Free Access
Genet. Sel. Evol.
Volume 34, Number 1, January-February 2002
Page(s) 23 - 39

Genet. Sel. Evol. 34 (2002) 23-39
DOI: 10.1051/gse:2001002

Non-random mating for selection with restricted rates of inbreeding and overlapping generations

Anna K. Sonesson and Theo H.E. Meuwissen

Institute for Animal Science and Health (ID-Lelystad), P.O. Box 65, 8200 AB Lelystad, The Netherlands

(Received 24 November 2000; accepted 8 August 2001)

Minimum coancestry mating with a maximum of one offspring per mating pair (MC1) is compared with random mating schemes for populations with overlapping generations. Optimum contribution selection is used, whereby $\Delta F$ is restricted. For schemes with $\Delta F$ restricted to 0.25% per year, 256 animals born per year and heritability of 0.25, genetic gain increased with 18% compared with random mating. The effect of MC1 on genetic gain decreased for larger schemes and schemes with a less stringent restriction on inbreeding. Breeding schemes hardly changed when omitting the iteration on the generation interval to find an optimum distribution of parents over age-classes, which saves computer time, but inbreeding and genetic merit fluctuated more before the schemes had reached a steady-state. When bulls were progeny tested, these progeny tested bulls were selected instead of the young bulls, which led to increased generation intervals, increased selection intensity of bulls and increased genetic gain (35% compared to a scheme without progeny testing for random mating). The effect of MC1 decreased for schemes with progeny testing. MC1 mating increased genetic gain from 11-18% for overlapping and 1-4% for discrete generations, when comparing schemes with similar genetic gain and size.

Key words: mating / overlapping generations / selection / rate of inbreeding / genetic response / optimum contribution

© INRA, EDP Sciences 2002