Quantitative nutrition of deer: energy, protein and water

Abstract

The quantitative requirements of deer for energy, protein and water are reviewed, using where possible a factorial approach to defining requirements. Deer may be more efficient than cattle and sheep in metabolising digested energy and in utilising metabolisable energy as a source of net energy. The average net energy requirement for maintenance (NEm) of adult, non-lactating deer in winter–spring is 0.39 MJ/W (kg)0.75 per day. Temperate species have a higher requirement in summer–autumn, and tropical species in a subtropical environment have a greater requirement in winter. NEm declines with age, and is increased in lactating females. Diet protein contents that are reported to be adequate for maintenance and production are ~4–9% and 16–22%, respectively. It is difficult to use a factorial approach to describe deer protein requirements because of a lack of information on basal endogenous N excretion rates, the outflow of metabolisable protein from the rumen and the efficiencies of utilisation of metabolisable protein. Differences in digestive function between deer and other ruminants mean that data for cattle and sheep may not be applicable to deer. Guides to drinking water consumption by deer are a water  : dry matter intake ratio of ~3.5 : 1 and 139 g drinking water/W (kg)0.75 per day; but ambient temperature, physiological state and diet composition greatly affect water requirements. The salinity tolerances of cervine and rusine deer and of fallow deer are ~8000 and 12 000 mg/kg drinking water, respectively.