The agency responsible for livestock development in Tamil Nadu is the:

Department of Animal Husbandry
National Dairy Development Board
State Livestock Board
Krishi Vigyan Kendras

The correct answer is: Department of Animal Husbandry.

The Department of Animal Husbandry is a state government department responsible for the development of livestock in Tamil Nadu. It was established in 1960 and is headquartered in Chennai. The department is responsible for the promotion of livestock production, improvement of livestock breeds, and prevention and control of livestock diseases. It also provides veterinary services to farmers and livestock owners.

The National Dairy Development Board (NDDB) is a statutory body under the Ministry of Agriculture and Farmers Welfare, Government of India. It was established in 1965 with the objective of promoting dairy development in the country. The NDDB is responsible for the development of dairy cooperatives, production and marketing of milk and milk products, and research and development in the dairy sector.

The State Livestock Board is a state government body responsible for the development of livestock in a state. It is responsible for the promotion of livestock production, improvement of livestock breeds, and prevention and control of livestock diseases. It also provides veterinary services to farmers and livestock owners.

Krishi Vigyan Kendras (KVKs) are agricultural extension centers established by the Indian Council of Agricultural Research (ICAR). They are located in rural areas and provide extension services to farmers. KVKs offer training and demonstrations on various agricultural practices, including livestock management.

In conclusion, the Department of Animal Husbandry is the agency responsible for livestock development in Tamil Nadu. It is a state government department that was established in 1960. The department is responsible for the promotion of livestock production, improvement of livestock breeds, and prevention and control of livestock diseases. It also provides veterinary services to farmers and livestock owners.