Decisive management must be introduced to control inbreeding levels in the critically endangered Sorraia horse, according to researchers.
A research team set out to investigate the impact of inbreeding on fitness-related traits in the threatened breed which is indigenous to the Iberian peninsula.
Helena Kjöllerström and her colleagues, writing in the journal Livestock Science, said the Sorraia horse population can be regarded as a universal equine genetic resource, most likely the representative of the ancestor of Iberian saddle horses and probably the ancestor of several New World horse breeds.
The breed was recovered in 1937 and managed without further additions to the initial founding group of 12 horses, giving rise to the existing population with extremely high inbreeding levels.
There are only about 300 animals representing the Sorraia horse population worldwide, which places it in a critical risk status.
There was a need to establish a conservation-breeding plan aiming at a long-term self-sustaining population, they said.
The researchers used data on all registered horses in the Sorraia Studbook to study the impact of inbreeding on offspring’s viability at birth and at six months of age. A sub-sample was used to determine the influence of inbreeding on stallion and mare fertility rates, foaling intervals and parental age at first birth.
Their findings pointed to reduced survival rates in young stock in matings that reflected higher inbreeding. This, they said, pointed to the need for a long-term self-sustaining conservation-breeding plan.
“Decisive management-breeding plans must be taken to control inbreeding levels in Sorraia horses, and contribute to the conservation of this breed,” they said.
Impact of inbreeding on fitness-related traits in the highly threatened Sorraia horse breed
H.J. Kjöllerström, L.T. Gama, M.M. Oom.
The abstract can be read here.