Genetic analysis of juvenile survival in the captive population of Mhorr gazelle (Nanger dama mhorr) and the effect of inbreeding

Abstract

Minimizing the effects of inbreeding is one of the main challenges facing conservation managers of small populations. When inbreeding negatively affects the offspring survival, the short- and long-term viability of the species can be severely compromised. In the present study, we evaluated the genetic parameters affecting calf survival during the perinatal period (PS) and between the perinatal period and weaning (WS) in the captive population of the critically endangered mhorr gazelle (Nanger dama mhorr). The dataset analysed included 2185 calf records from a total pedigree of 2739 animals born between 1971 and 2021. The models with the best predictive value showed heritabilities of the direct genetic effect of 0.259 (SD = 0.052) for the PS and 0.123 (SD = 0.047) for the WS. Only the WS was affected by maternal permanent environmental effect (c2 = 0.035, SD = 0.026). No genetic correlation was observed between the direct genetic effects of both traits. The maximum inbreeding coefficient of the calf was shown to reduce the PS almost 30% points and the inbreeding coefficient of the dam, around 15% points of the WS. Despite this, the genetic and phenotypic trends over the years of both traits were positive, which demonstrates the effectiveness of the mating strategy applied and the effect of no artificial selection that has occurred in this captive population.