The conventional criteria used for selection of dairy test bulls (sons of proven bulls) for better libido, fertility and higher milk production are expected producing ability, breed and cytogenetical characteristics, growth and physical conformity, sexual behaviour, seminal characteristics including freezability and consistency of semen donation capacity under progeny testing programme. Till now practical selection criteria through molecu1ar approach were not developed and implemented for the selection of dairy test bulls. Gene mapping research has been revealed polymorphic sites in bovine genome even if relatively little is known about the significant association between specific molecular genetic markers and performance traits. Polymorphism of GH, FSHB, Prolactin, Thyroglobulin, GHR, GHRH. IGF-I, SPADHI genes can be used in future as candidate genes (genetic markers) for assessing the libido and fertility of dairy bulls under future breeding programme for which more study is needed on Indian dairy bulls.