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National chimpanzee breeding program: Primate research institute
William C Hobson1, Charles E Graham1, Thomas J Rowell1
1Primate Research Institute, New Mexico State University, Holloman Air Force Base, New Mexico.
Insights
The National Chimpanzee Breeding and Research Program (NCBRP) improved chimpanzee breeding success by reducing fetal and infant mortality. Early pregnancy detection and maternal care interventions made the colony self-sustaining.
Area of Science:
- Primate reproductive biology
- Conservation genetics
- Animal behavior
Background:
- The Primate Research Institute (PRI) established a breeding colony for the National Chimpanzee Breeding and Research Program (NCBRP).
- Early efforts focused on maximizing breeding pairs and infant survival.
- Reducing fetal wastage and neonatal mortality were key objectives.
Purpose of the Study:
- To implement and evaluate programs aimed at reducing fetal wastage and neonatal mortality in a chimpanzee breeding colony.
- To assess the viability of achieving a self-sustaining chimpanzee population through improved breeding and infant care practices.
Main Methods:
- Utilized radioimmunoassay (RIA) for serum chorionic gonadotropin and ultrasound for early pregnancy diagnosis (prior to day 30).
- Implemented a minimum 18-month infant-mother bonding period when feasible.
- Modified maternal care protocols by isolating females two weeks pre-delivery to mitigate maternal abuse and manage premature births.
Main Results:
- Fifteen of 65 detected pregnancies (23%) resulted in fetal loss, with RIA and ultrasound detecting 7 additional losses compared to standard methods.
- Infant mortality was 13% (7 of 53 live births), primarily due to maternal abuse or premature delivery.
- Maternal abuse-related losses decreased due to pre-delivery isolation; 25 of 37 mothers successfully cared for their infants.
Conclusions:
- Early pregnancy detection and intervention significantly reduce undetected fetal losses.
- Modified maternal care strategies effectively decrease infant mortality from abuse and improve infant survival rates.
- The NCBRP's breeding program is demonstrating viability towards establishing a self-sustaining chimpanzee population.
Abstract:
The Primate Research Institute (PRI) dedicated a colony of 81 proven breeders (60 females, 21 males) to the National Chimpanzee Breeding and Research Program (NCBRP). When possible, infants were left with their mothers for a minimum of 18 months. Programs to define and reduce fetal wastage and neonatal mortality were implemented. Pregnancies were diagnosed both by RIA for serum chorionic gonadotropin and by ultrasound prior to day 30 of pregnancy. Of 65 pregnancies detected by ultrasound and RIA, 15 (23%) resulted in fetal loss. Without the use of ultrasound and RIA, only 8 of these losses would have been detected. Infant mortality (7 of 53 live births; 13%) was primarily due to maternal abuse or problems related to premature delivery. The incidence of losses due to maternal abuse has been reduced by placing females in single cages 2 weeks prior to their estimated delivery date so endangered infants can be recognized and removed. The new system provided the first opportunity for most of the mothers to care for their infants; 25 succeeded (in 2 instances in the second pregnancy only) and 12 did not (infants from 2 mothers were removed due to delivery of twins). During this 26-month period the colony grew by 46 infants (58%), half of which will be retained as future breeders. Thus, the NCBRP goal of achieving a self-sustaining population appears viable.
