Population structure and inbreeding in Harnali sheep through pedigree analysis

The present investigation was carried out to study population structure using pedigree records and to estimate the inbreeding coefficient in closed flock of Harnali sheep. The data records consisted whole population with 2404 animals produced over 24 years (1998-2021) and reference population of 466 animals (year 2018 to 2021) were obtained from closed flock of Harnali sheep at Department of Animal Genetics and Breeding, LUVAS, Hisar (India). The pedigree under analysis included a maximum of nine generations, with 452 animals used as founder. The results showed that mean maximum, complete, and equivalent generations were 3.20, 1.51 and 2.17, respectively. The effective population size was estimated as 202.63. Number of founders contributing to reference population and effective number of founders (fe) for reference population were 115 and 21. The mean average relatedness and generation interval in whole and reference population were 1.86 and 2.19%, and 4.49 ± 0.06 and 4.19 ± 0.10 years, respectively. The average inbreeding rate among studied population was 0.46% in whole population and 0.50% in reference population. Estimated average relatedness (AR) suggested limited allele sharing within the population. The results of general linear modeling showed that there was no significant (P > 0.05) association of inbreeding on various growth and reproduction traits in studied animals. The study concludes that to minimize generation intervals and counteract inbreeding within the closed flock of Harnali sheep, it's imperative to utilize pedigree records to select unrelated sires and to commence the selection of breeding stock at an early stage. These actions could be vital for enhancing genetic advancement and preserving genetic diversity within the flock.