Reproductive efficiency related traits evaluation in beef genotypes under humid tropical conditions

Abstract

The objective of the study was to quantify genetic and nongenetic effects, and to estimate genetic variance, on reproductive efficiency traits in a herd with Romosinuano inheritance managed under tropical conditions. Records collected from 1959 to 1989 at the Tropical Agronomic Center for Research and Education, Costa Rica (CATIE), were used to calculate age at first calving (AFC; days) and calving interval (CI; days). Animals with 50% or less Romosinuano inheritance (BG1; n= 496) and with more than 50% Romosinuano inheritance (BG2; n= 1045) were classified as different breed groups. Age of dam influenced AFC and CI (P<.01). Differences by breed group were identified for CI (P<.05), where BG2 had a shorter CI than BG1 (402 ± 6 days and 418 ± 7 days, respectively). Interactions between breed group and environment, and between breeding group and age of dam were observed for CI (P<.05). Repeatability for CI was 0.07 ± 0.0015. Heritability for AFC and CI were 0.28 ± 0.16 and.004 ± 0.0001, respectively. These results indicate that animals with Romosinuano inheritance are reproductively efficient under tropical conditions.