Use of Human Chorionic Gonadotropin in a Male Pacific Walrus ( Odobenus rosmarus divergens) to Induce Rut and Achieve a Pregnancy in a Nulliparous Female
Abstract: Walrus in US zoos have a very low reproductive rate of 11 births in 80 years, and little is known about Pacific walrus ( Odobenus rosmarus divergens ) reproductive biology. To address this, we initiated a program in which detailed biological data were recorded on captive walrus. As part of...
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crwiley:10.2164/jandrol.111.015032 2023-12-03T10:28:33+01:00 Use of Human Chorionic Gonadotropin in a Male Pacific Walrus ( Odobenus rosmarus divergens) to Induce Rut and Achieve a Pregnancy in a Nulliparous Female Muraco, Holley S. Coombs, Leah D. Procter, Dianna G. Turek, Paul J. Muraco, Michael J. 2012 http://dx.doi.org/10.2164/jandrol.111.015032 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.2164%2Fjandrol.111.015032 https://onlinelibrary.wiley.com/doi/pdf/10.2164/jandrol.111.015032 en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor Journal of Andrology volume 33, issue 5, page 789-797 ISSN 0196-3635 1939-4640 Urology Endocrinology Reproductive Medicine Endocrinology, Diabetes and Metabolism journal-article 2012 crwiley https://doi.org/10.2164/jandrol.111.015032 2023-11-09T14:34:29Z Abstract: Walrus in US zoos have a very low reproductive rate of 11 births in 80 years, and little is known about Pacific walrus ( Odobenus rosmarus divergens ) reproductive biology. To address this, we initiated a program in which detailed biological data were recorded on captive walrus. As part of a 7‐year study, 1 male and 1 female 16‐year‐old captive Pacific walrus were carefully monitored with weekly serum hormone analysis, daily glans penis smears for spermatozoa, and abdominal ultrasound for pregnancy. The female ovulated once annually from late December through mid‐January and then exhibited 9 months of sustained elevated progesterone. This nonconceptive estrous cycle profile is consistent with reports from wild walrus females. In contrast, the male's seasonal rut routinely occurred in late February through May with a serum testosterone peak in March. This profile differed from the reported adult male cycle in wild walrus of November through March. During the period of the female's ovulation, the male had nadir testosterone levels and was consistently azoospermic. Likewise, during the male's spermatogenic rut in the spring, the female was anovulatory with elevated progesterone. On this basis, the male was treated for 14 weeks with human chorionic gonadotropin (hCG) in an attempt to increase testosterone levels in synchrony with the female's annual ovulation. The treatment successfully induced rut characterized by sustained elevated serum testosterone levels and production of spermatozoa. The male and female successfully bred, and the female became pregnant. Upon discontinuation of hCG treatment, the male resumed baseline testosterone levels. We theorize that the lack of synchronization of rut and ovulatory cycles is a primary reason for reproductive failure in these captive walrus. Article in Journal/Newspaper Odobenus rosmarus walrus* Wiley Online Library (via Crossref) Pacific Journal of Andrology 33 5 789 797 |
institution |
Open Polar |
collection |
Wiley Online Library (via Crossref) |
op_collection_id |
crwiley |
language |
English |
topic |
Urology Endocrinology Reproductive Medicine Endocrinology, Diabetes and Metabolism |
spellingShingle |
Urology Endocrinology Reproductive Medicine Endocrinology, Diabetes and Metabolism Muraco, Holley S. Coombs, Leah D. Procter, Dianna G. Turek, Paul J. Muraco, Michael J. Use of Human Chorionic Gonadotropin in a Male Pacific Walrus ( Odobenus rosmarus divergens) to Induce Rut and Achieve a Pregnancy in a Nulliparous Female |
topic_facet |
Urology Endocrinology Reproductive Medicine Endocrinology, Diabetes and Metabolism |
description |
Abstract: Walrus in US zoos have a very low reproductive rate of 11 births in 80 years, and little is known about Pacific walrus ( Odobenus rosmarus divergens ) reproductive biology. To address this, we initiated a program in which detailed biological data were recorded on captive walrus. As part of a 7‐year study, 1 male and 1 female 16‐year‐old captive Pacific walrus were carefully monitored with weekly serum hormone analysis, daily glans penis smears for spermatozoa, and abdominal ultrasound for pregnancy. The female ovulated once annually from late December through mid‐January and then exhibited 9 months of sustained elevated progesterone. This nonconceptive estrous cycle profile is consistent with reports from wild walrus females. In contrast, the male's seasonal rut routinely occurred in late February through May with a serum testosterone peak in March. This profile differed from the reported adult male cycle in wild walrus of November through March. During the period of the female's ovulation, the male had nadir testosterone levels and was consistently azoospermic. Likewise, during the male's spermatogenic rut in the spring, the female was anovulatory with elevated progesterone. On this basis, the male was treated for 14 weeks with human chorionic gonadotropin (hCG) in an attempt to increase testosterone levels in synchrony with the female's annual ovulation. The treatment successfully induced rut characterized by sustained elevated serum testosterone levels and production of spermatozoa. The male and female successfully bred, and the female became pregnant. Upon discontinuation of hCG treatment, the male resumed baseline testosterone levels. We theorize that the lack of synchronization of rut and ovulatory cycles is a primary reason for reproductive failure in these captive walrus. |
format |
Article in Journal/Newspaper |
author |
Muraco, Holley S. Coombs, Leah D. Procter, Dianna G. Turek, Paul J. Muraco, Michael J. |
author_facet |
Muraco, Holley S. Coombs, Leah D. Procter, Dianna G. Turek, Paul J. Muraco, Michael J. |
author_sort |
Muraco, Holley S. |
title |
Use of Human Chorionic Gonadotropin in a Male Pacific Walrus ( Odobenus rosmarus divergens) to Induce Rut and Achieve a Pregnancy in a Nulliparous Female |
title_short |
Use of Human Chorionic Gonadotropin in a Male Pacific Walrus ( Odobenus rosmarus divergens) to Induce Rut and Achieve a Pregnancy in a Nulliparous Female |
title_full |
Use of Human Chorionic Gonadotropin in a Male Pacific Walrus ( Odobenus rosmarus divergens) to Induce Rut and Achieve a Pregnancy in a Nulliparous Female |
title_fullStr |
Use of Human Chorionic Gonadotropin in a Male Pacific Walrus ( Odobenus rosmarus divergens) to Induce Rut and Achieve a Pregnancy in a Nulliparous Female |
title_full_unstemmed |
Use of Human Chorionic Gonadotropin in a Male Pacific Walrus ( Odobenus rosmarus divergens) to Induce Rut and Achieve a Pregnancy in a Nulliparous Female |
title_sort |
use of human chorionic gonadotropin in a male pacific walrus ( odobenus rosmarus divergens) to induce rut and achieve a pregnancy in a nulliparous female |
publisher |
Wiley |
publishDate |
2012 |
url |
http://dx.doi.org/10.2164/jandrol.111.015032 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.2164%2Fjandrol.111.015032 https://onlinelibrary.wiley.com/doi/pdf/10.2164/jandrol.111.015032 |
geographic |
Pacific |
geographic_facet |
Pacific |
genre |
Odobenus rosmarus walrus* |
genre_facet |
Odobenus rosmarus walrus* |
op_source |
Journal of Andrology volume 33, issue 5, page 789-797 ISSN 0196-3635 1939-4640 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.2164/jandrol.111.015032 |
container_title |
Journal of Andrology |
container_volume |
33 |
container_issue |
5 |
container_start_page |
789 |
op_container_end_page |
797 |
_version_ |
1784253274756481024 |