Model comparisons for genetic evaluation of gait type in Mangalarga Marchador horses

Author(s):Show less -

Bussiman, Fernando de Oliveira ^[1] ; e Silva, Fabyano Fonseca ^[2] ; Bueno Carvalho, Rachel Santos ^[3] ; Ventura, Ricardo Vieira ^[1] ; de Oliveira, Henrique Nunes ^[4] ; Abreu Silva, Barbara da Conceicao ^[5] ; Fonseca, Mayara Goncalves ^[6] ; dos Santos, Bruna Aparecida ^[7] ; Pereira, Guilherme Luis ^[7] ; Eler, Joanir Pereira ^[5] ; Sterman Ferraz, Jose Bento ^[5] ; Mattos, Elisangela Chicaroni ^[5] ; Curi, Rogerio Abdallah ^[7] ; de Carvalho Balieiro, Julio Cesar ^[1]

Affiliation

^[1] Univ Sao Paulo VNP FMVZ USP, Coll Vet Med & Anim Sci, Dept Anim Nutr & Prod, Bioinformat & Anim Breeding Lab, Av Duque de Caxias Norte 225, BR-13635900 Pirassununga, SP - Brazil

^[2] Fed Univ Vicosa DZO UFV, Dept Anim Sci, Av PH Rolfs S-N, BR-36570900 Vicosa, MG - Brazil

^[3] Univ Sao Paulo ZAB FZEA USP, Coll Anim Sci & Food Engn, Dept Basic Sci, Av Duque de Caxias Norte 225, BR-13635900 Pirassununga, SP - Brazil

^[4] Sao Paulo State Univ FCAV UNESP, Coll Agr & Vet Sci, Dept Anim Sci, Via Acesso Prof Paulo Donato Castellane S-N, BR-14884900 Jaboticabal, SP - Brazil

^[5] Univ Sao Paulo GMAB ZMV FZEA USP, Coll Anim Sci & Food Engn, Dept Vet Med, Grp Anim Breeding & Biotechnol, Av Duque de Caxias Norte 225, BR-13635900 Pirassununga, SP - Brazil

^[6] Sao Paulo State Univ FCAV UNESP, Coll Agr & Vet Sci, Dept Morphol & Anim Physiol, Access Route Paulo Donato Castellane, BR-14884900 Jaboticabal, SP - Brazil

^[7] Sao Paulo State Univ FMVZ UNESP, Coll Vet Med & Anim Sci, Dept Anim Improvement & Nutr, Rua Jose Barbosa de Barros 1780, BR-18618307 Botucatu, SP - Brazil

• Document type: Journal article
• Source: LIVESTOCK SCIENCE; v. 239, SEP 2020.
• Web of Science Citations: 0

Abstract

Mangalarga Marchador (MM) is a very important Brazilian gaited horse breed. These animals show two gait types, differing in proportion of lateral or diagonal movements. Thus, it is possible to consider the gait type as a binary categorical trait in our statistical models. Threshold models (TM) are strongly recommended to handle binary traits for genetic evaluation purposes. However, TM are susceptible to the extreme categorical problem (ECP). ECP is usually observed due to the absence of variation within subclasses for a given systematic effect and can be avoided after handling this effect as random or by combining different systematic effects in the model. In this context, we aimed to find the most suitable systematic effect (based on goodness-of-fit and predictive ability) to be included in Bayesian threshold model for the genetic evaluation of gait type in MM horses. The dataset consisted of 1,231 gait type records and 3,172 animals in the pedigree file. Phenotypic record associated with gait type was treated as a categorical trait (MP = 0 and MB = 1). In summary, models with small complexity were benefited by smaller bias and average prediction errors. Additionally, these models showed higher heritability estimates. ECP was an important issue, and should always be approached when using threshold models for genetic evaluation. (AU)

• FAPESP's process: 16/17834-0 - Genome-Wide Association Study for genetics differences between the batida and picada gaits in Mangalarga Marchador equine
• Grantee: Fernando de Oliveira Bussiman
• Support Opportunities: Scholarships in Brazil - Master
• FAPESP's process: 16/19081-9 - Prospection of chromosomal regions, genes and SNP related to Batida gait and genomic analysis of the population structure in horses of the brazilian breed Mangalarga Marchador
• Grantee: Rogério Abdallah Curi
• Support Opportunities: Regular Research Grants