title: Factors influencing breeding success, ovarian cyclicity, and cub survival in zoo-managed tigers (Panthera tigris).
abstract: Understanding factors that influence reproduction and offspring survival in zoo populations is critical for management of threatened and endangered species. Examination of long-term data (1989-2011) compiled from the Association of Zoos and Aquarium's zoo-managed tiger breeding program provides the basis for a more thorough understanding of reproduction and scientifically based decisions for effective population management in this endangered felid. Biological and management-related factors that could influence tiger breeding success and cub survival were evaluated using logistic mixed models. Breeding success improved with female age until approximately age five, then declined thereafter. Experienced female breeders had greater breeding success than inexperienced females. Litter size was most predictive of cub survival, with average-sized litters (3-4 cubs) experiencing the highest proportional survival. Management-related factors, such as whether the breeding institution had a recent tiger litter and whether both animals were already located at the same institution, also influenced breeding success and cub survival. These results highlight the importance of institutional husbandry experience and the need to retain knowledge through staff turnovers to achieve optimal reproductive success. Using fecal estrogen data, frequency of ovarian cyclicity and mean cycle length did not differ by female age or parity; thus, lack of cyclicity and/or increased cycle duration are not likely explanations for declining breeding success with age. These results provide valuable reproductive information that should improve scientific management of zoo-based tiger populations.
authors: Conservation Biology Graduate Program, University of Minnesota, 2003 Upper Buford Circle, Suite 135, St. Paul, MN 55108, USA. Electronic address: saund196@umn.edu.
authors: Sarah P
authors: SP
authors: Saunders
authors: Minnesota Zoo, Conservation Department, 12101 Johnny Cake Ridge Road, Apple Valley, MN 55124, USA. Electronic address: tara.harris@state.mn.us.
authors: Tara
authors: T
authors: Harris
authors: IUCN SSC Conservation Breeding Specialist Group, 12101 Johnny Cake Ridge Road, Apple Valley, MN 55124, USA. Electronic address: kathy@cbsg.org.
authors: Kathy
authors: K
authors: Traylor-Holzer
authors: Point Defiance Zoo & Aquarium, 5400N Pearl Street, Tacoma, WA 98407, USA. Electronic address: karen.goodrowe@pdza.org.
authors: Karen Goodrowe
authors: KG
authors: Beck
mesh_terms: D000367:Age Factors; D000818:Animals; D000836:Animals, Zoo / Q000502:physiology*; D001947:Breeding / Q000592:standards*; D003247:Conservation of Natural Resources; D005243:Feces / Q000737:chemistry; D005260:Female; D042341:Gonadal Hormones / Q000032:analysis; D008098:Litter Size / Q000502:physiology; D016015:Logistic Models; D008297:Male; D008597:Menstrual Cycle / Q000502:physiology; D011247:Pregnancy; D012098:Reproduction / Q000502:physiology*; D013534:Survival; D046010:Tigers / Q000502:physiology*
chemical_list: D042341:Gonadal Hormones
keywords: Breeding success; Cub survival; Ovarian cyclicity; Panthera tigris; Tiger; Zoo-managed