Ultrasonography of the urogenital tract in elephants (Loxodonta africanaand Elephas maximus): An important tool for assessing female reproductive function

Abstract

At present, the worldwide captive elephant population is not self‐sustaining. The major reason for low reproductive rates is the heretofore undiagnosed reproductive disorders of nulliparous females of prime breeding age. Recent advances in ultrasound technology have facilitated the detection of these disorders in non‐sedated animals. Approximately 2,000 ultrasonographic examinations were performed in more than 280 captive and wild African and captive Asian female elephants. The entire urogenital tract was scanned, measured, and documented to provide a reference for ultrasound specialists involved in elephant breeding programs. The primary pathological lesions that influenced reproductive rates in these females were uterine tumors and endometrial cysts and ovarian cysts that resulted in acyclicity. The detection of these disorders and their stage of development can be used by elephant managers to make decisions approximately which animals to include in breeding programs. Ultrasonography can be used as an effective tool for assessing the reproductive fitness of female breeding candidates in both African and Asian elephants. Zoo Biol 19:321–332, 2000. © 2000 Wiley‐Liss, Inc.

Ultrasonographic and laparoscopic evaluation of the reproductive tract in older captive female cheetahs (Acinonyx jubatus)

“…Asymmetric reproductive aging has been demonstrated in cheetahs similar to other captive populations of non-carnivore species such as elephants and rhinoceros where older captive females demonstrate irregular oestrous cycles or may cease cyclic activity [6,19,20].…”

Luteogenesis during the estrous cycle in Asian elephants (Elephas maximus)

“…Histological interpretation of CL origin is difficult. The finding of so called 'ovulation stigmata' (trauma of ovulation) in more than one CL (Perry 1953, Hanks & Short 1972, Smith & Buss 1975 disagrees with both the generally accepted fact that elephants are monovular as well as ultrasound observations of only a single ovulation per cycle in this and in other reports (Hermes et al 2000, Hildebrandt et al 2000a). This suggests that there is a different reason for the origin of these stigma-like appearing protuberances.…”

“…The ultrasound procedures were performed transrectally as described previously (Hildebrandt et al 2000a). In 75% of the examinations, the ovaries were visualized with a hand-held ultrasound probe, in 15%, a plastic extension (made out of PVC pipe, with the end angled downward 130 8C) was taped to the probe to gain 20 cm extra reach, and in 10% of the cases a longer metal extension (Hildebrandt & Schnorrenberger 1996;patent no.…”

“…Luteal tissue undoubtedly is crucial for pregnancy maintenance, but despite determined research efforts, the factors controlling CL formation and function in elephants have remained elusive (Hodges et al 1994, Allen 2006. The technological advances of transrectal ultrasonography have been a major breakthrough, enabling us to depict and follow the ongoing physiological ovarian process over time in elephants (Hermes et al 2000, Hildebrandt et al 2000a, 2000b. The first sequential ultrasound study which was performed in African elephants focused on the interluteal phase and demonstrated that multiple CLs were formed in every cycle (and not only during pregnancy; Hermes et al 2000).…”

Successful artificial insemination of an Asian elephant at the National Zoological Park

“…Even after the elephants are introduced to each other, they may exhibit a lack of sexual interest [Schmidt, 1993]. Older females often develop uterine fibroids, ovarian cysts, and unexplained ovarian quiescence that may prevent conception [Brown, 1999[Brown, , 2000Hildebrandt et al, 2000a]. Furthermore, it appears that many adult bulls are experiencing fertility problems associated with poor sperm quality and lack of libido [Hildebrandt et al, 2000b] (D. Schmitt and T. Hildebrandt, unpublished results).…”