Impacto da seleção de touros pelo mérito genético para fertilidade na eficiência reprodutiva de rebanhos Leiteiros
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2020-02-04
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Universidade Federal de Goiás
Resumo
The widespread use of artificial insemination favored that different genotypes were distributed in
different regions around the world. The lack of adaptation to some environmental conditions can
cause an effect called genotype x environment interaction, especially in polygenic traits, causing
changes in animal performance. Thus, the objective of this study was to evaluate and validate the
effect of daughter pregnancy rate (DPR) based sire selection on the fertility of the national
herds, contributing to the good direction in the genetic improvement of Holstein cows. Reports
about performance reproductive information were collected from six herds located in three different
states. The properties were selected based on the following criteria: a) milk production in feedlot
systems, b) at least 300 lactating cows, c) use of fixed time artificial insemination in female
reproductive management and d) participation in the program of genetic improvement of the Holstein
breed. Variance analysis was performed to assess the impact of different categories of DPR and CCR
(cow conception rate) on the number of days open in the herd. All statistical analyses were
performed using custom packages and scripts of the R program. Although the results are not
statistically significant (P <0.05), the decrease in open days and the increase in conception rates
have a favorable impact on the profitability of production systems. Pearson's correlation between
the RPD and RCC groups is 88%, which shows that bulls with high RPD mostly have RCC of the same
magnitude.
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SANTOS, Marcello Mamedes dos. Impacto da seleção de touros pelo mérito genético para fertilidade na eficiência reprodutiva de rebanhos Leiteiros. 2020. 34 f. Dissertação (Mestrado em Zootecnia) - Universidade Federal de Goiás, Goiânia, 2020.