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@ 1991 J.C. Haigh MRCVS

University of Saskatchewan

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identification of hybrid offspring. One externally visiblecharacteristic of the hybrids is that the gland on theoutside of the lower leg (the metatarsal gland) has anappearance half way between that of the pure-bredanimals.

IntroductionThere is almost no published information on the

farming of mule deer, yet the species is one of the most

numerous in southern Saskatchewan and Alberta, and in

some areas ranch and farmland have been almost overrun

by them. One 30 odd section ranch in the sand hills is

reputed to have as many as 20,000

head running on it in 1991. A series of easy winters and the high .j

percentage of twins, and even

triplets, that have been born have

led to an explosion that has not

been controlled by hunting..

DistributionMule deer and their relatives

are found in much of the westernhalf of the North America all theway from Alaska to Mexico. It maybe that their failure to move east-wards is related to the fact that theyare susceptible to brain-worminfection carried by white-tailed deerthroughout most of the eastern halfof the continent. By far the biggestarea for any particular sub-species isthat covering the Rocky Mountainstates of the US and Alberta, the

western half of Saskatchewan and eastern British Colum-bia on up into the southwestern Yukon. Throughout thisarea it is d1e Rocky Mountain mule deer that is found. Itappears d1at d1e mule deer in Saskatchewan have gradu-ally been extending d1eir range northwards, and it is nowby no means uncommon to see them just north ofSaskatoon.

In both Alberta and Saskatch-ewan, mule deer farming is permit-ted, and a few operations have beenstarted. Some of these began whentrapping permits were let in Al-berta, and many farmers ran into aseries of disease problems with the animals.

TaxonomyMule deer and white-tailed deer are members of the

Odocoiliinae, a family of deer restricted to the Americas,and within the genus Odocoileus limited to to the twospecies O. virginianus and O. hemionus, the latter beingthe mule deer and its relatives, the various forms of black-tailed deer. Handling

Mule deer are readily trapped into feeding sites inlate winter, but their run down nutritional condition at thistime makes them poor candidates for survival of theassociated stress. Modem trapping techniques, instead ofbox trapping of individual animals, would probably haveled to less trouble after capture in the past. Because muledeer are sociable animals, group capture in a training andtaming scene would probably be the best method.

Crosses between mule deer and white-tailed deer areknown from the wild, and have caused considerableconfusion for hunters and wildlife control officers alike.Recent work with blood proteins and DNA probes hasallowed clear differentiation of the two species, and

Metatarsal glands of Odocoileus

On farms mule deer tend to be less individualisticthan do white-tailed deer. They usually run together inloosely associated herds, but without the tightly knitstructure of a fallow deer or wapiti group. The exceptionto this is for a period after fawning, when individual doesare very territorial and aggressive. For much of the yearthey can therefore be handled in much the same way as

GF-MD-I-OIPublication supported by the Canada/Saskatchewan ERDA agreement

length ranges from 189 to 218 days, with an average ofabout 203.

fallow deer. However I have seen them jump a 2.1 metre(7') fence when under pressure. The basic principle ofalleyways, the opportunity to flow around comers, sightboards or shade netting at pressure points, a walled yard(slatted boards to at least 2.45 m or 8'), and a darkenedshed all apply.

Opinions vary on the actual handling inside sheds. Inthe days before drug immobilization was common in zoosand research centres these deer were commonly handledby being crowded into small compartments in dimly litsheds. They could be handled by applying lateral pressureagainst a wall, and downward pressure over the shouldersand back. If they fell, or turned, so that their feet camefree they would inflict rapid kicks with their very sharphooves. I have handled mule deer in dark chute compart-ments, and it absolutely necessary to keep pressure ontheir backs in order to deal with them.

In common with many deer, females may come intoestrus when they reach about 70% of adult weight Thereare not many data on mature liveweights of does, but theaverage bled carcass weight of shot Rocky Mountain muledeer does is about 60 kg, which would indicate aliveweight not much over 65 kg. Maximums as high as 86kg liveweight, and 76 kg carcass weight have beenrecorded. It is well recognized that well grown white-tailed deer fawns may conceive in their first year of life,but this is apparently less common, although possible, infree-ranging mule deer. On farms the experience has beenthat these doe fawns will conceive if not separated fromthe bucks. Even the buck fawns may be fertile at less than12 months of age. If doe fawns are born in June they maygrow fast enough, under good nutritional conditions, tocome into heat by the age of about 7 months, and soconceive as fawns, albeit later than mature does. Thefawns born to the 13 to 16 month old animals will ofcourse arrive very late in the year, and in the wild theymight not survive. On farms they are likely to performless than optimally, particularly as their mothers will lackgood quality grazing in order to produce milk.

A better option is to run them into darkened shedswhere the ONLY light source is controlled by humans. Inthe rotunda a red light can be used, and allows handlers togo in with the deer. Other lights should be on a dimmerswitch. The deer will run up a chute towards light, but notas readily as fallow deer, and may need persuasion tomove. They can easily be handled in a drop floor chute!squeeze. Light pressure on the back allows completecontrol and many procedures can be carried out. Al-though I have not seen one reported, a chute and squeezesimilar to the one used for white-tailed deer at HoughtonLake in Michigan, a photo of which is reproduced in thepamphlet on white-tailed deer (GF- WT -1), is likely to beeffective.

Not only are the fawns likely to perform inad-equately, but their mothers may not regain sufficientcondition to breed in their second November of life. All-in-all it is probably better to restrict the breeding of doefawns. This can either be done by separating them frombucks by the end of December, which will mean that aproportion of the early born rapidly grown fawns willconceive, or by weaning them before the rut, and ensuringthat they do not conceive until they are 16 months of age.Until more information on diet and management on farmsis generated he practice of aiming for more fawns byrunning everything together in one paddock shouldprobably be viewed with caution.

There is little doubt that these deer are susceptible tothe stresses associated with handling, and a good quietroutine, with minimal noise and disruption, is important.Deer that are handled roughly may take several weeks torecover condition.

Weights of adult males fluctuate very widely over theyear, and they lose as much as 20% of maximum weightafter the rut. Bled carcass weights average 74 kg, butmaximum weights as high as 159 kg liveweight for a tamebuck, and 112 kg bled carcass weight for a wild buck havebeen recorded.

DrugsIn common with virtually all other medications used

on deer, there are no licensed products available for muledeer. Those whiC;h work well include xylazine HCI, ormixtures of opioids and xylazine. Similar doses to thoseused for wapiti are effective, and vary according to thetameness of the animal and its degree of confinementwhen treated. Yohimbine works satisfactorily as anantidote to xylazine.

Birth weights of fawns depend upon whether singleor multiple births occur, singleton fawns usually beingconsiderably heavier than twins or triplets. Male fawnsare usually heavier than females, 3:t least when twins ofeither sex are born. The range of average birth weightsfrom several studies is from 2.74 to 3.99 kg, with indi-viduals ranging from 2.27 to 5.0 kg.

ReproductionMule deer,like all deer from temperate zones, are

short day breeders. The onset of the rut differs throughoutthe continent, but for most areas the peak occurs in mid tolate November and early December. However in someregions of California it may be as much as a month laterthan this. The breeding season, when either sex may befertile, extends for a much longer period, even into lateFebruary and early March in some cases. The gestation

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NutritionMule deer are mixed feeders, tending towards the

concentrate selector end of the spectrum, but, like white-tailed deer, quite happy to spend considerable amounts of

time in summer hay fields grazing. In common withother temperate zone deer mule deer lose weight in winter,even if offered high quality diets. For farmed deer,artificial rations that ensure an adequate mix of protein,carbohydrate, fat, fibre and mineral / vitamin mixes areessential, as the animals are in no position to select thewide range of forage available to them in the wild. Littleresearch has been done to show how to maintain deer onfarms, but the ration suggested for white-tailed deer, andoutlined in pamphlet GF-F-3, has proved to be an excel-lent one for a number of zoo animals. This ration is basedupon the deer ration developed at Michigan State univer-sity, and is widely used for captive ruminants in zoos. If itis offered together with a good quality alfalfa hay, produc-tivity is high and disease incidence low. In summerconsumption of the ration will decline sharply if there isgood quality grazing available. Mule deer will alsoreadily accept oats, but this should probably not be theonly grain component of a ration on a year round basis.At times of high demand, during lactation, and at weaningof fawns, a 16-17% protein ration is optimum. There islittle doubt that an adequate fibre content of the ration isessential.

Hemorrhal!ic diseasesMule deer are susceptible to both bluetongue and

epizOOtic hemorrhagic diseases of deer, but to a lesserextent than white-tailed deer. They are transmitted bygnats (Culicoides). Neither disease has been seen inCanada since 1975, when Bluetongue occurred in theOkanagan Valley. They are probably not important asdiseases of farmed deer in Canada, but may occur furthersouth. Any deer being imported from the USA should nodoubt be tested.

NecrobacillosisMule deer, especially stressed animals, are very

susceptible to necrobacillosis (GF-S-5). There have beenoutbreaks in which entire research herds were lost to thiscondition over the course of a few weeks. Affectedanimals are often seen with rough stary coats, lookingdepressed, and losing condition. If there are lesions in themouth or respiratory tract excess salivation and/or harshbreathing will be noticed, and there will be exerciseintolerance. Vigorous early treatment is essential. Iflesions are visible in the mouth, they can be debrided andflushed with hydrogen peroxide. The bacterium issusceptible to several antibiotics, so that culture is prob-ably important. to ensure the right choice, and an adequatedose is a must.

ProblemsThe main problems encountered by those who

maintain mule deer in captivity are handling stress andparasite susceptibility. Handling stress has already beendiscussed, and it is clear that mule deer farmers will haveto go through some of the same learning processes thatfallow deer farmers experienced a few years ago. Parasitecontrol is discussed below.

Andrew Breunig, who farms mule deer in Alberta hasalso seen dominance exhibited by some does during thefawning season, which has led to some does being unableto graze or gain access to adequate nourishment. Domi-nant does, often the first to fawn, wil!., for about 6 weeks,occupy a small (2-4 acre) territory, and hardly allowanother animal to cross it. The net effect of this is thatsubordinate does cannot get enough good quality forage tosupport their fawns optimally. This problem has not beenseen in zoo situations, but the increased crowding mayhave prevented it. A solution might be to pen fawningdoes separately, as is done at Houghton Lake for white-tailed deer. This would of course be very expensive.Alternatively, a substantial number of portable feeders canbe placed in fawning paddocks so that all does can findone. Unfortunately this will increase labour costs.

Bacterial oneumoniaSeveral species of bacteria may be involved in cases

of pneumonia. In particular, Pasteurella andFusobacterium playa role. Clinical signs are similar tothose of necrobacillosis, with harsh breathing usuallybeing evident. Treatment is similar to that fornecrobacillosis, but may be futile if not initiated early inthe course.

DiseasesThere is a long list of disease to which mule deer are

susceptible. The more crowded their conditions, and theless well that they are looked after, especially in terms ofnutrition, the more likely is that these diseases will assumeimportance. It would be pointless to list all of them butsome outline notes on a few are included below.

ParasitesThere are two classes of parasites with which the

mule deer farmer must be particularly concerned. ThefIrst two do not occur in Canada, and are really of concernonly in that importation of the deer from the USA may beproscribed, either entirely, or at certain times of year.Mule deer are susceptible to brainworm infection (GF-S-2), which may explain why they have not become estab-lished, either in the wild or on farms, where this parasiteoccurs. The other parasite that does not occur in Canada,but is important in relation to mule deer, is the arterialworm Elaeophora schneideri. This parasite is foundcertain areas of in a number of states of the USA. It istransmitted from deer to deer, and to other species bybiting flies, particularly tabanid flies. Mule deer show noclinical signs, as the parasite appears to have evolved arelationship with them over the centuries. When theparasite is transmitted to other species, it may becomevery important, as it may entirely block arteries, especiallyto regions of the head, including the muzzle, brain, orantlers or eyes. One of the names for the resulting clinicalcondition in wapiti is clear-eyed blindness. A recentoutbreak of arterial worm disease in Arkansas caused all

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red deer fawns to die within about 2 weeks of birth.Hinds that had calved were also affected, showing severeneurologic signs. Wapiti are also affected. and may sufferextensive necrosis of areas to which arterial supply hasbeen blocked by the adult or larval stages of the worm.Sheep and goats may also develop lesions. The conditionin the former is known as sorehead.

Diagnosis in the living mule deer is possible, using abiopsy taken from the forehead, but care must be takenboth in obtaining the biopsy, and in its interpretation. Notreatment has been described.

Neither of these diseases is of direct importance tothe Canadian mule deer farmer, but gastrointestinalnematodes, lungworm and coccidia may have a directimpact upon stock. Routine checks for nematode infec-tions should be carried out in the summer months, espe-cially in warm wet years. Both types of parasite can causeserious problems.

intestine. T~ir imp~ce as agents of disease dependsupon a number of in~!ac9ng factors that are outlined inthe accompariying table:' .

Coccidia are protozoan parasites that are well knownin several domestic species. ' Most deer harbour them but

it appears that the only report of clinical disease clearlylinked to coccidia in deer comes from mule deer. There islittle doubt that the same sort of interacting factors as forintes~~al.worms will ~I?pa~t:VFon the onset of clinicalcoccIdioSIS. The condItion IS commonly seen aroundfawning time, especially ifoonditions are muddy, and latein winter or at spring thaV)::;when young animals are beingweaned and are finding the competition for food rathersevere. Clinical signs are usually limited to a rough coat,loss of condition, and diarrhea. Treatment with appropri-ate sulfa drugs, Of arnproliurn, will effect a temporarycure, but it is almost impossible to eradicate the diseaseonce it appears in~ herd. Control with coccidiostats infeed is possible. Great care must however be exercisedwith monensift; ~s'overdose is often fatal. An alternativecoccidiostat is Decoxx, which appears to be rather safe.Any feed incorporated drug is limited in efficacy both bythe ampunt of feed that an individual deer may eat, and bythe level of challenge. Subordinate deer may not be ableto gai~ access to feeders, so that care in distribution mustbe exercised. If breakthroughs occur it is possible andeffective to use an alternative drug for short-term treat-ment.

Elaeophora schneideri in the artery of a mule deer

Lungworm infection of mule deer has not been asclosely studied as it has in red deer and wapiti, but if thesyndrome is similar, there will not be the coughing andhusk-like symptoms associated with this disease in cattle,but rather the build up of adult parasites in the bronchialtree, which will lead to an accumulation of froth surround-ing the worms, and the blockage of the airways. The mainpresenting sign will be loss of condition. New Zealandscientists have shown that levamisole is inappropriate forthe treatment of red deer parasitism. A better choice islikely to be ivermectin, but the efficacy of the variousforms, injectable, oral and topical, has not been ad-equately tested in deer. Andrew Breunig reports that thetopical preparation is unsuitable at certain times of year,especially when the summer coat is present.

BibliographyWallmo, O.C. (ed) Mule and Black-tailed Deer of NorthAmerica. A Wildlife Management lnstitue Book. Univer-sity of Nebraska Press. Lincoln.

Photo creditsFig 1,2. J. C. Haigh. Fig 3. C.P. Hibler

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GasU'ointestinal nematodes can also cause debilityand diarrhea in mule deer. Several species have beenreported from wild deer. They mainly belong to theOstertagiinae, and parasitize the abomasum and small

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