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In mountain farms, challenges posed by the degree of land slope, altitude and harsh climate further compound multiple other possible constraints, particularly in relation to the distance of the farm from the farmstead. This study focused on how mountain-area dairy farmers factor the geographical characteristics of their fields into their field-use decisions. To that end, we surveyed 72 farmers who farm the traditional Salers breed of cattle and 28 specialised dairy system farmers in the central Massif region, France. Information was collected on the uses and geographical characteristics of all grassland fields (n = 2341) throughout the entire outdoor grazing season, without identifying farmers’ rationales for their field-use decisions. Field-use classes were constructed for the traditional Salers system per group of fields (grazed-only, cut-only, grazed-and-cut) and then used to classify fields in the specialized dairy system. The geographical characteristics, which were associated afterwards, were significantly different between the field groups and between field-use classes. Grazed-only fields were found to be more sloping and cut-only fields were smaller and further from the farmstead. Distance/area combinations were different according to field use (animal category, earliness of first cut, grazing and cutting sequence) and were decisive for all field-use classes. This study allowed the identification of generic relationships between field uses and their geographical characteristics in mountain-area dairy cattle farms.

This work aims to identify the rearing practices which increase the carcase weight according to slaughter age. For this purpose, an innovative statistical method, the decision tree method, was used to identify the most influential action levers on the carcase weight, with associated thresholds values and modalities, among the rearing practices applied throughout the animals' life. The data of 636 heifers carcases were collected from the slaughterhouse and the rearing practices from 45 farms by survey. Firstly, classifications were done to define slaughter-age classes and carcase-weight classes. Three slaughter-age classes (younger, mid-age, older) and 3 carcase-weight classes (lighter, intermediate, heavier) were defined, then these two classifications were crossed. The decision tree method highlighted that the influence on carcase weight of the life periods of the animals (i.e. suckling, growth, and finishing periods) and the related rearing practices were different according to the slaughter age of the heifers. For the younger-slaughtered animals, the most influential rearing practices on the carcase weight were the suckling duration, the concentrate supply during growing, the distributions of compound feed and grass silage in-stall during growing. For the mid-age slaughtered animals, the rearing practices identified as the most influential were the concentrate amount distributed in-stall during finishing, the meal supply in-stall during finishing and the cereals supply at pasture during growing. For the older-slaughtered animals, the compound feed supply at pasture during finishing and the concentrate amount distributed in-stall during growing were the most influential on the carcase weight. HIGHLIGHTS Decision tree: an innovative statistical method to identify action levers on carcase weight among the applied rearing practices throughout the life. The influential periods and rearing practices were distinct according to the slaughter-age of the animals.

To improve their income, European cattle breeders have to produce cattle carcasses with the best score on the EUROP system. The objectives of this study were to identify the rearing practices applied on farms at each period of a heifer's life and to study the relationship between these practices and the carcass characteristics. Farm surveys (n = 45) were performed to assess the rearing practices. A factorial analysis of mixed data followed by a hierarchical clustering on principal components was performed for each life period. The clusters resulting from these typologies were related to the carcass characteristics (weight, conformation and fat scores). For the suckling period, the cluster characterised by a calving season in autumn, a short pasture period and systematic supplies of stored grass and concentrate in stall gave heavy carcasses with the highest conformation scores. For the growth period, the best cluster for producing favourable carcass characteristics was characterised by the longest pasture period, feeding the most stored grass and feeding a regular concentrate supply throughout the year. For the fattening period, the cluster characterised by the oldest age at the beginning of the period and at slaughter, slaughter in winter and autumn, a long pasture period and regular concentrate supply gave the heaviest carcasses with the highest conformation scores. This study highlights several rearing practices that could be used as a means to influence the carcass characteristics, and also the life periods at which animals are sensitive to changes in management practices to improve weight and conformation scores. Highlights Carcass characteristics are related to rearing practices applied at each life period of heifers. Rearing practices can be used as a means to influence carcass characteristics.

The aim of this work was to study the variability in the composition of bulk milk mixtures of fat-soluble compounds (vitamins A and E, carotenoids, and terpenoids) and assess the links with milk production conditions. Milk from 10 collection trips in the French department of the Haute-Loire (10 to 36 herds per trip) was sampled in the tanker twice during the winter period and 3 times during the grazing season. The collection trips differed in their altitude (440 to 1,150m) and the forage system (grass or based on corn silage). Vitamins A and E, carotenoids, and terpenoids of the 50 tanker loads of milk were analyzed. Data of milk production conditions in the 204 farms made it possible to constitute indicators for the collection trip and to define 50 mean herds. The relationships between mean herd characteristics (breed, stage of lactation, and feed) and milk characteristics were investigated. The constituents of tanker loads of milk were comparable to those observed in milk produced by groups of animals receiving contrasting diets (rich in concentrate or corn silage vs. pasture). The characteristics of the milk differed according to the period; those produced at grazing were more yellow (1.02±0.4; mean of difference) and richer in β-carotene, lutein, vitamin E (2.0±1.2, 0.23±0.12, and 6.1±5.0μg/g of fat, respectively), and sesquiterpenes (2.7±2.5) than winter. The variations observed for β-carotene, lutein, and vitamin E were linked to the proportion of grazed grass or grass silage in the forage (r=0.66, 0.69, and 0.51, respectively), unlike the vitamin A content. During grazing, 20 of the 32 terpenoids identified were associated with the proportion of permanent grassland available for grazing or cut. These results show that feeding is an effective way to modify the quality of dairy products, even in the case of bulk tank milk mixtures. Dairy plants could market different milks, which would contain specific compositions.