The impact of DNA parentage verification on EBV estimation and sire ranking in South African Angora goats

Abstract

South Africa is the world’s largest mohair-producing country, contributing over 50% of the world’s mohair, and therefore genetic improvement of Angora goats in South Africa is imperative in order to maintain this position in the market and the quality of the mohair clip. Pedigree integrity is vital for the success of any breeding programme. DNA parentage testing has become a useful tool in amending inaccuracies in on-farm records of various species. Previous studies have determined that errors in pedigree records may have a negative effect of up to 15% on genetic improvement in livestock. In the current study the extent of incorrect paternity records was quantified in 381 South African Angora goats using a panel of 12 microsatellite markers selected for parentage verification. 14.3% of the on-farm records were missing or incorrect. The microsatellite marker panel had a CPE of 99.6%, PIC of 0.700 and average HE of 0.738. Estimated Breeding Values for fleece traits (fibre diameter and fleece weight) and body weights (birth weight, weaning weight, eight month weight, yearling weight and 16 month weight) were estimated for 21 sires using ASREML, firstly using the breeder’s recorded pedigree and secondly using the DNA marker-verified pedigree. Sires were ranked according to EBVs for each trait. The sires ranked lowest in the breeder’s records for fibre diameter, birth weight and weaning weight were moved to the top three ranks in the DNA verified pedigree. The ranking for fleece weight was not as severely affected. The significant change in sire ranking after DNA pedigree verification confirms the importance of pedigree integrity for selection accuracy in the South African Angora goat industry.