Genetic and clonal responses in closed dairy cattle nucleus schemes

Abstract

The additive genetic response per generation and the genetic superiority of female genotype(s) selected for commercial cloning (clonal response) were maximized for a closed adult nucleus scheme, with 256 or 1024 test places, by varying the mating design (number of clones, full-sibs and half-sibs). Responses were corrected for effects of finite sample size and correlated index values on the selection intensity, and variance reduction due to selection. Additive genetic responses, which varied from 0-153 to 0-514 phenotypic standard deviations per generation, were 0-68 to 0-89 of corresponding uncorrected predictions. Reductions were largest when the intensity and accuracy of male selection were high. Clonal responses varied from 0-460 to 2-506 phenotypic standard deviations, increasing with the intra-clone correlation, the intensity of clonal selection and the test capacity. Reductions in clonal responses, which varied from proportionally 0-04 to 0-27, were smallest when dominance variance was high. Increasing the test capacity resulted in a proportionally 0-21 to 1-55 increase in genetic responses, while proportional increases in clonal responses varied from 0-09 to 0-36. With selection of only one male per full-sib family, designs which maximized genetic and clonal responses were different in all cases. Differences were largest when the heritability and the intra-clone correlation were low and the intensity of clonal selection was high. Without the restriction on male selection, optimal mating designs were different, unless dominance variance and intensity of clonal selection were both low.

Combining use of embryo sexing and cloning within mixed MOETs for selection on dairy cattle

“…The complexity of current algorithms for predicting F values under selection (Wray and Thompson, 1990and Verrier et al, 1990, 1991 (Dempfle, 1990;Senou, 1990;Toro and Perez-Enciso, 1990;Verrier et al, 1991 (Teepker and Smith, 1989;Woolliams, 1980;De Boer and Van Arendonk, 1991 The first derivatives of u and v with respect to m l , m 2 , m 3 , m 4 , m!, f l , f 2 , f 3 , f 4 , f 5 are very simple:…”

“…Schemes using the full reproductive capacity of a given genotype allowed by cloning were found to be superior (+5 to +10% ) when the number of live replicates per cloned heifer was moderate (3-5). They were even more superior for higher number of replicates (10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20) (Van Vleck, 1981;Nicholas and Smith, 1983;Smith, 1989;Teepker and Smith, 1989;Woolliams, 1989;De Boer and Van Arendonk, 1991 (Colleau, 1991) …”

A Method of Modelling Pig Breeding Schemes

“…Selection intensities for uncorrelated breeding values corrected for finite population size were calculated using the approximation suggested by Burrows (1972). Correlations between estimated breeding values of relatives were calculated as suggested by De Boer and van Arendonk (1991).…”

An ethical evaluation of animal biotechnology: the case of using clones in dairy cattle breeding

“…Several studies have focused on the use of clones in dairy cattle production, because of their potential use for rapidly increasing the average genetic level of milking cows (Van Vleck, 1981;Nicholas and Smith, 1983;Woolliams, 1989;Teepker and Smith, 1989;de Boer and van Arendonk, 1991;Colleau, 1992;de Boer, Meuwissen and van Arendonk, 1994;). To illustrate the approach we will consider the use of clones in dairy cattle breeding.…”