Genetic parameters for birth and weaning weights in Simmental-Brahman herds under Mexican subtropical conditions
Purebred and crossbred Simmental and Brahman records from three unconnected herds were used to estimate within-herd variance components for additive direct and maternal genetic effects for birth weight and 205 d-adjusted weaning weight. Herds were located in the subtropical region of Tamaulipas, Mexico. Variances were estimated by restricted maximum likelihood procedures using a sire-dam mixed model. Fixed effects were contemporary group, age of dam ´ sex of calf ´breed group of dam interactions. Genetic group effects were sire intrabreed additive direct, dam intrabreed additive maternal, sire interbreed Simmental-Brahman nonadditive direct, and dam interbreed Simmental-Brahman nonadditive maternal. Random genetic effects were sire additive genetic direct, dam additive genetic direct plus maternal, and residual. Effects in the model varied according to trait and breed composition of the herd. Within-herd heritability estimates were: 0.05 ± 0.03 for BWTD, 0.09 ± 0.03 for BWTM, 0.23 ± 0.08 for WW205D, 0.11 ± 0.04 for WW205M in herd 1, 0.84 ± 0.17 for BWTD, 0.63 ± 0.28 for WW205D, and 0.33 ± 0.22 for WW205M, in herd 2, and 0.03 ± 0.07 for BWTD, 0.15 ± 0.07 for BWTM, 0.22 ± 0.15 for WW205D, and 0.17 ± 0.10 for WW205M, in herd 3. These intra-herd heritabilities showed that more genetic variability was expressed or weaning weight than for birth weight traits. Thus, more genetic progress could be achieved for weaning weight direct for weaning weight than for birth weight traits. Thus, more genetic progress could be achieved for weaning weight direct and maternal than for birth weight traits in these herds. Producers should consider connecting these herds by using common sires. Connecting these herds would yield more accurate estimates of genetic parameters and genetic predictions, thus larger selection progress for weight traits could be expected.
| Main Authors: | , , , , |
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| Format: | Digital revista |
| Language: | spa |
| Published: |
Instituto Nacional de Investigaciones Forestales, Agrícolas y Pecuarias
2012
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| Online Access: | https://cienciaspecuarias.inifap.gob.mx/index.php/Pecuarias/article/view/1406 |
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