Abstract

DOMINGUEZ-VIVEROS, J.; RODRIGUEZ-ALMEIDA, F.A.  and  ORTEGA-GUTIERREZ, J.Á.. Inbreeding and estimation of genetic parameters for morphology characters in the Lusitano horse breed of Mexico. Arch. zootec. [online]. 2014, vol.63, n.241, pp.37-44. ISSN 1885-4494.  https://dx.doi.org/10.4321/S0004-05922014000100004.

The Lusitano horse breeders association in Mexico proposed the development of genetic evaluation for morphological traits (VM: head-neck (CC), withers (CR), chest (PC), back and loin (DR) and croup (GR)) considered in the selection criteria; however, in earlier studies found high levels of inbreeding (F; 6,6 % average), with constant trend. The objectives were to analyze the effects of F through three indicators (IDF: F of animal (IF); average correlation coefficient (CRP); and, change rate of F (ΔF)) on the average performance, the estimate of heritability (h²) and genetic correlation (r_g) for the VM. Including alternately the IDF as covariate of first order were performed four univariate analysis (UNV) for each VM, and four multivariate analyses with the five VM. The covariate solutions of IDF were equal to zero (p>0,05). The h² with the UNV ranged from 0,08 (DR) to 0,30 (CC), the general average was 0,18. The maximum change with IDF was 0,01. In the MUV, the h² ranged from 0,11 to 0,35, the general average was 0,198; in the rg, the average without IDF was 0,53, in the interval of 0,01 to 0,97; with IDF the average was 0,59, with estimates above 0,20. The h² of UNV vs. MUV without IDF were similar. For PC and GR the h² decreased 0,03 of UNV to MUV with IDF; to contrast of CC, CR y DR with increments of 0,06. Inside MUV, for CC, CR and DR the h² increased with IDF, with more effect CRP; however, in PC and GR decreased, with more effect of F.

Keywords : Genetic correlation; Genetic variance; Heritability; Inbreeding depression; Portuguese autochthonous breed.

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