Influence of ration composition on nutritive and digestive variables in captive giraffes (Giraffa camelopardalis)...

The nutrition of captive giraffe (Giraffa camelopardalis), a browsing ruminant, is challenging because browse availability is limited in zoos and rations need to be composed of compensatory feeds. In this study, ration composition for giraffes in 12 German zoos was documented and linked to animal variables that indicate suitability of nutrition. Rations differed in proportion of ration items and chemical composition resulting in various grades of accordance with feeding recommendations. An estimated daily metabolisable energy (ME) intake (MEI; mean ± SD) of 0.61 MJ ME/kg^0.75 body weight (BW; ±0.1) was sufficient to cover estimated energy requirements. Daily dry matter (DM) intake (DMI) was 61 g DM/kg^0.75 BW (±10) and correlated negatively to dietary ME content (p = .009; r = -.596). Apparently, feed intake was regulated by energetic satiety and not by physical properties of forage. A negative correlation between produce proportion and DMI (p = .002; r = -.676) led to the assumption of a low ruminal pH in giraffes fed high proportions of produce. Increasing dietary forage proportions led to an increasing duration of feed intake (p = .045; r = .477) and decreasing occurrence of oral stereotypies (p = .047; r = -.474). The weighted average faecal particle size was larger than reported for free-ranging giraffes, but no relation to ration characteristics among the facilities existed. The abrasiveness of rations was not excessive, as contents of silicate in faeces were similar to values from the wild. Body condition was generally acceptable, but there was no evident relation to ration characteristics. The capacity to self-regulate DM and ME intakes with lucerne hay may work at higher forage proportions than often assumed for captive giraffes. Rations with less energetic density can result in a greater DMI, including maximisation of forage intake and reduction of oral stereotypies.