Seasonal and Altitudinal Effects on Chemical Composition and Rumen Degradability of Blackberry Leaves in Northwestern Italian Alps

The blackberry poses a threat as an invasive plant in various regions worldwide, where it aggressively competes with native species and risks delicate ecosystems. Livestock grazing has emerged as a potential strategy to mitigate its spread. This study investigated the effects of seasonal variations and altitude on the chemical composition and in vitro degradability of blackberry leaves. The leaves accessible to goats were collected in the Northwestern Italian Alps across all seasons at three altitudes (low: 450 m, medium: 700 m, high: 1000 m). The findings indicated that blackberry leaves can serve as a cost-effective, high-protein, and high-fiber feed for ruminants in these regions. However, the goats exhibited a limited capacity for fiber degradation. Furthermore, the nutritional value of these leaves was significantly influenced by the season, altitude, and their interaction. Spring leaves had the highest protein content (241.9 g/kg dry matter) and the best digestibility, with lower lignin levels (69 g/kg dry matter). At higher altitudes, lignin content decreased significantly during winter compared to the other seasons, resulting in a significant increase in fiber degradability. These insights offer crucial guidance for optimizing the utilization of the blackberry plant in goat feeding systems and underscores the necessity of considering both seasonal and altitudinal factors in grazing management practices.