Impacto da seleção de touros pelo mérito genético para fertilidade na eficiência reprodutiva de rebanhos Leiteiros

• Autor(a) principal: Santos, Marcello Mamedes dos
• Data de Publicação: 2020
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFG
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tede/10364
• topic: Melhoramento genético; Prenhez; Reprodução; Genetic improvement; Pregnancy; Reproduction; ZOOTECNIA::PRODUCAO ANIMAL

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.