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REVIEW OF ENERGY REQUIREMENTS
AND RUMEN FERMENTATION IN MOOSE
AND OTRER RUMINANTS
•
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Les auteurs dressent un bilan saisannier des besoins energetiques et de
I'utilisation de la nourriture chez I'orignal (A Ices alces)en Ie comparant 11 celui
obtenu chez d'autres ruminants sauvages et domestiques,L'absence de mesures
precises du metabolisme basal chez I'arignal et la grande variabilite de ce para-
metre chez les autres ruminants domestiques et sauvages rendent tres difficile
I'estimation de leurs besoins energetiques.Les auteurs posent comme hypothese
de depart que Ie metabolisme basal (SMR)obeit 11 la relation suivante:
SMR (kcal/jour)~70 W·75
ou W represente Ie poids corporel en kg;ils estiment en outre que Ie regime
d'entretien necessite 1,7 lois la quantite d'energie requise par Ie metabalisme
basal.Les besoins energetiques des lemelles gestantes s'accroissent soudaine-
ment en mars,en raison du developpement du loetus et ces besoins vont atteindre
un niveau de trois 11 quatre lois'plus eleve que ceux qu'exige Ie.metabolisme
basal durant Ie mois de juin,consequence de la lactation et de la lipogenese.
Les auteursdecrivent les principales differences saisonnieres dans Ie contenu
du rumen et dans la consommation de nourriture.Le degre de remplissage du rumen
chez la lemelle atteint un maximum au debut de I'hiver,un minimum 11 la lin du prin-
temps et une valeur intermediaire I'ete.Le pourcentage de matieres seches dans Ie
contenu du rumen passe par un maximum I'hiver et par un minimum I'ete.Le
filtrat provenant du lavage du contenu du rumen avait une teneur plus elevee en
proteines brutes et plus laible en matieres cellulosiques et lignine durant I'ete
que durant I'hiver,ce qui rellete la meilleure qualite de la nourriture consommee
durant la saison chaude.Les sources bibliographiques consultees proposent des
estimes lort variables de la quantite de nourriture ingeree,mais toutes semblent
etablir que la consommation de nourriture est plus forte durant I'ete que durant
I'hiver.Les auteurs considerent que les lemelles adultes consomment jusqu'a
trois et me me quatre lois plus de matiere seche I'ete que I'hiver.lis estiment
egalement que I'augmentation du degre de remplissage du rumen et la diminution
de la consommation de nourriture durant I'hiver sont,d'une part,Ie resultat d'un
ralentissement dans Ie transit d'une nourriture de qualite inlerieure et,d'autre part,
d'une reduction volontaire de la consommation par I'animal.•
Environ 57 pourcent de toute I'energie digestible chez les ruminants pro-
vient des acides gras volatils (VFA)derives de La fermentation microbienne des
hydrates de carbone et des proteines de la diete,Les auteurs ont mesure les
changements saisonniers dans la production d'acides gras volatils chez des animaux
a I'etat sauvage et ont etabli que celle-ci est une fonction directe de la qualite
de la nourriture.En hiver,la moyenne du taux de production d'acides gras volatils
se situait "ux environs de 18 p.eq VFA/ml de liqueur du rumen par heure tandis
que durant I'ete,la moyenne etait de 60 p.eq VFAlml par heure,
L'orignal subit des changements considerables de poids corporel durant
I'annee et ces changements correspondent a des changements dans la production
d'energie derivee des acides gras volatils.L'energie utilfsable pour Ie metabolisme
(ME),calculee d'apres I'estime de production d'acides gras volatils,passe de
~,--7,300 kcal/jour pour une lemelle,I'hiver,11 20,900 kcal/jour pour cette meme
Resume
A/aska Department af Fish and Game,State af Alaska,
Fairbanks,Afaska,United States
W.C.GASAWAY and J.W:COADY
REVIEW OF ENERGY REQUIREMENTS AND RUMEN FERMENTATION
IN MOOSE AND OTHER RUMINANTS
!iallira/iSIO can.,101:227-~62 (lfJ74J1
F r
228 LE NATURALISTE CANADIEN,VOL.101,1974
feme lie durant les mois d'ete alors qu 'elle est en lactation.Les auteurs evaluent
a 6,000 kcal par jour la quantite d'energie utiJisable requise pour Ie metabolisme
basal.Or,durant I'hiver,environ 3,900 kcal par jour doivent etre obtenus du cata-
bolisme des graisses et des proteines de reserve pour compenser I'insuffisance
de I'energie fournie par Ie broutement tandis que rete,environ 7,600 kcal par
jour sont mis en reserve sous forme de proteines et de graisses.Les effets de fa
malnutrition indiquent que toute reduction,soit de la quantite,soit de la qualite de
la nourriture reduit la flore bacterienne ainsi que les taux de fermentation.
Les auteurs expriment enfin divers points de vue sur J'a propos d'utiliser
J'un ou J'autre des parametres lies 1;1 la fonction du rumen dans Ie but d'evaluer
la condition physiologique de divers ruminants ainsi que la qua lite de leur habitat.
Abstract
A review of seasonal energy requirements and utilization of food by moose,
(Alces alces)with reference to other wild and domestic species,is presented.
Energy requirements are difficult to estimate because no'metabolic studies have
been conducted with moose and comparative data from other wild and domestic
species differ widely.It is assumed that basal metabolic rate (SMR)conforms to
the empirical relationship of weight to metabolic rate,where
SMR (kcal I day)=70 W.75
and where W =body weight,in kg and that maintenance demands approximate
1.7 x SMR.Energy requirements of female moose begin to increase significantly
in March due to pregnancy and reach a peak of three to four times SMR in June,
due to lactation and lipogenesis.
Major seasonal differences in rumen contents and estimates of food con-
sumption by moose are described.Rumen fill in cow moose was greatest during
early winter,lowest during late spring,and intermediate during summer.Percent
dry matter was lowest during summer and highest during winter.Washed rumen
contents were higher in crude protein and lower in acid detergent fiber and lignin du-
ring summer than during winter,reflecting the superior quality of summer forage.
Estimates of food intake by moose vary greatly in the literature,although there
is considerable evidence indicating that a greater quantity of food is consumed
during summer than during winter.Dry matter consumed by adult females was
estimated to be three to four times greater during summer than during winter.
Increased rumen fill and decreased food intake during winter apparently result
from slow passage of low quality food which restricts additional food intake,and
from voluntary reduction of forage consumption.
Volatile fatty acids (VFA)produced by rumen microbes from the fermentation
of dietary carbohydrates and proteins constitute approximately 57 percent of
the digestible energy of ruminants.VFA production,which is directly related to
food quality,was determined seasonally on free-ranging moose in interior Alaska
using the "zero time rate"method.Production rates varied from a mean low of
18 JLeq VFAlml rumen liquor/hr during winter to 60 JLeq VFAlml rumen liquor/hr
during summer.
Moose undergo a large seasonal change in body weight which corresponds
closely 'to seasonal rates of VFA energy production.Metabolizable energy (ME),
calculated from estimated VFA production,increased from 7,300 kcal/day in females
during winter to 20,900 kcal/day in lacti;lting moose during summer.It was estimated
that approximately 6,000 kC31/day of ME was required for SMR.During winter an
estimated average of 3,900 kcallday was obtained from catabolism of fat and protein
reserves to meet the energy requirements not provided by forage,while during summer
7,600 kcallday of fat and protein were deposited.
A review of effects of malnutrition on rumen function show that decrease
in food quantity or quality depresses microbial popUlations and rates of fermenta-
tion.
GASAWAY AND COADY:ENERGY REOUIREMENTS IN MOOSE
The value and practical application of using various parameters of rumen
function to evaluate nutritional status of ruminants and quality of the habitat are
discussed.
:.'"
.>~.,
229
BMR is a measure of caloric require-
Energy requirements
In this review,gross energy of .food
consumed by an animal will be parti-
tioned into apparent digestible and me-
tabolizable energy.Apparent digestible
energy (DE)is that portion of gross
energy not excreted as feces,and it re-
presents a first approximation of the ef-
ficiency of food digestion.Metabolizable
energy (ME)is that portion of DE not
excreted in urine or lost as gaseous pro-
ducts of rumen fermentation.ME is a
measure of the energy available to or
needed by an animal at a particular time
for all metabolic requirements,and may
be used for work,heat,and ti.ssue
synthesis.
Metabolic rate of homeotherms varies
greatly within and between species,
since it must meet all requirements for
diverse physical and physiological ac-
tivities.Basal metabolic rate (BMR)is
the measure of a mammal's minimum
energy demand and has been widely
used for intra-and interspecies compar-
isons and as a base-line for computing
effects of other metabolic functions.
Energy requirements for maintenance
(thermoregulation,activity.,and specific
dynamic action)and for production (Le.
body growth,gestation,milk prodUC-
tion)are requirements above BMR and,
together,these processes constitute the
total energy requirements of an animal.
By integrating the temporal pattern of
metabolic rate,a seasonal energy bud-
get can be calculated and the total
impact of both the animal on its food
supply and the environment on the ani-
mal can be evaluated.
BASAL METABOLIC RATE (BMR)
The following discussion reviews sea-
Sonal energy demands for basal,mainte-
nance and production requirements of
moose,and the digestive processes
which convert food into useful energy.
Introduction
As the management of wildlife spe-
cies becomes more intensified,the
study of wildlife nutrition becomes more
critical.Food habits data were once
the only food resource information con-
sidered important.However,certain
deficiencies in this approach have pro-
moted studies of greater scope to better
understand relationships between wild
ruminants and their food resources.
/nvitro digestibility studies have been
undertaken on foods of wild ruminants
to rate the quality or usefulness of
various forages to the animal (Short,
1971;Ward,1971;Oldemeyer,1974).
Clinical blood chemistry techniques
have recently provided a new avenue of
approach to gain insight into the nu-
tritional status of wild ungulates (LeRes-
che and Davis,1971;LeResche et a/.
1974).Digestibility and maintenance re-
quirements have been studied on wild
ruminants held in pens and provide in-
formation .on how the animals may utili-
ze various diets in the wild (Ullrey et a/.
1967,1969,and 1971).Field studies of
rumen fundiqn bave enabled investiga-'
tors .to evaluate nutrition status and
energy balance by estimating the energy
wild ruminants derive from their diet
(Coady and.·Gasaway,1972).Wild life
nutrition must De concerned not only
with availability and utilization of forage
species,but also with the nutrient re-
quirements of ruminants and their abili-
ty to convert plants to animal tissue.
~ ~ ; j { :i:, f~ t! !~ i !• } t~ --230 LE NATURALISTE CANADIEN. VOL. 101. 1974 ments for minimum physiological functions. Ideally, test conditions for measuring BMR include postabsorp-tive. state, complete inactivity. and "comfortable" microclimate (Benedict, 1938). In practice. however, these .conditions may be difficult if not impossible to attain, particularly with wild species. The extent to which psychological, physiological and physical stresses on ctn animal can be reduced vary greatly among individuals and species. Consequently, the circumstan-ces appropriate for measuring BMR will vary with the species. and the acct,~racy of measurement will largely depend upon the extent to whir.h stresses can be mini-mized. While strk:t use of the term BMR may frequently not be applicable, it is a useful comparative concept, providing the technical difficulties of its measure-ment are realized. It is well known that BMR of mammals increases as an exponential function of body weight. Brody and Proctor (1932} and Kleiber (1961) concluded from comprehensive studies that average BMR of mammals equals 70W 734 and 70W 75, respectively where BMR = kcal/day and W =body weight in kg. Differences between the two equations are strictly pedantic, altbough Kleiber's relationship, adopted by···the Third Symposium on Energy Metabolism for lnterspecies Comparisons (Biaxter and Wainman. 1964), has been more widely used in recent years. Another useful metabolic term is fast-ing metabolic rate (FMR), which is greater than BMR by the amount of energy expended is standing and small postural movement during measure-ment (Silver eta!., 1969). Kleiber (1961) preferred measurement of FMR over BMR since he felt it better rep~esented minimum energy requirements among animals unable to remain voluntarily inactive. Blaxter (1962) indicated that differences between BMR and FMR are small among domestic ruminants. How-ever. differences may be greater among wild species due to stress im-pose-d by captivity. FMR of wild ungutp.tes varies widely among species, within species mea-sured during different seasons, and even within species measured during the same season (Table 1). FMR 's range from 67.8 kcal/kg 7Yday to 143.6. kcal/ kg 75 /day. Silver et at. (1959) working with white-tailed deer (Odocoileus vir-ginianus) during winter and summer, and Maloiy et a!. (1968) working with red deer (Cervus elaphus) recorded me-tabolic rates similar to those predicted for animals of their size (Table 1). How-ever, most values for FMR range from 15 percent to 1 OQ percent higher, and average approximately 40 percent great-er than the predicted BMR. The origin of these differences is not known, al-though numerous factors associated with age, reproductive state, nutrition, activity, insulation, and acclimatization must be considered (Whittow, 1971). Estimation of BMR of moose is dif-ficult, particularly considering that me-tabolic data have not been reported for the species. Silver et a!. (1969, 1971) and McEwan and Whitehead (1970) in-dicate major seasonal differences in BMR of white-tailed deer and resting metabol-ic rate of reindeer (Rangifer tarandus) respectively. Thus, a constant relation-ship between heat production and a . fixed exponent of body weight may not be adequate to cover all species under all s'ituations. For the purpose of this review and pending appropriate metab-· olic studies. we assume that moose under basal conditions obey Kleiber's (1961) empirical formula relating metab-olims to body weight. Therefore, BMR of a 425 kg (937 I b) animal, for example. equals 70 x 425 75 or 6,550 kcal/day. The BMR shown in Figure 1 was cal--:n~;,;-,_._,~~',,'"~~r~;~·~;;i(,.~; _,;~-' ""' '""""""""' .... ..., ..... ~~,. •• ,~~·.:-::;~~:_·"Yitri
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231
,,
Maintenance --'------i
could maintain body temperature at an
ambient temperature of -40°C and wind
velocity of nearly 2 mph.Fed deer could
tolerate a wind velocity of over 8 mph.
at -40°C without increasing their metab-
olic rate (Moen,1968).
Factors such as relatively large body
size,decreasing the surface to weight
ratio,heat production associated with _
rumen fermentation,and behavioral
responses assist in conserving heat
and enhance cold tolerance of moose.
Activity patterns observed for moose
agree with this,as they may bed in open
areas during very cold Alaska tempera-
tures,rather than seeking heavy cover
where a more favorable energy flux
usually exists.Also,substantial move-
ments of radio-collared moose during
temperatures of -40°to -50°C have
recently been recorded (Coady,1974).
Markgren (1966)noted that captive
moose calves in Sweden did not appear
inconvenienced by temperatures as
low as -28c C and mild wind.Although
high winds during very cold temperatu-
res are unusual in most areas,these
conditions could create an unfavorable
energy balance for exposed moose.
However,behavioral response in pos-
ture and habitat selection to cold
temperature and high wind would bring
the animal in a more favorable micro-
GASAWAY AND COADY:ENERGY REQUIREMENTS IN MOOSE
J,
~o.
~300
CD
'6 200
j--.c::::==::::::::"~~~~~~~_~~~~~--1
400 ~,--~~--~._--------------------,
BMR
MAINTENANCE ENERGY
Maintenance.energy is a composite
of requirenients for basal or fasting me-
tabolism,thermoregulation,activity as"
sociatedwith ·obtaining "food and water,
and the heat increment or "specific
dynami_c action"of digestion and assi-
milation of food,It is that portion of
the metabolizable energy required for
existence at a minimum level of acti-
vity,where energy retention by the ani-
_mal is zero.While clearly an underesti-
mate,SMR does represent a significant
portion of maintenance energy require-
ments.
Energy requirements by moose for
thermoregulation in the cold have not
been studied.Scholander et al.(1950)
suggest that most large northern mam-
mals do not increase their metabolic
rate until temperatures are at least
minus 40 c C.In agreement with this
hypothesls (Hart et al.,1961)found no
increase in metabolic rate of a 9-month
old caribou (Rangifer tarandus)from
25°C __to _minus 55°C.Moen (1968)
calculated that a 70 kg fasting deer
standing under clear night skies with a
heat production of 75.1 kcal/kg 75 /day
cilated from Kleiber's formula and was
considered to be constant throughout
the year.
OL..--c::---'O---o...--...---,>.::::----c::--"---c>:::---a.----->---u--'
o Q)a.0 :>:>:>Q)U 0 Q)
Jl.L.2 <!2 J J <!(f)0 Z 0
Figure 1.Seasonal energy required and metabolizable energy produced by adult female
mOOse in interior Alaska.
Month
(1968)concluded that maintenance
energy demands for cattle (80S taurus)
in normal range activities,and perhaps
for wild herbivores under usual range
conditions,is 15 percent above FMR.
Blaxter (1962)generalized that main-
tenance requirements of ruminantsavef-
aged 36 percent greater than FMA.
The above estimates appear low,
especially considering that increased
resting metabolic rate (RMR)of fed
but quiet animals may be considerably
greater than FMR (Table I).Brockway
and Maloiy (1968)found an increase
of 29 percent in RMR over BMR in
red deer,while McEwan and Whitehead
(1970)found an increase of 49 percent
in RMR over BMR in reindeer during
winter.Similarly,Hart et al.(1961)
measured an increase of 49 percent
in RMR of caribou during winter over
BMR determined by McEwan (1970)
for caribou during the same season.
Energy demands by free ranging ungu-
lates for movement would further ele-
vate requirements above that for RMA.
Brody (1945)suggested that.mainte-
nance energy requirements for large
herbivores average approximately 2 x
BMA.Ullrey et al.(1969)calculated
maintenance requirements of white-
tailed deer during winter to be 1.9·
times BMR,where ME =131kcal/day
and BMR =69 kcal/kg·75 /day.How-
ever,the excitable nature of white-tail-
ed deer may increase maintenance re"
requirements above that required for less
excitable moose...
Based on partitioning available energy
between SMR,maintenance,and tissue
pUduction,we estimate that main-
tenance requirements for moose range
between 1.5 and 1.8 x SMR,and
may average near 1.7 x SMA.
as shown in Figure 1.Since metabolic
requirements for both thermore.gulation
and activity are considered to remain
relatively constant throughout the
LE NATURALISTE CANADIEN,VOL.101,1974
climate.Therefore,it seems unlikely
that metabolic thermoregulation ever·
constitutes a significant energy requi-
rement for moose.
232
t,
..~.
While activity patterns of moose
have been studied and reviewed by
n'umerous'workers (Murie,1934;Pe-
terson,1955;Denniston,1956;Geist,
1959;1963;Berg,1971),duration
of daily activity has rarely been deter-
mined.Restricted movements and small
home range of moose during winter,
particularly during periods of deep
snow,have 'been suggested by numer-
ous authors (cf.Coady,1974).However,
limited movement patterns do not neces-
sarily indicate reduced activity and
energy expendure.LeResche and
Davis (1971)found that tame moose
in Alaska fed for an average of 7.7 hours
during 12 daylight hours in winter,and
for 6.8 hours during 18 daylight hours
during summer.No observations were
made during periods of darkness.
Knorre (1959)found that moose were
active,primarily in feeding,42 percent
of the 24-hour day during winter and
58 percent of the 24-hour day during
summer.Similar observations have
been made for other ruminants.Silver
(1971)recorded lowest daily activity
and feed consumption for wh ite-tailed
deer during winter,and Silver et al.
(1969)cited unpublished data indicating
.reduced activity and food consumption
of white-tailed deer during winter.
The above studies suggest that
duration of activfty may be similar or
somewhat less for moose during winter
than during'summer.Reduced activity
conserves energy and may be particu-
larly important in minimizing metabolic
requirements when snow conditions
hinder movement (Coady,1974).
While maintenance energy for moose
is uncertain,maintenance requirements
for wild and domestic species have
been estimated.Short and Golley
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!.~~,
,-
·..•1'I
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TABLE I
Fasting (FMR)and resting (RMR)me·tabolic rate of wild ruminants
,._-_..~-r--··------··.-'----
\
i Heat
Number X body
I
Air Temp.Production RMR
Age .(kca/l ReferenceSpeciesSeasonofwt(kg)(CC)FMR (kca/l
animals (yrs.)
W·7s /day)W·7s /day)
I-_._•.__.
White-tailed Deer Winter 2 56.8 1 Vr2 -0.4 to 3.9 67.8 Silver et al.1959
White-Iailed Deer Summer 2 45.6 1 '12-2 21.2-21.5 71.2 Silver et al.1959
White-tailed Deer Winter 17 65.3 Adult 16-21.5 97.1 Silver et al.1969
While-tailed Deer Summer 9 58.6 Adult 16-21.5 143.6 Silver et al.1969
While-tailed Deer Winter 4 30.6 Fawns 16-21.5 90.2 Silver et al.1969
White-tailed Deer Summer 2 36.1 Fawns 16-21.5 130.8 Silver et al.1969
While-tailed Deer Winter 4 67.6 2.5-11.5 17.50-21.5 81.0 Silver et al.1971
While-tailed Deer Summer 2 49.0 2-11.5 17.4-19.3 139.8 Silver et al.1971
Caribou Winter 2 9 mos.15 96.8 McEwan,1970
Reindeer Winter 3 74.7 Calves 15 102 157.4 McEwan &Whitehead,1970
Reindeer Summer 3 73.3 Calves 15 196.9 McEwan &Whitehead,1970
Caribou Winler 1 31.7 9 mos.25 to ·52 144.0 Hart et al.1961
Reindeer 1 100 5-6 -10 132.6 Hammel,1962
Pronghorn 4 4 mo-6 mo 21 92.6 Wesley,1969
Red Deer 2 58 Adult 16 90.0 116.0 Brockway &Maloiy,1966
Red Deer 1 45·50 --70.0 Maloiy et·al.1968
Wildebeest .1 ---91.0 Rogerson,1966
Wildebeest 1 --28 104.3 Rogerson,1968
Eland 2 --28 111.2 Rogerson,1968
.~-,
i" ~~ r~ ~-r~l f~-<• l~~; ;,-1 ~1'-1'~ t':~ L ~1 fi " . t-1. q J i~). ,._,. ··• ---~---o ...... ·----~---~-~-----~"--234 LE NATUAALISTE CANADIEN VOL. 10: 1974 year, seasonal maintenance requ i-rements probably follow a similar pattern. Therefore, the maintenance energy requirements during both win-ter and summer of a 425 kg moose with a BMR of 6,550 kcl/day is estimated to be 1.7 x 6,550 or approximately 11,000 kcal/day. REPRODUCTION-Energy requirements for pregnancy, lactation, and weight gain are major processes in adults which ·-elevate metabolic rate above the maintenance level. A limited number of studies have been conducted to determine energy requirements among domestic rumi-nants for various productive processes, while few, if any, such studies have been undertaken with wild species. Measurements of energy require-ments for gestation among domestic ruminants differ widely, but generally indicate a substantial energy accumu-lation in fetal 'material and increase in maternal metabolism occurs . only during the last one-third of pregnancy (Flatt and Coppeck, 1965; Flat et a/., 1969; Halls, 1970; Moe and Tyrrell, 1972). For example, Moe and Tyrrell (1972) found that ME requirements for cattle increased from 15 percent to 75 percent above that for the non-pregnant animal during the last one-third of pregnancy, representing an increase from 21 percent to 107 percent over BMR. Assuming a gestation period tor moose of approximately 243 days (Peterson, 1955) and a parturition date of June 1, a sign~ficant increase in energy requirements for fetal develop-ment probably begins in early March. Reid (1968) suggested that ME requir-ed for gestation can be estimated as 350 kcal/kg/day. Based on fetal growth rates of Alaskan moose (Rausch, 1959), ME for gestation increases form 875 kcallday in March to 5,250 kcal/day at term near June I (Table II). Since weights of pregnant moose in interior Alaska range near 360 kg during spring, ME requirement per kg body weightls of the female increases from 15 percent to 91 percent over BMR of the non-pregnant animal (Table ll). We assume that energy requirements for gPstation in moose are similar to those fo_r cattle, and range from approximately 15-20 percent of BMR after two-thirds of the pregnancy in early March to nearly 100 percent of BMR near term, as shown in Figure 1. Production of milk by wild ruminants has received I ittle attention, although milk intake by moose calves (Knorre, 1959, 1961) and by reindeer and caribou calves (McEwan and White-head, 1971) has been studied. By weighing before and after nursing, Knorre (1959) found maximum milk TABLE II Fetar growth rates and energy requirements by moose for fJ"';tation in interior Alaska. Fetal growth rates from Rausch (1950) --------;·· Date March 1 April 1 May 1 June 1 I Fetus WI (kg) 2.7 4.8 8.8 15.0 ME Requirement (kcal /day) · 875 1680 3080 52!':>0 -L MF nequirr:fllf.'rtl per 1((1 1'• IJI (kcal/ri"Y) 10 (; /() :1 :J ( .:1 fi~t I) %Increase over BMR 15 29 53 91
TABLE III
Body weight and total length of lactating and
.non-lactating moose over two years of age
during June in interior Alaska 1
235
367-390
269-284
395-463
242-275
!No.Mean Range!---t---+----
Non-Lactating !
Weight (kg)i 4 429 I
Length (em)II 4 264 I
Lactating
Weight (kg)I 4 380 I
_Length (C~_J "__~_~_'!!~.I
1 Coady.unpublished.
liter/day.This represented an energy
intake of approximately 1,900 kcal/day.
If caloric requirements of moose
calves for milk were similar to those
lor reihdeer and caribou calves,milk
consumption could be estimated.
Based upon metabol ic body size,
if reindeer and caribou calves weighing
5 kg (5 kg·75 =3.34 kg)consume an
average of 1,900 kcal/day in milk (Lu}ck
and White,1971).then moose calves
weighing 15 kg (15 75 =7.62 kg)consu-
me 4,300 kcal/day as milk.Since calo-
ric value of moose milk is approximately
1,446 kcal/kg,moose calves would
consume approximately three liter per
day.
Milk production by domestic ani-
mals is also considerably higher than
that measured for moose.Payne
and Wheeler (1968)suggested that
milk yield in dairy cattle is represented
by the equation kcal/day =124 W .75,
where W =body weight of the female
in kg.Since average weight of lactat-
ing moose in June was approximately
380 kg (380 75 =86.1 kg)(Table III),the
calculated milk production based on
dairy cattle would be 10.676 kcal/day or
7.4 (liter/day).Both estimates of
mild-yield of 3 liter/day and 7.4 liter/day
are considerably higher than was
measured by Knorre (1961),even .by
intensive experimental milking.
GASAWAY AND COADY:ENERGY REQUIREMENTS IN MOOSE
consumption by moose calves in Russia
to range from 1.5 to 2.0 liter per day
during June.and to decrease during
July to approximately 0.5 liter per day
in August.Total milk consumption .per
calf until weaning in.August or Septem-
ber was between 100 to 200 liter.
Knorre (1961)noted that aHef 1.5 to
2 months of age the diet of calves con-
sists primarily of solid foods.We have
"found considerable amount of"her-
baceous material in rumen contents
of calves in Alaska ,towards the end of
June.
To calculate metabolic requirements
for lactation in moose,the gross energy
of milk is required.Overman and Gaines
(1933)indicated"that caloric'value of
milk can be estimated by a formula where
kcal/kg milk =304.8 +114.1 x F,and
F =percent milk fat.Although fat
content of moose milk varies among
individuals and with stage of lactation,
10 percent may be considered an
average value (Knorre,1959,1961 ;Cook
at al.,1970).Therefore,gross energy
of moose milk can be calculated as
304.8 +114.1 x 10 or 1,446 kcal/kg.
It follows that maximum milk consump-
tion of two liter/day would represent a
caloric intake of about 2,900 kcal.
Knorre's studies (1959,1961)indicate
that milk consumption by moose
is somewhat lower than would be pre-
dicted from studies on reindeer and
caribou,and high-yielding domestic
species.Using tritiated water McEwan
and Whitehead (1971)"calculated that
average milk intake of reindeer and
caribou calves during the first month
of lactation ranged between 1.2 and
1..8 liter/day,or 2,760 to 4,140 kcl/day,
assuming a caloric equivalent for
reindeer and caribou milk of 2,300
kcal/liter.Luick and White (1971)report-
ed that milk consumption by reindeer
..c~)v.es during the first two weeks of
life averaged approximately 0.95
.,
.-...'-
an average weight loss of approXi~
mately 115 kg or 24 percent between
fall and spring.Weight gain pro.ba-
bly o~curs during approximately 125
days per year between late May and
late September,when live or dead
herbaceous plants and deciduous
leaves are .most available in interior
Alaska.Thus,rate of gain is approxima~
tely 1 kg per day.
Jordan et a/.(1970)concluded
that seasonal body weight fluctuations
of moose amounted to only 6.6 percent
for females and 10.3 percent for males.
However,Rausch (1959)and LeResche
and Davis (1971)reported seasonal
body weight fluctuations of 20 percent
and 15-30 percent,respectively,for
moose in southcentral Alaska.Verme
(1970)found that a "winter-killed"
bull in Michigan had lost 33 percent of
his pre-winter weight.
Seasonal weight loss in moose is
probably not limited to fat,but also
includes substantial amounts of protein.
Paquay et a/.(1972)have demonstrated
that mature cows have a capacity to
store and lose up to 20-25 percent of
their body protein,depending on level
of feeding.Additional studies reviewed
by Paquay et a/.(1972)suggest that
mobilization of reserves·from liver.
viscera.and especially muscle can
contribute to maintenance'during
undernutrition in several species.SinCe
percent protein in a carcass apparently
fluctuates with level of protein intake
(Paquay "at a/.,1972)'large seasonal
variations in dietary protein of moose
in interior Alaskasuggest that labile pro-
tein reserves probabiy exist in the spe-
cies ..For purposes of this review,we
assume that 25 kg or 20-25 percent of the
115 kg seasonal weight fluctuation of
moose in interior Alaska is due to loss or
gain of protein,while the remaining 90
kg weight fluctuation is due to loss or
gain of fat.
LE NATURALISTE CANADIEN.VOL.101,1974236
Based largely upon the above work
on reindeer and caribou,we feel
that milk production by wild moose
during the first few weeks after birth
of a single calf is at least 3 liter/day,
and may be greater.
Metabolizable energy is converted
into gross milk energy with an effi~
ciency of approximately 70 percent,
although it is influenced by a number
of factors such as quality of diet and
stage of lactation (Reid,1968;Blax~
ter,1962).Therefore,approximately
5,600 kcal of ME are required daily
to produce 3 liter of milk with a gross
energy of 4,300 kcal.This amounts to
65 kcal/380 kg·75 day,or a value almost
equal to one SMR of the female during
spring,as shown in Figure 1.
Metabolic costs of lactation are illus-
trated by lower body weights of lactat-
ing moose compared with those of
dry females (Table 1/1).Average body
weight of four non-lactating adult fema-
les during late June in interior Alaska
was 12 percent greater than that of
lactating moose,in spite of a longer
total length indicating larger average
body size for the lactating animals.
Lactating moose had gained approxima~
tely 20 kg while non-lactating moose
had gained approximately 70 kg at the
end of June over average spring weights
of 360 kg.Sequential weights of indivi~
dual females with and without calves
.at the Kenai Moose Research Center,
Alaska,indicated that calf rearing
..costs".were 8 to Hr percent of a
cow's July-August weight (LeResche
and Davis,1971).
WEIGHTGAIN
Moose experience marked seasonal
fluctuation in body weight.Average
body weights for breeding female
moose older than three years in interior
Alaska ranged from near 360 kg in
late spring to approximately 475 kg or
larger in fall.These values suggest
GASAWAY AND COADY:ENERGY REQUIREMENTS IN MOOSE
..
,.,
Efficiency of fat synthesis has been
.measured for domestic species,Flatt
and Coppecl<(1965)concluded from
the literature that .ME is converted
into body fat in the lactating animal
with'an efficiency of approximately 70
(:ercent,equal to that·of milk produc-
tion.This efficiency averages about
58 percent in the non-lactating'anima·'
(Slaxter,1962;Flatt and Coppeck,1965).
However,lipogenesis is closely related
.to diet,and the effeciency of converting
ME into body fat may decrease on low
quality forage (Short and Galley,1968).
Since the efficiency of protein produc-
tion is uncertain,we tentatively assume
that it is similar to that for lipogenesis.
Differences in the efficiency of fat and
protein production are probably not
great and therefore should not cause
significant error in estimating metabol ic
requirements.
Energy requirements for weight gain
in moose can be calculated from rate
of tissue production.Ninety kg of fat
and 25 kg of protein gained during
125 summer days amount to an average
weight gain of 0.72 kg of fat and
0.20 kg of protein,or 0.92 kg of tissue
per day.Therefore,gross energy of
tissue deposited amounts to 6,696
kcal/day of fat (9.3 kcal/g fat)and 860'
kca/lday of protein (4.3 kcal/g protein),
or a total of 7,556 kca/lday.Assuming
70 percent efficiency for tissue pro-
duction,an average of 9,800 kcal ME/day
are required to produce approximately
one kg of fat and protein per day.
Summer fattening in lactating moose
is probably not constant.During early
summer weight gain is relatively small,
while by mid-summer lactation is greatly
reduced and wei.ght gain probably
OCcurs at a more rapid rate.Metaboliz-
able·energy shown in Figure I which is
available for fat and protein prodUC-
tion in the lactating moose probably
ran.ges from slightly more than one
237
time SMR during early summer to
nearly two times SMR during mid -to
late summer.Weight gain in the non-
lactating moose is probably more uni-
form throughout the summer,and
maximum fall weights may be some-
what greater than in the lactating animal.
Rates of fattening may decline during
late summer because of a reduction
in quC!lity of forage during the growing
season (Oelberg,1956).
Nutrition
Energy for maintenance,growth
and reproduction is supplied through
the digestion of plants.Moose,like
other ruminants,rely to a great extent
on microbial digestion and fermen-
tation of plant carbohydrates and pro-
teins in the rumen to yield useful
nutritional products since they lack
some of the essential digestive enzymes
required to make efficient use of plant
tissues.The following discussion will
be directed toward the nutrient compo-
sition of moose foods,food consump-
tion and the processes of transforming
plant material into usable energy to
fUlfill the needs previously discus$ed.
NATURE OF RUMEN CONTENTS
Rumen·contents include solid
particles of food plants,soluble energy
sources,microbial waste products,bac-
teria,protozoa,gases,sal iva,water
and many other materials.Rumen con-
tents may be thought of as microbial
culture medium maintained in relative
stability by the steady input,outflow
and absorption of constituents.
Dry matter in the rumen
Dry matter (DM)content varies
with diet and season,and ranges from
8 to 20 percent of rumen contents in
moose and most other ruminants (Short
et al.,1969 a,b;Church,1969;Luick
et al.,1972).Dry matter content is
lE NATURALISTE CANADIEN.VOL.101.1974238
influenced by the nature of food ingest-
ed,the time since feeding and drinking,
salivary flow,passage of materials
out of the rumen,and the rates of di-
gestion and absorption (Church,1969;
Waldo et al.,1965;Ingalls et al.,1966).
The above factors result in diurnal
variations in percent OM of rumen
contents.Short et al.(1969a),working
with white-tailed deer,reported that the
highest percel'lt OM occurred early in
the morning following feeding,and the
lowest percent OM occurred during
midday.Intermediate values were found
in the late afternoon.
In moose the percent OM changes
seasonally.Moose on summer range
have low percent of OM in the rumen
because of the high moisture content of
succulent vegetation and availability of
water.In winter the low moisture
content of woody browse causes OM to
increase to its highest value (Table IV).
Moose may also reduce water intake in
winter when only snow is available.
Chemical make up of rumen contents
The gross chemical compositions of
rumen contents reflects the food eaten
by the ruminant (Klein,1962,1965, 1968,
1970;Klein and SchQnheyder,1970;
Klein and Standgaard.1972;Short,
1966).Rumen contents whi.ch remain on
a·sieve when washed with water in-
clude primarily ingested forage and
indigestible residues.and may be used
to determine the'approximate nutrients
in the diet.Washed rumen contents
probably represent a minimurnestimate
of protein in the forage because soluble
protein and amino acids are readily
digestible components.Analyses of
washed rumen contents from moose
in interior Alaksa indicate that dietary
protein was 12 percent in summer and
6 percent in winter (Table V).LeResche
(pers.comm.).also found similar pro-
tein levels (6 percent)in washed rumen
contents during winter in moose from
the Kenai Peninsula and south central
Alaska (Table V).This protein content
reflects a low protein diet.Protein
content of winter moose browse on the
Kenai Peninsula was ,slightly greater
than that found in rumen contents.
Hand picked browse samples rang-
ed between 5 to 9 percent protein and
averaged 8 percent (LeResche,pers.
comm.).
Food selected by moose in winter is
probably near the minimum required
protein level.This value is considered
to be about 7 percent for ruminants
(Corbett,1969).Murphy and Coates
(1966)found that wh ite-tailed deer fed
7 percent protein diets throughout the
year were phys:cally stunted and that
does fed on low protein diets (7-11
percent)produced fewer fawns than
those fed higher protein diets.
Deer in North America select browse
similar in protein content to that of
moose.Klein (1965)found that winter
forage of black-tailed deer (Odocoileus
hemionus sitkensis)in southeastern
Alaska contained about 6 percent pro-
tein.Spring forage contained 25 per-
cent protein and late summer forage
12.5 percent protein.Short (1969,1971)
and Torgerson and Pfander (1971)
found white-tailed deer foods contain-
ed 5-8 percent protein.during winter
and 15-16 percent during spring.
Forage can be divided into two
basic components (soluble cell COil-
tents and cell wall components)by
the neutral detergent fiber (NOF)anal-
ysis of Goering and van Soest
(1970).The cell contents are considered
98 percent digestible,while the cell
wall component (hemicellulose,cellulo-
se and lignin)varies in digestibility de-
pending on lignin content.Fiber (cell
wall component)is an abundant cons-
tituent of most ruminant forage and is
....
m
Zm
:D
G)
-<
:Dmo
S
:Dms:m·z
-len
z
s:ooenm
TABLE IV
Seasonal changes in body weight and rumen characteristics of moose collected in the Tanana Valley,
Interior Alaska 1
-_._---_...-'--r---'-..-..--.....-----.--.------------,-------------.
I
Sex,age,Number Rumen %Rumon %Dry Dry matter
I
Estimated 2Seasoncontentsmattermonth,reproduction in Body contents of in rumen in rumen digested organic
year status sample wt (kg)(kg wet wt)(kg)I matter (kg dry wt)body wt 90ntents I
--_..._~._.._..._.,_.
Spring Female 4 338 29 8.7 12.7 3.7 2.2
May adult
1971 pregnant
Summer Female 4 430 41 9.5 12.5 5.2 5.6
June adult
1972 non-lactating
Summer Female 227 18 8.0 11.3 2.1 2.7
June yearling
1972 non-lactating
Summer Female 3 379 43 11.4 10.8 4.8 6.3
June adult
1972 lactating
with calf
Early winter Female 5 501 52 10.4 15.9 8.3 2.2
October I adult
1972 I non-lactatingI
I without calf
Early winter Male 2 525 51 9.6 16.9 8.6 2.2
October
,
adult
I1972Irut I
!......-.........__•..__.-..J .._~..._----.~-_......_.__..•.._..-.-._.._------._-. I
1 Coady and Gasaway,unpublished.
2 Estimate based on 8.5 moles VFA produced per kg organic mailer digested (Weston &Hogan.1968a).
VFA production data is show in Table IX.
f .,~
\
'\
'~;'h!'.~'¥~:."~~;i),4+I~,~~.lMt •••
TABLE V
Seasonal variation in percent crude protein of washed rumen contents from moose and
black-tailed deer in Alaska
.TABLE VI
Fiber content of washed rumen samples taken from'moose in interior Alaska 1,2
0.39
0.50
0.29
0.31
12
Summer
10
24
16
Early
spring
6
6
6
Mid-
winter
Percentage crude protein
and lignin values noted in Table VI
for February and May are partially
explainable upon the basis of technique.
The rumen contents collected in these
months were washed on a larger mesh
sieve than those collected in June and
October.The large mesh sieve retained
proportionally more coarse,woody
material than the sieve used for sam-
ples obtained in June and October.
Seasonal changes in rumen fill
The weight of female moose rumen
contents varies with season and diet
in interior Alaska,being greatest during
winter and smallest during.spring (Ta~
6
Early
winter
LE NATURALISTE CANADIEN.VOL.101.1974
1 Coady and Gasaway.unpubl.
2 LeResche.pers.comm.
J Klein.1965.
MOOSE
Interior Alaska 1
Kenai Peninsula 2
South central Alaska 2
BLACK-TAILED DEER
Woronkofski Island
Southeast Alaska J
Coronation Island
Southeast Alaska J
Month
February
May
June
October
240
slowly digested by rumen microbes
(Hungate,1966).Goering and van Soest
(1970).found that low NDF and low
lignin:cellulose ratio are characterist!c
of more digestible forages.
Cell wall components and lignin:
cellulose ratios of washed rumen
contents from moose in interior Alaska
were lower in summer than in winter,
indicating the higher digestibility of
summer forage (Table VI).We estimated
digestibility of forage in JUlie and
October to be 50 and 40 percent,res-
pectively,using the lignin ratio me-
thod and the summation equation (Goe-
ring and van Soest,1970).High ADF
------T------;---.
Cell wall Acid 'I
i:IcomponentsdetergentLignin'Cellulose Lignin/ADF
(NDF)fiber (ADF)_____;.,..~..
1 ~~~:;;~:~I ~~:~I
51.7 40.2 11.7 II 28.5 !
68.9 58.9 18.5 40.4 I_______ ...__.,.,_l _...._
• 1 Analyses.performed by WARF Institute.Inc.Madison.Wisconsin
.2 Coady and Gasaway,unpublished ..~.
f-
t-it~""~l"~""",,~,!,,,,:~'~:~'~«~''''~'''',,~o>,,<'!ii'
GASAWAY AND COADY:ENERGY REQUIREMENTS IN MOOSE 241
.ble IV).During winter,th.e greater rumen
fill in moose may act to compensate
in part for poorer quality forage.Mi-
crobes are provided with more subs-
trate which leads to increased utiliza-
tion of lower quality food.Rumen fill
of cows was lowest prior to calving in
late May,possibly because growth of
the fetus occurs at the ·expense of ru-
men volume as has been demonstrated
i'1 domestic sheep and cattle (Camp ling,
1970).This decrease in rumen fill re-
sults in a reduction in total DE attained
from the diet.Intermediate rumen
fill occurs throughout the summer
(Table IV).Increased digestibility and
turnover of succulent food in the rumen
during summer probably results in lower
rumen fill in spite of greater food con-
sumption.By contrast,rumen fill in
white-tailed deer is lowest during win-
ter (Short,1971).
pH of rumen contents
The pH of.moose rumen liquor is
similar to that of other ruminants.Sam-
ples collected from freshly killed
moose in interior Alaska during Oc-
tober and February contained rumen
liquor with a pH of 6.The pH of
rumen liquor in a moose killed in Oc-
tober was monitored for four hours
following death.The pH dropped
from 6 at death to 5 three hours after
death.At this time fermentation had
nearly stopped suggesting that pH
would probably not decline further.
These values were determined using pH
indicator paper and are therefore only
approximate.pH values are not avail-
able from moose in summer,although
they may be lower-than winter
values because of increased fermenta-
tion rate-and higher volatile fatty
acid concentration.Short et al.(1966)
fourrf a lower pH in rumen liquor
of mule deer (Odocoileus hemionus)
during summer than during winter.
Therefore,pH values may be of some
-,---"
use as a very general indicator of
relative fermentation rates.
FOOD INTAKE,PASSAGE AND DIGESTIBILITY
Food intake,passage rates and diges-
tibility in moose have received little
consideration.However, these parame-
ters are important to the understanding
of moose nutrition and require further
investigation~
Verme (1970)reported that captive
moose consume 18-23 kg fresh browse
per day in winter and 23-27 kg food in
summer.Palmer (1944)estimated
that moose required 16 kg of forage per
day (air dried weight).Attempts
to estimate food consumption by Alas-
kan moose are reported by LeResche
(1970)and LeResche and Davis (1971).
The utilization of wint.er browse was
studied in pens by estimating the bio-
mass of browse removed by known
numbers of moose during the winter.
Variability in estimates of food intake
was high,ranging from 1.3 to 5.4 kg/
animal/day (wet weight)and were
considered unreliable.A second method
was tried where tame moose were
observed and number of bites and types
of plants were recorded.Bites were then
.converted into pounds of food consu-
med.An estimate 1.7 kg/animal/day
(wet weight)(1.3 kg dry wt/day)was
consumed in winter and 19 kg ani-
mal/day (wet weight)during summer
(Table VII).The estimate for winter was
felt by LeResche and Davis (1971)to
underestimate actual •consumption.
These same moose were capable of
consuming 11 to 16 k.g of pelletized
commercial food per day in the pre-
vious winter.
Estimates of required digestible
OM and food intake during winter
can be made for moose in interior
Alaska.Approximate values used in
the calculation of OM consumed were
-:-
TABLE VII
LE NATURALISTE CANADIEN.VOL.101.1974242
the following:organic matter digest-
ed =4,500 kcal/kg digested;metaboliz-
able energy (ME)=3,690 kcal/kg or-
ganic matter digested (ME =0.82 x DE,
Annison and Armstrong,1970);diges-
tibility of 40 percent in winter and 55
percent in summer,based on estimates
made by the summation equation and
lignin ratio methods discussed pre-
viously.Dairy energy requirements
for moose during winter are assumed
to be near 1.7 x BMA.
Applying the above assumptions an
estimate of the required food for moose
can be calculated as follows.Cow
moose in mid to late winter weigh
about 400 kg and have a BMR of
about 6,300 kcal/day.Metabolizable
energy requirements at that time are
approximately 10,700 kcal/day (6,300
kcal/day x 1.7).Body fat and pro-
tein reserves were catabolized at an av.:
erage rate·of 3,900 kcal/day (based on
winter weight loss of 90 kg fat and 25 kg
protein in 240 days).Thus,6,800 kcal
ME were supplied by the forage.
It requires 1.9 kg digestible OM to
supply this 6,800 kcal ME,and since
OM is 40 percent digestible,4.6 kg OM
or about 6.5 kg wet weight of winter
browse would be consumed (Table VII).
Dry matter digested and food con-
sumed by moose can also be estimated
from volatile fatty acid (VFA)production
using the relationship described for
domestic sheep by Weston and Hogan
(1968a).They found a relatively constant
production of VFA per unit of organic
matter digested (8.5 mole VFA/kg OM).
Using Weston and Hogan's relationship,
Estimates of food consumption by moose are presented for several studies in kilograms per day.
Note that values are in dry,air dried,and wet weigh ts making direct comparison diffieult
i
Lactating !
Summer
Non-lactating
Reproductive
Status Unknown
Wincer Conditions I
I
Reference
I..__. ._1_-
-.
11.5 dry wI.
19 wei wI.
10.2 dry wI.
23-27 wei wi.
16 air dried
18-23 wei wI.
16 air dried
1.3-5.4 wet wI.
1.7 wei wi.
(1.3 dry wI.)
4.6 dry wi.
(6.5 wet wI.)
5.5 dry wI.
(6.0 wet wI.)
Penned.hand I
cut browse I
Estimate for
penned
Natural browse.j
estimated from !
browse removed :
in large pen j
Natural browse.!
estimates from I
bites eaten by I
tame moose in
large pen I
Natural browse.I
estimated from
energy require-
ments ot 1.7 x
basal metabolic
rate
Natural browse.
estimaled from
digestible DM
required for
measuredVFA
production
Verme.1970
Palmer.1944
LeResche.1970
LeResche and Davis.
1971
Coady and Gasaway.
unpub!.
Coady and Gasaway.
unpub!.
,.
GASAWAY AND COADY:ENERGY REQUIREMENTS IN MOOSE 243
.~
-;
,;..-
increase during the plant growing sea-
son.The increase in food consumption
is reflected in rapid weight gains dur-
ing the summer and the winter de-
crease in food intake by weight loss
(see Table XI).
The more rapidly the breakdown and
digestion of foods in the rumen,the
faster can be the rate of passage of
digesta onward from the rumen to the
remainder of the gastro-intestinal tract;
hence the greater is the quantity of feed
that must be eaten to maintain a cer-
tain degree of rumen fill.Food con-
sumption is therefore a function of the
rates of digestion in,and of passage
from the rumen (Corbett,1969).Cor-
bett et a/.(1963)demonstrated this
relationship between digestibility and
food intake in cattle.During a five week
study the digestibility of grass decreas-
ed from 80 to 68 percent,and food
intake fell about 20 percent.Weston
and Hogan (1968b)attribute low food
intake of poor quality feed to long
turnover time in the rumen of domestic
sheep.However,consumption increas-
ed when food was ground and pellet-
ed because rumen turnover time was
shortened.
Voluntary reductions in food intake
during winter have been noted in deer
fed good qual ity food ad libitum
(Thompson,1972;Wood et a/.,1962).
This factor may also play an important
role in regulating winter food consump-
tion in moose.
the mean value for production of VFAs
in moose feeding on winter browse
in interior Alaska was equal to 2.2 kg
digestible OM/day (Table IV).There-
fore,OM consumed equals 5.5 kg per
(iay with a 40 percent digestibility or
<.bout 7.9 kg/day wet weight.Calor.ic
value of food digested is 2.2 kg x It is unlikely that lower food intake
3,590 kcal ME/kg=8,118 kcal or 1.3,during the winter is a result of limited
;<SMR.This is less than the estimated food availability.The probable cause is
17 SMR mentioned above.However,increased retention time of food in
~hen the additional energy (3,900 the rumen because of decreased diges-
kcal/day or 0.6 x SMR)from tissue tibility.Food intake in ruminants is
reserves is considered the total energy partially regulated by the passage rate
available equals 1.9.x SMR (12,000 kcal)of digesta through the gut (Weston
which is close to the estimated requi-and Hogan.1968b;Corbett,1969;Cor-
rement of 1.7 x SMR.bett et a/.,1963,and Salch,1950).
Similar calculations can be made
for lactating moose which are in positive
energy balance during summer.Estima-
ted digested OM equals 6.3 kg (Table
IV),or,assuming 55 percent digestibility
for summer forage,11.5 kg OM consum-
ed.Caloric 'value of the 6.3 kg OM
is equal to 23,200 kcal ME/day or 3.8
x SMR (SMR =6,035,seeTable XI).
Non-lactating cow moose during
summer digested an estimated 5.6 kg
OM per day equal'to 20,700 kcal ME,
or 3.4 x SMR (SMR =6,100,see Table
XI).This represents 10.2 kg of OM con-
sumed or 1.3 kg less than lactating
cows.Moose appear to increase food
intake while lactating as do domestic
cows (Campling,1970).Corbett (1969)
reported lactating dairy cows may con-
sume as much as 50 percent more
food than non-lactating cows.Dairy
cattle have higher energy demands for
lactation than moose since they are
bred for inordinately high milk produc-
tion rather than reqiJir~'ments of the calf.
Estimates of food consumption dis-
Cussed here vary considerably accord-
ing to the method by wh ich they were
calCUlated (Table VII).Aithough all
food consumption estimates are
approximate,they show a marked
".
A;,.~::-. I{•• -_;-'rz,.•; t~ . ., :·.l' . ! ~ .~ .. l ~ ,~ it:~_ l-Jt . -·-·~·-'•·-·~··-·..,;,.._;,..t"~·-~-""'·-. 244 LE NATURALISTE CANADIEN. VOL 101. 19l4 The stage of maturity of pasture plants has a marked effect on rumen function parameters in domestic sheep (Hogan et a/., 1969). Similar effects probably occur in moose as the growing season progresses and plants mature. Hogan et a/. (1969) found that as the grass, Pha/aria tuberosa, matured food consumption, passage rates through the gut, digestibility and VFA production decreased and chewing activities increased. Short (1971) found that grasses and forbs utilized by white-tailed deer in Texas varied in diges-tibility with the stage of maturity. He sampled deer browse throughout the year and found that immature sta-ges were more digestible than mature plants. Since plants in immature stages of growth are most digestible and nu-tritious it is advantageous for un-gulates to inhabit areas with diversity in habitat types, browse, topography, and long seasonal progressions of plant growth. These conditions permit selection of highly nutritious foods for the greatest length of time during the growing season. Klein (1965) found the environmental factors, altitu-de and topographic variation, to be primarily responsible for differences in the quality of browse and conse-quently for differences in growth rates of black-tailed deer in Alaska. He sug-gests that similar factors are of impor-tance to Oall sheep (Ovis dalli) and mountain goat (Oreamnos americanus). These factors are no doubt impor-tant in determining the quality of moose browse and subsequent distribution and seasonal movement of moose. While information regarding rumen turnover times or forage digestibility in moose are not available. fermentation data can be used to indicate seasonal trends. Quantity of rumen OM was greatest in moose feeding on woody browse during October in interior Alaska, while estimated OM digested was low during this time (Table IV). October forage may have a long turn-over time in the rumen because of the low remc;>val rate by diges-tion. By comparison, moose feeding on green plants in June apparently digested more OM per day than was present in the rumen; hence, the turn-over of OM was more rapid than in winter. The on.ly comparable study on wild ruminants of which we are aware was undertaken by Mantz and Petrides (1971) on white-tailed deer. They reported that natural browse had a greater retention time in the rumen than did a ground, pelleted, and readily digestible standard diet which mighf be considered equivalent to summer forage in terms of turnover. Seasonal turnover patterns described in moose and white-tailed deer are also similar to those observe.d in do-mestic ruminants. RUMEN FERMENTATION AND UTILIZATION OF VFA Rumen fermentation is one of the major adaptations favoring success-ful coexistence among ruminants and other large herbivores. The "fermen-tation vat" has allowed for digestion of the ubiquitous cellulose molecule and other difficult to digest polysaccha-rides. Over one half of the digestible OM consumed by ruminants is altered by microbial digestion and fermentation in the rumen, and from 53-62 percent of the DE goes through the rumen VFA pool alone (Gray eta/., 1967; Berg-man et a!., 1965; Annison and Arms-trong, 1970; Blaxter, 1962). Rumen metabolism of carbohydrates and proteins Carbohydrates (CHO) are the most abundant energy source for moose, l"''l~ ~;,_ <;.'.· . n · 1 -~~-··>,~:""!';!
making up about 60-70 percent of
the diet.Carbohydrates found in plants
are primarily polysaccharides,cellu-
lose,hemicellulose,pectins,starches,
and fructans.A very small portion of
CHO is in the form of mono -and di-
sE.ccharides such as fructose,glucose
and sucrose (Church,1969;Leng,
1970).Microbes digest and ferment
much of the CHO consumed,and the
ease of digestion varies with the d if-
ferent CHO molecules.Digestion of
cellulose and hemicellulose is slower
than that of starch and soluble CHO.
Large,complex molecules such as cel-
lulose,hemicellulose,and starch are
first broken down by extracellular
enzymes into small units.This is fol-
lowed by digestion and fermentation
within the microbial cell (Leng,1970).
The general scheme of CHO metabo-
lism is for conversion of dietary CHO
into a common unit,glucose,and then
to pyruvate which is metabolized to
acetic,propionic,butyric and valerie
acids (VFA)plus carbon dioxide and
methane (Leng,1970;Baldwin,1965;
Hungate,1966;Hungate,1968;Church,
1969).
245
Acetic acid is produced in the great-
est molar quantity and is followed
in order by propionic,butyric and va-
lerie acids in moose and other rumi-
nants (Table VIII).A schematic diagram of
CHO degradation in the rumen is shown
in Figure 2 (from Chu rch,1969 and
Leng,1970).
Dietary proteins are broken down
into amino acids which are fermented
to produce energy for biosynthetic
processes.Amino acids may be incor-
porated directly into microbial cells
or deaminated and fermented to produ-
ce ammonia,carbon dioxide and
VFA.The proportion of VFA originating
from protein is not well understood,
although feeds rich in highly soluble
proteins may yield substantial amounts.
Branched chain VFA present in the
rumen,Le.isobutyrate and isovalerate,
arise from fermentation of certain amino
acids (Hungate,1966).These branched
VFA represent a small percentage of the
total VFA,although they provide a
relative indication of the magnitude of
protein fermentation.Proteins and
amino acids may escape fermentation in
the rumen and pass into the lower
GASAWAY AND COADY:ENERGY REQUIREMENTS IN MOOSE
·,
Hemicellulose Cellulose Storch
Pectins '--.~./Sucrose
"---Glucose ~ans
l
F_ate p~:::a~tt_kacta\te
A Acetyl CoA .Succi nat.e .
C02yH2 ,/\
Acetate Butyrate Propionate
Metliane ~\.Ketones
\Energy
Host
Metabolism
Microbial
Metabolism
Figure 2.Carbohydrate digestion and metabolism by rumen microbes and their host (from
Church.1969 and Leng.1970).
TABLE VIII
Comparison of initial concentration and molar percentages of VFA in rumen liquor of several specie!>of
ungulates
o
rm
2»
C!
.~
r
(fJ
-im
()»
2»
9m
?:-
<or
Weller et al.,1969
Short et al.,1966
Hogan et a/.,1969
Short,1971
Short et al..1969b
Coady &Gasaway,
unpubl.
4.191873
,Spocies
Moose
Mule Deer
White-tailed
deer
White-tailed
deer
Diel or SeaSOn con:;~~:'~lion L-----.....~olar percen~..Reference
__________.,-:-_I_Il_e_q_l_m_I_I_iq_U_o_rl__11 __~,,"~_~,op~:n:"_j---~uty",e~"'Op_i_o_n_a_le_I--_
Spring.mixed woody browse +
some green forage 65 l.
Summer,green forage 93
Early winter,woody browse 69
Mid-winter,woody browse 70 74 17 8 4.3
Winter to early spnng 68 20 10 3.4
Late spring and summer 63 22 13 2.9
Autumn 66 20 11 3.3
Winter,diet largely acorns 108 59 22 15 2.9
Winter.diet browse and,grasses 107 73 16 9 4.5
Winter -February 97 74 19 7 4.2
May 80 72 19 9 3.9
July 130 59 32 9 1.9
November 110 54 34 12 1.6
February 76 62 28 10 2.2
Domestic Early growth.low fiber 104 66 20 12 3.3
sheep Intermediate maturity 100 68 20 10 3.4
Domestic ~r~t~~e~s~it fiber 1~~I ~~I ~~t':~;:~
sheep i Wet growing season 117 58 i 25 17 2.3
,_.__.:..__...__~:_seas~_~~_1O_0 J__6_8__,L_~~__.,__1_2__-l--__4_._0__L-_
247
Seasonal changes in rumen fill and
changes in the proportion of liquor
have a pronounced effect on the cal-
culated total rate of VFA production
observed in moose.Moose in winter
have greater rumen fill than in summer.
This has the effect of compensating
somewhat for the reduced winter VFA
production rate per ml of liquor by
increasing the volume of substrate
exposed to fermentation at anyone
time.VFA production in the total rumen
VFA production rates per ml of liquor
in the rumen of moose varies markedly
with season and consequent changes
in quality of the diet.Winter diets of
woody browse are of low enough
quality to limit fermentation rates
to approximately one-third of the
VFA production rates in summer
(Table IX).Apparently,the low fermen-
tation rates in winter result from
reduced quality of browse rather than
a shortage in quantity,since the
moose were collected on quantitatively
good winter range.In late May the
diet consists of some newly emerging
green vegetation mixed with wood
browse.VFA production rates at this
time were greater than in winter but still
only 'half that of summer values (Table
IX).
content sample under cond itions approx-
imating those in the rumen.Isolation
of the sample in a polyethylene jar
prevented absorption of microbial
end products while allowing fermenta-
tion to continue fora period of time.
Subsamples from the jar were with-
,drawn at approximately half hour
intervals and prepared for total VFA
determination by steam distillation
and titration with NaOH.Total daily
VFA production for moose was calcul-
ated by multiplying the in vitro pro-
duction rates per ml of rumen liquor
by the total volume of liquor present
in the rumen.
GASAWAY AND COADY:ENERGY REOUIREMENTS IN MOOSE
1,
-;.....•___4
~VFA production in moose in i~ter
ior Alaska was studied during spring,
summer 'and winter using the zero time
rate methods of Carrol and Hungate
(1954)(Coady and Gasaway,unpubl.).,
The method was slightly modified for
Use in field studies.The procedure in-
vorije'S~in vitro incubation of a rumen
VFA production
More VFA is produced in the rumen
from forages containing high levels of
soluble CHO and protein than from
foods high in fiber and insoluble
components.Thus,immature stages of
plants generally result in high VFA
production rates whereas plants
consumed in the.winter or dormant
'p~iiiod are generally 'difficult to digest
~ari({~''Yie1d',Iow-'VFA production rates
AWastonand Hogan,,1968a,b,c;Hogan
fefai:;--1969;Hogan:and Weston,1969).
Ammonia formed by deamination
of amino acids is utilized by the
microbes as a nitrogen source for
protein synthesis.The host ruminant
also absorbs ammonia from the rumen.
It is converted into u rea and recycled
into the rumen via salivary secretion
and secretion through the rumen wall.
Nitrogen in urea is converted to
ammonia in the rumen and used in
microbial syntheses (Hungate,1966;
Nolan and Leng,1972;Weston and
Hogan.1967;Church,1969).Recy-
cling of nitrogen is an important pro-
cess which presumably allows all
ruminants including moose to effecti-
vely utilize low protein diets.
digestive tract where they are absorbed
by the host ruminant (Hungate,1966;
Leng.1970;Nolan and.Leng,1972;'
Tillman and Sidhu,1969;Mangan.
1972).However.the major source of
protein for ruminants is of microbial
origin (Hungate,1966;Nolan and Leng,
1972)..
..
;:;,,:~,
~ ',;~'lllil 248 LE NATURALISTE CANADIEN. VOL. 101. 1974 of moose during summer was 2.6 to 2.9 times that during winter, although the rate of VFA production per ml of liquor was over three times higher during summer than during einter. Thus, the effect of increased rumen fill was that of providing more VFA to the· animal than the production rate alone would suggest. The effect of changing rumen fill on total VFA pro-duction was more pronounced in cow moose during May when theJumen fill was at its lowest level. Daily VFA production in the May sample equaled that of large rumen volumes in winter because of the increased production rate per ml of rumen liquor due to the recent emergence of green plants. Lactating cow moose during summer had greater total VFA production than did non-lactating cows in spite of the similar VFA production rates. This was due to a greater rumen fill and a higher proprotion of rumen liql!or in the rumen contents of lactating moose (Table IX). Recently, many investigators have measured the VFA production in do-mestic animals, but few studies of VFA RfOduction in wild animals have been undertaken (Table X). To compare animals of different body size, VFA production rates were expressed with respect to metabolic body size (kg.7s) in Table X. Wide variations in the pro-duction rates exist among species de-pending on the forage fed on and pro-bably the technique used to estimate VAF production. Moose on an annual basis encompass the extreme variation seen in the other species. Seasonal variations in total VFA production are illustrated in only three studies in Table X. Two studies were carried out on grazing domestic sheep in Australia (Weller et a/., 1969, and Weston and Hogan, 1 968a) and the other study was on moose in Alaska (Coady and Gasaway, unpubl.). Moose showed greater seasonal extremes in total VFA production than did sheep on their respective high and low quality ranges which are a result of wet .and dry seasons. This may be expected since moose have only a short summer period to replenish depleted protein and fat reserves in preparation for a wi'nter of eight months in length. During winter, only low quality food is available and a negative energy balance persists. VFA concentration in rumen liquor has been used as a seasonal indicator of VFA production for comparing forage quality in wild ruminants (Prins and TABLE IX Season, Month Spring May Summer June Summer June Early winter October VFA production in moose collected in the Tanana Valley, Alaska' Sex, Age I Number R d . I VPA Initial VFA Produc.tion I Total VFA . in epro uctlve concentration rate production I -. status · sample 1--~~ ~~J=~ _ ( J.L eq!hr. ml l (moles/day_, Female 4 ! Pregnant ! 65 adult I Female 4 Non·lactating I 98 adult I Female 3 Lactating adult i 1 Female 5 Non-lactating : adult without calf i 89 18 31 18.81 47:15 58 I --------·--~ l 61 53.20 18.40 69 1 Coady and Gasaway, unpublished.
.GASAWAY AN'O COADY;ENERGY REQUIREMENTS IN MOOSE
.~•
Geelen,1971:Short,1963,1971:Short
et al.,1969a,Short et a/.,1969b;Ullrey
et a~,1964,1967,1968,1969,1970;
Bruggemann et a/.,1968).The correla-
tion of VFA concentration and VFA
production described'by Leng (1966),
Leng and Brett (1966),Leng et al.
(1968)and Weston and Hogan (1968a;
indicates VFA production can be
estimated from the concentration once
the relationship is established for the
species.However,variation in the re-
lationship between VFA production
and concentration is considerable.
Over a small range of VFA concentra-
tion,variability is likely to obscure
changes in production.Therefore,in
wild game.studies we feel VFA con-
centration can be used only as an
approximate indicator of fermentation
rates rather than a tool to estimate ac-
tual VFA production.
Molar percentages to VFA present in
the rumen is related to the gross
chemical nature of the diet and
fermentation patterns.Generally,
forages rich in easily fermented material
result in increased propionate relative to
acetate.Forages high in fiber result in
increased proportion of acetate
(Hungate,1966;Weller et al.,1969;
Hogan et al.,1969).Specific incidents in
closely controlled studies of domestic
animals have revealed exceptions to the
generalization cited above (Weston and
Hogan,1968a).Therefore,great
significance should not be placed on
c'this.parameter as .an indicator of food
o'Cc;>T'ripositionanOdquality,particularly if
the-_investigator has relatively few
samples.Table'VIII .summarizes VFA
molar proportions in several species of
ungulates.Acetate:propionate ratios
show an increase during the winter,·x
.dry season which indicates a diet low in
soluble CHO and proteins.
Energy value of VFA
-The importance of VFA as an ener-
249
gy source in ruminants is well establish-
ed.The energy contained in the VFA
is equivalent to about 57 percent of the
DE and about 70 percent of the ME for
ruminants assuming that ME is about
82 percent of DE (Annison and
Armstrong,1970).Estimated VFA energy
extends our understanding of moose
nutrition and energy requirements
because ME of free ranging animals may
then be estimated.
Metabolizable energy of VFA produc-
ed in the rumen of moose which is
equal to gross energy of VFA was
calculated by multiplying the total mo-
les produced per day by the molar
percentage of indivudal VFA.This
gave an estimated production of each
acid.The number of moles of each
VFA times its respective heat of com-
bustion (kcal/mole)equals kcal of
ME per day available from each VFA
through oxidation.Moles produced per
day (Table IX)were converted to kcal
of ME as shown in Table XI.Calculat-
ed BMR was used as the standard
energy unit for moose to which VFA
energy was compared.Energy available
from VFA in moose feeding on woody
winter browse in October was calculat-
ed at 69 percent of the BMR (Table
XI).This is probably a low estimate
because the moose were very fat in
this early winter period.Lipid deposits
in these moose are approximately 100
kg and adipose tissue is-metabolically
less active than most other tissues.
Correcting for this less active body
mass would lower the theoretical BMR
and increase the percentage of energy
supplied by VFA.The BMR for lean body
weight for these moose was about 6,300
kcal per day and VFA energy supplied 81
percent of this amount (Table XI).We
suspect VFA production remains
relatively constant through a -·'normal"
winter while dormant plant parts are
browsed.thus VFA energy contribution
6-}#
_..~).#b
~'!!1!f1!!!!rr'"c
r-m
~
-l
C
~
C
Ul
-lm
()
~z
~
Qm
~
<or
<5
",eno
9
9
9
TABLE X
A comparison of rumen VFA production based on body weight in several species of untlulates
n -1
Species
Conditions Body mMoles/mMoles/Sex,Age,Diet (Body wt)O.75 Reference
No.in Sample Season Wt (kg)References day/kg ~.l5
Moose Free ranging Winter browse +338 79.0 56 238 Coady &Gasaway,
Cow Adult Spring,May some new green unpubl.
n :.4 pregnant forage
Moose Free ranging Green forage 430 94.4 111 506 Coady &Gasaway,
Cow Adult Summer,June unpubl.
n '"4 Non-lactating
Moose Free ranging Green forage 379 86.0 140 619 Coady &Gasaway,
Cow Adult Summer,June unpubl.
n =3 lactating
Moose early winter 105.7 37 174 Coady &Gasaway,;Cow adult non-lactating unpubl.
n =5 without calf I
Eland !Free ranging 520 108.9 37 176 Hungate et al.1959
(Taurotragus)
n =1
Zebu Free ranging Grass pasture 241 61.1 52 207 Hungate et al.195
(80S indicus)
n =1
Grant's Free ranging I 49 18.5 34 98 Hungate et al.195
Gazelle I(Gazella sp.)
In~,1 IThompson's Free ranging 24
I
10.5 34 98 Hungate et al.195
Gazelle
(Gazella sp.)
-
",~
Suni Free ranging 3.7 2.7 105 146 Hungate et al.1959
n =1
Reindeer Penned Commercial 52.8 19.5 53 143 Luick et al.1972
n =4 winter pellets
n ~2 Penned Commercial 105 32.8 83 267 Lu ick et al.1972
winter pellets +
lichens +
straw
n =4 Penned Lichens
wint~r 59 .21.3 66 183 Luick et al.1972 Q .,'+',~;1>Domestic Penned Early stage rye-en-;1>sheep,grass (27 %prot)43 16.8 128 329 Weston &Hogan,~
Intermediate rye-1968a »ewes,-<
adult grass (12%prot)43 16.8 125 319 Weston &Hogan.»zn.~15 Mature ryegrass 1968a 0
(6%prot):43 16.8 79 202 Weston &Hogan
()
0
1968a ;1>
0
Domestic Penned Lucerne chaff 43 16.8 125 319 Leng &Leonard -<
sheer,I 1965 rn
I'zrnewes,::JIQadult-<
n=6 :0
,."
Domestic,Grazing Wet season 53 19.6 94 255 Weller etal.1969 0csheepGrazingDryseason6322.4 64 179 Weller et al.1969 :x;
rnewes.:!::
adult rn-zn.=4 --ien
Z
1 The weight not given by authors and was estimated to be 43 kg for purposes of calCUlations in t~ble.:!::
0
0enm
TABLE XI
i
Estimates of VFA and metabolizable energy with respect to the basal metabolic rate in moose,sheep
and reindeer
,
Energy VFA
Species;Body Derived Theoret·energy ME
Sex,Age Wt (kg)Season Diet Conditions from VFA ica/BMR (%of (%of Reference
(kcallday)(kcallday)BMR)BMR)
Moose 338 May Mixed Free 5,320 5,505 98 140 Coady &Gasaway
adult cows (1971)winter Ranging unpubl.
pregnant Spring woody
n =4 browse &
new green
forage
Moose 430 June Green Free 13,160 6,585 198 283 Coady &Gasaway
adult cows (1972)forage Ranging (6,100)(218)(311)unpubl.
non-lactating Summer
n,=4
Moose 379 June Green Free 14,660 6,035 243 347 Coady &Gasaway
adult cow (1972)forage Ranging unpubl.
lactating Summer
n =3 IMoose 501 October Woody Free 5,080 7,410 69 99 Coady &Gasaway
adult (1972)winter Ranging (6,300)(81)(115).unpubl.
cows Early browse
non-lactating
0=5
,..
m
z
~
~
C
Ul
-im
~z
l>o
iii.z
(§
r
Domestic 40 Lucerne Penned 1,490 1,110 133 191 \Leng &Leonard,
sheep Chaff 1965
ewes 900 g/day
n=6
Domestic 35.5 Growing Grasses .Grazing 1,900 1,020 186 266 Corbett,Leng &
sheep Season Young,1970
ewes
n =10
Domestic 40 Grass Penned 1,845 1,110 166 237 Hogan,Weston &
sheep I Early Lindsay,1969
ewes Stages
n =6 (high quality)
40 Intermediate 1,525 1,110 137 196 Hogan,Weston &
Lindsay,1969
40 Mature 855 1,110 77 110 Hogan,Weston &
(poor quality)Lindsay,1969
Domestic 37.5 Grasses Grazing 1,140 1,06 107 153 Leng,Corbett &
sheep Varying Brett,1968
ewes Stages of
n=9 Maturity 990 1,065 93 133 Leng,Corbett &
Brett,1968
Domestic 59 Lichens Penned I 1,075.1,490 72 103 Luick et a/.IreindeerSimulated 1972
n=4 Winter Diet
n=4 53 Commercial Penned 765 1,37 56 80 Luick et a/.
Pellets 1972
n=2 105 Commercial Penned 2,415 2,295 105 150 Luick et a/.
Pellets +1972
Straw +
Lichens
'Numbers in ( )are calculated using the estimated lean body weight.
G)
fn>:E:<.>zo
()o»o-<"
254 LE NATURALISTE CANADIEN. VOL 101. 1974 may increase slightly relative to the decreasing lean body .weight and BMR. It may appear that the estimated VFA energy production is insufficient and that maintenance of moose through winter is energetically impossible. How-ever, moose i-n October derived and es-timated 7,300 kcal/day ME from the diet, and an estimated additional 3,900 kcal/day was derived from catabolism of body tissue stores. Therefore, total ME availabl~ per day was approxi-mately 11 ,200 kcal (7 ,300 + 3,900) or 1.8 x BMR when using the calculated BMR of 6,300 kcal/day. This value, 11,200 kcal, compares closely with the~ 12,000 kcal ME/day estimate, based on the conversion of VFA into kcal of digestible organic matter using Weston and Hogan's (1968a) data, discussed previously. The spring greenup appears rapidly during late May in interior Alaska. Within a week, the region where studies by Coady and Gasaway were conduc-ted, turns from a drab brown to a sprakling green and the moose change from a diet of wood forage to lush green foods which are digested more easily. Calories are abundant on the new diet and depleted stores of fat, carbohydrate and protein are rapidly repl~nished. Moose collected in May (during the spring transition) in the Tanana Flats were near their annual low body weight. VFA energy at this time amount-ed to about 98 percent of the BMR, and total VFA production was simi-lar to that during early winter {Table XI). Energy demands at this time were high because of pregnancy which left the cows in a negative energy balance and necessitated a high dependence on catabolism of stored tissues. By late June, lactating cow moose had gained about 20 kg and VFA energy had increased to 14,700 kcal/day (Ta-ble XI). This VFA energy exceeded the BMR (calculated to be 6,035 kcal/day) by about 240 percent (Table XI). Esti-mated ME is 20,900 kcal/day or 3.5 X BMR, putting the moose into a highly positive caloric balqnce. The period of weight gain each year was approxi-mately 125 days, and during this time an average of 7,600 kcal per day were put into stored tissue energy. In late June, non-lactating cow moose were approximately 50 kg heavier than lactating cows, indicating that the cost of pregnancy and lactation is high in terms of potential weight gain. The energy in VFA's produced amount-ed to about 13,200 kcal/day; thus ME would be approximately 18,800 kcal/ day. The lean, body mass of non lactat-ing cows is prob'ably slightly greater than that of lactating cows because most of the weight gain is fat. To establish a value for calculation oJ BMR for nonlactating moose, 15 kg was arbi-trarily added to the mean weight of lac-tating moose. The BMR was then cal-culated to be 6,100 kcaJ and VFA energy was 2.2 x BMR and ME was 3.0 x BMR. These values would be Jess if BMR were calculated using actual body weight, but adjusted weights were considered more representative of energy requirements. Table XI gives values based on actual weights. Domestic ruminants on open range generally undergo less dramatic chan-ges in seasonal energy balance than some wild ruminants like moose (Table XI. Sheep (Ovis aries) did not reach the extremes of negative or positive energy balance seen in moose even when fed very high and low quality forage. Energy balance of free ranging reindeer is probably more like that of moose, but captive reindeer used by Iuick et a/. (1972) were in negative ba-lance on all diets tested. These studies
GASAWAY ANb COADY:ENERGY REQUIREMENTS IN MOOSE
were conducted in the winter when
intake is lowered which may account
for these low energy values.For moose
in interior Alaska the seasonal energy
picture appears to be feast or famine
with little in between.
EFFECTS OF UNDERNUTRITION ON RUMEN
FUNCTION
Undernutrition will be considered
as reduced caloric intake leading to
less than optimal weightg~in or weight
loss.This definition is broad enough
to apply to .,normal"winter weight
loss,starvation,or even inadequate
summer range resulting in reduced fat
deposition prior to winter.
During winter,the food intake of
moose undergoes a normal decrease,
but under certain circumstances intake
may be reduced still further.Abnormally
deep snow or particularly cold tempe-
ratures (-500 C or colder)may decrease
food availability by restricting moose
mobility.
Decreased food intake lengthens turn-
over time of rumen contents and de-
creases rumen fill (Hungate,1966).
Numbers of rumen microorganisms
decline as food intake is reduced
(Church,1971)and _may drop to very
low numbers if inanition is prolonged
(Hungate,1966).Sheep deprived of
food for three of four days show
marked changes in the composition of
bacterial and protozoan.populations
in the rumen and have reduced diges-
tive capability (Church,1971).Recent
studies by Swope (1972)indicate that
starvation in mule deer does not reduce
the viability of rumen microbes.Ru-
men liquor from starved mule deer
digested forages about as well as
deer on normal rations,and counts of
bacteria showed no significant decl ines
during starvation.These results con-
tradict earlier studies on domestic
sheep and indicate all species of ru-
255
minants may not respond to starvation
in similar manners.Hungate (1966)
suggests that bacterial populations can
remain high in the rumen of starved
animals because of reduced saliva
flow which cause an increase in rumen
turnover time.Bacteria do not leave
the rumen as {ast and the population
remains high.Because the available
nutrients in the forage contained
in the rumen will eventually become
too low to sustain the microbial popu-
lations this condition is temporary.The
mule deer in Swope's study were starv-
ed from 7 to 47 days,which seems
too long to sustain normal numbers
of viable bacteria yet numbers of bac-
teria were reported to remain high.
Moose that die from undernu-.
trition in interior Alaska generally have
substantial amounts of forage in the
rumen.This is a result of consump"
tion of less palatable and digestible
browse as well as lengthened turn-
over time in the rumen.The fact that
the digesta found in starving ruminants
is large makes the diagnosis of starva-
tion difficult (Hungate,1966).Hungate
suggests the use of VFA concentra-
tions and production rates as indica-
tors of undernutrition.Rumen VFA
concentrations are of value only when
samples are taken immediately after
death.This usually requires that the
investigator kill the animal.Although
VFA concentrations and production ra-
tes are expensive and time consum-
ing to measure,they are relatively con-
clusive indicators of the·animal's nu--
tritional balance at that time.
Summary and conclusions
Seasonal energy requirements of
adult moose and ME available for
meeting those requirements can be es-
timated from data presented in Figure
1.Energy required for diverse physio-
logical functions can be described as
~------------------------~--~--·--256 LE NATURALISTE CANADIEN, VOL 101. 1974 percent of BMR, where BMR equals 70W·7s kcal/day. Maintenance energy requirements were considered to re-main-relatively constant, near 70 per-cent of BMR, throughout the year. Metabolizable energy requirements for gestation begin to significantly increa-se in March and reach approximately 100 percent of BMR at term in early June. Metaqolizable energy require-ments for lactation shortly after birth were approximately 100 percent of BMR. Milk production remains high for a rela-tively short time, and by Augusf repre-sents a relatively small energy demand. Weight gain by moose in Alaska occurs between late May and late September. Energy available for lactation and weight gain probably averages about 200 percent of BMR throughout the first half of the summer, and then declines as forage quality decreases. However, lactation during early summer signi-ficantly reduces the energy available for weight gain. The quality of foods available to and selected by moose is superior during summer to that consumed in win-ter based on chemical analysis and rumen fermentation rates. Food con-suiT)ption data from several studies indicate greater food intake during the plant growing season than during win-ter. Estimates of food intake that supply the required energy during winter and summer are 4.5-5.5 kg and 10-12 kg dry weight, respectively. The re-duction in winter food consumption results from slower rates of digestion and passage through the gut and pre '"'ably from a voluntary decrease in food iQtake as has been observed in other wild ruminants. Microbial fermentation of plant CHO and protein in the rumen yields VFA. The ME energy in VFA represents about 70 percent of the total ME de-rived from the diet. Plants in the growing season, particularly immature stages, yielded the highest fermenta-tion rates in the rumen whereas dor-mant plants and woody browse, being lower in digestible nutrients, resulted in lowest fermentation rates during winter. The total VFA produc-tion in moose during summer is nearly three times that of production in win-ter. Moose undergo greater seasonal variation in the quality of the forage and fermentation rates than do do-mestic ruminants which have been studied in this manner. The energy de-rived from rumen fermentation in moo-se was about 80 percent of the BMR in winter and increased to nearly 250 percent of BMR in summer~ Esti-mated metabolizable energy obtained from forage by moose during winter was only 115 percent of the BMR, where as in summer moose produced up to 350 percent of basal requirements. In late summer and fall the quality of the forage declines until the winter values of fermentation are attained. Lipid and protein stores supply the ener-gy required in winter which is not provided from the dietary sources, thus making ample lipid storage in summer a necessary requirement .of annual production. The quantity or quality of winter browse is occasionally restricted by weather conditions. The effect of reduced intake on rumen function is to lengthen turnover time of rumen con-tents and decrease rumen fill. Num-bers of microorganisms may decline to low numbers if intake remains low for an extended period of time causing a marked reduction in the fermentation rate. Rumen function studies on wild cer-vids and bovids will provide comparati-ve information on their seasonal energy balance and status. Ruminants, wtlether in the tropics. temperate or arctic zone
GASAWAY AND COADY.:ENERGY REOUIREMENTS IN MOOSE
•
..
.'
characteristically are exposed to season-
at variation in forage quality.Energy
is generally stored as fat and protein
during the portion of the year when
forage quality is high.Stored fat and
protein is catabolized during the re-
mainder of the year when ME is below
lhe maintenance level.and moose are
in negative e'nergy balance.The estimat-
ed caloric value of VFA produced
in the rumen while feeding on the va-
rious seasonal diets and subsequent
.estimates of ME allows for direct
comparison of the animals'ability
to utilize the forage and derive energy.
This provides a clearer understanding
of the temporal relationship of the
animal to its food resource.Biologists
can then recognize the importance of
a particular season in relation to others.
determine the importance of various
foods and determine the duration of
seasons based on food utilization and
available energy.
Range evaluation techniques can be
very time consuming.expensive and
often result in information which is
difficult to interpret in a usable form.
Therefore,the animal utilizing the ran-
ge may be an alternate evaluator and
provide a more direct and sensitive
indicator _of range quality provided
techniques can be developed to mea-
sure physiological changes in the ani-
mal.While digestive performance of
moose on summer and winter range
show striking differences,only subtle
differences may exist among moose
ranges when compared during the same
season.A system using digestive in-
formation to compare various ranges
could include estimates of VFA produc-
tion rates,energy derived from fermen-
tation and ME,food consumption,
digestibility of .forage and chemi-
cal and botanical composition of rumen
contents.Data obtained from this
method,especially when used in con-
junction with other techniques,may
257
provide a useful means of comparing
ranges and the nutritional status of the
animals.
Acknowledgments
We thank Drs.R.White.J.Peek,G.West
and Mr.K.Neiland for their critical review of the
manuscript.This work is a contribution from
Federal Aid in Wildlife Restoration Project
W-17-R.We thank the International Symposium
on Moose Ecology Committee for providing
travel funds which allowed us to attend the
conference.
References
ANNISON;E.F.and D.G.ARMSTRONG.1970.
Volatile fatty acid metabolism,and energy
supply.p.422-437.In:A.T.Philipson (ed.).
Physiology of digestion and metabolism in
the ruminant.Oriel Press Limited.Newcastle
upon Tyne.England.636 p.
BALCH.C.C.1950.Factors affectin.g the utili-
zation of food by dairy cows.I.The rate of
passage of food through the digestive
tract.Br.J.Nutr.,4(4):361-388.
BALDWIN,A.L.,1965.Pathways of carbohy-
drate metabolism in the rumen.p.379-389.
In:RW.Dougherty.R.S.Allen,W.Burroughs.
N.L.Jacobson and A.D.McGilliard (eds).
Physiology of digestion and metabolism
in the rumen.Butterworth Inc.•Washington.
D.C.
BENEDICT,F.G.•1938.Vital Energetics.Publ.
503 Carnegie Inst..Washington.D.C.
BERG,W.E.,1971.Habitat use.movements.
and activity patterns of moose in Northwest-
ern Minnesota.M.Sc. Thesis.Univ.of Min-
nesota 98p.(Unpubl.)
BERGMAN.E.N.•A.S.REID.M.G.MURRAY.
J.M.BROCKWAY and F.G.WHITELAW.
1965.Interconversions and production of
volatile fatty acids in the iheep rumen.Bio-
chern.J.97:53-58.
BLAXTER,K.L.and F.W.WAINMAN.1964.
Proceedings of the Third Symposium on En-
ergy Metabolism.Academic Press,New
York.
BLAXTER.K.L.,1962.The Energy Metabolism
of Ruminants.Hutchinson and Co..Ltd .•
London.329 p.
BROCKWAY.J.M.and G.M.O.MALOIY.1968.
Energy metabolism of red deer.J.physiol.•
194 (1):22-24.
---258 LE NATURALISTE CANADIEN, VOL. 101, 1974 BRODY, S., 1945. Bioenergetics and growth. Reinhold Publ. Co .. New York. 1023 p. BRODY, S. and R. C. PROCTER, 1932. Growth and development with special reference to domestic animals. Further investigations of surface area in energy metabolism. Mo. Res. Bull. 166. (cited by Kleiber 1961). BRUGGEMANN, J., D. GIESECKE and K. WAL-SER-KARST, 1968. Methods for study-ing microbial digestion in ruminants post mortem with -special reference to wild species. J. Wild!. Mgmt, 32 (1): 198-207. CAMPLING, R. C., 1970. Physical regulation of voluntary intake, p. 227-234. In: A . .I. Phillip-son (ed.), Physiology of digestion and metab-olism in the ruminant. Oriel Presse Ltd. Newcastle upon Tyne, England, 636 p. CARROLL. E. J. and R. E. HUNGATE. 1954. The magnitude of the microbial fermenta-tion in the bovine rumen. Appl. Microbial., 2:2505-2514. CHURCH. D. C., 1969. Digestive physiology and nutrition of ruminants. Vol. I. D. C. Church, Corvallis, Ore. 316 p. CHURCH, D. C., 1971. Effects of stresses on nutritional physiology, p. 763-790. In D. C. Church (ed.), Digestive physiology and nu-trition of ruminants, vof. 2 Nutrition. D. C. Church. Corvallis, Oregon 801 p. COADY, J. E., 1974. Influence of snow on beha-vior of moose. Naturaliste can., 101: 417-436. COADY, J. W. and W. C. GASAWAY, 1972. Rumen fyl')ction and energy production of moose in interior Alaska. 8th N. Am. Moose Conf. Works.. Thunder Bay, Ontario, Ont. Minis!. Nat. Resourc., Toronto, p. 80-104. COOK, H. W., R. A. RAUSCH and B. E. BAKER. 1970. Moose (Aices alces) milk; gross composition, fatty acid, and mineral consti-tution. Can J. Zoo!., 213-215. CORBETT. J. L., 1969. The nutritional value of grassland herbage. International encyclope-dia of food and nutrition, 17(2): 593-644. Int. Encicl. Fd Nutr .. CORBETT. J. L., J. P. LANGLANDS and G. W. REID, 1963. Effects of season of growth and digestibility of herbage on intake by grazing dairy cows. Anim. Prod .. 5 (2): 119-129. CORBETT. J. L .. R. A. LENG and B. A. YOUNG. 1970. Measurements of energy expenditure by grazing sheep and the amount of energy supplied by volatile !a tty acids produced in the rumen, p. 177-186. fn: K. L. Blaxter J. Kelanowski and G. Thorbedk (eds). Energy metabolism of farm animals. Oriel Press Ltd., Ef)gland, 522 p. DENNISTON, R. H., 19SQ. Ecology, behavior, and population dynamics of the Wyoming or Rocky Mountain moose. Alces alces shirasi. Zoologica, 41 (3): 105-118. FLATT, W. P. and C. E. COPPOCK, 1965. Physiological factors influencing the energy metabolism of ruminants, p. 240-253./n: R. W. Dougherty (ed.), Physiology of digestion in the ruminant. Second Int. Symp. on physiol. and digestion in the ruminant. Bet!erworths, Washington. 480 p. FLATT, W. P., P. W. MOE and L. A. MOORE, 1969. Influence of pregnancy and ration composition on energy utilization by dairy cows. Proc. Fourth Symp. on Energy Meta-bolism. Eur. Ass. Anim. Prod. Pub/., 12:123-129. GEIST, V., 1959. Diurnal activity of moose. Memoranda societatis pro fauna et flora. Fennien, 35: 95-100. GEIST, V., 1963. On the behavior of the North American moose (A. a. andersoni Peterson, 1950) in British Columbia. Behavior. 20: 378-416. GOERING, H. K. and P. J. Van SOEST, 1970. Forage fiber analyses (apparatus, reagents, procedures and some applications). Agric, Handb. No. 379, U.S. Dep. Agric., Washington, D. C., 20 p. GRAY, F. V .. A. WELLER A. F. PILGRIM and G. B. JONES, 1967. Rates of production of volatile fatty acids produced in the rumen of sheep. Aust. J. agric. Res., 18: 625-638. HALLS, L. K., 1970. Nutrient requirements of livestock and game. p. 1018. In: Range and wildlife habitat evaluation -a research symposium. USDA For. Serv. Misc. Pub!. No. 1147, 220 p. HAMMEL, H. T., 1962. Arctic Aeromed. Lab. TOR 61-54. (cited by Whittow, 1971). HART, J. S .. 0. HEROUX. W. H. COTTLE a j C. A. MILLS, 1961. The influence of climate on metabolic and thermal responses of in-fant caribou. Can J. Zoo/. 39: 845-856. HOGAN, J. P and A. H. WESTON. 1969. The digestion of pasture plants by sheep. Ill. The digestion of forage oats varying in maturity and in the content of protein and soluble carbohydrate. Aus. J. agric. Res .. 20 : 34 7-363.
0ASAWAY AND COADY:ENERGY REOUIREMENTS IN MOOSE
•
..
HOGAN,J.P.,R.H.WESTON and J.R..L1NDSAY.
1969.The digestion 'of pasture plants by
sheep.IV.The di'gestion of Phalaris tuberosa
at differe'lt stages of maturity.Aust.J.agoc.
Res.,20:925-940.
HUNGATE.R.E.,1966.The rumen and its
microbes.Academic Press.New York,533 p.
HUNGATE.R.E.,1968.Ruminal fermentation,
p.2725-2745.In:C.F.Cade,(ed.).Handb~ok
of physiology,sect.6,vol.6.Am.PhyslOl.
Soc.,Washington,D.C.
HUNGATE,R.E.,G.D.PHILLIPS,A.McGREGOR.
D.P.HUNGATE and H.IK.BUECHNER.1959.
Microbial fermentation in certain mammals.
Science,130 (33~3):1192-1194..
INGALLS.J.R .•J.W.THOMAS,M.B.TESAR
and D.L.CARPENTER.1966.Relations
between ad libitum intake of several forage
species and gut fill.J.Anim.Sci..25 :
283-289.
JORDAN.P.A.,D.B.BOTKIN and M.L.WOLFE.
1970.Biomass dynamics in a moose popula-
tion.Ecology,52 (1):147-152.
KLEIBER,M..1961.The Fire of Life.John
Wiley and Sons,Inc..New York,454p.
KLEIN,D.A.,1962.Rumen contents analysis
as an index to range quality.Trans.N.Am.
Wildl.Cont.,27:150-164.
KLEIN.D.R.,1965.Ecology of deer range in
Alaska.Eco/.Monogr.•35:259-284.
KLEIN,D.R..1968.The introduction,increase,
and crash of reindeer on St.Matthew Island.
J.Wildl.Mgmt.32(2):350-367.
KLEIN,D.R.,1970.Food selection by North
American deer and their response to over-
utilization of preferred plant species.p.25-46.
In:A.Watson (ed.),Animal populations in
relation to their food resources.Blackwell
Scientific Publications,Oxford.England,477 p.
KLEIN,D.R.and F.SCH(jlNHEYDER,1970.Varia-
tion in ruminal nitrogen levels among some
cervidae.Can.J.Zoo/.,48 (6):1437-1442.
KLEIN.D.R.and H.STRANDGAARD.1972.
Factors affecting growth and body size of
roe deer.J.Wildl.Mgmt,36 (1):64-79.
KNORRE.E.P.,1959.Ekologiya locya.TrUdy Pe-
chora-llychsk.gas.Zapov.,7:5-167.
KNORRE,E.P.,1961.Itogi i perspektiv adomash-
neniya't"cya.TrUdy Pechora-llychsk.gas.Za-
pav.,9::>-113.
259
LENG.R.A.,1966:Volatile fatty acide produc-
tion in the rumen of sheep.Proc:Aust.Soc.
Anim.Prod.,6:389-394.
LENG,R.A.,1970.Formation and production
of volatile fatty acids in the rumen.p.406·
421.In:A.T.Phillipson (ed.),Physiology
of digestion and metabolism in the ruminant.
Oriel Press ltd.,Newcastle upon Tyne.En-
gland,636 p.
LENG,R.A.and D.J.BRETT,1966.Simulta-
neous measurements of the rates of produc-
tion of acetic,propionic and butyric acids in
the rumen of sheep on different diets and the
correlation between production rates and con-
centrations of these acids in the rumen.
.Br.J.Nutr.,20:541-552.
LENG,R.A.,J.L.CORBETT and D.J.BRETT,
1968.Rates of production of volatile fatty
acids in the rumen of grazing sheep and
their relation to ruminal concentrations.Br.
J.Nutr.22:57-69.
LENG,R.A.and G.J.LEONARD,1965.Measu-
rements of the rates of production of acetic,
propionic and butyric acids in the rumen
of sheep.Br.J.Nutr.,19:469-484.
LeRESCHE.R.E.,1970.Moose report.Fedl
Aid Wildl,Restor.Proj.Seg.Rep.,Vol XI
W-17-2.Alaska Dep.Fish Game,Juneau.
LeRESCHE,R.E.and J.L.DAVIS,1971.Moose
research report.Fedl adi Wildl.Restor.
Proj.Prog.Rep.,Vol.XII W-17-3.Alaska
Dept.Fish Game.Juneau,88 p.
LeRESCHE,R.E.,U.S.SEAL,P.D.KARNS
and A.W.FRANZMAN,1974.A review
of blood chemistry of moose and other
cervidae,with emphasis on nutritional assess-
ment.Naturaliste can.,101:263-290.
LUICK.J.A..D.F.HOLLEMAN and A.G.WHITE.
1972.Studies on the nutrition and me-
tabolism of reindeer-caribou in Alaska
with special interests in nutritional and
environmental adaptions.1971-72 Tech.
Prog.Rep.,on U.S.Atom.Energy Commn,
Contract AT (45-1)-2229.
LUICK,J.R.and A.G.WHITE,1971.Food in-
take and energy expenditure of grazing
of reindeer.p.103-107 In:Bowen (ed.).The
structure and function of the tundra ecosys-
tem.U.S.Tundra Siome Program Prog.Rep.
Vol.1,282 p.
MALOIY,G.M.0;,R.N.B.KAY and E.D.GOOD-
ALL.1968.Studies on the physiology
of digestion and metabolism of the red deer
.",
·f,.,;
J,:-
····1···.··'.:~.",:'1;,.".~
t::,.".
~.,..
~~.
.~;
i.~
.i ~~
;0
•
:;'--
,-,:~ ~ 260 LE NATURAUSTE CANADIEN, VOL. 101, 1974 (Cervus elaphus), p. 101-108. In: M. A Craw-ford (ed.), Comparative nutrition of wild ani-mats. Symp. Zoot. Soc. London No. 21. Acade-mic Press. New York, 429 p. ~-.... -PAQUAY, R., R. DeBAERE and A. LOUSSE, 1972. The capacity of the mature cow to lose and recover nitrogen and the significance of protein reserves. Br. J. Nutr., 27: 27-37. MANGAN, J. L., 1972. Quantitative studies on . PAYNE. P. A. and E. F. WHEELER, 1968. Compa-nitrogen metabolism in .the bovine rumen. rative nutrition in pregnancy and lactation. Br. J. Nutr., 27: 261-283. Proc. Nutr. Soc., 27 :,_129-138. MANTZ, W. A. and G. A. PETRIDES, 1971. Food passage rate in the white-tailed deer. J. Wildt. Mgmt, 35{4): 723-731. MARKGREN, G., 1966. A study of hand-reared moose calves. Viltrevy, 4 (1): 1-42. McEWAN, E. FL. 1970. Energy metabolism of barren ground caribou (Rangifer tarandus). Can J. Zoot., 48: 391-392. McEWAN, E. H. and P. E. WHITEAEAD, 1970. Seasonal changes in the energy and nitrogen intake in reindeer and caribou. Can. J. Zoo/., 48 (5): 905;-913. McEWAN, E. H. and P. E. WHITEHEAD, 1971. Measurement of the milk intake of reindeer and caribou calves using tritiated waters. Can. J. Zoo!., 49: 443-447. MOE, P. W. and H. F. TYRRELL. 1972. Metab-olizable energy requirements of pregnant dairy cows. J. Dairy Sci., 55(4): 480-483. MOEN, A. N., 1968. Energy exchange of white-tailed deer. western Minnesota. Ecology, 49(4): 676-682. MURIE, A., 1934. The Moose of Isle Royale. Univ. Michigan Mus. Zoo!. Misc. Pub!. No. 25. Univ. Mich. Press, Ann Arbor, 44 p. MURPHY. D. A. and J. A. COATES, 1966. Effects •of dietary protein on deer. Trans. N. Am. Wildt. and Nat. Res. Cont., 31: 129-138. NOLAN, J. V. and R. A. LENG, 1972. Dynamic aspects of ammonia and urea metabolism in sheep. Br. J. Nutr., 27: 177-194. OELBERG, K., 1956. Factors affecting the nu-tritive value of range forage. J. Range Mgmt, 9: 220-224. OLDEMEYER, J. L., 1974. Quality of forage plants moose eat. Natura/is.~ can .. 101: 217-226. OVERMAN, 0. R. and W. L. GAINES, 1933. Milk-energy f.ormulae for various breeds of cattle. J. Agric. Res., 46: 1109. PALMER, L. J., 1944. Food requirements of some Alaskan game mammals. J. Mammal .. 25: 49-54. PETERSON, R. L., 1955. North american moo-se. Univ. of Toronto Press, Toronto, 280 p. PRINS, R. A. and M. J. H. GEELEN, 1971. Rumen characteristics of red deer, fallow deer, and roe deer. J. Wildt. Mgmt, 35(4): 673-680. RAUSCH, R. A., 1959. Some aspects of popula-tion dynamics of the railbelt moose popula-tions of Alaska. M. Sc. Thesis, Univ. of A-laska, College. 81 p. (Unpubl.) REID, R. L., 1968. Rations for maintenance and production, p. 190-200. In: F. B. Golley and H. K. Buechner (eds). A practical guide to the study of the productivity of large herbivores. IBP Handb. No. 7. Blackwell Scientific Pub!., Oxford, 308 p. ROGERSON, A., 1966. The utilization of metab-olizable energy by a wildebeest. E. Afr. Wild/. J., 4: 149. ROGERSON, A., 1968. Energy utilization by the eland and wildebeest, p 153-161./n: M. A. Crawford (ed.), Comparative nutrition of wild animals. Symp. Zoot. Soc. London No. 21. Academic Press, New York, 429 p. SCHOLANDER, P. F., R. HOCK, V. WALTERS, F. JOHNSON and L. IRVING, 1950. Heat regulation in some arctic and tropical mam-mals and birds. Bioi. Bull., 99 (2): 237-258. SHORT, H. L., 1963. Rumen fermentations and energy relationships in white-tailed deer. J. Wild!. Mgmt, 27(2): 184-195. SHORT, H. L., 1966. Methods for evaluating forages for wild ruminants. Trans. N. Am. Wild/. and Nat. Res. Cont., 31:122-128. SHORT, H. L., 1969. Physiology and nutri'ion of deer in southern upland forests, p. 14-18./n; White-tailed deer in the southern forest habi-tat. Symp. U. S. Dep. Agric. For. Serv. St1. Forest Exp. S!n, 130 p. SHORT, H. L., 1971. Forage digestibility and diet of deer on southern upland range, J. Wildi. Mgmt. 35(4): 6'38-706. SHORT, H. L. and F. B. GOLLEY, 1968. Metabo-lism. p. 95-105. In: F .. B. Galley, and H. K. Beuchner (eds), A practical guide to the ~~~~!~,~~~""'"'""'"'':<'~'f,.'tl.<~~"'''""~~"'~""'~'~'"'''"'~"''"'.l?.:t=:;"2;"n/·•·
GASAWAY AND COADY:ENERGY REOUIREMENTS IN MOOSE•
II
•
•
..
study of the productivity of large herbivo-
res.IBP Handb.No.7.Blackwell Scientific
Publ..OXford.308 p.
SHORT,H.L..D.E.MEDIN and A.E.ANDERSON.
1966.Seasonal variations in volatile fatty
acids in the rumen of mule deer.J.Wildl.
Mgmt,30 (3):466-470.
SHORT.H.L~,E.E.REMMENGA and C.E.BOYD,
1969a.Variations in rumina-reticular contents
of white-tailed deer.J.Wildl.Mgmt,33 (1):
187-191.
SHORT,H;l.,C.A.SEGELQUIST,P.D.
GOODRUM and C.E.BOYD,1969b.Rumino-
reticular characteristics of deer on food
of two types.J.Wildl.Mgmt,33(2):380-383.
SILVER,H.,1971.Effect of level of intake and
environmental temperature on heat prodUC-
tion,and measurement of physiological
parameters and/or activities of.deer.
Job Prog.Rep.New Hampshire Fish Ga·
me Dep.,20 p.
SILVER,H.,N.F.COLOVOS and H. H.HAYES,
1959.Basal metabolism of white-tailed
deer - a pilot study.J.Wildl.Mgmt,
23(4):434-438.
SILVER,H.,N.F.COLOVOS,J.B.HOLTER and
H.H,HAYES,1969.Fasting metabolism of
white-tailed deer.J.Wildl,Mgmt.33(3):
490-498.
SILVER,H.,N.F.COLOVOS,J.B.HOLTER and
H.H.HAYES,1971.Effect of falling tempera-
ture on heat production in fasting white-tailed
deer.J.Wildl.Mgmt,35 (1):37-46.
SWOPE,H.M.,1972.Big.game research,p.1-4.
In:l.E.Yeager (ed.)Colorado game research
review 1970-71.Colo.Dlv.Game,Fish Pks.
THOMPSON,C.B.,1972.Nutrition of white-
tailed deer fawns.M.Sc.Thesis.Univ.of
New Hampshire,Durham.
TILMANN,A.D.and K.S.SIDriU,1969.Nitrogen
metabolism in ruminants:rate of ruminal
ammonia production and nitrogen utiliza-
tion by ruminants - a review.J.Anim.
Sci.,28(5):689·697.
TORGERSON,O.and W.H.PFANDER,1971.Cel-
lulose digestibility and chemical composi~ion
of Missouri deer foods.;J.Wildl.Mgmt,
35(2):221-231.
ULLREY,D.E.,W.G.YOUATT,H.E.JOHNSON.
P.·K.KU and L.D.FAY,1964.Digestibility
of cedar and aspen browse for the white-tail-
ed deer.J.Wildl.Mgmt,28(4):791-797 .
261
ULLREY.D.E.,W.G.YOUATT,H.E.JOHNSON,
L.D.FAY and B.E.BRENT,1967.Digesti-
bility of cedar and jack pine browse for the
white-tailed deer.J.Wildl.Mgmt,31(3)448-
454,
ULLREY,D.E.,W.G.YOUATT,H.E.JOHNSON,
L.D.FAY,B.E.BRENT and D.E.KEMP.
1968.Digestibility of cedar and balsam
fir browse for the white-tailed deer,J.Wildl.
Mgmt,32(1):162-171.
ULLREY,D.E.,W.G.YOUATT,H.E.JOHNSON,
l.D.FAY,B.l.SCHOEPKE and W.T.MAGEE,
1969.Digestible energy requirements for win-
ter maintenance of Michigan white-tailed does.
J.Wildl.Mgmt,33(3):482-490.
ULLREY,D.E.,W.G.YOUATT,H.E.JOHNSON,
l.D..FAY,B.L.SCHOEPKE and W.T.
MAGEE,1970.Digestible and metabolizable
energy requirements for winter maintenance
of Michigan white-tailed does.J.Wild.Mgmt,
34(4):863-869.
ULLREY,D.E.,W.G.YOUATT.H.E.JOHNSON,
L.D.FAY,D.B.PURSER,B.L.SCHOEPKE
and W.T.MAGEE.1971.Limitations of win-
ter aspen browse for the white-tailed deer.
J.Wildl.Mgmt,35(4):732-743 .
VERME,l.J.,1970,Some characteristics
of captive Michigan moose.J.Mammal.,
51 (2):403·405.
WALDO,D.R.,R.W.MILLER,M.OKAMOTO
and l.A.MOORE,1965.Ruminant utiliza-
tion of silage in relation to hay.pellets.and
hay plus grain.I.Composition,digestion.
nitrogen balance,intake,and growth.J.Dairy
Sci.,48(7):910-916.
WARD,A.L.,1971.In vitro digestibility of elk
winte.r forage in southern Wyoming.J.
Wild/.Mgmt,35(4):681-688.
WELLER,R.A.,A.F.PILGRIM,and F.V.GRAY,
1969.Volatile fatty acid production in the ru-
men of the grazing sheep:its use as
an indicator of pasture val~e,Sr.J.Nutr.,
21:97-111.
WESLEY,D.E.,1969.Energy flux and water
kinetics in pronghorn antelope,p.142-151 In:
J.A.Bailey and J.G.Nagy (eds),Recent
advances in wildlife nutrition.Colorado St.
Univ.,178 p.
WESTON,R.H.and J.P.HOGAN.1967.The
tranfe.r of nitrogen from the blood to the ru-
men in sheep.Aust.J.bioi,Sci.,20:967-973.
WESTON,R.H.and J.P.HOGAN,1968a.The
digestion of pasture plants by sheep.I.Ru-
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262 LE NATURALISTE CANADIEN, VOL. 101, 1974
minal production of volatile fatty acids by
sheep offered diets of ryegrass and forage
oats. Aust. J. agric. Res., 19:419-432.
WESTON, R. H. and J. P. HOGAN, 1968b. Fac-
tors limiting the intake of feed by sheep.
IV. The intake and digestion of mature rye-
grass. Aust. J. agric. Res., 19: 567-576.
WESTON, R. H. and J. P. HOGAN, 1968c. The
digestion of pasture plants by . sheep. fl.
The digestion of ryegrass at different stage
of maturity. Aust. J. agric. Res. 19: 963-979.
WHITTOW, G.C., 1971. Unguiates. p. 191-281. lr
G. C. Whitlow (ed.). Comparative physiology c
thermoregulation, val. 2, Mammals. Academi
f:>ress, New York, 410 p.
WOOD, A. J., MeT. COWAN and H. C. NORDA'r
1962. Periodicity of growth in ungulate
as shown by deer of the genus Odocoileus
Can. J. Zoo/., 40(4): 593-603.
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