Effect of Level of Intake on Digestion, Rate of Passage and Chewing Dynamics in Hay-Fed Bactrian Camels (Camelus bactrianus)

Citation

Cahill LW, McBride BW. 1995. Effect of the level of intake of digestion, rate of passage and chewing dynamics in hay-fed Bactrian camels (Camelus bactrianus). In Proceedings of the First Conference on Zoo and Wildlife Nutrition, AZA Nutrition Advisory Group, Scarborough, OT.

Abstract

Four female Bactrian camels (Camelus bactrianus) were offered a diet of chopped mixed hay, composed predominantly of timothy, at three levels of intake. Digestibility of the hay was measured by total collection and rates of passage using cobalt (III) ethylene diamine tetra acetate and Chromium-mordanted hay. The time spent eating and ruminating per day was ascertained by continuous observation for 24 hours. Results from this experiment indicate that Bactrian camels appear to digest a predominantly grass hay to a similar extent seen with sheep and cattle, but at approximately 1 /4-1 /2 of the dry matter intakes (g/kg BW) observed with the latter species. Increases in daily metabolic faecal out-put and metabolic faecal N per kg DM intake compare favourably with ruminant data. Total mean retention (TMR) time of liquid and particulate markers was quite long but fall within a range exhibited by domestic ruminants fed restricted levels of roughages. The long TMR values were due to very long intestinal transit times. Fractional turn-over rates in the forestomachs and caecum-proximal colon were higher than would be expected for cattle at similar intakes. The observed relatively large changes in passage parameters but small depressions in digestibility with increasing intake are similar to that seen with sheep or cattle fed hay diets. This experiment also indicates that camels appear to spend an amount of time eating, ruminating or chewing per unit intake that is commensurate with that seen in adult cattle. However, at ad libitum (AL) intakes, the maximum amount of time spent ruminating was 5.39 h/d. Since camels possess an efficiency of rumination (min/g) similar to that of cattle but appear to be limited to 5-5.5 h of ruminating per d, the low AL intakes observed may be due to an inability to process highly fibrous forages as well as sheep or cattle.

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