Exploring genetic diversity in an Italian horse native breed to develop strategies for preservation and management

Abstract

Genetic diversity is a key factor for both adaptation and response to selection. The loss of genetic diversity causes a decrease in individual fitness, and it has a dramatically negative effect on population lifespan in the long term. This study aimed at exploring the genetic diversity at pedigree level of the Bardigiano horse breed, which is a native breed from Italy shaped for living in rural areas. In 1977, the Bardigiano studbook was founded to preserve the breed and for improving its use for riding and draft purposes. Pedigree data contained 9,469 horses, of which 3,416 were alive. Demographic and genetic parameters were estimated on subpopulations to evaluate potential genetic diversity differences among breeding and nonbreeding animals, and animals showing different breeding values (EBVs) for an index combining 18 conformation traits. Throughout the studied period, inbreeding steadily increased, reaching in the last birth year cohort a mean value equal to 0.10. The rate of inbreeding per generation, assuming a mean generation interval of 8.74 years, was equal to 1.64%. Moreover, significant differences on both average relatedness and inbreeding among horses with high and low EBVs were shown. Our study unravelled the state of genetic diversity in the Bardigiano breed, highlighting that breeding strategies for optimizing the contribution of breeding animals in the coming generations are needed to ensure long-term survival of the Bardigiano horse breed.

Genetic parameters estimation in an Italian horse native breed to support the conversion from agricultural uses to riding purposes

“…The fixed effects of event (place–date), sex and age were included in the model. We accounted for the effect of inbreeding by including the individual inbreeding coefficients in the model as percentile classes, which were calculated as described in a previous study (Ablondi et al, ). The variance components were estimated by restricted maximum likelihood (REML) with univariate animal model and an additive relationship matrix by using the software ASReml 4.0 (Gilmour, Gogel, Cullis, Welham, & Thompson, ).…”

“…Since local breeds are nowadays recognized as an important part of biodiversity, conservation efforts have been attempted to save endangered breeds. Within the framework of breed conservation, several studies have explored genetic diversity to safeguard breed integrity (Ablondi, Vasini, Beretti, Superchi, & Sabbioni, ; Dorji, Tamang, Tshewang, Dorji, & Dorji, ; Druml, Baumung, & Sölkner, ; Onogi, Shirai, & Amano, ; Senju et al, ; Solé, Valera, Gómez, Cervantes, & Fernández, ). However, there is a scarcity of research on genetic parameters estimation in local horse breeds, even though they could be used to create new genetic indices and be used to exploit the unique value of those breeds.…”

“…However, a recent study showed that the inbreeding rate has increased steadily in the last years, being equal to 1.64% calculated for the two latest generations. In addition, a gradual decrease in the annual number of registered horses was observed, dropping to 165 horses in 2016, pointing out that the breed might have lost popularity (Ablondi et al, ). Bardigiano horses show unique characteristics ranging from excellence resilience to harsh climate to gentle temperament and willingness to work.…”

Genetic Variability and Management in Nero di Parma Swine Breed to Preserve Local Diversity

“…The major difference in terms of average inbreeding was found from the comparison of the first and last percentile, with an average F of 0.32 and 0.28, respectively. 1 Four percentile classes based on the herd size were calculated using the total number of registered animals; 2 Farms = number of farms in each herd class; 3 N = average number of pigs born in the herd; 4 Own Father = percentage of piglets born from boars belonging to the same herd; 5 SD = standard deviation; 6 Highest = highest inbreeding (F) and average relationship (AR) coefficient within herd percentile class.…”

“…Pedigree analysis is an effective tool to characterize the genetic diversity of a population due to its cost- Nowadays, the live population counts 1603 pigs. In small populations the risk of permanent loss in genetic material is dramatically high, and the maintenance of genetic diversity represents one of the most important breeding goals [4]. The conservation of a breed is strictly linked to its economic relevance as it guarantees the survival of the breed in the long term.…”