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Proc. Aust. Soc. Anim. Prod. 1996 Vol. 21

NITROGEN METABOLISM IN RUSA DEER ( Ce r v u s t i mo r e n s i s )

 N.W. TOMKINS and N.P. McMENIMAN 

Dept of Farm Animal Medicine and Production, The University of Queensland, St Lucia, Qld 4072

SUMMARY

Dry matter intake, nitrogen intake, nitrogen digestibility, rumen ammonia-N and plasma urea-N

concentration were measured in young rusa deer fed 4 diets containing 90 to 205 g/kg DM crude protein.

The level of crude protein associated with maximal voluntary food intake and dry matter digestibility for

these animals was found to be about 160 g/kg DM. Plasma urea-N was positively related to rumen ammonia

concentration.

Keywords: deer, Cervus timorensis, protein, digestibility

INTRODUCTION

It is estimated that in south-east Queensland there are 160 deer farms, farming approximately 20,000 deer

(Mackenzie et  1993) of which up to 50% are rusa deer timorensis) (Woodford pers corn. 1995).

Farmed deer are grazed on a variety of native, annual or perennial pastures with or without irrigation.

In Queensland, the sub-tropical species Rhodes grass gayana),     and

kikuyu (Pennisetum form the basis of most pastures, with irrigated ryegrass-clover swards

being used during the winter/spring period. The use of supplementary feeds such as sorghum, maize or

proprietary pellets varies.

There are little data available on specific nutrient requirements for rusa deer. Grimaud and Chardonnet

(1989) demonstrated continuous and regular liveweight gains over a 12 month period on a diet of green

grass (Brachiaria together with maximum hay, supplemented with a commercial

concentrate. Unpublished University of Queensland (Gatton College) work suggests that on high quality

diets, rusa will do no better than temperate deer species. Under normal paddock conditions rusa appear

better at utilising stalky pasture than red deer (Cervus 1989). Rusa appear better ableto deal with varying levels of feed supply than red deer by readily storing body fat and so surviving periods

of nutritional stress (Woodford and Dunning 1991).

The object of this experiment was to determine the crude protein requirements of growing rusa deer.

MATERIALS AND METHODS

 Animals

Eight entire male rusa deer calves, (4-26 days old;   liveweight) were obtained from The University

of Queensland at Gatton College and hand reared. At 8 months of age the animals were adapted to pelleted

feeds and introduced to metabolism crates. The experiment commenced when the deer were 9 months old

and weighed approximately 32kg liveweight.

 DietsFour pelleted diets containing 91, 134, 168 and crude protein/kg DM were fed to each of the eight

deer in a replicated latin square design. The composition of the diets is shown in Table 1. The diets were

fed ad  at 0800 and 1600 hours.

Sampling procedures and analysesThe deer were fed their respective diets during adaptation periods before they were placed in

enclosed metabolism cages for a further 7 days during which total feed intake, faeces and urine output weremeasured. Ten and 20% sub-samples of faeces and urine were collected daily and bulked over the collectionperiod, respectively. On the day after each collection period samples of  liquor were obtained and

 jugular blood samples were collected into 10 tubes containing lithium heparin 2 hours following themorning feed. liquor samples were obtained with a stomach tube. Five milliltres of liquor was

placed in an equal volume of    for subsequent NH, analysis.and feed samples were dried at for 24 hours, ground to pass through a mesh and

analysed for dry matter (DM), organic matter (OM), neutral detergent (NDF) and nitrogen (N) content.Samples were in an electric muffle furnace at for 3 hours. NDF was determined according to

Goering and Van Soest (1970). The N content of the feed, faeces and urine was determined by a combustiontechnique using an autoanalyser (Nitrogen Determination Systems FP-428, LECO Aust. Pty Ltd). The NH,-

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Aust. Anim. Prod. 1996 Vol. 21

N content of the liquor was found by titration on a Kjeltec Auto 1030 Analyser (Tecator Sweden).Plasma urea-N concentrations were determined spectrophotometrically using an enzymicendpoint method (Trace Scientific Aust).

Results of the experiment were analysed by analysis of variance using Statistical Analysis SystemInc. Indiana, USA).

RESULTS

The chemical composition of the diets are shown in Table 1. The diets contained tog crude protein/kg DM. On all diets, animals maintained an average liveweight of 38.0 kg.

Table 1. Composition of diets (dry matter)

The mean intake for diets III and IV (1365, 13 14 g was significantly higher than thatfor diets I and II (1234, 1238 g   When comparing diets II and IV DMI was notsignificantly different.

Dry matter digestibilities were similar for diets II, III and IV, and were significantly higher than that fordiet I (Table 2).

Nitrogen intake and digestibility increased as the protein content of the diet increased. The mean Nbalance of the animals increased up to a N intake of 36.7 g/day (diet III), above which added nitrogen in thediet had only a marginal effect.

Plasma urea-N and ammonia-N tended to increase as dietary N increased (Table 2).

Table 2. Effect of diet on intake, digestibility and nitrogen measurements,

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DISCUSSION

If N balance is regarded as reflecting protein requirements, the results of this experiment indicate that the

crude protein requirement for young entire male rusa deer approaching 40 kg liveweight is 160 g/kg DM

or 37 g N/day. Crude protein requirements are a combination of  digestible protein (RDP) and by-pass

or undegraded dietary protein (UDP) requirements. If it is assumed that the degradability of the diet

containing 160 g DM in this experiment was 0.6, the theoretical supply of RDP and UDP were 138

and 92 g/day respectively. If the efficiency of microbial protein production is similar to that of sheep and

cattle (8.4 g microbial ME intake) (Anon. 1990) then the RDP requirements for diets II and III would

have been 81 and 82 g/kg DM respectively. The supply of RDP for diets II and III was sufficient to meet

these calculated requirements, but for diet II it may be assumed that UDP was limiting because the N balance

was not maximal. Whether the UDP supply was in excess of requirements for diet III is not known.

Satter and Roffler (1976) found that for efficient microbial crude protein production a NH,-N

concentration of at least 5 ml was required. This concentration was achieved with diets II and III.

That diet IV produced excess RDP is indicated by the elevated NH,-N and significantly higher plasma

urea-N concentrations. From the data presented in Table 2 it appears that a NH,-N concentration in

excess of 5 ml is associated with a plasma urea-N concentration in excess of 15 ml. This

is similar to the relationship between ruminal-NH, and plasma urea-N reported by Elliott et al. (1984) in

sheep.

Increasing dietary CP concentration had the effect of increasing DMI up to a dietary CP concentration

of 160 g/kg DM, the same concentration that was associated with maximal N balance. A mean DMI across

all diets indicated an intake of 3.4% liveweight. This apparently high value corresponds to a period of 

expected rapid growth rate for early maturing animals. Javan rusa calves show high growth rates for the first

6-9 months, recording liveweight gains of  g/day under farmed conditions (Woodford and Dunning

1989, 199 1) compared to the animals in this experiment which at a similar age gained 200 to 240 g/day

unpubl data). Over a period Grimaud and Chardonnet (1989) reported that male rusa

gained 64 kg, equivalent to about 175 .

Calculated ME content of diets and apparent DMD values indicate that these animals digest diets as

efficiently as sheep or cattle. Based on industry observations, rusa deer perform better than the temperate

deer species during periods of poor pasture quality, indicating some degree of nutritional advantage overtemperate species. It is possible that this advantage is conferred by the rusa deer having a shorter

retention time than red deer; Fennessy et al. (1980) concluded that this was the mechanism that gave red

deer an advantage over sheep. While a relatively rapid passage of food could be expected to result in less

complete digestion, it permits a greater intake.

In conclusion, N balance of these animals was directly related to increasing dietary crude protein. It was

found that for rusa deer at this age and liveweight the crude protein requirement is 160 g/kg DM which

would be expected for animals at this physiological state.

REFERENCES

ANON. (1990).  In “Feeding standards for Australian livestock. Ruminants”, p.8. (CSIRO: Melbourne).

ELLIOTT, R., N.P., NORTON, B.W. and CORTES, F.J. (1984). Aust.

Anim. Prod. 15: 337-40.

FENNESSY, P.F., GREER, G.J., FORBES, D.A. (1980).     Anim. Prod. 40: 158-62.

GOERING, H.K. and VAN SOEST, P.J. (1970).  In “Forage Fibre Analysis”, U.S.D.A. Agricultural

Handbook.No.379, Washington, DC p.8.

GRIMAUD, P. and CHARDONNET, P. (1989).     Grassland Congress, Nice, p. 1281.

MACKENZIE, A.R. (1985b). In “Biology of Deer Production”, Roy.   Vol. 22, (Eds P.F. Fennessy

and K.R. Drew) p.213.

MACKENZIE, A.R., DANIEL, D.J., EVANS, G.R. and BURTON, D.W. (1993). “A Guide to Deer

Farming in Queensland”, QDPI.

L.D. and ROFFLER, R.E. (1976).  In “Tracer Studies on NPN for Ruminants. III”, IAEA, Vienna.

WOODFORD, (1989). “Deer Seminar Notes”, p. 11, (Queensland Agricultural College: Lawes).

WOODFORD, and DUNNING, A. (1989). Fed. Deerbreeder. 5.

WOODFORD, and DUNNING, A. (1991). “The Biology of Deer”, (Ed. R. Brown) p.197

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