A 1000-cow study across four European countries was undertaken to understand to what extent ruminant microbiomes can be controlled by the host animal and to identify characteristics of the host rumen microbiome axis that determine productivity and methane emissions. A core rumen microbiome, phylogenetically linked and with a preserved hierarchical structure, was identified. A 39-member subset of the core formed hubs in co-occurrence networks linking microbiome structure to host genetics and phenotype (methane emissions, rumen and blood metabolites, and milk production efficiency). These phenotypes can be predicted from the core microbiome using machine learning algorithms. The heritable core microbes, therefore, present primary targets for rumen manipulation toward sustainable and environmentally friendly agriculture.

Milk characteristics are affected by heat stress, but very little information is available on changes of milk protein fractions and their relationship with cheesemaking properties of milk. The main objective of the study was to evaluate the effect of hot season on milk protein fractions and cheesemaking properties of milk for Grana Padano cheese production. The study was carried out in a dairy farm with a cheese factory for transforming the milk to Grana Padano cheese. The study was carried out from June 2012 to May 2013. Temperature and relative humidity of the inside barn were recorded daily during the study period using 8 electronic data loggers programmed to record every 30 min. Constant managerial conditions were maintained during the experimental periods. During the experimental period, feed and diet characteristics, milk yield, and milk characteristics were recorded in summer (from June 29 to July 27, 2012), winter (from January 25 to March 8, 2013), and spring (from May 17 to May 31, 2013). Milk yield was recorded and individual milk samples were taken from 25 cows selected in each season during the p.m. milking. Content of fat, proteins, caseins (CN), lactose and somatic cell count (SCC), titratable acidity, and milk rennet coagulation properties were determined on fresh samples. Milk protein fraction concentrations were determined by the sodium dodecyl sulfate-PAGE. Data were tested for nonnormality by the Shapiro-Wilk test. In case of nonnormality, parameters were normalized by log or exponential transformation. The data were analyzed with repeated measures ANOVA using a mixed model procedure. For all the main milk components (fat, protein, total solids, and solids-not-fat), the lowest values were observed in the summer and the greatest values were observed in the winter. Casein fractions, with the exception of γ-CN, showed the lowest values in the summer and the greatest values in the winter. The content of IgG and serum albumin was greater in summer than in the winter and spring. A mild effect of season was observed for milk SCC, with greater values in summer than in the winter and spring. A worsening of milk coagulation properties was observed in summer season. The alteration of cheesemaking properties during hot season seems strictly linked with changes of milk protein fractions mainly with the decrease of αS-CN and β-CN and the increase of undefined proteins.

Acute acidosis was induced in sheep, and gastrointestinal permeability was assessed by using lactulose as a permeability marker. Metabolism was evaluated by monitoring blood metabolites. Four rams (72.5 ± 4.6 kg BW) were used in a 2 × 2 changeover design experiment. The experimental period lasted 96 h from -24 to 72 h. After 24 h of fasting (from -24 to 0 h) for both controls and acidosis-induced rams (ACID), 0.5 kg of wheat flour was orally dosed at 0 and 12 h of the experimental period to ACID, while the basal diet (grass hay, ad libitum) was restored to control. At 24 h, a lactulose solution (30 g of lactulose in 200 mL of water) was orally administered. Blood samples were collected at -24, 0, 24, 48, and 72 h of the experimental periods for the analysis of metabolic profiles and during the 10 h after lactulose dosage to monitor lactulose changes in blood. In addition, rumen and fecal samples were collected at 24 h of the experimental period. The acidotic challenge markedly reduced (P < 0.01) rumen pH and VFA but increased rumen d- and l-lactic acid (P < 0.01). Concurrently, a decrease of fecal pH and VFA occurred in ACID (P < 0.01), together with an abrupt increase (P < 0.01) of lactate and fecal alkaline phosphatase. Blood lactulose was significantly increased in ACID peaking 2 h after lactulose dosage. Blood glucose, β-hydroxybutyrate, Ca, K, Mg, and alkaline phosphatase showed a significant reduction (P < 0.05) at 24 h, whereas urea and NEFA declined (P < 0.05) from 48 to 72 h. A strong inflammatory acute phase response with oxidative stress in ACID group was observed from 24 to 72 h; higher values of haptoglobin (P < 0.01) were measured from 24 to 72 h and of ceruloplasmin from 48 (P < 0.05) to 72 h (P < 0.01). Among the negative acute phase reactants, plasma albumin, cholesterol, paraoxonase, and Zn concentration also decreased (P < 0.05) in ACID at different time points between 24 and 72 h after acidotic challenge start. A rise (P < 0.05) of reactive oxygen metabolites and a drop of vitamin E (P< 0.01) between 24 and 72 h were indicative of oxidative stress in ACID. The perturbation of these blood metabolites suggests that acute acidosis was effectively induced by our model. The increase of lactulose in blood in ACID indicates that gastrointestinal permeability for the marker increased and the large increment after 2 h from dosage suggests that most of the passage occurred through the rumen or abomasal walls.

Organic trace mineral (ORG) supplementation to dairy cows in substitution of sulfate (INO) sources has been associated with improvement in immune function during stressful states such as the peripartal period. However, the effect of supplemental ORG during pregnancy on the neonatal calf is unknown. Therefore, our aim was to investigate the effects of ORG supplementation during late pregnancy on the immune system and growth of the neonatal calf. Of specific interest was the evaluation of inflammation-related microRNA (miRNA) and target gene expression in blood neutrophils as indicators of possible nutritional programming. Forty multiparous cows were supplemented for 30d prepartum with 40 mg/kg of Zn, 20 mg/kg of Mn, 5 mg/kg of Cu, and 1mg/kg of Co from either organic (ORG) or sulfate (INO) sources (total diet contained supplemental 75 mg/kg of Zn, 65 mg/kg of Mn, 11 mg/kg of Cu, and 1 mg/kg of Co, and additional Zn, Mn, and Co provided by sulfates), and a subset of calves (n=8/treatment) was used for blood immunometabolic marker and polymorphonuclear leukocyte (PMNL) gene and miRNA expression analyses. Samples were collected at birth (before colostrum feeding), 1d (24 h after colostrum intake), and 7 and 21d of age. Data were analyzed as a factorial design with the PROC MIXED procedure of SAS. No differences were detected in BW, but maternal ORG tended to increase calf withers height. Calves from INO-fed cows had greater concentrations of blood glucose, GOT, paraoxonase, myeloperoxidase, and reactive oxygen metabolites. Antioxidant capacity also was greater in INO calves. The PMNL expression of toll-like receptor pathway genes indicated a pro-inflammatory state in INO calves, with greater expression of the inflammatory mediators MYD88, IRAK1, TRAF6, NFKB, and NFKBIA. The lower expression of miR-155 and miR-125b in ORG calves indicated the potential for maternal organic trace minerals in regulating the PMNL inflammatory response at least via alterations in mRNA and miRNA expression. Overall, these results indicate that maternal nutrition with organic trace minerals could alter the neonatal innate immune response at least in part via changes in gene and miRNA expression. Further studies involving inflammatory challenges during the neonatal period should be performed to determine the functional benefit of maternal organic trace minerals on the neonatal immune response.

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