In European countries, silage-free feeding is an ancient tradition and has a particularly positive reputation among consumers. In the present study, we compared grass-based forages from the same plot conserved as hay or silage or fed fresh either on pasture or indoors, and we evaluated the differences in sensory properties of milk and uncooked pressed cheese. All herbage from the first cut of a grassland dominated by perennial ryegrass was harvested on the same day and preserved either as hay or silage. The first regrowth of the same plot was used for strip grazing or green feeding indoors. Balanced by breed, 24 Montbéliarde and 24 Holstein cows were allocated to the 4 treatments. Apart from the forages, the late-lactation cows received 3 kg/d of dry matter from concentrate. After 2 wk of dietary adaptation, the bulk milk of 3 subgroups, each with 4 cows, was collected. Part of the milk was pasteurized, and part was left raw and partly transformed to small-sized Cantal-type cheese ripened for 9 wk. Milk and cheese underwent descriptive sensory analysis by a trained sensory panel, as well as analyses of physicochemical traits. Volatile organic compounds of the cheeses were also analyzed. Raw and pasteurized milk from hay-fed cows had less intense odors of cooked milk, cream, and barnyard than milk from grazing cows, whereby the effect of pasteurization did not differ between herbage utilization methods. Cheeses obtained from cows fed fresh herbage (grazing and indoors) were clearly yellower than cheeses from silage- and hay-fed cows, which coincided with the color intensity perceived by the panelists. Moreover, cheeses from cows fed fresh herbage had more intense barnyard and dry fruit flavors, were perceived as creamier and having less lactic odor, and exhibited more fat exudation than those from cows fed conserved herbage. Only a few differences were observed in milk and cheeses from hay-fed compared with silage-fed cows, and those differences were far less pronounced than those of milk and cheeses from cows fed fresh herbage. In conclusion, the present study did not substantiate assumptions of clear sensory differences of milk and uncooked pressed cheese from hay-fed compared with silage-fed cows. For the first time, this study reports that the global flavor intensity of cheeses from indoor green-fed cows is similar to that of cheeses derived from cows fed conserved forages, whereas cheeses from grazing cows have the greatest global flavor intensity.

In dairy cattle, teat disinfection at the end of milking is commonly applied to limit colonization of the milk by pathogenic microorganisms via the teat canal. The post-milking products used can irritate the teat skin and unbalance its microbial population. Our study aimed to assess the impact of different milking products on the balance of the microbial communities on the teat skin of cows and in their milk. For 12 weeks at the end of each milking operation, three groups of seven Holstein dairy cows on pasture received either a chlorhexidine gluconate-based product (G) or a hydrocolloidal water-in-oil emulsion (A), or no post-milking product (C). The composition of the bacterial and fungal communities on the teat skin and in the milk were characterized using a culture-dependent method and by high-throughput sequencing of marker genes to obtain amplicon sequence variants (ASVs). The individual microbiota on the cows’ teat skin was compared for the first time to that of a cow pool. In contrast to the milk, the post-milking treatment influenced the microbiota of the teat skin, which revealed a high microbial diversity. The water-in-oil emulsion appeared to slightly favour lactic acid bacteria and yeasts and to limit the development of undesirable bacteria such as Pseudomonas and Staphylococcus.

The supplementation of animal feed with microbial additives remains questioning for the traditional or quality label raw milk cheeses with regard to microbial transfer to milk. We evaluated the effect of dietary administration of live yeast on performance and microbiota of raw milk, teat skin, and bedding material of dairy cows. Two balanced groups of cows (21 primiparous 114 ± 24 DIM, 18 multiparous 115 ± 33 DIM) received either a concentrate supplemented with Saccharomyces cerevisiae CNCM I-1077 (1 × 10¹⁰ CFU/d) during four months (LY group) or no live yeast (C group). The microbiota in individual milk samples, teat skins, and bedding material were analysed using culture dependent techniques and high-throughput amplicon sequencing. The live yeast supplementation showed a numerical increase on body weight over the experiment and there was a tendency for higher milk yield for LY group. A sequence with 100% identity to that of the live yeast was sporadically found in fungal amplicon datasets of teat skin and bedding material but never detected in milk samples. The bedding material and teat skin from LY group presented a higher abundance of Pichia kudriavzevii reaching 53% (p < 0.05) and 10% (p < 0.05) respectively. A significant proportion of bacterial and fungal ASVs shared between the teat skin and the milk of the corresponding individual was highlighted.

In semi-mountainous grass-based dairy systems, summer droughts frequently reduce grass availability, with implications for animal performance as well as milk and cheese quality. The objective of our study was to investigate the effect of a simulated summer forage shortage in a traditional semi-mountainous grass-based system versus a corn-based system with part-time grazing. During a 19-wk experiment, 26 Holstein and 14 Montbéliarde cows were blocked in 4 balanced groups of 10 cows. During the first 8 wk, 2 groups were fed a grass-based diet (75% of grazed grass, 25% of hay and concentrates) and the remainder were fed a corn-based diet (75% mixed ration, 25% of grazed grass). During the following 11 wk, one group in each feeding system was subjected to a reduction in grazed grass intake and a corresponding increase in indoor feeding, resulting in 50% of grazed grass for grass-fed cows and removal of grazed grass for corn-fed cows. Milk yield and composition were recorded during the whole trial, in addition to indoor individual intake. Grass intake was modeled to calculate feed efficiency and estimate methane emissions. At the end of the experiment, bulk milk from each group was sampled for physicochemical and microbiological analyses and processed into Cantal-type cheeses. After 9 weeks of ripening, cheeses underwent physicochemical, microbiological and descriptive sensory analyses. Results showed that the complete removal of grazed grass in corn-based system had no effect on milk production but impaired feed efficiency; grass reduction in the grass-based diet better maintained milk yield, enhanced feed efficiency, and reduced methane emission intensity. Cheese softness increased with proportion of grass in the diet, and it was positively correlated with primary proteolysis (α_S1-casein and β-casein breakdown) but negatively correlated with the C16:0/C18:1 ratio and the calculated fat melting point. Cheese from cows fed with more grazed grass were the yellowest and had the most pronounced flavors, as well as higher counts of heterofermentative lactobacilli and lactic acid bacteria. Removal of grazed grass from the corn-based diet led to cheese that was less yellow and had less flavor, in line with lower levels of secondary proteolysis. In conclusion, our study suggests that maintaining fresh herbage in corn-based diets is crucial for maintaining cheese quality without impairing animal performance. In grass-based systems, complementation with indoor feeding may have limited effects on product quality but promotes the maintenance of animal performance.

MicroRNAs (miRNAs) are small regulatory RNAs that regulate numerous biological processes and potentially impact human health. Despite their abundance in raw milk, little is known about their content in processed dairy products or how manufacturing affects their abundance and bioavailability. We characterized and compared the miRNA profiles of yogurt and cheese produced from the same raw milk from cows raised under agroecological or intensive systems, assessing compositional changes during processing, while accounting for farming system effects. High-throughput sequencing identified a total of 1,384 miRNAs, including 258 common to all matrices, forming a conserved milk-derived core. Processing into yogurt or cheese reduced milk-specific miRNAs while introducing microbial small RNAs from fermentation bacteria such as Lactococcus and Streptococcus thermophilus. Differential analysis revealed stable miRNomes across agroecological and intensive farming systems, but substantial processing-associated changes involving 29 and 353 miRNAs during cheese and yogurt production, respectively, and some miRNAs showed matrix-specific stability. These miRNAs were predicted to influence cell proliferation, metabolism, and protein-related pathways, suggesting shifts in the regulatory impact of milk-derived miRNAs in fermented dairy products. Overall, these findings underscore the dynamic nature of dairy miRNomes and the combined influence of processing and microbial activity in shaping miRNA composition.