In my opinion, the best source of secondary data is sourced from the government. Depending on the location of the study. If at the sub-district level it may be more appropriate to use a subdistrict data source. If the province should also use data sources at the provincial level. For example in Indonesia, there are Central Bureau of Statistics at district and provincial, and national levels. However, it should also be compared with secondary data sources from related technical agencies, according to the research topic. Thankyou

Thank you so much! Will definitely try to respond to the suggestions of yours. The only dilemma to analyse such data that if the Government data are not updated overtime and also the presence of alternate data sources at same time apart from Govt., convenient but not sure of their reliability.

You should be specific as to what type of data you need and for which state/ country. For India and its states some basic secondary data on number and type of livestock, milk output, availability of milk, export, import, prices etc can be had from 'Agricultural Statistics at a glace' , Statistical abstract of India' , various cites of Dairy Development Corporations and so on.  

Ministry of livestock or agriculture in your country, 

Central statistic agency in your country if it there (source of head census, with type, age etc, marketing price tome series data)

Internationally; International livestock research institutes

IFPRI -may be  

Yes sir. But it has to spell out the type of information required.

Thanks a lot for your valuable suggestions.

Hello Deepshikha, also you can check the data bases from FaoStat and the USDA Foreign Agricultural Service (FAS).

http://www.fao.org/faostat/en/

https://apps.fas.usda.gov/psdonline/app/index.html

The Central Statistical Bureau should be the most reliable source of these data.

Publications of the Ministry of Agriculture, Department of Animal Husbandry, Government of India.  

You can go through government publications. Provincial governments also keep such records. if you need to concern import and export it is good to use FAOSTAT as well. 

If you need times series data for India, please check PSD online database of USDA (United States Department of Agriculture). Furthermore, please refer to the various Annual Reports of DAHD available http://www.dahd.nic.in/documents/reports (Annexures at the end). If for milk, visit NDDB's website

For Trade related data, visit website of INTRACEN. I hope this is useful.

Thankful for all the suggestions. 

I guess the manual doings and investigations could be more useful in this sector