Regu-Mate® In Reproductive Management: A Synchronizing Project Using Regu-Mate® In Six Cetaceans Resulted In Five Ovulations At A Specific Time With Two Subsequent Pregnancies
Alternogest (Regu-Mate®, Hoechst Roussel Vet, DPT Laboratories, San
Antonio, TX 78215), a synthetic progestin, has been utilized for birth control in cetaceans at
various facilities. It has also been evaluated as a synchronizing tool in killer whales and
bottlenose dolphins3. Advances in ultrasonographic monitoring of ovaries (Fiona,
Brook 1997)1, have led to improved monitoring of reproductive paradigms by
At Miami Seaquarium, Regu-Matzhas been utilized therapeutically in a
geriatric dolphin with ovarian abnormalities for the past five years. Additionally, a healthy
calf was born after an Atlantic bottlenose dolphin had been receiving Regu-Mate® for two
years2. This clinical data, along with the experiences gained from other facilities,
indicated that Regu-Mate® was sufficiently safe to incorporate it in our reproductive
The six cetaceans in our project included two Pacific white-sided dolphins
(Lagenorhynchus obliquidens) and four bottlenose dolphins (Tursiops truncatus).
After intensively monitoring the reproductive activity of these dolphins for two years we
utilized Regu-Mate® at 1 ml per 110 lb. body weight for several reasons. The two Pacific
white-sided dolphins showed anestrus for two years. One bottlenose dolphin received it for two
years to prevent pregnancy at a physically immature age. One bottlenose dolphin received it to
prevent a pregnancy around two extensive surgical procedures. Two other dolphins are founder
stock animals, not well represented genetically, and were placed on it to encourage
reproduction. The animals were taken off Regu-Mate® when historical data indicated that
ovulatory activity had or should occur in that species. Thus the winter months of November
through March were excluded. All cetaceans were housed with males.
Dolphin: #1 Atlantic bottlenose dolphin ovulated on day 20 post cessation of
Regu-Mate®. Confirmed by both ultrasonography and elevated serum progesterones. She became
pregnant and the period of gestation can be predicted to culminate in April 2002.
Atlantic/Pacific bottlenose dolphin ovulated on day 20 post cessation of Regu-Mate®.
Confirmed by both ultrasonography and elevated serum progesterones. A fluid filled uterus with
what appeared to be a fetus was observed but then lost two months later. The serum progesterones
were also elevated and dramatically dropped in two months.
Atlanic bottlenose dolphin ovulated on approximately day 20 post cessation of Regu-Mate®.
Confirmation by only elevated serum progesterones. A fluid filled uterus was observed but a
fetus could not be confirmed since the dolphin only tolerated the ultrasound for one second at
that time. The serum progesterones dramatically decreased two months after ovulation. She did
ovulate again and became pregnant two months later. Although the pregnancy is well received, it
is not directly attributed to Regu-Mate® and is not being counted in this study.
Atlantic bottlenose dolphin had active bilateral ovaries with several large follicles and
exhibited sexual behavior at the same time frame as those that ovulated. She did not ovulate
confirmed by both ultrasonography and lack of elevated serum progesterones. We will be repeating
the Regu-Mate® cycle in her in the Spring of 2002.
Pacific white-sided dolphin ovulated on day 20 confirmed by both ultrasonography and elevated
serum progesterones. This dolphin subsequently became pregnant. The period of gestation can be
predicted to culminate in June 2002.
Pacific white-sided dolphin ovulated on day 21 the second time she was cycled off
Regu-Mate®. Both ultrasonography and elevated serum progesterones confirmed this.
Reproductive behavior followed the same trend as the others and coitus was confirmed with a
postcoital sample showing mobile spermatozoa. She however did not become pregnant. Another cycle
of Regu-Mate® will be attempted in the summer of 2002.
Five out of the six cetaceans ovulated post Regu-Mate®, but not
necessarily after the first cycle on it. Four of the five ovulations occurred at day 20 and one
on day 21 post cessation of Regu-Mate®. Ovulation is defined as the last day the follicle
was observed as the ovulatory day. Three of the five dolphins that ovulated are still pregnant,
but one is not attributed to Regu-Mate® directly. A trend in reproductive behavior was
documented during this project since all dolphins were housed with males. The males elicited the
females as early as day eight post-Regu-Mate® and the females showed receptivity and even
elicitation on approximately day 16 post Regu-Mate®. Reproductive behavior dramatically
stopped the day after ovulation. Whenever possible post coital samples were collected to confirm
coitus and evaluate the spermatozoa.
Regu-Mate® was utilized to encourage ovulation in two pacific
white-sided dolphins that had been in anestrus after two years of monitoring. This may be
important to encourage ovulation in animals that are non-reproductive yet genetically important.
The date of ovulation will give us an exact gestation period for an Atlantic bottlenose dolphin
and a pacific white-sided dolphin. Three of the ovulations did not result in pregnancy but two
showed evidence of possible miscarriages at an early stage. Regu-Mate® does not
consistently cause ovulations, but in this ongoing project the results were very promising and
further studies to obtain information on the variables of when it causes ovulation or not need
to be further evaluated. In our hands, a cycle of at least 30 days on Regu-Mate® was
sufficient to encourage ovulation.
We would like to thank all the studies that have moved cetacean
reproduction forward from scientists such as Fiona Brooks and Todd Robeck. We would like to
thank Rafaella Simoni, graduate student from Italy, for organizing the data. We would like to
thank the trainers at Miami Seaquarium.
1. Brook F. 1997. The use of diagnostic ultrasound in assessment
of the reproductive status of the bottlenose dolphin, Tursiops aduncus, in captivity and
applications in management of a controlled breeding programme. The Hong Kong Polytechnic
University, Kowloon, Hong Kong.
2. Dougherty M, Bossart G, Renner M. 2000, Case study: Calf born
thirteen months post-Regu-Mate® contraception with social complications, in Report from
the Bottlenose Dolphin Breeding Workshop, Duffield, D.A., and Robeck, T.R. (eds.), American
Zoological Association Marine Mammal Taxon Advisory Group, Silver Spring, MD, 41-42.
3. Robeck TR, E Jensen, F Brooks, N Rourke, C Rayner, R Kinoshita,
in Proceedings of the American Association of Zoo Veterinarians and International Association
for Aquatic Animal Medicine Joint Conference, 2000, New Orleans, Lousiana, p.222.