INPA   24560
UNIDAD EJECUTORA DE INVESTIGACIONES EN PRODUCCION ANIMAL
Unidad Ejecutora - UE
artículos
Título:
Accounting for unknown foster dams in the genetic evaluation of embryo transfer progeny
Autor/es:
MARÍA J SUÁREZ; SEBASTIÁN MUNILLA; RODOLFO JC CANTET
Revista:
JOURNAL OF ANIMAL BREEDING AND GENETICS-ZEITSCHRIFT FUR TIERZUCHTUNG UND ZUCHTUNGSBIOLOGIE
Editorial:
WILEY-BLACKWELL PUBLISHING, INC
Referencias:
Lugar: Londres; Año: 2015 p. 21 - 29
ISSN:
0931-2668
Resumen:
Animals born by embryo transfer (ET) are usually not included in the
genetic evaluation of beef cattle for preweaning growth if the recipient
dam is unknown. This is primarily to avoid potential bias in the estimation
of the unknown age of dam. We present a method that allows including
records of calves with unknown age of dam. Assumptions are as follows:
(i) foster cows belong to the same breed being evaluated, (ii) there is no
correlation between the breeding value (BV) of the calf and the maternal
BV of the recipient cow, and (iii) cows of all ages are used as recipients.
We examine the issue of bias for the fixed level of unknown age of dam
(AOD) and propose an estimator of the effect based on classical measurement
error theory (MEM) and a Bayesian approach. Using stochastic simulation
under random mating or selection, the MEM estimating equations
were compared with BLUP in two situations as follows: (i) full information
(FI); (ii) missing AOD information on some dams. Predictions of
breeding value (PBV) from the FI situation had the smallest empirical
average bias followed by PBV obtained without taking measurement error
into account. In turn, MEM displayed the highest bias, although the differences
were small. On the other hand, MEM showed the smallest MSEP,
for either random mating or selection, followed by FI, whereas ignoring
measurement error produced the largest MSEP. As a consequence from
the smallest MSEP with a relatively small bias, empirical accuracies of PBV
were larger for MEM than those for full information, which in turn
showed larger accuracies than the situation ignoring measurement error.
It is concluded that MEM equations are a useful alternative for analysing
weaning weight data when recipient cows are unknown, as it mitigates
the effects of bias in AOD by decreasing MSEP.