Exploitation of the effects of different dairy milk production systems on animals and their products

Grassland and pasture-based dairying have been shown to support animal welfare (Arnott et al., Animal 2017), grassland phytodiversity, product quality (Avondo et al., Ital J Agron 2013) and it is highly appreciated by consumers and the society as a whole (van den Pol van Dasselaar et al., Sustainability 2020). Grazing animals can select and combine forage items with different nutrient profiles, digestibility, and bioactive substances (Rutter, Appl Anim Behav Sci 2006; Villalba et al., Animal 2010) which improve digestive efficiency, metabolic health (Leiber et al., J Sustainable Organic Agric Syst 2020), livestock performance (Nakajima et al., Grassland Sci 2021), and in turn positively affect the quality of dairy products derived from it. However, in modern dairy production systems high individual milk yields are generally produced on the basis of highly designed total mixed rations (Leiber et al. 2020). Literature reveals that dairy and meat products, which are produced from pastures contain higher amounts of plant secondary compounds such as terpenes or phenols (Avondo et al. 2013) which can be adsorbed by the gastrointestinal tracts and incorporated into milk and meat (Beck and Gregorini, Front Vet Sci, 2020) and/or improve health. In particular, terpenes are known to have an effect on the aromatic profile and on the sensory characteristics of cheese (Avondo et al. 2013). However, dairy cows with high individual milk production require high energetic feed to meet their nutritional demand. Therefore, there is the necessity to include cattle breeds adapted to low-input systems (Knaus, J. Sci. Food Agric 2015) into future livestock production systems. Interactions between grassland and breeds on product quality and the human health value of milk were rarely considered so far. Consequently, there is urgent need to disentangle such possible interactive effects.

The concept of the food system from animal to product will be the approach of the proposal to ensure the chemical and microbiological quality of milk and derived products. Two systems with different input strategies will be established at an experimental farm. The high-input system is defined by year-round housing, Fleckvieh breed and a concentrate-based ration in the feed. The low-input system is characterized by predominantly grazing on a complemented short-grass pasture during the vegetation period, the Tyrolean grey cattle breed and a basic feed-based and silage-free ration. Over the entire study period the following parameters will be recorded: individual feed intake of the animals in the barn, amount and quality (including the fatty acid profile) of milk produced, feed intake on pasture and health status of the animals. In addition, repeated measurements will be done on the same animals over time regarding the composition of the rumen and the product microbiome. As long as, the volatile profile of feces, milk produced and derived cheeses.

The proposed project aims to estimate the effects of different diets, husbandry systems (concentrate bases vs. pasture based) and breeds on the health of dairy cows, their fecal microbiome, chemical and microbiological quality of milk and derived products (e.g., cheeses). Therefore, two cattle breeds (Fleckvieh (FV), Tyrolean Grey (TG)) will be kept either in a high-input system (FV; indoor, high level of concentrates) or a low-input system (TG; whole year access to pasture, low level of concentrates. Fecal rumen microbiota will be associated with the microbiota of milk and other dairy products, in relation to different diets and husbandry systems, and the final composition of the volatilome (rumen to milk and other products). Consequently, possible interactive effects between the breeds and production systems on the cascade along dairy performance, welfare and behavior, and dairy product quality will be estimated. Based on this the dairy production systems will be optimized and recommendations given to the stakeholders.