Excretory Fate of Estradiol and Progesterone in the African Elephant (Loxodonta africana) and Patterns of Fecal Steroid Concentrations throughout the Estrous Cycle

Fecal 20-oxo-pregnane concentrations in free-ranging African elephants (Loxodonta africana) treated with porcine zona pellucida vaccine

“…This study is the first to examine the effects of pZP treatment on faecal progestagen concentrations in female African elephants while further demonstrating the usefulness of noninvasive faecal endocrine monitoring in assessing reproductive status in wild populations of African elephants [18,22,26,29]. The results generated in this study underline earlier efficacy of (333 mm) fell below the average 601 mm reported for the study area [30].…”

“…In the female African elephant (Loxodonta africana), estrous cycle length is reported to range between 13 to 17 weeks [17][18][19][20][21][22][23][24][25]. The cycle is divided into a 4 to 6 week follicular phase after 4 which an increase in progesterone levels, believed to trigger ovulation, marks the onset of an 8 to 11 week luteal phase [17,[20][21][22].…”

“…Monitoring luteal endocrine function via faecal hormone analysis has made it possible to examine the reproductive biology of wild and captive animals [1,18]. Faecal samples can be easily collected and non-invasive methods have already been developed and successfully tested to enable the measurement of progestagen metabolites in elephant faeces [22,29].…”

“…However, Delsink et al [11,16] found no significant change in core and total range use, matriarchal status, cow/calf interaction, herd fragmentation/isolation, musth occurrence, bull hierarchy, and no aberrant or unusual behaviour witnessed among the herds. Furthermore, concerns were raised as to the potential effect of the pZP vaccine on luteal function, but to date, there has been no attempt to examine endocrine correlates associated with pZP vaccine use in African elephants.In the female African elephant (Loxodonta africana), estrous cycle length is reported to range between 13 to 17 weeks [17][18][19][20][21][22][23][24][25]. The cycle is divided into a 4 to 6 week follicular phase after 4 which an increase in progesterone levels, believed to trigger ovulation, marks the onset of an 8 to 11 week luteal phase [17,[20][21][22].…”

“…However, the knowledge acquired regarding the reproductive endocrinology of the African elephant is predominantly from studies on captive individuals. Amongst wild populations, the information gleaned regarding estrous cycles has been inconclusive due to the common occurrence of pregnancy or lactation among females [26][27][28].Monitoring luteal endocrine function via faecal hormone analysis has made it possible to examine the reproductive biology of wild and captive animals [1,18]. Faecal samples can be easily collected and non-invasive methods have already been developed and successfully tested to enable the measurement of progestagen metabolites in elephant faeces [22,29].…”