Well, I usually do not work with FeLV, but people in my old lab used primers from this publication:

HOHDATSU, T.; YAMADA, M.; OKADA, M. et al. Detection of feline immunodeficiency proviral DNA in peripheral blood lymphocytes by the polymerase chain reaction. Veterinary Microbiology, v.30, p.113-123, 1992.

Thank you Dr. Fonseca Jr, 

but this publication describes just primers for FIV detection and not for FeLV.

Thanks for you answer.

I know about detection and quantification of FeLV provirus by quantitative real-time PCR

To search for the primer sets you can refer to the following link:- 

http://vir.sgmjournals.org/content/82/7/1589.full.pdf

Thank you Dr. Chakraborty.