title: Pregnancy rate and conception date in a wild population of Japanese monkeys.
abstract: This study is the first to determine the conception dates of specific individuals and estimate the pregnancy rate of a wild population in Japanese monkeys. The conception dates estimated from the embryonic ages of 37 fetuses were distributed over 128 days between September 17 and January 23, with a mean conception date of November 19 (SD=29.2 days). A comparison of the mean conception dates among age groups showed a significantly delayed conception in the subadult animals (aged 4 to 5 years; December 5, n=8) than in the adult animals (aged 6 or more years; November 15, n=29; P<0.03). The mean pregnancy rate among animals aged 4 years or more in this local population was estimated to be 48.5% (32/66).
authors.affiliation: Laboratory of Wildlife Medicine, Nippon Veterinary and Life Science University, Musashino, Tokyo 180–8602, Japan. hayama@nvlu.ac.jp
authors.forename: Shin-ichi
authors.initials: S
authors.lastname: Hayama
authors.forename: Sachie
authors.initials: S
authors.lastname: Nakiri
authors.forename: Fumiharu
authors.initials: F
authors.lastname: Konno
mesh_terms: D000818:Animals; D000835:Animals, Wild; D003247:Conservation of Natural Resources; D005260:Female; D005306:Fertilization / Q000502:physiology*; D005333:Fetus; D008251:Macaca / Q000502:physiology*; D011247:Pregnancy; D018873:Pregnancy Rate