Is the 'cow' sacred or in reality, a taboo in India?

In India, since time immemorial, slaughter of the milk giving cow was prohibited. There are several verses in the Rigveda which refer to the cow as being divine and often compared to Aditi (mother of the gods) herself. Although, meat eating was permitted, vegetarianism was encouraged. A line from Manu's Smriti or The Laws of Manu (V/56) says, "There is no sin in eating meat... but abstention brings great rewards." 

Not preferring beef as food probably had practical reasons rather than just spiritual. It was very expensive to sacrifice an animal for rituals or feasts. And cows provided many important products, including milk, browned butter for lamps, and fuel from dried dung. 

Some people believe that vegetarianism was adopted from Jainism, another religion that had its birth in India along with Buddhism. The Jains believe in the existence of soul in all living and some non-living things  and practice very strict vegetarianism. However, the cow continued being revered, especially after the notion of cow killing being equivalent to the killing of a brahmin (those belonging to high caste, usually, priests) became popular in Indian feudal society after the Aryans took to agriculture and strengthened the varna or caste system. The importance of the pastoral element in the Krishna stories, particularly from the 10th century onward, further reinforced the sanctity of the cow. 

Hinduism still holds the cow to be a sacred animal and Hindus still refrain from eating beef. In most rural households, there is at least one cow, often treated as a family member, to provide milk which can be used to prepare curd, butter and ghee. Cows also help in supplying fuel to these households, where the animal excreta are made into dung cakes and used as fuel for fire in mud stoves. The animal's urine is used in worship as charnamrita. Indians do not get repulsed by cow excreta but consider it a useful, natural product, something which can even be used to fertilize crops. 

However, cows are often seen walking around in city streets feeding on garbage and sewers, neglected and uncared for. This is a surprise given their sacred status. But at least once a year, on Gopastami, cows are bathed and given offerings so that they may continue to bestow their life nurturing gifts to us.