Genetic comparison of breeding schemes based on semen importation and local breeding schemes: framework and application to Costa Rica
Local breeding schemes for Holstein cattle of Costa Rica were compared with the current practice based on continuous semen importation (SI) by deterministic simulation. Comparison was made on the basis of ge- netic response and correlation between breeding goals. A local breeding goal was d...
| Autores Principales: | VAN ARENDONK, J.A.M., Vargas, Bernardo |
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| Formato: | Artículo |
| Idioma: | Inglés |
| Publicado: |
American Dairy Science Association
2022
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| Materias: | |
| Acceso en línea: |
http://hdl.handle.net/11056/24078 https://doi.org/10.3168/jds.S0022-0302(04)73301-9 |
| Sumario: |
Local breeding schemes for Holstein cattle of Costa
Rica were compared with the current practice based
on continuous semen importation (SI) by deterministic
simulation. Comparison was made on the basis of ge-
netic response and correlation between breeding goals.
A local breeding goal was defined on the basis of prevail-
ing production circumstances and compared against a
typical breeding goal for an exporting country. Differ-
ences in genetic response were <3%, and the correlation
between breeding goals was 0.99. Therefore, difference
between breeding objectives proved negligible. For the
evaluation of genetic response, the current scheme
based on SI was evaluated against a progeny testing
(PT) scheme and a closed nucleus (CN) breeding
scheme, both local. Selection intensities and accuracy
of selection were defined according to current popula-
tion size and reproduction efficiency parameters. When
genotype × environment interaction (G × E) was ig-
nored, SI was the strategy with the highest genetic
response: 5.0% above the CN breeding scheme and
33.2% above PT. A correlation between breeding values
in both countries lower than one was assumed to assess
the effect of G × E. This resulted in permanent effects on
the relative efficiencies of breeding strategies because of
the reduction in the rate of genetic response when SI
was used. When the genetic correlation was assumed
equal to 0.75, the genetic response achieved with SI
was reduced at the same level as local PT. When an
initial difference in average genetic merit of the popula-
tions was assumed, this only had a temporal effect on
the relative ranking of strategies, which is reverted
after some years of selection because the rate of change
in genetic responses remains unchanged. Given that
the actual levels of genetic correlation between coun-
tries may be around 0.60, it was concluded that a local breeding scheme based on a nucleus herd could provide
better results than the current strategy based on SI. |
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