Genetic analysis of ‘breeding field test status’ in Icelandic horses.

The research article examines the genetic variations and correlations of the ‘test status trait’ for Icelandic horses participating in breeding field tests.

Objective of the Research

• The study seeks to determine whether the ‘test status trait’ of Icelandic horses – that is, whether a horse was assessed in a breeding field test – possesses genetic variation, and how it genetically correlates to other traits in the breeding goal. Essentially, the researchers are investigating if certain genetic traits predispose a horse to be included in official breeding field tests.

Methodology

• Researchers relied on breeding field test data from 39,443 mares born in Iceland from 1990 to 2001, with 7431 of these being assessed in the period from 1994 to 2007.
• The ‘test status trait’ was then defined in relation to age, gender, and stud of the horses.
• Variance and covariance components were calculated using the Markov Chain Monte Carlo method by applying the Gibbs sampler procedure in the DMU program.
• Three multivariate analyses were conducted, where the test status trait was analyzed alongside various other breeding field test traits.

Findings

• Based on estimated heritabilities (0.51-0.67) and genetic correlations (0.00-0.87), the test status trait demonstrated meaningful genetic variation and was strongly related to some traits.
• The presence of the test status trait indicates preselection – presumably on the basis of performance or quality – in the breeding field test traits.

Recommendations

• The researchers recommend including the test status trait in genetic evaluations, as this action could enhance the overall procedure, reduce selection bias, and improve the estimation’s accuracy.