Data di Pubblicazione:
2019
Abstract:
The inclusion of genotype information in several cattle breeding programmes all around the world lead to the genomic selection (GS) era. One of the main advantages of GS over the
traditional selection is the possibility of an early estimation of
breeding values of candidates based on their genotypes. The
optimisation of genotyping and phenotyping strategy represents
a key point for GS programmes. Aim of this study was to evaluate the effect of using different phenotyping and genotyping
strategies on sire breeding values (BV) accuracies. Using
QMSim a dairy bovine population was simulated. Five replicates
of ten recent populations were simulated starting from 200
males and 50,000 females. Best animals were selected and
mated using a positive assortative mating design; sire and dam
replacement were fixed at 40 and 30%, respectively. Ten identical chromosomes each with 1000 markers were generated for
the last three generations. About 26,000 females per generation
were available. The phenotypes of the last generation were
masked in order to represent the candidates of a breeding programmes. Using blupf90 family programmes, breeding values
were estimated for 160 sires of female belonging to the tenth
generation. Some of those sires had daughters also in the ninth
generation. BV accuracies were computed as root square of
reliabilities. Masking phenotypic and genetic information of
candidate females, the average BV accuracy of sires was
0.54±0.48. The high standard deviation can be ascribed to the
different number of daughters in the previous generations.
Increases were observed when phenotypes or genotypes were
added in the analyses: 0.92±0.02 and 0.75±0.15 for phenotypes
and genotypes, respectively. The best scenario was found using
both phenotypes and genotypes, with an average accuracy of
0.93±0.01. Using phenotypes in lieu of genotypes lead to
higher BV accuracies. However, the phenotypes registration
implies longer generation intervals and increase of costs. The
quite good accuracies highlighted using only genotypes and
the low genotyping price at this point can suggest the use of
this strategy instead of waiting for phenotypes collection also
for the well-known advantage of having BV already available at
candidate birth. As expected, the highest accuracies were found
when all possible sources of information (phenotypes+genotypes) were included in the model.
[Ital J Anim Sci vol.18:s1, 2019] [page 91]
Italian Journal of Animal Science 2019; volume
Tipologia CRIS:
04E-Meeting abstract in rivista
Elenco autori:
Nicolò Pietro Paolo Macciotta
, Alberto Cesarani1
,
Massimo Cellesi
, Corrado Dimauro
, Giustino Gaspa
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