Genetics of linear type traits scored on young foals belonging to the Italian Heavy Draught Horse breed

• Published in: Livestock science Vol. 219; pp. 91 - 96
• Main Authors: Folla, Fabio, Sartori, Cristina, Guzzo, Nadia, Pigozzi, Giuseppe, Mantovani, Roberto
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.01.2019
• Subjects: body condition; body conformation; data collection; draft horses; Foals; genetic analysis; genetic correlation; Genetic correlations; genetic improvement; head; heritability; horse breeds; Italian Heavy Draught Horse; Linear type traits; Local horse breeds; meat production; Model comparison; pedigree; vaccination; Foals; Model comparison; Linear type traits; Local horse breeds; Italian Heavy Draught Horse; Genetic correlations
• ISSN: 1871-1413; 1878-0490
• DOI: 10.1016/j.livsci.2018.11.019

•In small horse breeds as IHDH many stud-farms are small and excluded from selection.•We evaluated diverse grouping criteria for small stud-farms to keep them in analyses.•The best fitted model used the grouping criterion including more characteristics.•We estimated genetic parameters for linear type traits for heavy draught and meat.•Traits’ heritability and correlations support a reliable selection process in IHDH. In small horse breeds, the small size of stud-farms can bias genetic parameters’ estimations, excluding many breeders from the selection. The study aimed to find a method to include small stud-farms in genetic analysis and to estimate genetic parameters for linear type traits in Italian Heavy Draught Horse (IHDH). Stud-farms were grouped according to an increasing number of criteria: (i) geographical location and housing system; (ii) target productions and vaccination of foal; (iii) stud's body condition. These groups allowed 6 contemporary groups (CG) of environmental units (CG1-CG6) in a dataset of 11,357 scores of young foals and 17,441 subjects in pedigree. Model fitting increased with the number of CG levels. Considering the CG6, heritability varied from 0.149 (upper line direction) to 0.375 (head size/expression). The greatest genetic correlations (from 0.810 to 0.887) involved fleshiness, fore, and rear diameters. The use of CG allowed retaining many records. Genetic estimates indicated a possible genetic improvement for heavy draught and meat production. [Display omitted]