People who ask if cows are considered sacred should understand that Hindus regard all living creatures as sacred-mammals, fishes, birds and more. The cow symbolically represents all other creatures to the Hindu. The cow is a complete ecology, a gentle creature and a symbol of abundance. Yes, the cow is considered very sacred in Hindu religion and for very good reason. It's good qualities are those that we can emulate.
Traditionally, the bulls work in the agricultural farms, cows provide milk — as a baby, mother provides milk, later it is the cow. The generous cow gives milk and cream, yogurt and cheese, butter and ice cream, ghee, buttermilk etc. That makes one respect and love the cow. This is largely true in India even today!. Even after their natural death their skin provides leather. In modern times, however, the tanneries which use extremely carcigenous chemicals to process leather, have been polluting the scarce drinking water. It is true that most people respect the right of way to cows and in fact to any animal, when they stray in a street. They are viewed as food producers and not as food itself. Actually, the word for cow in Tamil is "pasu". The word for animal in Sanskrit is the same "pasu". In other words, the cow personifies "animals" in general. All animals are sacred in Hinduism.