Yes, if those plants are too coarse, bitter, or simply don't taste good. Some types of grasses, like Meadow Foxtail, Johnson grass, Cheat Grass, and some species of Canary Grass are some plants that cows won't touch.
Cows eat plants only and not meat or bugs, but they aren't the only ones who eat plants. All the herbivores and omnivores eat plants.
plants that do not taste good
Cows don't eat animals. They are herbivores, which means they eat strictly plants, not animals.
Nobody. Cows don't eat donkeys. Cows are herbivores, meaning they only eat plants, not other animals.
They are called herbivores.
No. Cows are herbivores, not omnivores or carnivores, which means they eat plants like grass, not animals like tuna.
Same thing as other cows do. See related question below for more.
They get the fibre from the plants (i.e., grasses and legumes) that they eat.
Plants being grasses and forbs.
Many animals eat plants. Mammals (cows, deer, horses), fish, invertebrates (snails).
Some fish eat water plants. Manatees, or sea cows, also eat water plants. Humans also eat some sea plants.
Cows eat plants. Herbivores.