Associação genética entre características de carcaça, crescimento e de reprodução em bovinos braford e brangus
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Data
2021-02-22
Autores
Zuim, Deise Mescua
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Universidade Federal de Mato Grosso
Resumo
The study was developed with the objective of estimating the genetic
association between growth, reproduction and carcass traits obtained by ultrasound
in Braford and Brangus cattle. Longissimus muscle area (LMA), and backfat
thickness (BFT), postweaning average daily weight gain (ADG), visual scores of
conformation (C), precocity (P), muscling (M), size (S), scrotal circumference (SC) at
around 420 and 550 days of age, and days to first calving (DFC). The heritability
estimates obtained were of moderate magnitude for LMA (0.23 to 0.27) and low for
BFT (0.07 to 0.16), supporting the possibility of a favorable response to selection,
especially LMA. The most favorable genetic correlations found for visual scores were
between P550 and LMA (0.39 to 0.51) and between M550 and LMA (0.32 to 0.41) for
Braford, and for Brangus they were between P550 and LMA420 or LMA550 (0.56)
and between M550 and LMA (0.17 to 0.51). Estimates of genetic correlation between
BFT and P550 were positive and of moderate to high magnitude for Braford (0.33 to
0.58) and Brangus (0.26 to 0.61). The genetic associations between SC and LMA
were of low magnitude, however stronger when SC was measured around 550 days
for Braford (0.12 to 0.30) and Brangus (0.01 to 0.21). Between SC and BFT, the
genetic correlations varied from -0.18 to -0.12 for Braford and from -0.26 to 0.42 for
Brangus. There was evidence of a favorable genetic relationship of DFC with LMA (-
0.22 to -0.12) and BFT (-0.26 to -0.22) at different ages in Braford cattle, the same
was not observed for Brangus for LMA (0.03 to 0.29) and BFT (0.04 to 0.57). In view
of the differences in estimates of genetic correlation between breeds and
measurement ages of animals, it is necessary to develop specific selection strategies
for each case.
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ZUIM, Deise Mescua. Associação genética entre características de carcaça, crescimento e de reprodução em bovinos braford e brangus. 2021. 48 f. Dissertação (Mestrado em Zootecnia) - Universidade Federal de Mato Grosso, Campus Universitário de Rondonópolis, Instituto de Ciências Agrárias e Tecnológicas, Rondonópolis, 2021.