what is cattle rearing? ans 2

Livestock (also cattle) refers to one or more domesticated animals raised in an agricultural setting to produce commodities such as food or fibre, or labor. The term "livestock" as used in this article does not include poultry or farmed fish; however the inclusion of these, especially poultry, within the meaning of "livestock" is common.
Livestock generally are raised for subsistence or for profit. Raising animals (animal husbandry) is an important component of modern agriculture. It has been practised in many cultures since the transition to forming from hunter-gather lifestyles.
‘Livestock’ are defined, in part, by their end purpose as the production of food or fibre, or labour.
The economic value of livestock includes:
Meat
the production of a useful form of dietary protein and energy
Dairy products 
Mammalian livestock can be used as a source of milk, which can in turn easily be processed into other dairy products, such as yogurt, cheese, butter, ice cream, kefir, and kumis. Using livestock for this purpose can often yield several times the food energy of slaughtering the animal outright.
Fibre 
Livestock produce a range of fibre/textiles. For example, sheep and goats produce wool and mohair; cows, deer, and sheep skins can be made into leather; and bones, hooves and horns of livestock can be used.
Fertilizer 
Manure can be spread on fields to increase crop yields. This is an important reason why historically, plant and animal domestication have been intimately linked. Manure is also used to make plaster for walls and floors, and can be used as a fuel for fires. The blood and bone of animals are also used as fertilizer.
Labour 
Animals such as horses, donkey, and yaks can be used for mechanical energy. Prior to steam power, livestock were the only available source of non-human labour. They are still used for this purpose in many places of the world, including ploughing fields, transporting goods, and military functions.
Land management 
The grazing of livestock is sometimes used as a way to control weeds and undergrowth. For example, in areas prone to wild fires, goats and sheep are set to graze on dry scrub which removes combustible material and reduces the risk of fires.


If talking about its advantades and disadvantages, just read through:

Confinement at high stocking density is one part of a systematic effort to produce the highest output at the lowest cost by relying on economies of scale, modern machinery, biotechnology, and global trade. Confinement at high stocking density requires antibiotics and pesticides to mitigate the spread of disease and pestilence exacerbated by these crowded living conditions.[7] In addition, antibiotics are used to stimulate livestock growth by killing intestinal bacteria.[8] There are differences in the way factory farming techniques are practiced around the world. There is a continuing debate over the benefits and risks of factory farming. The issues include the efficiency of food production; animal welfare; whether it is essential for feeding the growing global human population; the environmental impact and the health risks