Impact of Paternity Errors in Cow Identification on Genetic Evaluations and International Comparisons

Abstract

The impact of paternity identification errors on US genetic evaluations and international comparisons of Holstein dairy bulls for milk, fat, and protein yields was investigated. Sire identification was replaced for 11% of Holstein cows that were sired by AI bulls and had records in the US database for national genetic evaluations; US evaluations were computed based on those modified pedigrees and compared with official national evaluations. Estimated breeding values from the data with introduced paternity errors were biased, especially for later generations. Estimated genetic trends decreased by 11 to 15%. Estimates of standard deviations of sire transmitting ability also decreased by 8 to 9%. International multitrait across-country comparisons of bulls were computed based on national evaluations from the United States, Canada, New Zealand, and The Netherlands. Estimates of genetic correlations between the United States and other countries decreased by 0.04 to 0.06 when US evaluations were based on modified pedigree. The resulting bias toward selection of domestic bulls and the inability to identify truly superior animals that are available internationally could decrease potential selection differentials by 0.07 to 0.09 standard deviation units on the US scale, which corresponds to sire breeding values of approximately 50 kg for milk, 3 kg for fat, and 1.7 kg for protein.Losses for the other countries were lower and ranged from 0.02 to 0.05 standard deviation units, because a correlation of less than unity with the United States decreased the impact of US cow paternity errors on the scales of other countries. Although paternity verification is desirable and technically feasible, commercial implementation would require low testing costs.

A simple method to approximate gene content in large pedigree populations: application to the myostatin gene in dual-purpose Belgian Blue cattle

“…Such data would be useless. This method has some important advantages: standard genetic evaluation software can be used and gene contents can be easily computed for the whole population; population mean gene content will be computed at the same time; the model can be adapted to account for genetic groups due to different origins of animals; ratio 1 between variances can be small but still different from zero, therefore the method allows for rare but not impossible genotyping errors, 1 may also account for pedigree errors, that could be in certain cases up to over 20% of the animals (Banos et al, 2001). …”

Genetic diversity and assessment of 23 microsatellite markers for parentage testing of Santa Inês hair sheep in Brazil

“…Paternity misidentification has been shown to vary from 10 to 20% in breeding programs in developed countries (e.g., Banos et al, 2001;Visscher et al, 2002;Weller et al, 2004;Jiménez-Gamero et al, 2006) and was estimated to be over 35% in Gyr cattle breeding in Brazil (Baron et al, 2002).…”

Evaluation of 11 microsatellite loci for their use in paternity testing in Yugoslav Pied cattle (YU Simmental cattle)

“…A small misidentification percentage excessively endangers genetic patterns estimation. The paternity misidentification rate of 11% would result in a decrease of 11-15% in the genetic trend for milk traits (Banos et al, 2001). Pedigree errors may reflect in the structure of selection indexes (Přibyl et al, 2004;.…”