Studies on digestive physiology and feed digestibilities in captive Indian rhinoceros (Rhinoceros unicornis)

Abstract

We performed intake, digestibility and ingesta passage studies in 11 Indian rhinoceroses (Rhinoceros unicornis) from four zoological institutions, using total faecal collection for the quantification of faecal output. The regularly fed zoo ration of roughage and concentrates (ration RC) and a roughage-only ration (ration R) were used; the roughage source differed between the facilities and comprised grass hay, grass silage, straw and lucerne hay. Dry matter intake ranged between 0.8 and 1.3% of body weight on ration RC and 0.5-1.2% on ration R. Digestibility coefficients achieved were similar to those reported for horses on diets of comparable composition. Endogenous losses as determined by linear regression analysis were within the range reported for horses. Measurements of faecal volatile fatty acids, faecal lactate and faecal pH also showed similarity to similar measurements in horses. The mean retention times of fluids (Co-EDTA) and particles (Cr-mordanted fibre <2 mm) in the whole gastrointestinal tract averaged 42 and 61 h, respectively, and were the longest ever recorded in a monogastric ungulate with this marker system. The results suggest that the horse is a useful model animal for designing diets for Indian rhinoceroses. Why digestive parameters are similar between these species in spite of enormous differences in body weight and retention times remains to be answered.

Fluid and particle retention times in the black rhinocerosDiceros bicornis, a large hindgut-fermenting browser

“…The ratio of particle MRT : fluid MRT, ranging between 1.10-1.33 in the black rhinoceroses, has been reported to be 1.04-1.14 in horses and 1.13-1.30 in donkeys (Pearson et al 2001), and 1.36-1.58 in Indian rhinoceroses (Clauss et al 2005), indicating a certain degree of selective particle retention. In horses, a selective retention mechanism for small particles (in contrast to larger ones) was reported by Björnhag et al (1984); these authors demonstrated differences in the ingesta particle size composition between the caecum and proximal colon on the one, and the distal colon on the other hand.…”

“…Illius and Gordon (1992) derived allometric equations for the estimation of MRT from body mass based on a compilation of literature data, mainly from Foose (1982), Clauss and Lechner-Doll (2001) showed that, for ruminants, their equation tended to give realistic results for grazers but overestimated MRT in browsers, when compared to actual measurements from other studies. If Illius and Gordon's (1992) (Pearson et al 2001), horses (Wolter et al 1976, Orton et al 1985a, b, Pagan et al 1998, Pearson et al 2001, Moore-Colyer et al 2003, white rhinoceroses (Kiefer 2002), and Indian rhinoceroses (Clauss et al 2005). the derivation of the equation (cf Introduction).…”

Digestion studies in captive Hippopotamidae: a group of large ungulates with an unusually low metabolic rate

“…The laboratory analyses and calculations followed the same protocol as outlined for Indian rhinoceroses in Clauss et al. (2005).…”

Comparative digestion studies in wild suids at Rotterdam Zoo

“…Actually, other comparisons between hindgut fermenters and ruminants also do not suggest lower metabolic fecal nitrogen (protein) losses in ruminants as compared with e.g. hindgut-fermenting rhinoceroses [Clauss et al, 2005b]. This is most likely owing to the fact that ruminants, like both babirusa and peccaries, do not only have a forestomach compartment but also a site of bacterial fermentation in the hindgut, from which bacterial matter will be lost in the feces.…”