Value of genomics in breeding objectives for beef cattle

Abstract

-The objective of this research was to discern the contribution of genomic information to multiple-trait breeding objectives and thus understand the economic value of that information. True genetic values were simulated for each of n, possibly correlated, traits. These true genetic values, combined with uncorrelated random noise, resulted in both genomic and phenotypic estimated breeding values, EBVg and EBVp, respectively. The separate EBV were then merged (blended) as a function of their respective accuracies to produce a unified EBV for each of the n traits. Finally, for each simulated animal (N = 10000), the sum of products of economic weights and EBV was calculated to predict the economic value (net merit) of the individual. Accuracies of the EBV for the individual traits and net merit were calculated as correlations between predicted and true values. Predicted responses to selection for individual traits included in the breeding objectives were enhanced from 9% to 76% with the greatest benefit accorded to those economically relevant traits that are recorded after selection decisions are made at one year of age, measured less frequently in national cattle evaluation, or often predicted using information from indicator traits. Combining the EBV to predict net merit for terminal and maternal breeding objectives resulted in predicted increases in selection response due to incorporation of genomic information of 27% and 57%, respectively. The results are interpreted to suggest that the economic benefit to be derived from selection based on a multiple-trait economic breeding objective, which is predicted using genomically enhanced EBV, can substantially exceed the present day cost of genotyping the candidates for selection.

Comparison of economic returns among genetic evaluation strategies in a 2-tiered Charolais-sired beef cattle production system1,2

“…Additionally, if selected animals can consequently produce progeny at younger ages, the implementation of this strategy results in a reduction of generation interval ( Buch et al, 2012 ; Meuwissen et al, 2013 ). The development of the single-step approach for genetic evaluation has enabled the combination of traditional pedigree relationships with genomic relationships into a combined relationship matrix, termed H ( Legarra et al, 2009 , 2014 ; MacNeil, 2016 ). This combined relationship matrix can be incorporated into the mixed model equations to estimate breeding values for genotyped and nongenotyped animals in a single model when pedigree information is partially missing ( Meuwissen, 2009 ).…”

“…Adoption of genomic technology in the beef cattle industry has improved selection accuracy ( r TI ), which affects the rate of genetic gain ( ΔG ) and increases income when used in conjunction with an economic selection index ( Dekkers, 2007 ; Meuwissen et al, 2013 ; Todd et al, 2014 ; MacNeil, 2016 ). In a vertically integrated production system, there is opportunity to capture value generated by implementing a genetic evaluation program using a combination of phenotypes, pedigree information, and genotypes from both nucleus animals and commercial ( CM ) offspring ( Aguilar et al, 2010 ).…”

Genetic selection indices for growth traits in Blanco-Orejinegro cattle

“…For , parameters estimated in the literature based on bioeconomic models under similar management systems (grazing and extensive systems and full productive life cycle) were used. The economic values obtained by Júnior et al (2006) , Brumatti et al (2011) , Moreira (2015) , de Souza (2016) , Macneil (2016) were averaged and expressed in US dollars.…”

Management of lethal recessive alleles in beef cattle through the use of mate selection software

“…Ochsner et al [44, 45] outlined procedures on how to develop a maternal economic selection index ($M) given EPD information. These procedures were followed based on selection objective weightings described by MacNeil [46]. These included heifer pregnancy, calving ease direct, calving ease maternal, weaning weight direct, weaning weight maternal (milk), and stayability.…”