INNOVATIVE STRATEGIES TO IMPROVE THE SUSTAINABILITY LEVELS OF THE CATTLE PRODUCTION SYSTEMS

Food production is crucially involved in the ability for humanity to reach a “sustainable development” as described in the Agenda 2030, as balance between multiple different aspects correlated to the environmental, economic, and social pillars of sustainability. On one side, indeed, there is the need to feed a growing world population, with healthy, safe, and secure food. On the other side, the food sector is facing many challenges, that cover both environmental, social, and even economic points. Inside the food sector, livestock farming and thus the production and consumption of animal derived products are often extremely criticized for their “sustainability”. From an environmental point of view, emissions of GHGs are the main critical aspects, with enteric fermentations of ruminants being especially criticized due to their important share of the emissions of methane (CH4). Also, excessive consumption of the water sources and pressure on agricultural lands and forests, to produce feed raw materials, are the other issues in which the zootechnical sector is involved. This latter aspect leads also to another criticism often made upon livestock farming: the use of arable land, water sources and of human-edible raw materials to produce animal feeds instead of being directly used for humans. Thus, there is the need for more “circular” and resilient animal production systems, that rely less on those scarce resources, while also allowing an optimal recovery of all the nutrients and inputs along the food chain. Indeed, reducing wastes production and increasing cooperation between the different parts of the food chain are other critical issues for the social pillar of sustainability. Other concerns are the need to improve animal welfare, to reduce the reliance on antibiotics as well as to satisfy the consumers’ expectations. Indeed, excessive, and incorrect use of antibiotics at the farm level, frequently driven by poor welfare conditions, is one of the possible triggers for the development of antimicrobial resistance. Among all the zootechnical productions, cattle farming, is often the most criticized for sustainability issues, especially in terms of GHGs emissions and consumption of competitive and impactful raw materials. Also, animal welfare and antibiotic use are under the scope also for cattle farming, specifically for some stage of the fattening and production cycle. Also, the CAPs policies give a high importance to the improvement of those two latter aspects, with the more general goal to reach a “sustainable” livestock and agricultural production. Also, animal welfare and health are deeply connected to the topic of production efficiency, that have a crucial role in assuring an optimal farm profitability as well as in reducing the environmental load per unit of final product. The general aim of this thesis was to evaluate innovative strategies to enhance the sustainability levels of cattle farming, both dairy and beef, including all the previously cited topics. Particularly this thesis was focused on three major topics that still can be improved: improving animal health and welfare, reducing the emissions of enteric CH4, and increasing the circularity and resilience of the system. Consequently, different managerial and nutritional strategies were included in the present thesis, to give practical guidelines to efficiently improve management and nutrition in order to reach better sustainability levels in cattle farming raised in feedlots and conventional indoor farming conditions. Considering the need to reduce the use of antimicrobials in cattle farming, a great attention was placed on the critical moment of the arrival period in beef cattle farming. Thus, the effects of the implementation of ameliorative managerial strategies, that are connected to improved animal welfare, during that phase were evaluated on health status, incidence of pathologies and antimicrobial use. Also, the potential positive effects of the inclusion of a blend of essential oils and natural products in the diet was tested on the immune functionality during the arrival period and on the overall production performance, as a strategy to boost the resilience and resistance of the animals. Also, gastrointestinal diseases and imbalance are other causes of deprived animal welfare and reduced production efficiency during the entire fattening period. Thus, a strategy to safeguard ruminal stability and improve efficiency was evaluated. In particular, the effect of heated water during winter to keep the ruminal temperature stable were evaluated on ruminal parameters, incidence of gastrointestinal diseases, and overall production performances. All the tested strategies have shown good potential to be applied with the main aim of boosting animal productivity and efficiency during the most critical points of the fattening period. Improved management and diet have shown interesting results in terms of antimicrobial usage and animal health parameters. Also, those positive effects on animal health were related to general improvement in the production efficiency during the entire fattening period. Also, safeguarding the ruminal environment by avoiding important drops in the ruminal temperature have shown promising results in terms of production efficiency, as a result of a more functional rumen. Two different blends of essential oils were tested in different in vitro and in vivo trials in dairy cows, to reduce the direct emissions of CH4. Also, their effects on production efficiency, in terms of diet digestibility and milk production, was evaluated, to understand if using essential oils might be a good strategy that might combine potential positive effects on animal health and production efficiency with also direct inhibitory actions against the ruminal methanogenesis. Even if the in vivo results on CH4 emissions were still unclear, due to also the need of changing the protocol of measurement applied, the in vitro results were promising, as well as the effects on production performances. Considering the importance of improving the circularity and resilience of the food system, different approaches were included. Particularly, to reduce the use of highly impactful feeds, such as soybean meal, and to increase the circularity of the systems, the reuse of byproducts, such as distillers, and bakery former foodstuff was tested, as a partial replacement of soybean and of human edible raw materials, such as corn meal. The partial replacement of soybean meal with slow-release urea was tested in dairy cows. Its effect on production performance as well as on the carbon footprint of the diets were tested. The effects of the partial substitution of soybean and corn meals with respectively distillers and bakery former foodstuff were conversely tested in beef cattle, considering effects production performance and diet digestibility. The application of alternative and circular raw materials characterized by lower environmental impacts have led to an interesting reduction of the overall carbon footprint as well as of other environmentally related topics, such as water and land requirements and consumption of human edible resources, in both dairy and beef cattle. Also, the production efficiency was either not affected or improved by those substitutions. Also, the effects of the inclusion of different sources of selenium in the diets of finishing beef cattle on meat quality and stability parameters were tested, to improve meat stability in order to improve its shelf-life, that is needed to curb food waste at the retail and household level. The antioxidant properties of meat were improved by the application of organic sources of selenium, as well as its selenium content, improving thus the stability of the final product, as well as its nutritional properties. All the results obtained in the different three main areas of work included in the present thesis, highlight there is a high potential for the application of a plethora of different strategies aimed at working on the different topics correlated to livestock “sustainability”, even in industrialized and efficient farming systems such as the Italian one. Also, the potential role of increasing production efficiency was highlighted as an interesting strategy to obtain higher “sustainability” levels. Indeed, higher production efficiency levels can be considered as the image of a better animal health and welfare status, as well as of a maximized utilization of all the inputs used as feed sources, with even positive effects on the overall carbon footprint of the production. Also, the complexity of working on “sustainability” in cattle and generally livestock farming was underlined in the present thesis, highlighting how a balance between the different aspects is needed, as well as that a complex and union of different strategies is needed to fulfill this aim.