Role of ovarian failure in reproductive senescence in aged red deer (Cervus elaphus) hinds

Abstract

Physiological and endocrine factors associated with reproductive senescence were assessed in a group of 19 ageing red deer hinds. Reproductive success, defined as the percentage of hinds weaning a calf successfully, decreased gradually from 89% at 6-7 years of age to 50% at 17 years, and subsequently decreased markedly; only one hind reared a calf at 19-20 years of age. When the 12 surviving hinds were approaching 21 years of age, they were compared with ten mature 7-year-old females over the onset of the breeding season. All hinds were subsequently killed, the reproductive tracts were recovered and antral (>/= 2 mm in diameter) and preantral follicle populations were determined by dissection (n = 7 hinds per age group) or stereological analysis (n = 2 ovaries per age group), respectively. Cyclical ovarian activity (plasma progesterone) was evident in fewer aged hinds compared with mature hinds (3/12 versus 10/10, P < 0.001) and mean plasma LH concentrations were higher in aged animals than in mature animals (0.57 +/- 0.05 and 0.20 +/- 0.05 ng ml(-1), P < 0.001). Mean uterine (44.2 +/- 4.5 and 75.4 +/- 4.2 g; P < 0.001) and ovarian masses (0.88 +/- 0.11 and 1.52 +/- 0.12 g; P < 0.001) were lower in the aged hinds, which also had fewer antral follicles than did mature hinds (0.89 +/- 0.35 and 23.5 +/- 4.5 follicles per hind, respectively; P < 0.001). Only one primordial follicle was observed in one of the ovaries of the aged hinds, compared with 7000-21 000 in the ovaries of mature hinds. The high gonadotrophin concentrations, paucity of primordial and antral follicles and failure of ovulation indicate collectively that waning reproductive performance after 17 years of age is primarily due to ovarian failure.

Monitoring ovarian cycle and conception by fecal progesterone analysis in sika deer

“…Another female (number 3) maintained a low progesterone level until the conception, a phenomenon similar to those observed in aged red deer (Fisher et al . 2000).…”

“…2000). The age‐related progressive decrease in reproduction is a feature of many mammalian species (Levasseur & Thibaut 1980) and in red deer, reproductive senescence, such as the exhaustion of ovarian follicles and atrophy of the uterus and ovary, occurs at about 16–17 years of age (Fisher et al . 2000).…”

Weaned age variation in the Virunga mountain gorillas (Gorilla beringei beringei): influential factors

“…Later weaning in primiparous mothers and in sons of the oldest females, supports previous findings in mountain gorillas and other primate species suggesting an inverted U-shaped curve with relatively low reproductive performance in the young primipares and in the oldest females (Caro et al 1995;Robbins et al 2006). Despite a lack of extended postreproductive lifespan in female mountain gorillas, five out of seven miscarriages were observed in multiparous mothers above the age of 27 which may reflect a reduced physiological capacity to reproduce in older females (Robbins et al 2006); uterine and ovarian aging has been associated with declining fertility in aging women (Frank et al 1994), rodents (Kong et al 2012), red deer (Cervus elaphus) (Fisher et al 2000) and Japanese macaques (Nozaki et al 1995). Thus, our findings also lend some support for the terminal investment hypothesis which predicts that aging females invest more in their current offspring as their reproductive value declines (see review by Caro et al 1995).…”