy cows. Nine multiparous Holstein dairy cows (DIM: 94.11 ± 9 d, milk yield: 41.0 ± 2.5 kg) were each fed 3 experimental diets in a replicated Latin square design. The experimental diets contained corn silage, alfalfa hay, and mixed silage in 3 different forage proportions (diet 1, 40:10:0; diet 2, 30:5:15, and diet 3, 20:0:30; DM basis). Cotton seed meal (CSM) or soybean meal (SBM) were used as the protein source to balance the CP content. The mixed silage was made from oats and vetch grown together in a 50:50 ratio, and all diets were formulated to contain 16% CP and 50:50 forage-to-concentrate ratio (DM basis). Cows fed diet 3 had a 9% reduction in DMI compared with diet 1. Associated with this reduction in DMI, cows fed diet 3 also had reduced yield of milk protein (22.0%), fat (15.7%), and lactose (18.5%) compared with cows fed diet 1. Characteristics of rumen fermentation were similar among diets; however, cows fed diet 3 had lower rumen fluid valerate and higher acetate: propionate ratios compared with diet 1. The N intake was not different among cows fed the 3 diets, but cows fed diet 3 excreted 0.2% less urinary N compared with diet 1. The combinations of corn silage and mixed silage reduced the cost of the diets (diet 1, $0.543; diet 2, $0.503; diet 3, $0.465/kg DM), and whereas milk production was reduced, the feed cost per milk yield was lowest for cows fed diet 3 ($0.404) and highest for cows fed diet 1 ($0.407). We conclude that cows fed diets with combinations of corn silage, alfalfa hay, and mixed silage, consumed less feed and produced less milk but also produced less urinary N and had a lower cost of feed for milk production than cows fed corn silage diets. This demonstrated that partial displacement of expensive corn silage, alfalfa hay, and SBM with mixed silage and CSM reduced costs, but due to the reduced DMI and milk yields, more research on these diets will be needed before they can be recommended as viable options to replace corn silage and SBM diets.

Invited review: Interactions between prolactin and local regulation of the mammary gland.

Invited review: Interactions between prolactin and local regulation of the mammary gland.

Factors Influencing the Setting of Automatic Teat Cup Removal at the End of Machine Milking in Dairy Cows—An Overview

Overmilking occurs when the teat cups remain attached to the udder during milking, even though there is little or no milk flow. This puts pressure on the teat tissue and reduces milk production due to longer milking times, meaning fewer cows are milked per hour. Therefore, the correct removal of the teat cup at the end of mechanical milking is crucial for the milking process. The aim of this study was to describe the factors influencing automatic teat cup removal (ATCR) at the end of mechanical milking and to demonstrate its importance for udder health, milk production and milk quality. There are considerable differences between milking system suppliers and countries regarding the minimum removal of the teat cup at the end of the milking process. However, to ensure good milk quality, prevent teat damage and reduce the risk of mastitis, it is important to shorten the working time of the milking machine on the udder in both automatic and conventional milking systems. For this reason, several studies have shown that increasing the milk flow switch point effectively reduces milking time, especially in automatic milking systems where dairy cows are milked more than twice a day. However, when the ATCR setting was increased above 0.5 kg·min−1, milk production decreased, and the number of somatic cells in the milk produced increased. Therefore, the use of ATCR at a milk flow rate of 0.2 kg·min−1 significantly increased milk production, improved milk quality and maintained udder health when a low vacuum level (34–36 kPa) was used in milking machines such as MultiLactor and StimuLactor (Siliconform, Germany). In conclusion, ATCR at a milk flow of 0.2–0.3 kg·min−1 is a useful level to achieve various goals on dairy farms when a low vacuum of 34–36 is used in the milking machine. If the milking machine uses a higher vacuum, it is possible to program a higher ATCR at a milk flow of up to 0.5 kg·min−1.

Classification of Milking Animals Based on Production and Reproductive Performance for Effective Management Decisions: An Approach Using K-Means Clustering

This study was conducted to determine the feasibility of implementing principal component analysis (PCA) and K-means clustering method for grouping cows in a dairy herd based on their performance on multiple traits related to milk production and reproduction, for implementing need based, group specific management practices. The proposed method was tested on two different management systems, namely System A (Friesian x Jersey crossbreds managed intensively under Low Country Dry Zone) and System B (Sahiwal crossbreds managed semi intensively under Low Country Intermediate Zone). Six large scale state dairy farms were grouped into the two systems with 1507 lactation records of 643 cows belonging to System A and 552 lactation records of 185 cows in System B. Means of calf birth weight, age at first calving, lactation length (LL), total milk production (MP), average daily yield, and calving interval (CI) of System A were significantly superior to the respective means of System B (p<0.05). The PCA used MP, LL and CI traits where all three traits exhibited significant positive pairwise correlations (p<0.05). For both systems, the first two PCs explained over 85% of the total variation of traits. Traits MP and LL played a major component in PC1 (production component) and CI was loaded heavily for PC2 (reproduction component). For both systems, the K- means clustering approach was effective with the three clusters of cows formed within a system showing significant differences for MP, LL and CI (p<0.05).

Effect of supplementing high-fiber or high-starch concentrates or a 50:50 mix of both to late-lactation dairy cows fed cut herbage on methane production, milk yield, and ruminal fermentation.

Effect of supplementing high-fiber or high-starch concentrates or a 50:50 mix of both to late-lactation dairy cows fed cut herbage on methane production, milk yield, and ruminal fermentation.

Selenium content in milk and dairy products: Estimation of the daily intake and assessment of the potential risk to public health.

Selenium content in milk and dairy products: Estimation of the daily intake and assessment of the potential risk to public health.

Invited review: Somatotropin and lactation biology.

Invited review: Somatotropin and lactation biology.

A randomized controlled trial evaluating postpartum delayed milking strategy and oral calcium bolus administration on production and blood metabolites of Holstein cows.

Postpartum hypocalcemia has substantial economic impacts on dairy production systems. Our objectives were to investigate the effects of delayed milking and Ca bolus supplementation on lactation performance and blood metabolites of dairy cows. A total of 699 Holstein cows (175 primiparous and 524 multiparous) were stratified by parity group and randomly assigned within each group to 6 treatments in a 2 × 3 factorial arrangement. Factor 1 was supplementation with 2 Ca boluses (BL; 31 g Ca/bolus), administered twice: once within 30 min and the second one 24 h after parturition, or no supplemental Ca (NBL). Factor 2 was the milking strategy whereby cows were milked 3 times daily (M0) or delay-milked for 24 (M24) or 48 h (M48) after the colostrum harvest. This resulted in 6 treatment groups: M0-BL (n = 125), M24-BL (n = 118), M48-BL (n = 111), M0-NBL (n = 118), M24-NBL (n = 114), and M48-NBL (n = 113). Blood was collected immediately before calving and again at 1, 2, 3, 5, and 11 d postpartum. Milk production was recorded daily until 12 DIM, then monthly until 90 DIM. Generalized linear mixed models were used for the analysis of data. The BL supplementation did not affect milk yield or measured blood metabolites. In multiparous cows, blood Ca concentration at d 2 postcalving was 2.59 mmol/L (95% CI = 2.49 to 2.69 mmol/L) for M48 cows and 2.32 mmol/L (95% CI = 2.26 to 2.48 mmol/L) for M0 and M24 cows. Blood P concentration at d 2 postcalving was 2.33 mmol/L(95% CI = 2.19 to 2.47 mmol/L) for M48 cows, 1.81 mmol/L (95% CI = 1.66 to 1.96 mmol/L) for M24 cows, and 1.65 mmol/L (95% CI = 1.49 to 1.81 mmol/L) for M0 cows. At d 3 postcalving, blood P concentration was 2.01 mmol/L(95% CI = 1.80 to 2.22 mmol/L) for M48 cows, 1.78 mmol/L (95% CI = 1.63 to 1.93 mmol/L) for M24 cows, and 1.66 mmol/L (95% CI = 1.50 to 1.82 mmol/L) for M0 cows. Multiparous cows in the M48 group also had greater blood glucose at d 3 and lower BHB at d 2 after calving than M0-treated cows. In multiparous cows, the delayed milking strategy resulted in a lower daily milk yield from 3 to 12 DIM as compared with the M0 group. The 3 monthly test-day records remained unaffected across the experimental groups. Overall, delayed milking increased blood Ca and P and decreased BHB concentration in M48-treated cows. The effects of BL supplementation on production performance and blood metabolites and the potential synergy with delayed milking were not evident in this experiment.

Genetic relationships among methane emissions from breath, dry matter intake, body weight, and milk production traits of Dutch dairy cows.

Genetic relationships among methane emissions from breath, dry matter intake, body weight, and milk production traits of Dutch dairy cows.

Occurrence of pregnancy losses within the same lactation in grazing dairy cows.

Occurrence of pregnancy losses within the same lactation in grazing dairy cows.

Immunology of the Bovine Mammary Gland: Advances in Recent Years.

Immunology of the Bovine Mammary Gland: Advances in Recent Years.

Metallic, carbon-based, and polymeric nanomaterials: transforming dairy farming practices for sustainability.

Metallic, carbon-based, and polymeric nanomaterials: transforming dairy farming practices for sustainability.

The role of age at first calving in shaping production and reproductive outcomes in Italian buffaloes.

The age at first calving (AFC) is a critical parameter in dairy herd management due to its impact on feeding costs, genetic progress, longevity, and thus, farm profitability. With the growing global demand for buffalo milk products, recent advancements in reproductive practices and feeding techniques have contributed to a reduction in AFC in Italy. This study investigates the impact of AFC on the productive and reproductive performance of primiparous Italian Mediterranean buffaloes. Data were collected from 50,661 animals across 115 herds, covering 362,703 first-lactation test-day records from 2013 to 2023. The study analyzed productive traits, including milk yield (kg/d), days to milk peak (DMP, d), ECM (kg/d), fat and protein contents (%), and SCS. Reproductive traits, such as calving interval (CIN, d) and days open (DO, d), were analyzed from 2013 to 2021. Repeated mixed linear models were used to assess the effects of AFC on the afore-mentioned traits, accounting for DIM, calving year and season, and, when applicable, their interactions. Results highlighted a significant reduction in AFC (from 36 to 35 mo), CIN (from 457 to 447 d), and DO (from 147 to 136 d) over the studied period. Buffaloes with AFC >42 mo produced 0.52 kg/d more milk and 0.90 kg/d more ECM, with slightly higher fat content (+0.04%) compared with those with AFC ≤32 mo. This trend was consistent throughout DIM categories. Somatic cell score was significantly lower in buffaloes with AFC between 32 and 35 mo (2.78), whereas higher SCS was observed in those with AFC ≤32 mo (2.81) or >35 mo (2.80). Buffaloes with AFC comprised between 34 and 37 mo had significantly lower CIN and DO (449-450 and 137-139 d, respectively) compared with those with both lower or greater AFC (454 and 143 d, respectively), whereas DMP was not significantly affected by AFC. As expected, likely due to the out-of-breeding technique, the highest values for both CIN and DO were observed in buffaloes calving the first time in winter and spring (on average 455 and 145 d, respectively), and lower values were recorded for those calving in autumn and summer (on average 449 and 138 d, respectively). Buffaloes with AFC ≤30 mo that calved during winter exhibited significantly greater DO (>150 d) compared with those calving with AFC >42 mo during the same period (140 d). This is likely due to the lower capacity to restore ovarian activity that may reduce fertility in younger buffaloes compared with older ones. Conversely, buffaloes with AFC >42 mo that calved in summer tended to have extended DO (139 d) in respect to those with lower AFC (≤30 mo) in the same period (135 d). This may be due to the interaction between the increased photoperiod and the reduced feed intake caused by summer heat stress, which may have an effect on older buffaloes' fertility. Therefore, AFC between 34 and 37 mo represents the optimal window for Italian Mediterranean buffaloes, combining shorter CIN and DO with sustained milk production. The reduction of AFC could significantly enhance farm profitability and may be achievable through the integration of breeding programs, better reproductive technologies across seasons, and targeted nutritional strategies during the preweaning and prepartum phases.

Clustering of feeding strategies to improve the evaluation of enteric and slurry methane emissions in dairy cows: an observational study based on Italian dairy farms

The dairy sector is facing increasing challenges in terms of its environmental impact. Methane (CH4) is a focal point of research due to its role in enteric emissions from livestock. This study investigates the effects of various feeding strategies on CH4 emissions from lactating Holstein cows fed total mixed ration (TMR) silage-based diets. Four different equations for estimating CH4 emissions were chosen according with accuracy and equation variables, and then compared checking whether diet composition has an effect on average emission levels. Only Mills equation detected differences between nutritional clusters. Considering this equation on average, the CH4 emissions were equal to 460.36 ± 46.95 g/d, 18.90 ± 1.57 g/kg DMI, 12.89 ± 2.83 g/kg FPCM, equal to a loss of 5.93% of gross energy intake. Clustering based on feed composition identified four distinct groups of diets, with no statistically significant difference in CH4 emissions. The highest emissions were found in the nutritional cluster with higher fibre and starch content, with methane production (MeP) reaching 485.85 g/d, 19.47 kg/kg DMI and 14.82 kg/kg FPCM. This indicates that diet nutrients profile significantly impacts CH4 emissions, underscoring the importance of adopting sustainable feeding strategies in dairy production. Notably, a positive correlation exists between MeP and milk productivity, while methane intensity negatively correlates with feed efficiency. The findings emphasise the necessity for context-specific emission factors and underscore the importance of implementing sustainable feeding practices to mitigate CH4 emissions enhancing the efficiency of dairy production systems.

Fabrication of Integrated Monolithic Columns Based on Reduced Graphene Oxide-Deep Eutectic Solvents/Bimetallic Metal–Organic Framework@ Molecular Imprinted Polymer for Selective Solid-Phase Extraction of Vitamins D2 and D3 from Milk and Dairy Products

Fabrication of Integrated Monolithic Columns Based on Reduced Graphene Oxide-Deep Eutectic Solvents/Bimetallic Metal–Organic Framework@ Molecular Imprinted Polymer for Selective Solid-Phase Extraction of Vitamins D2 and D3 from Milk and Dairy Products

Estimating β-casomorphin-7 exposure from milk and dairy product consumption: a comprehensive assessment for the European population

β-Casomorphin-7 (BCM-7), a heptapeptide derived from β-casein hydrolysis, has gained attention for its potential role in gastrointestinal discomfort and certain diseases, yet its effects remain controversial. This study aimed to provide the first reliable estimation of BCM-7 exposure for low, medium and high consumers of milk and dairy products in the European population. We developed a database on BCM-7 released after simulated digestion, combining literature review and direct analysis of milk and selected dairy products. Using European food consumption data, we estimated BCM-7 daily exposure for adults (132–2541 μg), adolescents (163–2594 μg) and children (200–2357 μg). Milk emerged as the most significant source of BCM-7 exposure across all population groups. Statistical analysis revealed differences in exposure levels between adults and children at medium consumption levels. This work provides the first comprehensive estimation of dietary BCM-7 exposure, laying the groundwork for future research on its potential health effects.

Sustainable valorization of almond and peanut plant-based milk cakes: The use of terpenoid mixtures as ready-to-use solvents to enhance supercritical CO2 extraction.

Sustainable valorization of almond and peanut plant-based milk cakes: The use of terpenoid mixtures as ready-to-use solvents to enhance supercritical CO2 extraction.