Improve dairy farms sustainability and reduce feed-food competition by feeding high-quality forages and by products in dairy diets

Working on feeding systems has been identified as a main strategy to improve the environmental and the social sustainability of the dairy sector, the latter being mainly related to the feed-food competition. Due to the ruminal fermentation of feeds, ruminants can convert non-human edible material, like forages and by- products, in food of high-nutritional quality for human consumption, representing a net gain in food supply. Thus, the hypothesis of this work has been that the integrated use of high-quality forages and feed by- products can represent a strategy to mitigate the environmental impacts and reduce the feed-food competition. The thesis is based on three papers. The first paper is aimed at improving farm efficiency, environmental sustainability, and milk nutritional quality by acting on the management of the cropping system in two farms The second paper is aimed at testing the effects of replacing corn and soybean meal with an ensiled mixture of byproducts of food production and to analyze the productive performances and the net food production of late lactation dairy cows. The third paper is aimed at evaluating the effects of replacing human edible feeds (corn and soybean meal) with reduced fat distiller grains without solubles in a diet of high-producing dairy cows, based on high-quality forages, on the production and composition of milk, and on the net-food production. It has been concluded that working on feeding strategies represents an opportunity to improve the sustainability of the dairy sector, and to meet society’s demand for high-quality food for an increasing number of people. In this context, promoting the use of high-nutritional quality forages and by-products of food production in dairy cows diet represents the key strategy for sustainable feeding systems, because it allows to reduce the feed-food competition and to mitigate the impacts of milk production.