Prevalence, risk factors and genetic parameters of cresty neck in Pura Raza Español horses

Reasons for performing study: Cresty neck is a relatively common morphological defect in Pura Raza Espanol horses and other Baroque type horse breeds, which adversely affects the breeding industry. Objectives: To establish the within-breed prevalence, possible associated factors and heritability of cresty neck in Pura Raza Espanol horses. Study design: Cross-sectional analysis of a large worldwide database of Pura Raza Espanol horses. Methods: The database included evaluations of 10,929 Pura Raza Espanol horses from 24 countries. Cresty neck score, on a 9 point scale, girth-to-height ratio, height at the withers, length of neck, head–neck junction and neck–body junction were recorded. A Bayesian genetic animal model included the following systematic effects: girth-to-height ratio, age, sex, coat colour and geographical area of the stud. Animal and residual effects were included as random effects. Results: Within this Pura Raza Espanol population, 8.91% had a cresty neck score ≥5, which is the threshold for penalty or disqualification in the studbook of the breed. The age, sex, coat colour and stud geographical area were significantly associated with cresty neck score. The estimated heritability coefficient for cresty neck score was 0.37 (s.d. = 0.034) and genetic correlation between cresty neck score and other conformational traits ranged from −0.06 (height-at-withers) to −0.21 (neck–body junction). Conclusions: Cresty neck is a prevalent defect in Pura Raza Espanol horses, associated with age, sex, coat colour and other conformational traits, with a moderate level of heritability. Breeding to select against this condition may therefore be beneficial in this breed.