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competing for what it needs. Deer are bothbrowsers and grazers. Fallow deer, if notoverstocked, will preferentially consume a dietof75 to 90% grasses and forbes (leafy weeds),leaving only 10 to 25% of the diet as browse.This is so even though in the spring, leavesand twigs have a higher digestible energy (DE)and digestible protein (DP) than forbes orgrasses.

IntroductionThere are numerous factors which must

be considered in designing optimal feedingprograms for any animal. There are no cut anddried rules, especially when dealing withspecies which have been raised in captivity forunder two decades. Deer are quite differentfrom other more familiar domestic ruminantsin both their nutritional requirements and theirresponse to nutritional stress. This pamphletwill present basic principles of cervid physiol-ogy and nutrition in order to clarify some ofthe differences between them and domesticspecies. Given this information, the approachto feeding your deer can be done from a moreinsightful perspective. Whenever possibleinformation specific to fallow deer will beincluded, but most research has been done onfree ranging species; i.e.. white-tailed deer,red deer and caribou. These sources, plusextrapolation of cattle and sheep nutritionalprinciples, in conjunction with knowledge ofthe biology, feeding behaviour and physiologi-cal characteristics of deer, have been used tocompile the following information.

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Economic lossProbably the most significant economic

losses on deer operations apart from traumaassociated with handling, are related to nutri-tional mismanagement. These problems oftenarise from a lack of understanding of theunique seasonal metabolic adaptations andnutritional requirements of deer.

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Natural dietsIt is importlnt to keep in mind the

botanical complexity of the diet of free rangingdeer. Plant availability, and nutritional valueof the plants vary considerably throughout theyear. In the wild, deer range over a large areato choose the optimal nutritional combination.This situation is in marked contrast to farming,which involves limited species of plants andusually one species of herbivore harvesting and

In general, deer have the ability todigest higher fibre diets than do domesticruminants. This seems to be a function of thelarger relative size of the omasum (theforestomach compartment which grinds coarseroughage).

SurvivalWhat is it that allows fallow deer,

originally from the Mediterranean region, toacclimatize successfully to a much more severeCanadian climate? They have a remarkablecapacity for adaptation. Winter survival pro-vides the most dramatic example of this adap-tation. Temperate deer species are recognizedto undergo photoperiod and temperature medi-ated physiological changes.

WinterDeer in winter are less well adapted to

sudden deterioration of climatic conditionsthan cattle or sheep because of their reducedmetabolism. Deer thyroid gland activity(which mediates basal metabolic rate) de-creases during cold weather. (It increases inother ruminant species). This creates a physi-ological state similar to hibernation, but ofcourse much less extreme. Activity decreasesdramatically from summer ~d autumn levels.Deer seek shelter and reduce foraging activityto conserve body energy reserves duringwinter. There is a 40 to 60% reduction ofvoluntary feed intake during winter withrespect to maximum spring feeding! The net

Published with the support of the Saskatchewan Agricluture Development Fund GF-F-3-01

energy required for maintenance, is lowest inJanuary. Increased energy demands such asphysical disturbances or lack of shelter at thistime are potentially very detrimental. Windand wet can also have a detrimental effect andincrease energy needs.

SpringMetabolism begins to increase in

March, in response to increasing daylength.By this time body reserves have been depletedso the deer are more vulnerable than ever to anegative energy balance. It is therefore to-wards the ~ of winter, that deer on a lowenergy diet, exposed to a cold spell or a latewinter storm, are more likely to die thanduring a cold spell in January. Emergencyfeeding of starving deer at this time usuallycannot stop deaths because of the total deple-tion of theIr energy and protein reserves.

In spring in the prairies nutritional needs of the deermay exceed pasture availability if green-up is late.Supplements will be needed in these circumstances.

There may be more subtle effects ofnutrition on maternal behaviour. According tostudies on red deer in Scotland, mismotheringis much more likely to occur in poorly fedfemales.

With this infonnation in mind, one canappreciate that good summer and autumnnutrition are critical for winter survival. Eventhough deer experience winter anorexia, it isstill valuable to offer high energy winter sup-plement. This will help reduce energy wastedon foraging and trying to get nutrition fromhigh fibre roughage. Also, if deer are knownto be somewhat down in condition, the provi-sion of good wind and rain shelter will helpprevent winter death losses.

Undernourishment during a singlesummer can effect the entire herd for a severalyears. Does that are underweight at breedingtime may not conceive. These relationshipsare illustrated in the pamphlet GF-F-2 "Maxi-mizing your fawn crop". Even if they doconceive, their fawns will be born light, as adirect relationship between maternal weight atbreeding, and fawn weight has been shown.The birth weight of fawns is directly related tosurvival, and to weaning weight. A singlekilogram of increased weight at birth can leadto 3 or 4 kg increase at weaning. The heavierthe weaning weight, the heavier the femalefallow deer will be at 15 months of age, andtherefore the more likely to conceive -and ofcourse, the heavier she is at breeding time, thehigher the chances of conception, and thehigher the weight of her fawn the next sum-mer, and so on and so on.

Reproductive PerformanceEarlier pamphlets have given target

weights at various ages and times during theannual cycle. These are weights at which farmmanagers can be assured that they are ap-proaching maximal productivity. Pubertyoccurs in fallow deer at about 28 kg. Althoughthey are theoretically able to breed at thisweIght, production records show that toachieve conception and fawning rates of over75% for yearling does, pre-rut weights shouldbe at least 38 kg. The mature does should be42 to 50 kg and have weaning rates of over90%. Competent nutritional managementhelps reach these goals. As in domestic rumi-nants, late gestation demands a high plane ofnutrition. Unlike domestic ruminants, deertend to sacrifice fetal growth to maintain theirown body condition if undernourished. Incontrast, cattle and sheep develop 'pregnancytoxaemia', a life threatening metabolic disease,in order to maintain fetal growth! In deertherefore, poor nutrition will show up asincreased numbers of stillbirths and highperinatal mortality, even though the doesmay not appear to be in poor condition.

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Feeding the bucksMature bucks have high spring and

summer nutritional demands to make up forthe cumulative weight loss which would havebegun the previous rutting season and contin-ued throughout the winter. Beginning inspring, bucks also invest large amounts ofenergy in antlerogenesis. Th~ size of antlersdepends a great deal on nutritional factors.Winter feed restriction does not affect antlersize provided unrestricted feed is availableduring the growth phase. Mineral require-ments for antlerogenesis are almost equal tothose of lactation. Twenty to 40% of themineral required for antler growth comes frommobilizing skeletal reserves, as the best diet

can only provide 60 to 80% of what is re-quired.

The following tables give the approxi-mate dietary energy and protein requirementsfor deer. These values can be used by feedcompanies to formulate balanced rations foryour deer. The energy units are given inmegajoules.

Fawns should be onto their supplemental feedby late summer in order to minimize the stressassociated with weaning. A creep feedersystem can be built to exclude the does, bucksand yearlings, while preparing the fawns forwinter with preferential feed. Prof Dr. HermanBogner's design in Yon Kerckerinck's book'Deer farming in North America', has creepopenings of 18 cm wide X 59 cm high forfallow fawns.

Feeding for GrowthPreweaning growth rates of fallow

fawns have been measured at 175g/d forbucks, 150g/d for does. These rates can be30% lower if the dams are not receiving topquality feed to meet lactational demands.

Even though weaners should havesupplemehtary feed all winter, their proteinrequirements are rather low, dropping from thespring/summer level of 18%, to about 12%.Over-winter growth rates fall significantly to

FALLOW DEERDaily Metabolizable Energy (ME ) Requirements in megajoules (MJ)

NOTE: these figures are calculatedfor animals in New Zealand. They may be higher in winter in colderregions of Canada, or when wet windy conditions prevail

Fall weight (kg) Autumn Winter Spring SummerMaturedoes 45-55 12.9-15 13.9-16.1 15.8-17.5 21.6-23.4Mature bucks 85-105 20.7-24.3 19.6-23.0 20.3-24.1 20.3-24.1Young does 18 9.7 10.4 11.3 11.3Yearling does 38 11.3 13.1 15.2 20.7Yearling bucks 47 13.3 15.4 16.0 15.0

DatafromJL. Adam 1988 Growth. In: Progressive Fallow Farming.AllenJL. & G.W. Asher (eds) Ruakura. New Zealand. p. 51

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50 and 25g/d for buck and doe fawns respec-tively, given an adequate diet. This is relatedto the numerous physiological events discussedin the introduction of the pamphlet. Extrapola-tions from other deer species indicate the MErequirements (MJ) for young fallow deer overautumn, winter and spring/summer are ap-proximately 70, 80 and 90% of that requiredby the mature ani-mals in spite of theirsmaller SIze. -

receiving adequate nutrition!

Minerals and vitaminsWe have not addressed the topic of

mineral and vitamin needs, but they should notbe forgotten. In most cases, these needs can bemet by usin~ the same figures as would beseen in a dairy ration. There are however a

couple of exceptions.

Deer are flighty, andsomewhatsuscepti-ble to capture my-opathy if not handledwith care. Dr. DuaneUllrey's research atMichigan State hasshown that highlevels of vitamin Ecan play an impor-tant role in protect-ing deer from thisaffliction. Currentrecommendationsare for a minimumof 200 internationalunits of this vitaminper kg of feed. Thisdoes mean an in-creased cost for theration, but a singlepreventable deathwill more thanoverride any sav-ings.

In the autumn,weanling deer haveless than 4% body fat(steers have 12%,lambs 18%). Thebest way to preparethem for winterseems to be with pre-rut weaning. Theweaner mob wouldbe exposed to lesssocial stress associ-ated with ruttingactivity, and theywould have lesscompetition for feedthan if run with theadults. An addedadvantage of pre-rutweaning is that thedoes have severalweeks after lactationto maximize theirpre-rut weight.

A mineral supple-ment of some sort must be offered. For in-stance oats and hay in Canada are very low incopper levels, and a suitable mineral willprevent problems from deficiency of this andother essential trace minerals.

It is well known that deer, regardless offeed availability, have variable feed intakeaccording to seasonal influences, resulting ingreat changes in body growth and condition.For young deer in which the goal is to maxi-mize growth over the fIrst 15 to 17 months,i.e.. by puberty, managers must attempt toavoid any winter weight loss or even a sus-tained slow-down in growth rate. Even thoughdeer have a tremendous capacity for compen-satory growth over the spnng and summerperiod, young deer which experienced nutri-tional stress during their fIrst autumn andwinter, never catch up in size to those whichdid not suffer a deficiency.

References1. Denholm, L.I. 1984. Nutrition of farmed deer.Deer Refresher Course. The Post-graduate Committeein Veterinary Science, U. of Sydney. Pp 662-7072. Hofmann, R.R. 1985. Digestive physiology of thedeer. In: Biology of Deer Production, The Royal Societyof New Zealand. Bulletin No. 22. pp.393-4083. Loudon, A.S.I., Milne I.A. 1985. Nutrition andgrowth of young red deer. In: Biology of Deer Produc-tion, The Royal Society of New Zealand. pp. 423-4274. Yerex, D., Spiers, I. 1987. Modem Deer FarmManagement. Ampersand Publishing Associates Ltd.Catterton, New Zealand. pp. 49-68

During the autumn, fawns lay down fatdeposits to ensure winter survival. Theycompensate for inadequate nutrition by stunt-ing growth. Because of this, necropsy findingsof moderate fat deposits found in small fawns,does not necessarily mean that they were

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Photo credits: J. Smits

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