Effective reproductive management is the primary role of Reproductive Science at the Zoo and is fundamental to the Zoo's ability to:
- maintain genetically healthy, sustainable zoo animal populations; and
- avoid producing more offspring than we can care for at the high standards we set for animal health and welfare.
Zoos work cooperatively using pedigree analysis, a kind of "computer dating," to make breeding recommendations that prevent inbreeding and contribute to the overall genetic diversity of the species. Managing reproduction by spacing births also can be important to the mother's health. Thus, in any given year, some animals are recommended to breed while others are not. Both enhanced reproduction and contraception may be needed to achieve these goals.
Successful reproductive management requires a multifaceted approach that includes:
- conducting basic research to reveal and to describe reproductive patterns and processes,
- identifying and addressing failures in zoo breeding programs,
- providing monitoring and diagnostic techniques, and
- developing methods to enhance and maintain fertility or to temporarily prevent reproduction.
Reproductive failure can have many causes, ranging from incompatibility of the male and female pair to inadequate sperm in males or uterine abnormalities in females. Diagnosis and treatment of infertility requires knowledge of normal reproductive characteristics of each species, knowledge that comes from systematic research.
A new approach to maintaining fertility in individual females, while still accomplishing genetic and demographic goals for the population, uses Lifetime Reproductive Planning.
Assisted reproduction techniques such as ovulation induction and artificial insemination (AI) can be important tools for managing breeding. In particular, AI can be useful for animals with a breeding recommendation that are not behaviorally compatible or that are living at different zoos, thus avoiding the stress of transfer to a new location.
Preventing reproduction can be as simple as separating males and females or as sophisticated as using the appropriate contraception method. Contraception has the advantage of allowing families and social groups to remain together while achieving genetic and demographic goals for the population. Permanent sterilization is not an option for genetically valuable animals that may need to reproduce again in the future, making safe, reversible contraception the preferable choice.
Reproductive research relies on technology such as microscopy, biopsy, ultrasound, biotelemetry and computerized semen analysis systems and on hormone analyses, a service of the Zoo's Endocrinology Lab. Routine monitoring of hormones (for example, testosterone in males or estrogen and progesterone in females) and of behavioral interactions provide information about reproductive status that is essential to sound management decisions.
Cryopreservation of gametes (sperm and eggs), stored in liquid nitrogen, provides the opportunity for long-term reproductive management, beyond an animal's lifespan. Frozen gametes can also be shipped between zoos to accomplish breeding recommendations without the need to ship the animals.