Dairy

The combined effects of human chorionic gonadotropin (hCG) treatment on Day 5 (Day 0 = the day of artificial insemination: AI) and intravaginal progesterone device (IVPD) treatment from Day 5 to 19 on the conception rate and plasma sex steroid hormone were examined in lactating dairy cows. In Experiment 1, cows were divided into a non-treatment group (n = 181), untreated; an IVPD group (n = 74), with an IVPD inserted into the vagina from Day 5 to 19; and an hCG + IVPD group (n = 87), with 3000 IU hCG administered intramuscularly on Day 5 and an IVPD inserted into the vagina from Day 5 to 19. The conception rates of the hCG + IVPD group, which underwent ≤3 AIs (52.8%) and >3 AIs (73.3%), and the IVPD group, which underwent >3 AIs (63.0%), were significantly higher than that of the non-treatment group, which underwent ≤3 AIs (34.2%). In Experiment 2, blood samples were collected from the non-treatment group (n = 6), the IVPD group (n = 6), and the hCG + IVPD group (n = 7) on days 5, 8, 12, and 15 from estrus to measure plasma progesterone (P₄) and total estrogen (E) concentrations. The plasma P₄ concentration of the hCG + IVPD group tended to be higher than that of the non-treatment group on Day 15; however, plasma E concentrations were not different among groups. These results suggest that the conception rate was improved by hCG + IVPD treatment regardless of AI number because of higher plasma P₄ concentrations later in the estrous cycle. Full article

Buffalo milk is a rich source of precursor fatty acids for bioactive compounds and provides an optimal environment for bacterial growth. This study aimed to isolate and select lactic acid bacteria strains with potential to conjugated linoleic acid (CLA) production for technological application in fermented buffalo milk. Fifty-eight strains were isolated from raw milk, kefir, artisanal cheese, kombucha, and jaboticaba juice and tested for CLA biosynthesis. In milk fermentation, selected strains with linoleic acid (LA) conversion rates ranging from 65.66% to 21.86% were L. paraplantarum, L. plantarum, P. pentosaceus, and L. fermentum. The highest viability average values between 11.85 and 11.15 Log CFU/mL were observed after 8 h of fermentation for the L. plantarum, control L. plantarum, and L. fermentum treatments, while it took 10 h of fermentation for L. paraplantarum and P. pentosaceus to reach a stationary phase, with pH stabilizing at 4.60 ± 0.1 after 30 h. Despite L. paraplantarum showing the highest in vitro CLA production (0.99 mg/mL), in buffalo milk, all strains similarly produced c9t11 CLA, with no detectable t11c12 CLA. P. pentosaceus and L. fermentum showed a fatty acid profile with higher PUFA content, especially in CLA and MUFA, related to a lower degree of atherogenicity (IA) and thrombogenicity index (ThI). These findings boost understanding of dairy (raw milk, artisanal cheese, and milk kefir) and non-dairy substrates (kombucha and jaboticaba juice) as reservoirs for functional bacteria and highlight buffalo milk as a matrix for diversification of naturally enriched fermented dairy products. Full article

This study explores the microbiota and metabolite profile of raw cow’s milk, analyzing the correlation between them and their potential impact on consumer health, focusing on factors like cow’s feeding regimen (conventional vs. grazing), the herd’s geographical location (coastal vs. inland), and the thermal stability of raw milk samples. To achieve this, raw milk quality was assessed through mesophilic bacterial count and thermal stability using the 70° and 80° ethanol test. Metataxonomic analysis was performed using Illumina 16S rRNA hypervariable region sequencing, and untargeted metabolomics was conducted using UHPLC-Q/TOF MS/MS, followed by multivariate correlation analysis. All samples met quality standards. A total of 1258 prokaryotic ASVs were identified, spanning 48 bacterial phyla and one archaeal phylum, with 909 genera and 349 unidentified ASVs. Additionally, 70 metabolites were identified, including essential amino acids, vitamins, and bioactive compounds with antimicrobial, anti-inflammatory, and prebiotic properties. Significant correlations between bacterial diversity and metabolite profiles were observed. Feeding regimen and geographical location influence microbial composition and metabolite abundance, while thermal stability was linked to specific metabolites like oleamide and pyridoxal. These findings suggest that microbiota-derived metabolites can enhance the nutritional and functional value of milk. Further research is needed to understand how environmental and processing factors influence these dynamics. Full article

The present study explored the combined effects of CC (Opuntia stricta [Haw.] Haw.) and full-fat corn germ (FFCG) as a source of supplementary PUFA on milk fatty acid (FA) composition of dairy goats fed elephant grass (EG). Twelve Saanen goats were used in a replicated 4 × 4 Latin square design in a 2 × 2 factorial arrangement of treatments (GC or FFCG as energy sources, and the inclusion or not of CC in the diet as a partial substitute for EG). The proportions of various milk FAs were influenced by CC, FFCG, or both. Significant interactions between CC and FFCG were noted for most trans-C18:1 and CLA isomers. Specifically, including CC in the FFCG-supplemented diet increased the levels of trans-11 C18:1 and cis-9, trans-11 CLA in milk fat, whereas these isomers were unchanged or slightly reduced with CC in the GC diet. Similar patterns were observed for C18:2 n-6, while C16:0 increased with CC in the GC diet. Ratios of trans-C18:1/C18:0 and trans-11 C18:1/C18:0 were notably higher when CC was included in the FFCG-supplemented diet. These findings suggest that CC inhibits the last step of rumen biohydrogenation in dairy goats, enriching milk with trans-11 C18:1 and cis-9, trans-11 CLA when supplementary PUFA is provided in the diet. Full article

This review highlights a paradigm shift in our understanding of hypocalcemia during milk fever by introducing the concept of the Calci-Inflammatory Network. Traditionally viewed as a pathological deficiency necessitating rapid correction (e.g., through calcium borogluconate infusions or dietary adjustments like dietary cation-anion difference), periparturient hypocalcemia is reinterpreted here as an adaptive, protective response. Within this new framework, reduced circulating calcium levels may help temper systemic inflammation by limiting lipopolysaccharide (LPS) aggregation and curbing excessive macrophage activation. The review discusses how calcium signaling, the calcium-sensing receptor (CaSR), and immune cell functions adapt under hypocalcemic conditions to modulate inflammatory processes. This integrated perspective not only redefines the role of hypocalcemia but also proposes the Calci-Inflammatory Network as a novel concept through which we can understand how changes in calcium homeostasis mitigate inflammatory cascades—potentially lowering the incidence of periparturient diseases and enhance overall cow health and farm productivity. Future research should investigate the long-term effects of hypocalcemia, the environmental influences on this Calci-Inflammatory Network, and their collective impact on disease susceptibility and inflammation. Full article

The acid whey derived during the production of Greek yoghurt, i.e., yoghurt acid whey (YAW), is considered as environmental pollutant due to its low pH and high lactose content. YAW may be obtained by centrifugation or ultrafiltration or filtration through cloth bags (traditional method) of the initial yoghurt, methods that could affect its composition. In the last years, efforts have been made to improve its composition using membrane technology. In the present work, the composition of 35 different YAW samples from Greek Yoghurt dairies was studied. The YAW samples were grouped according to the way of production and the kind of milk in the case of the traditional method. The results showed that both the kind of milk and the way of yoghurt staining affected its composition. Ovine YAW derived from traditional straining was richer in lactic acid and calcium than bovine YAW. Moreover, the composition of bovine YAW varied among the different ways of straining, and this affected its behaviour during membrane processing. Nanofiltration of three representative bovine YAW samples and one ovine YAW sample at their natural pH, i.e., pH 4.5, and at 25 °C removed the lactic acid at a range from 40 to 55%, and the monovalent cations > 60% and retained lactose and galactose at percentages > 95% and 80% respectively. Full article

There are few studies on how dairy × beef crossbred calves perform during the pre-weaning phase compared to dairy calves. This observational study evaluated birth weight, average daily gain (ADG), and disease occurrence in Angus × Holstein (Ang × Hol) crossbred and Holstein calves reared under the same conditions on a commercial dairy farm. Retrospective data from 379 calves (290 Holstein females; 89 Ang × Hol crossbreds: 46 males, 43 females) born between January 2022 and August 2023 were analyzed. Variables included dam parity, calving type, birth weight, colostrum Brix levels, serum total protein (STP), mortality, disease occurrence, ADG, and weaning weight. Statistical analysis used linear and logistic regression models. Ang × Hol male calves had higher odds of assisted calving. Male and female Ang × Hol calves had greater birth weights than Holstein calves, with males being the heaviest. No differences in STP were observed. Ang × Hol calves (both sexes) showed higher ADG than Holsteins but did not differ from each other. Holstein calves had higher odds of diarrhea (OR: 2.95, 95% CI: 1.63–5.35), while Bovine Respiratory Disease (BRD) incidence was similar across groups. Overall, Ang × Hol crossbred calves demonstrated superior growth and lower diarrhea risk under the same management conditions. Full article

The dairy industry relies on the health and well-being of dairy cows for the optimal production of milk and dairy products. Mastitis, a prevalent and economically burdensome disease characterized by udder inflammation, poses significant challenges to dairy farmers worldwide. In this study, we employed peptidomics to explore the peptide profiles of dry secretions collected from dairy cows at specific intervals during the dry-off period. We hypothesized that alterations in peptide composition during the dry period may influence pathogen proliferation and immune cell functioning, thereby impacting mastitis susceptibility. Our objectives were to investigate the following: (i) differences in peptide composition and alterations between healthy cows and those with subclinical mastitis, potentially serving as biomarkers for early mastitis detection and offering insights into udder bioprocesses; (ii) variations in peptide profiles between the early (day 2) and later (day 21) stages of the dry-off period during both health conditions. Dry secretions were collected from 16 udder quarters of 8 cows at two defined time points—Day 2 (D2) and Day 21 (D21)—during the dry period. Our results revealed distinct peptide patterns between healthy and subclinical mastitis cows, as well as temporal variations in peptide profiles throughout the dry-off period. A total of 1235 peptides, originating from 59 distinct proteins (primarily β-casein), were detected across the four groups: subclinical mastitis day 21 (SCM-D21), subclinical mastitis day 2 (SCM-D2), healthy day 21 (H-D21), and healthy day 2 (H-D2). Furthermore, 56 out of the 1235 peptides identified in total matched known functional peptides, with a total of 17 different functions including antimicrobial, antioxidant, and immunomodulatory, suggesting their potential roles in mastitis pathogenesis and mammary gland physiology. Comparative analyses revealed changes in the levels of these functional peptides across the four different groups, suggesting their potential roles in regulating immune responses, oxidative stress, inflammatory processes, and other biological activities during subclinical mastitis and the dry-off period. These findings provide valuable insights into mastitis detection, management strategies, and dairy cow health monitoring, offering promising avenues for enhancing milk quality and dairy industry sustainability. Full article

The prevention of human infectious diseases associated with waterborne pathogens is reliant on the effective disinfection of water supplies by drinking water treatment plants and adequately maintained distribution networks. For decades, the chlorination of water has safeguarded public health, where chlorine is broadly applied in both water disinfection and food production facilities, including the dairy industry, from farm to fork. The identification of chlorine disinfection byproducts in water supplies and dairy food produce is of great concern, however, due to their cytotoxic, genotoxic, mutagenic, teratogenic, and potential endocrine-disrupting activity. The association between the trihalomethanes (THMs) and haloacetic acids (HAAs) and tumour formation is documented and has led to the implementation of maximum contaminant levels enforced by the European Union. Furthermore, chlorine resistance in bacterial species is associated with multidrug resistance in clinically relevant pathogens, where antibiotic- and biocidal-resistant genes are also environmental pollutants. Increasing the concentration of chlorine to surmount this resistance will ultimately lead to increasing concentrations of byproducts in both water and food products, exceeding the EU requirements. This article provides insight into chlorine DBPs as a toxicological public health risk and the relationship between chlorine resistance and antibiotic resistance in microbes relevant to dairy food production. Full article

This pilot study investigated whether reductions in enteric CH₄ emissions could be obtained without affecting dry matter intake (DMI) when iodoform was mixed into total mixed rations (TMRs). The experiment consisted of four periods of 14 d with four rumen-cannulated Holstein dairy cows. In the pre-period, no iodoform was added to TMR, while either 8, 16, or 20 mg iodoform/kg DM was added to TMR in the remaining periods in a change-over design. However, the experiment was not balanced across treatments and periods due to unexpected animal responses in the second period. Dry matter intake and gas exchange were measured the last 3 d in each period using respiration chambers. Rumen grab samples were collected for microbial analyses on d 14. Dry matter intake was unaffected by the addition of iodoform to TMR at or below 20 mg/kg DMI. Methane and H₂ yields (g/kg DMI) quadratically decreased (up to 46%) and increased (up to 1127%), respectively, with the increasing dose. This pilot study indicated that CH₄ reductions can be obtained with an addition of up to 20 mg iodoform/kg DM in the diets of dairy cows without affecting DMI. However, high iodine concentration in iodoform limits its use in commercial herds within the EU. Full article

Use of pair housing for preweaning calves has shown positive benefits in terms of health and production, with it also being thought to offer social support in times of stress such as when calves are disbudded. Calf disbudding through thermal cautery is a common procedure, with recognized physiological and behavioral implications. This study’s objective was to utilize continuous monitoring accelerometers to compare the impact of disbudding on the behavior of pair and individually housed calves. Data from an all-year-round dairy herd in the southwest of England were collected via an accelerometer (ABS breeder tag, Genus, Cheshire, UK) fitted to a forelimb of a convenience subset of calves (n = 265) within two weeks of age. Data were collected between March and December 2020 and covered the period 7 days prior to disbudding until 30 days post disbudding. Calves underwent thermal cautery disbudding by farm staff using local anesthesia and a systemic nonsteroidal anti-inflammatory drug. Data from 205 calves (125 pair-housed and 80 individually housed) were included in analysis through generalized estimating equations models. The calf activity (p = 0.98), number of lying bouts (p = 0.40), and lying time per day (p = 0.75) were not associated with the housing treatment of the calves. Calf activity was associated with the day compared to disbudding (p < 0.001), with both housing treatments having decreased activity in the days following disbudding, taking approximately 14 days to return to pretreatment levels. Full article

Cow’s milk is an important part of the human diet, primarily due to its high nutritional content, particularly proteins and fats. The processing of milk enhances its safety while modifying its composition and structure, influencing bioactive peptide release, which impacts protein quality, digestion, and allergenicity. Recently, filtered milk, which undergoes pasteurisation and microfiltration, has become available in UK supermarkets, offering a longer shelf life than pasteurised milk. This study aimed to evaluate the effects of microfiltration on the protein structure of cow’s milk, compared with pasteurisation, including analysis of the peptide profile released after in vitro gastrointestinal digestion of commercially available semi-skimmed filtered and pasteurised cow’s milk. Dynamic light scattering analysis revealed that the Z-average particle size of filtered milk was significantly (p < 0.05) larger than that of pasteurised milk across all brands. Additionally, filtered milk exhibited a significantly (p < 0.05) lower free thiol concentration compared with pasteurised milk, indicating structural modifications in proteins. Confocal laser scanning microscopy (CLSM) further highlighted heterogeneities in the distribution of fat and protein, with filtered milk samples showing increased interaction between fat globules and proteins. After gastrointestinal digestion, the numbers of peptides released from filtered milk exceeded those of peptides released from pasteurised milk by an average of 5%. These results provide new insights into the potential impact of microfiltration on the microstructure of milk. Further investigations using advanced analytical techniques are needed to assess the implications of these changes on protein bioavailability and human health. Full article

Colostrum is a nutrient-dense food rich in proteins, immune modulators, and growth factors essential for neonatal development. Its lipids serve as a key energy source and facilitate cellular functions. While yak colostrum (YC) and buffalo colostrum (BC) exhibit high nutritional value, their lipid compositions remain unclear. This study employed lipidomics to analyze and compare the lipid profiles of YC and BC with cow colostrum (CC), identifying 872 lipids across 33 subclasses. Differential analysis revealed 137, 100, and 131 lipids, with significant expression differences between YC vs. CC, BC vs. CC, and YC vs. BC, respectively. YC exhibited higher levels of α-linolenic acid and docosahexaenoic acid, suggesting a potential role in enhancing neurodevelopment and cognitive function. In contrast, the upregulation of specific lipid components in BC, such as phosphatidylethanolamine (PE) and phosphatidylinositol (PI), coupled with the downregulation of specific lysophosphatidylcholine (LPC) and lysophosphatidylethanolamine (LPE), indicated a potential benefit for lipid metabolism and inflammatory regulation. These findings suggest that YC may be particularly suitable for neonates requiring enhanced energy support, while BC may offer advantages in lipid metabolism modulation. The study provides critical insights into the distinct lipid compositions of YC and BC, laying a scientific foundation for the development of tailored nutritional supplements. These results also hold significant implications for the dairy industry, driving innovation and optimization of colostrum-based products to meet diverse nutritional demands. Full article

Pseudomonas aeruginosa is a ubiquitous environmental bacterium that causes a variety of infections in humans and animals. Although antibiotic resistance in livestock has been extensively documented, continuous surveillance remains crucial for tracking emerging resistance trends and assessing control measures. During 2017 and 2018, 234 strains of P. aeruginosa were identified from 1063 strains of pathogenic and nonpathogenic bacteria isolated from raw milk of healthy and mastitis cows. In this study, 132 convenience P. aeruginosa isolates were recovered and tested for antimicrobial susceptibility and the presence of antimicrobial resistance genes and virulence factors. Antimicrobial susceptibility testing revealed that these P. aeruginosa isolates were resistant to three (gentamicin, tobramycin, and ceftazidime) out of eight antibiotics. Real-time PCR targeting 21 antibiotic resistance genes indicated that aminoglycoside modifying enzyme (AME) gene ant(3″)-I was most frequently identified in both antimicrobial-resistant and -susceptible P. aeruginosa isolates, followed by aac(6′)-II and aac(6′)-Ib. The β-lactamase encoding gene, bla_PDC, was mainly identified in susceptible P. aeruginosa isolates. Virulence factors screening revealed the presence of exoS, exoT, exoU, pyo, aprA, toxA, plcH, algD, lasB, lasI, lasR, rh1L, and rh1R in resistant isolates, with the detection rates ranging from 16.7% to 88.9%. Additionally, next-generation sequencing was conducted on three resistant isolates to validate these findings. This study showed the antibiotic resistance of P. aeruginosa in raw milk samples from large-scale dairy farms in Jiangsu and Shandong provinces, China. Full article

In this study, the total phenolic and anthocyanin contents, antioxidant activity, color, pH, serum separation, water holding capacity (WHC), rheology, texture and viscosity of cranberry (Cornus mas L.)-enriched yogurt were determined. The addition of cranberries (5–15%) to yogurt resulted in a proportional increase in antioxidant activity, total anthocyanin and phenolic contents. In yogurt samples to which cranberries were added, the WHC increased, while the serum separation values decreased. Due to the red color of the cranberry fruits, the L* (lightness) and b* (yellowness) values decreased, and the a* (redness) values increased (p < 0.05). The sensory evaluation showed that the 10% (w/w) cranberry-added yogurt had the highest general acceptability score when compared to the other samples. Also, it was found that the addition of 10% (w/w) cranberries to the yogurt samples contributed positively to the physicochemical (textural properties, rheological behavior, color and serum separation) and biochemical (antioxidant activity, phenolics and anthocyanins) properties of the samples. The addition of cranberries to yogurt influenced the growth of microbial populations. The number of starter bacteria (counts for Lactobacillus delbrueckii subsp. bulgaricus) in the yogurt samples with cranberries was slightly lower than in the control sample; but was at an acceptable level. E. coli and coliform bacteria were not detected in either the control yogurt sample or the samples with added cranberries. In conclusion, the addition of 10% (w/w) cranberries to yogurt can be recommended in order to achieve acceptable physical and sensory properties as well as the enrichment of yogurt with nutritional and functional aspects. Full article

This study aims to clarify the use of Limosilactobaillus reuteri (Lmb. reuteri) in dairy products, emphasizing its main characteristics and limitations through a comprehensive literature review. Lmb. reuteri, previously classified as Lactobacillus reuteri, is a lactic acid bacterium (LAB) generally present in the gastrointestinal tracts of humans and other animals, such as sheep, chickens, and rodents. Lmb. reuteri was reclassified as part of the genus Limosilactobacillus in April 2020, reflecting advancements in biomolecular research that identified distinct metabolic and biochemical characteristics among strains. This species is an important producer of reuterin, an antimicrobial compound facilitated through glycerol fermentation via specific enzymatic pathways. In addition, selected strains of Lmb. reuteri can be considered probiotic bacteria with numerous health benefits and that lead to well-being improvements. It is consistently related to improvements in gut health, immune function enhancement, and cholesterol reduction. Furthermore, its application in dairy products has gained prominence and is increasingly reported in the literature due to its technological and sensory benefits. Despite the challenges of its incorporation into the dairy matrix, largely due to the need to supplement these products, it has already demonstrated significant effects on several dairy products’ technological, sensory, and quality characteristics. Future research should address challenges like strain-specific efficacy and regulatory hurdles for the application of Lmb. reuteri in foods. Full article

Doce de leite is a caramel-like confection, mainly produced in several Latin American countries, with increasing popularity worldwide. This overview outlines nine distinct industrial technologies for the production of doce de leite: (1) total batch manufacturing process; (2) batch manufacturing system with fractionated mix addition; (3) manufacturing with pre-concentration in a vacuum evaporator and finishing in an open pan; (4) manufacturing with pre-concentration in a vacuum evaporator, finishing in an open pan, and lactose micro-crystallization; (5) continuous flow manufacturing with total concentration in a vacuum evaporator and a viscosity control holding tank (hot well); (6) manufacturing with total concentration in a vacuum evaporator and sterilization in an autoclave system; (7) manufacturing with sucrose pre-caramelization and a total batch system; (8) manufacturing in colloidal mill without an evaporation process; and (9) manufacturing based of doce de leite bars with a sucrose crystallization stage. We conducted a literature review to gather data on the discussed processes and their principal characteristics, which may be pertinent to doce de leite manufacturers. The choice of a specific process will depend on the desired doce de leite characteristics, the type of doce de leite to be produced, and the manufacturing company’s requirements. When properly integrated, these technologies contribute to efficient and profitable production, yielding high-quality products with appropriate chemical, microbiological, and sensory characteristics at an industrial scale. Full article

The biological and nutritional value of kefir makes it imperative to widen its customer reach by extending its shelf life, enabling its storage and transport at ambient temperatures, and reducing its packaging cost requirements. A well-documented and widely used food processing method that can achieve the above-mentioned outcomes is spray drying through the formulation of kefir powder, with quality attributes that will closely resemble that of the original product. In the present work, a variety of drying carriers (trehalose, fructo-oligosaccharides, maltodextrin, gum arabic, and whey proteins) were studied with regard to their effect on the properties of powdered and reconstituted kefir samples. Particularly, the physicochemical characteristics (moisture content, pH, acidity, color), powder properties (bulk density, tapped density, water solubility index, insoluble matter), adsorption isotherms, particle size distribution, microbiological properties, and structural characteristics of the samples were evaluated. Gum arabic and maltodextrin produced kefir powder samples with the lowest moisture content. Spray drying affected a reduced acidity and, as a consequence, an increased pH in the reconstituted samples, especially without any carrier addition and with trehalose and fructo-oligosaccharides irrespective of their concentration. Desirable color attributes were achieved on the kefir powder samples with trehalose, fructo-oligosaccharides, and maltodextrin regardless of their concentration in the product. Fructo-oligosaccharides, added at 3%, gave the highest values of bulk density, while whey proteins, due to their nature, exhibited the lowest. All carriers tested improved the water solubility index when compared to the control sample. The sample with 10% whey proteins exhibited the lowest moisture adsorption compared to the control at the highest relative humidity environments employed for the test. In the absence of agglomeration, powder granule size and structural morphology were not affected by the carriers. The survival of lactococci in the powdered kefir samples, in comparison to the control product, was higher in the case where 4% trehalose or 5 to 10% whey proteins were added. On the contrary, yeast populations decreased significantly during drying and they were not affected by the presence of the different carriers. As shown by the findings of the present study, trehalose proved to be the most effective carrier, among the others used, for producing high-quality kefir powder products. However, further work is required with regard to the keeping quality of the product during long-term storage. Full article

Dairy cows rely on their complex rumen microbial community to convert host-indigestible feed into nutrients usable for host growth, maintenance, and milk production. Previous work by our group found that the rumen bacterial community is dynamic over the course of two lactations and that cows with high and low milk production efficiency (MPE) have different taxa associated with either phenotype. Here, we characterized the ruminal fungal and archaeal communities to determine if these microbial populations exhibit properties similar to that of the rumen bacteria with respect to MPE over time. Our results show a decrease in fungal diversity over the course of both lactation cycles with an increase during the transition period. The fungal community had only a few taxa associated with efficiency. For the ruminal archaea, we found no change in diversity across both lactation cycles and only taxa in the genus Methanospera were found to be more abundant in high-MPE cows. Given that our previous study used 454 pyrosequencing, we also sought to determine if a resequencing of these communities using Illumina-based technology would alter our previous findings. We found that resequencing showed no significant deviation from our original broad conclusions, with the exception of some minor taxonomic associations. Full article