Under changing climate, growth and prevalence of many invasive and indigenous weeds are expected to boost up owing to their greater genetic diversity, competitive superiority and better plant architecture. Atmospheric CO2 enrichment and elevating global temperature are causing weeds invasion to new localities making prevalent weed management strategies ineffective. Weed utilization as forage for ruminants provided that their nutritional profile is available and can be a biologically feasible and economically viable approach compared to existing management system of eliminating them from agro-ecological systems. Different weeds like Bermuda grass (Cynodon dactylon), Johnson grass (Sorghum halepense), canary grass (Phalaris minor), nut sedge (Cyperus rotundus), yellow duck (Rumex crispus), drooping brome (Bromus tectorum), burr clover (Medicago polymorpha), button weed (Diodia scandens), and purslane (Portulaca oleracea) had acceptable nutritional profile with organic matter (89.0–91.3%), protein (7.1–19.5%) and fats (2.1–3.7%). Those were also rich in micro-nutrients (calcium, magnesium and zinc), while anti-nutritional factors (saponins, tannins, phytates and oxalates) were in safer limits for dairy animals. Lack of nutritional profiling and presence of anti-nutritional factors decreased feed intake and led to malnutrition, while higher concentration of tannins caused digestibility depression in small ruminants. There is need to conduct further studies for nutritional profiling of local weed species and development of techniques for reducing their anti-nutritional factors.
Part of the book: Invasive Species