The data comprised of 4127 lactations belonging to 1613 animals of FG, JG, FJG, JFG and BFG genetic groups, collected from Mahatma Phule Krishi Vidhyapeeth, Rahuri, (M.S.). The detailed inheritance charts of these animals born over a period of 29 years during 1972 to 2000 were prepared and inbreeding coefficient of individual animal was calculated. All the animals were grouped into six sub-groups as non-inbred, very distinct, distinct, moderate, close and very close inbred. The overall level of inbreeding during the study period was noticed as 7.03%. The inbred cows in the total herd were 38.46% in FG, 52.26% in FJG, 23.33% in JFG and 52.29% in BFG genetic groups. In JG genetic group none of the animal was found inbred. The effects of level of inbreeding was significant on age at first calving (P<0.01) in FJG genetic group only and remaining all the traits were non-significant in all the genetic groups.
