2 research outputs found
Fecal 20-oxo-pregnane concentrations in free-ranging African elephants (Loxodonta africana) treated with porcine zona pellucida vaccine
Because of overpopulation of African elephants in South Africa and the consequent threat to biodiversity, the need for a
method of population control has become evident. In this regard, the potential use of the porcine zona pellucida (pZP) vaccine
as an effective means for population control is explored. While potential effects of pZP treatment on social behavior of African
elephants have been investigated, no examination of the influence of pZP vaccination on the endocrine correlates in treated
females has been undertaken. In this study, ovarian activity of free-ranging, pZP-treated African elephant females was monitored
noninvasively for 1 yr at Thornybush Private Nature Reserve, South Africa, by measuring fecal 5 -pregnan-3 -ol-20-on
concentrations via enzyme immunoassay. A total of 719 fecal samples from 19 individuals were collected over the study period,
averaging 38 samples collected per individual (minimum, maximum: 16, 52). Simultaneously, behavioral observations were made
to record the occurrence of estrous behavior for comparison. Each elephant under study showed 5 -pregnan-3 -ol-20-on
concentrations rising above baseline at some period during the study indicating luteal activity. Average 5 -pregnan-3 -ol-20-on
concentrations were 1.61 0.46 g/g (mean SD). Within sampled females, 42.9% exhibited estrous cycles within the range
reported for captive African elephants, 14.3% had irregular cycles, and 42.9% did not appear to be cycling. Average estrous cycle
duration was 14.72 0.85 wk. Estrous behavior coincided with the onset of the luteal phase and a subsequent rise in
5 -pregnan-3 -ol-20-on concentrations. Average 5 -pregnan-3 -ol-20-on levels positively correlated with rainfall. No association
between average individual 5 -pregnan-3 -ol-20-on concentrations or cyclicity status with age or parity were detected.
Earlier determination of efficacy was established via fecal hormone analysis with no pregnancies determined 22 mo post-treatment
and onward. Results indicate the presence of ovarian activity amongst pZP-treated female African elephants in 2 yr after initial
immunization. Further study should now be aimed toward investigating the long-term effects of pZP vaccination on the
reproductive function of female African elephants.Thornybush Private Nature
Reserve, the US Fish and Wildlife Service-African Elephant
Conservation Fund, Humane Society International,
and the University of Pretoria.http://www.theriojournal.comab201
Concentrations of faecal glucocorticoid metabolites in physically injured free-ranging African elephants Loxodonta africana
Free-ranging African elephants Loxodonta africana use their front feet frequently during the process of foraging and
this could be the reason for the high prevalence of physical injuries to these parts of the body. Although the occurrence
of severe lameness caused by foot lesions in adult elephants has already been investigated and the clinical and
pathological findings have been reported, the effect of foot injuries on glucocorticoid levels as a potential physiological
stress response has not been examined. Given the practical difficulties involved in monitoring unpredictable events in
free-ranging animals, like the occurrence of foot injuries in elephants, it is not surprising that information regarding the
endocrine correlates of physical injury is still limited for elephants. In our study we investigated the effects of foot
injuries on concentrations of faecal glucocorticoid metabolites (GCM), body condition score (BCS) and reproductive
behaviour in two GPS/radio-collared elephant bulls in the Kruger National Park, South Africa.Wemonitored the bulls
aged 40+ (Bull 1) and 30+ (Bull 2) 2-3 times per week for 13 months starting in June 2007 and frequently collected
faecal samples for non-invasive hormone monitoring. Faecal samples were lyophilised, extracted and assayed with an
enzyme immunoassay which detects GCM with a 3a-hydroxy-11-oxo-structure. Both bulls acquired foot injuries
(right-front), which caused temporary lameness, but the effect of injury on GCM concentration differed between bulls
(P , 0.001). In Bull 1 the injury lasted 6 250 days and was associated with an up to four-fold increase in GCM
concentrations (P,0.001) and his BCS reduced from ’good’ to ’very thin’ by the end of the injury period. In Bull 2 the
injury lasted 65 days and was associated with a smaller increase in GCM concentrations (P ÂĽ 0.03) together with a
reduced loss in condition when compared to Bull 1. Following recovery, the condition of both bulls improved
progressively and faecalGCMreturned to baseline concentrations. Collectively, the data clearly underlined the value of
non-invasive hormone measurements as a tool to provide information on the level of stress experienced by elephants.
Thus, monitoring GCM levels could help improve the assessment of an elephant’s state of health