Bamboo is a giant evergreen grass.
Herbivores eat grass. Grass is good fodder for livestock. Bamboo is good fodder for livestock. When pasture grass dries up in drought or dies down in winter, cut some bamboo poles, place them in the pasture, and, let the livestock eat the leaves and twigs.
Livestock eat hay made of dried grass. They also eat hay made of dried bamboo. Bamboo hay is a fine food. Cut multiple poles. dry them in the sun for two days, then hang them in a shed with open sides to finish drying.
Below find three nutritional analyses of bamboo as fodder. A Georgia Cooperative Extension Analysis Report analyzes Bamboo Hay. A Forage Testing Laboratory in New York analyzes Bamboo hay, and, a North Carolina testing lab analyzes Bamboo leaves.