Reproductive efficiency of captive Chinese- and Indian-origin rhesus macaque (Macaca mulatta) females

摘要

Reproductive and survival records (n = 2,913) from 313 Chinese-origin and 365 Indian-derived rhesus macaques at the Tulane National Primate Research Center spanning 3 generations were studied. Least-squares analysis of variance procedures were used to compare reproductive and infant survival traits while proportional hazards regression procedures were used to study female age at death, number of infants born per female and time from last birth to death. Chinese females were older at first parturition than Indian-females because they were older when placed with males, but the two subspecies had similar first and lifetime post-partum birth intervals. Females that gave birth to stillborn infants had shorter first post-partum birth intervals than females giving birth to live infants. Post-partum birth intervals decreased in females from 3 to 12 years of age but then increased again with advancing age. Chinese infants had a greater survival rate than Indian infants at 30 d, 6 mo and 1yr of age. Five hundred and forty-three females (80.01 %) had uncensored, or true records for age at death, number of infants born per female, and time from the birth until death whereas 135 females (19.91 %) had censored records for these traits. Low and high uncensored observations for age at death were 3 and 26 years of age for Chinese and 3 and 23 years of age for Indian females. Uncensored number of infants born per female ranged from 1 to 15 for Chinese females and 1 to 18 for Indian females. Each of these traits was significantly influenced by the origin × generation interaction in the proportional hazards regression analyses, indicating that probabilities associated with age at death, number of infants born per female and time from last birth to death for Chinese and Indian females did not rank the same across generations.