Digestibility and roughage intake in a group of captive giraffes

Source: S. Schmucker, A. Hörhager, L. Kolter, Zoologischer Garten Köln, Germany
Adequate feeding and nutrition of giraffes is a constant topic of debate and discussion in zoo community.
Giraffes are adapted to browse on digestible leaves by intense lip and tongue movements. While some reports, based on post mortem findings, mention low or missing fat reserves indicating energetic undernutrition, other reports present data on oral disturbances, which are regarded to be caused by insufficient stimuli due to inadequately low intake of forage and high intake of produce and concentrates high in metabolizable energy. The latter are fed in addition to the roughage offered to meet nutritional requirements. Here we present data on composition, intake and digestibility of a diet low in easily digestible carbohydrates offered to the giraffes at Cologne Zoo.
The study group consisted of 3 adult females and 2 subadult females (3 and 1.5 years old). The diet was composed of lucerne hay ad lib., fresh browse (winter: leafless; summer: with leaves), dried chestnut leaves (only winter), fresh lucerne/grass mixture (only summer), different concentrates (pelleted zoo compounds, unmolassed beet pulp, soybean extraction chips) and some produce. Feed intake was quantified over 8-12 days on two occasions (representing summer and winter feeding conditions).
The proportion of roughage in the diet was 65 % in winter and 73 % in summer (on a dry matter base). Dry matter digestibility was 52%. The frequency of oral activities (activity/kg DM) differed considerably between feedstuffs. Intake of the whole group was evaluated to be lower in winter than during summer feeding. All animals were considered to be in a good condition. Compared to published data, the high proportion of forage consumed by the studied giraffes is remarkable. Thus sufficient energy provision could be managed despite a forage intake of 65-73 %. This agrees with recommendations proposing a forage proportion of 60-70 % for giraffe diets (Lintzenich and Ward, 1997). The results will be discussed with respect to nutrition and its potential effect on feeding behaviour.

Lintzenich, B.A.; Ward, A. M. (1997): Hay and pellet ratios: Considerations on feeding ungulates. Fact sheet 006 in: Nutrition advisory handbook.