Forage quality and methane emissions in dairy sheep

The work of this thesis focused direct methane measurements in in vivo and in vitro trials to test possible nutritional strategies aimed to reduce methane emissions from dairy sheep, specifically working on their diets in term of forage quality and inclusion of additives based on nitrate compounds. The first chapter included a review of literature and the rationale background.The second chapter present a trial planned with the aim to evaluate the effect of hays with different NDF content on milk production, digestibility and methane emissions in dairy sheep. It was observed that sheep fed hays with lower vs. higher content of NDF produced significantly more milk and lower methane emissions.The third chapter presents a study on the effect of haylages with low and high NDF content on lactating dairy sheep in late lactation. The results showed that milk production and methane emissions were not influenced by the diet. H-NDF vs. L-NDF group produced more methane per unit of milk without significant differences.The fourth chapter presented an In vitro aimed to evaluate the effects of nanocarriers associated in different combinations to nitrate based compounds and other additives to reduce the methane emission.Cumulative methane emissions at 48h were significantly affected by treatments. In terms of ml of methane per ml of produced gas, the use of aluminum nitrate NAl caused a reduction of emissions in respect to control without additives.