Epsilon Archive for Student Projects

Abstract

Since its foundation in 1967, the Swedish New Forest Pony Society (SNF) shows interest in breeding for performance in dressage, show jumping, and eventing competitions. The purpose of this study was to carry out genetic analyses on available recordings from young pony performance tests and competitions, in order to evaluate their usefulness in future selection for New Forest breeding ponies. Heritabilities, genetic correlations and breeding values were estimated using Best Linear Unbiased Prediction (BLUP) animal models. Data were composed of 467 ponies who participated in Young Pony Test (YPT) for 3-year olds between 2002-2014, 609 ponies who participated in Riding Pony Quality Test (RPQT) for 4- and 5-year olds between 1990-2014, lifetime competition results of 2225 ponies (that participated in dressage, show jumping and/or eventing between 1993-2011), and pedigree records for 60595 ponies.
Ten traits considering conformation, gaits and jumping ability were analysed in YPT and RPQT data, and four lifetime competition traits transformed with 10-log for each discipline (show jumping, dressage and eventing). Estimated heritabilities ranged from 0.06 (walk in hand) to 0.36 (jumping talent) in YPT, from 0.11 (jumping technique) to 0.62 (overall conformation) in RPQT, and from 0.00 (eventing) to 0.24 (show jumping) in competitions. Eventing data was not used for further analyses due to few participating ponies. Lifetime points in dressage and show jumping were found to be the most relevant traits to use for competition.
Within YPT, the highest positive genetic correlation was estimated between jumping technique and temperament for jumping (1.00). Conformation traits were similarly correlated with gaits (0.31 to 1.00) or with jumping traits (0.27 to 1.00), with one exception between trot in hand and correctness of legs (-0.12). The most strongly correlated gait with jumping traits was free canter (0.72 to 0.87). Within RPQT, all genetic correlations were positive, the highest being between overall conformation and temperament for gaits (0.84). Overall conformation had moderate to high but not significant correlations with jumping traits (0.29 to 0.49), and high correlations with gaits (0.53 to 0.70). The most strongly correlated gait with jumping traits was trot under rider (0.40 and 0.49) but not significantly. All significant genetic correlations between corresponding traits in YPT and RPQT were high (0.47 to 0.96). A few significant correlations were estimated between young pony test traits and competition traits, the highest being between jumping talent in RPQT and lifetime points in show jumping competitions (0.98).
The mostly moderate heritabilities and positive genetic correlations between young pony test traits and competition traits found in this study suggests that the traits are suitable to be used for future genetic evaluation of the breed. New Forest pony stallions having more than 10 tested or competed offspring were ranked according to their Estimated Breeding Values (EBVs) for talent traits in YPT and RPQT and two competition traits (lifetime points and ratio lifetime points/number of starts). However, the Swedish New Forest pony population is quite small and few ponies participate in YPT and RPQT, which contributes to less reliable genetic parameter estimations compared with larger populations. SNF should encourage breeders and owners to test their ponies in order to enable a reliable genetic evaluation for the breed in the future. All important traits should be stated in the breeding objectives and be measurable, which is not entirely the case for New Forest ponies.