Prediction and evaluation of response to selection with overlapping generations

Hill, William G.

doi:10.1017/s0003356100017372

Cited by 228 publications

(219 citation statements)

References 12 publications

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“…The dissemination of genetic progress in nucleus and commercial flocks was approximated using a discounting technique. The dynamics of the gene diffusion, in particular in multi-tier populations, is known to be not linear (Elsen and Mocquot, 1974;Hill, 1974) and could be modeled appropriately. Further investigations using such a model will help to balance the costs related to one cycle of selection and the returns resulting from the extra value of the individuals selected during this cycle, expressed by generations of progeny in the nucleus and in commercial farms.…”

Section: Modeling Optionsmentioning

confidence: 99%

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Economic evaluation of genomic selection in small ruminants: a sheep meat breeding program

Shumbusho

Raoul

Astruc

et al. 2016

Animal

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Recent genomic evaluation studies using real data and predicting genetic gain by modeling breeding programs have reported moderate expected benefits from the replacement of classic selection schemes by genomic selection (GS) in small ruminants. The objectives of this study were to compare the cost, monetary genetic gain and economic efficiency of classic selection and GS schemes in the meat sheep industry. Deterministic methods were used to model selection based on multi-trait indices from a sheep meat breeding program. Decisional variables related to male selection candidates and progeny testing were optimized to maximize the annual monetary genetic gain (AMGG), that is, a weighted sum of meat and maternal traits annual genetic gains. For GS, a reference population of 2000 individuals was assumed and genomic information was available for evaluation of male candidates only. In the classic selection scheme, males breeding values were estimated from own and offspring phenotypes. In GS, different scenarios were considered, differing by the information used to select males (genomic only, genomic + own performance, genomic + offspring phenotypes). The results showed that all GS scenarios were associated with higher total variable costs than classic selection (if the cost of genotyping was 123 euros/animal). In terms of AMGG and economic returns, GS scenarios were found to be superior to classic selection only if genomic information was combined with their own meat phenotypes (GS-Pheno) or with their progeny test information. The predicted economic efficiency, defined as returns (proportional to number of expressions of AMGG in the nucleus and commercial flocks) minus total variable costs, showed that the best GS scenario (GS-Pheno) was up to 15% more efficient than classic selection. For all selection scenarios, optimization increased the overall AMGG, returns and economic efficiency. As a conclusion, our study shows that some forms of GS strategies are more advantageous than classic selection, provided that GS is already initiated (i.e. the initial reference population is available). Optimizing decisional variables of the classic selection scheme could be of greater benefit than including genomic information in optimized designs.

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Section: Modeling Optionsmentioning

confidence: 99%

“…This approximation is rather conservative because it neglects the erratic results observed over the first few years (Elsen and Mocquot, 1974;Hill, 1974). (iv) The time horizon T that is, the moment when any prediction about the organization of the selection scheme looks too fragile (here 30 years).…”

mentioning

confidence: 99%

Economic evaluation of genomic selection in small ruminants: a sheep meat breeding program

Shumbusho

Raoul

Astruc

et al. 2016

Animal

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“…The average relationships in a population with overlapping generations are obtained by weighting the average relationships within and between age classes by the long-term contribution of the age classes (r), which is obtained from Hill's (1974) geneflow method (Meuwissen & Sonesson, 1998) :…”

Section: (I) Minimization Of Coancestry Selection For O Erlapping Genmentioning

confidence: 99%

Minimization of rate of inbreeding for small populations with overlapping generations

Sonesson¹,

Meuwissen²

2001

Genet. Res.

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SummaryWe propose a method that minimizes the rate of inbreeding (∆F ) for small unselected populations with overlapping generations and several reproductive age classes. It minimizes the increase in coancestry of parents and optimizes the contribution of each selection candidate. The carrying capacity of the population is limited to a fixed number of animals per year. When survival rate equalled 100 %, only animals from the oldest age class were selected, which maximized the number of parents per generation, slowed down the turnover of generations and minimized the increase of coancestry across sublines. However, the population became split into sublines separated by age classes, which substantially increased inbreeding within sublines. Sublines were prevented by a restriction of selecting at least one sire and one dam from the second-oldest age class, which resulted in an L times lower ∆F, where L equals the average generation interval of sires and dams. Minimum coancestry mating resulted in lower levels of inbreeding than random mating, but ∆F was approximately the same. For schemes where the oldest animals were selected, ∆F increased by 18-52 % compared with the proposed method.

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“…The discounted gene-flow method (Hill, 1974;McClintock and Cunningham, 1974;Van Vleck and Everett, 1976) has long been used to account for CDE of sire's genes in his descendant. The discounted gene-flow principles of Van Vleck and Everett (1976) were modified by Amer (1999) and Amer et al (2001) and were applied to sheep and beef breeding programs, respectively.…”

Section: Methodsmentioning

confidence: 99%

“…The work by Amer (1999) was extended to evaluate the value of using genetically superior animals for expression of a recessive single gene (Wood et al, 2004;Kearney et al, 2005) and to account for a situation where descendants of specific animals are mated to more than one breed (Berry et al, 2006). Recently, Nishio et al (2008) modified the conventional gene-flow method (Hill, 1974) to calculate the CDE of all genotypes when using sires of a particular genotype in the herd. In this study, this modified gene-flow method was applied to calculate the CDE of homozygous recessive animals with genetic defect as a result of using carrier sires.…”

Section: Methodsmentioning

confidence: 99%

Economic implications of using Japanese Black sires carrying recessive genes associated with genetic defects

Nishio

Kahi

Hirooka

2008

Animal

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The objective of this study was to calculate cumulative discounted expressions (CDE) for Japanese Black sires carrying a single defective allele in a herd by applying the gene-flow method to investigate the expression pattern of homozygous recessive genotype and to evaluate the monetary loss of using these sires. A single biallelic locus was considered with A representing the dominant allele and a representing the recessive allele. The gene-flow method was modified to consider the fitness of homozygous recessive genotype. Input parameters representing a typical situation in a Japanese Black cattle herd were used to calculate the CDE and the loss of using carrier sires. The effects of initial allele frequency and fitness on the CDE were determined for Aa and AA sires. The CDE of Aa sires were larger than those of AA sires under all initial allele frequencies and fitness. The difference in the CDE between using Aa and AA sires was largest when fitness was 0 (lethal recessive condition). The differences in the loss between Aa and AA sires were larger with increasing initial allele frequencies in lethal recessive condition. Applying the method used in this study to defects reported in Japanese Black cattle and with a population size of 628 000, the difference in the loss between using Aa and AA sires was US$48 575 800 and US$74 418 000 in the case of Band-3 and Claudin-16 deficiencies, respectively. The approach used in this study could be applied to other genetic defects in different breeds and species.

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Prediction and evaluation of response to selection with overlapping generations

Cited by 228 publications

References 12 publications

Economic evaluation of genomic selection in small ruminants: a sheep meat breeding program

Economic evaluation of genomic selection in small ruminants: a sheep meat breeding program

Minimization of rate of inbreeding for small populations with overlapping generations

Economic implications of using Japanese Black sires carrying recessive genes associated with genetic defects

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