Sports performance of descendants of CLCN1 gene mutation carrier New Forest Pony Stallions

In 2011, the CLCN1 gene mutation in New Forest Ponies (NF) was discovered by Wijnberg et al. This study tested the hypothesis that NF descending from a CLCN1 gene mutation carrier stallion (MCS) perform better in sports than NF that those not being descendants of the CLCN1 MCS. Data on the sport performance of 11.414 NF registered at Royal Dutch Equestrian Sports federation, were analyzed and descendants from MCS were identified. Ponies were divided in jumping, dressage and eventing categories. They were listed categorically from the lowest category to the highest sport level. Statistical analysis with logistic regression between the sport categories and within the categories was performed using SPSS version 19. Significance was set at p < 0.05. Ponies that were descendants of a MCS were performing significantly better in jumping, dressage and eventing. The odds of finding a descendant in the highest jumping category was 7.6 compared to the lowest. In dressage, descendants from the MCS were performing significantly better, as illustrated by an odds ratio of 4.1 for performing in the highest category. In eventing, the odds of finding a descendant from a MCS in the highest category was 2.9 compared to the lowest. This conclusion might lead to breeding programs which includes stallions who carry this mutation, aiming to breed better performing ponies in equine sports, which is in contrast of the aim of the Studbook to eradicate the mutation.