The economics of livestock feeding 

We have to take full responsibility for the livestock whose freedom of movement is under our control. We must provide them with such necessities as water, food, and medical care to keep them alive and in good health. But they are not pets such as dogs or cats. 

We keep them for a purpose that is bigger than just deriving fun and pleasure by their mere presence in the home. They are kept for their products such as eggs, skins, milk, meat and manure. The products can be sold and the farmer can earn money out of them.
Before we get milk from a cow, that cow has got to be fed. If it is starving it cannot yield enough milk, if any at all. Like us humans animals, birds, and fish must eat a balanced diet to be healthy. We must at least have the correct feeds in sufficient quantities to maintain the livestock under our care. 

Then we must ensure we give them the extra feeds known to increase the desired products which we want to consume or sell, usually referred to as production ratio. 
This of course has got to do with the breed of the animals or the birds that we keep. 
Some cow breeds can produce more than 20 litres of milk a day while other breeds may not deliver more than five litres no matter how well they are fed. These may be fed just to fatten them and to be sold at a high price due to their great weight.

It is always a big puzzle for farmers how much to spend on livestock feeds in relation to how much they expect to earn from the livestock products. Some cattle and goat farmers who have enough land plant nutritious fodder grass on which the animals can feed all over the grazing area of their farms. 
Such farmers only need to buy supplementary feeds for their animals once in a while. 

However other farmers work under very tight conditions and must buy all feed, ranging from ordinary grass to specially prepared feeds such as maize meal, cottonseed cake, sunflower cake and others, which tend to be quite costly. 
In some cases farmers spend more money to buy feed than they earn from selling the farm products. Yet they have to settle overhead expenses such as wages, water, and electricity.