Abstract

The red deer species (Cervus elaphus) is represented by morphologically disparate subspecies that freely crossbreed. All are highly seasonal breeders adapted to cold-temperate climates characterised by extreme annual oscillations in temperature and feed availability. Calves are born in summer following relatively long average gestation lengths of 234–250 days (depending on subspecies), with >70% of pregnancy mass acquired over spring/early summer. The ability of the smaller red deer hind (100 kg) to successfully gestate, birth and rear crossbred (e.g. wapiti x red deer) progeny of 40% increased foetal and post-natal growth potential is quite remarkable, and raises numerous questions about mechanisms of maternal and foetal control of reproductive processes. Recent research on moderate variations in late gestational nutrition to red deer hinds gestating red deer foetuses has revealed an interesting phenomenon in which nutritional influences on foetal growth trajectory appears to influence gestation length to ensure optimisation of birth weight (and, hence, neonate survival). This is quite contrary to expectations for sheep and cattle, but may have parallels amongst other wild ruminant species. Interestingly, hinds gestating crossbred (wapiti x red deer) foetuses of greatly increased growth potential appear unable to adopt such compensatory mechanisms, with hind under-nutrition leading to reduced birth weight relative to ad-libitum fed controls. These observations hint at some interesting and useful future research on mechanisms of maternal and foetal growth control in red deer.

GW, Asher, JA Archer, and DR Stevens

Proceedings of the New Zealand Society of Animal Production, Volume 64, Hamilton, 39-42, 2004