COMPARISON OF DIGESTIVE AND CHEWING EFFICIENCY AND TIME SPENT EATING AND RUMINATING IN SAMBAR DEER (CERVUS-UNICOLOR) AND RED DEER (CERVUS-ELAPHUS)

Artificially reared sambar (tropical) deer and red (temperate) deer we re confined indoors in metabolism cages and fed chaffed lucerne hay ad libitum for 4-week periods during summer and winter at Flock House Ag ricultural Centre, New Zealand, during 1992. Measurements were made of voluntary feed intake (VFI), apparent digestibility, faeces particle size distribution, eating and ruminating time and the rate of chewing during eating and ruminating. Red deer reduced VFI (kg DMI/day) marked ly from summer to winter, associated with a reduction in the duration of each eating bout. Sambar deer slightly increased VFI over this time , associated with an increase in chewing frequency. Digestive efficien cy was similar in both species, and the critical particle size for lea ving the rumen was passage through a 1 mm sieve for both species. Time spent eating/g DMI was greater for sambar deer than for red deer duri ng summer, but there was no difference during winter. Relative to red deer, sambar deer consistently spent more time ruminating/g DMI, and s pent a greater proportion of total ruminating time as daytime ruminati ng and had more daytime ruminating bouts. Duration of each ruminating bout (min) was similar for the two deer species, but sambar deer had l ess chews/bolus ruminated but more rumination boli/h than red deer. Di fferences between sambar deer and red deer were more pronounced in rum inating than in eating behaviour, and sambar deer may have evolved a d ifferent rumination pattern to break down low-quality tropical forages more effectively.