Genetic improvement and reproductive control of farmed red deer and wapiti (Cervus elaphus)

Farmed red deer are a recent domesticant that, aside from subspecies hybridisation, have been subjected to little genetic modification by man. However, the species exhibits useful variation in economic traits, some of which are highly heritable such that genetic progress can be easily achieved from mass selection. Whereas many breeders record performance details, few take advantage of modem techniques for analysing these records and ranking animals for selection or sale. The adoption of DNA technology for parentage recording is more advanced in the deer industry than other livestock sectors. Commercial venison and velvet producers exploit genetic improvement through sire selection and choice of strain (subspecies). A large variety of strains exist, and they vary markedly in their production characteristics. Deer farmers have been quick to realise the potential of assisted reproductive technologies (ART's) to improve the rate of genetic progress. However, while development and application of technologies such as Al and ET have been rapid, overall adoption has been at relatively low levels. Emerging ART's, including in vitro embryo production and cloning, hold considerable promise all powerful tools in breeding programmes. However, development is required to improve their overall efficiency. The inherent summer lactation patterns of the red deer are often poorly aligned with pasture production seasonality, resulting in poor calf growth. Techniques used to advance the onset of seasonal breeding, and hence align lactation and feed production, so far have met with variable success. In the last decade it has become clear that the thyroid glands play a permissive role in the termination of the breeding season. As with other mammals, ablation of thyroid hormones results in persistent reproductive activity in red deer, indicating another potential mechanism for manipulating conception dates. Although destruction of thyroid tissue is an unlikely avenue, temporary and reversible suppression of thyroid gland secretion at a critical time each year is a possibility. This will require understanding of the mode of action of thyroid hormones on hypothalamic function. present studies ies are focused on neurotransmitter pathways in hinds.