Preliminary assessment of trends in inbreeding and average relatedness of the former Valachian sheep

Abstract

The objective of this study was to analyse the trends in inbreeding and in average relatedness of the former Valachian sheep. Investigation was based on pedigree data of a single flock, population of which consisted of 27 animals born during the period 2007-2010 (reference population). A whole pedigree population (individuals with genetic ties to reference population) consisted of 137 animals. A total of 8 generations of ancestors were identified. Proportions of known parents decreased with an increasing number of generations (100% to 0.07% in the reference population vs. 63% to 0.01% in the whole pedigree population). Inbreeding (F%) and average relatedness (AR%) were investigated separately for each sex. Zero inbreeding coefficients were found in males. In females, average values of inbreeding ranged from 0% to 14% (across the years of birth). Inbreeding was of zero values in females born before 2003; the exceptions were females born in 1995 (average value of inbreeding about 3%). Inbreeding was of non-zero values since 2003; the exceptions were females born in 2010. Average relatedness was similar in males and in females; average values ranged from 2% to 12% across the years of birth. The analysis provided an insight to management practice and it may also be useful for mating policy. Regular monitoring of breed genetic structure is recommended.