Pedigree analysis in ten sheep populations in Mexico

Abstract

Pedigree analysis is vital in designing genetic improvement strategies. Population genetic parameters were analyzed in ten sheep breeds in Mexico: Blackbelly (BBL; n= 19,695); Charollais (CHA; n= 5,033); Dorper (DOR; n= 42,171); White Dorper (DOB; n= 4,213); Dorset (DOS; n= 5,557); Hampshire (HAM; n= 12,210); Katahdin (KAT; n= 77,955); Pelibuey (PEL; n= 42,256); Rambouillet (RAM; n= 11,951); and Suffolk (SUF; n= 14,099). All animals were born between 1992 and 2018. The analyses were run with the ENDOG software. Known parents values ranged from 76.4 % (SUF) to 95.3 % (KAT), with an 86.0 % average; animals with unknown parents corresponded to founders. The consanguineous population (as a percentage of total population) fluctuated from 12.3 % in DOS to 48.7 % in DOB, with a 29.7 % average. Average inbreeding (F) ranged from 3.9% (KAT) to 14.6% (DOB), with an 8.0 % average. The proportion of consanguineous individuals in all populations increased (P<0.05). Genetic relatedness was stable, and F had negative trends (P<0.05). The highest consanguineous population growth rates were present in the KAT, DOB and BBL populations. Inbreeding (F) was highest in DOB and DOS, while genetic relatedness was highest in DOB and CHA. Effective population size (Ne) was greater than 50 in six of the populations but less than 37 in the remaining four. These low Ne values highlight the need to monitor the evolution of F and its possible implications. The generational interval (GI) ranged from 3.0 to 4.15, with a 3.45 years' average. The highest GI values were for RAM and SUF, and the lowest for BBL and DOR.