The primary source of fodder for livestock in Odisha is:

Pasture lands
Crop residues
Forest grazing
Purchased feed

The correct answer is: b) Crop residues.

Crop residues are the plant parts that remain after harvesting a crop. They include leaves, stalks, and stems. Crop residues are an important source of fodder for livestock, especially during the dry season when there is less green fodder available.

Pasture lands are areas of land that are used to graze livestock. They can be natural grasslands or they can be planted with grasses and legumes. Pasture lands are an important source of fodder for livestock, but they can be limited in availability in some areas.

Forest grazing is the practice of allowing livestock to graze in forests. Forest grazing can provide livestock with a source of fodder, but it can also damage forests if it is not managed properly.

Purchased feed is feed that is bought from a feed supplier. Purchased feed can be a good source of nutrients for livestock, but it can be expensive.

In Odisha, crop residues are the primary source of fodder for livestock. This is because crop residues are abundant and they are a good source of nutrients. Pasture lands are also an important source of fodder, but they are limited in availability in some areas. Forest grazing is not a major source of fodder in Odisha because forests are not well-managed for grazing. Purchased feed is a good source of nutrients, but it is expensive.