Pregnancies following long luteal phases in southern white rhinoceros (Ceratotherium simum simum)

Abstract

All extant species in the Rhinocerotidae family are experiencing escalating threats in the wild, making self‐sustaining captive populations essential genetic reservoirs for species survival. Assisted reproductive technologies (ARTs) will become increasingly important for achieving and maintaining ex situ population sustainability and genetic diversity. Previous reports have shown that a large proportion of captive southern white rhinoceros (SWR) females are irregularly cyclic or acyclic, and that cycling females display two different estrous cycle lengths of approximately 30 or 70 days. It has been suggested that the longer estrous cycle length is infertile or subfertile, as no term pregnancies have been observed following long cycles. Here we report the achievement of two pregnancies following long luteal phases, using ovulation induction and artificial insemination with either fresh or frozen‐thawed semen. One female SWR conceived on the first insemination attempt and gave birth to a live offspring. A second female conceived twice in consecutive long cycles although the first embryo was resorbed by 33 days post‐insemination. A pregnancy from this female's second insemination is ongoing with expected parturition in November 2019. Whether prolonged estrous cycles in SWR are subfertile or infertile in natural breeding situations remains unclear. However, our findings demonstrate that the application of ARTs following prolonged cycles can result the successful establishment of pregnancies in SWR. Therefore, with ARTs, female SWR otherwise considered nonreproductive due to long estrous cycles may still have the potential for representation and contribution to the ex situ population.

Linking socio-sexual and vocal behaviour with faecal progesterone and oestrogen metabolite levels in Southern white rhinoceros females

“…Finally, the fPM profiles of the pregnant study females proved to correspond with previous descriptions of hormonal profiles in pregnant WR, describing elevated faecal pregnane levels with a steep increase exceeding luteal concentrations occurring around 3 months post-conception and remaining at high levels up until shortly before parturition ( Hildebrandt et al , 2007 ; Patton et al , 1999 ; Pennington et al , 2020 ; van der Goot et al , 2013 ). One of the two pregnant females endured stillbirth during late pregnancy, while the other one was at the early stage of pregnancy.…”

Rewinding Extinction in the Northern White Rhinoceros: Genetically Diverse Induced Pluripotent Stem Cell Bank for Genetic Rescue

“…By generating iPSCs, we have created a renewable resource for research and the potential recovery of endangered species. Furthermore, the information we and colleagues are obtaining about all aspects of rhinoceros reproduction [56,57] will aid conservation of other species.…”

Comparative reproduction of the female horse, elephant and rhinoceros: implications for advancing assisted reproductive technologies

“…Over a decade ago, Hermes et al (2007) reviewed ART being undertaken in elephants and rhinoceroses. Since then, improvements in AI techniques in both families and developments in other more advanced reproductive technologies such as ovum pick-up (OPU) and in vitro embryo production in rhinoceroses have been made ( Hermes et al 2009 b , Hildebrandt et al 2012 , 2018 , Stoops et al 2016 , Pennington et al 2020 ). However, the use of ART in pachyderms is far from routine.…”