A cow is a consumer. In the ecosystem, organisms are categorized based on their role in the food chain. Producers, such as plants, create their own food through photosynthesis. Consumers, like cows, rely on consuming other organisms for their energy and nutrients. Decomposers, such as fungi and bacteria, break down dead organisms and organic waste, returning nutrients to the soil.
Cows are herbivores, meaning they consume plants, which are producers. By eating grass and other vegetation, cows obtain the energy they need to survive and grow. This makes them primary consumers in the food chain. They do not produce their own food nor do they decompose organic matter, so they are neither producers nor decomposers.