Impact of ovarian fetal tissue xenotransplantation associated with in vitro embryo production in annual genetic gain estimates for cattle weight traits

Resumo

The present paper aims to estimate the impact of the reduction
of the generation interval, based on the model of fetal ovarian tissue
xenotransplantation associated with in vitro embryo production to
estimate the annual genetic gain of weight traits in a bovine herd. Weigh
data and genealogy of Brahman animals were used to estimate the annual
direct genetic gain for weight at birth, weight at 120 days, at 210 days,
and at 550 days of age. The genetic parameters were obtained by animal
model, via Bayesian inference, by Markov Chain Monte Carlo (MCMC)
methods. For the estimates, different generation intervals were defined as
the average value between the supposed maternal generation intervals
and the average sire generation interval based on the analyzed data (9.6
years). The shortest generation interval considered was 5.1 years, outlined
from the average of 0.66 year (corresponds to 8 fetal months, an
assumption defined based on the use of fetal ovarian tissue
xenotransplantation associated with in vitro embryo production) and 9.6
years (sire generation interval). The remaining intervals considered were
6.7, 8.7 and 10.2 years. The estimate of annual direct genetic gain for all
the evaluated traits was higher when considering the generation interval
outlined based on the model of fetal ovarian tissue xenotransplantation
associated with in vitro embryo production. The estimates were lower as
the generation interval increased. The use of fetal ovarian tissue
xenotransplantation associated with in vitro embryo production, may favor
the reduction of the generation interval and successively generate a
positive impact on the annual direct genetic gain estimates.