| Abstract |
- Most of the nutritionally related difficulties of winter feeding
deer apparently result from either poor acceptability of artificial
rations or digestive disturbances that result from feeding starved
animals feeds to which they are not accustomed. Reported in this
thesis are studies conducted with both captive and wild deer concerning
acceptability of artificial rations and on the affects of feeding
various rations to starving deer.
The relative acceptability of various physical forms of grains--
pelleted, rolled, and whole--and of the common commercial concentrates
was determined with captive black-tailed deer. When given a
choice between the three forms, the deer markedly preferred the
pelleted form in each of three separate trials with corn, barley and
oats. The intake of the pelleted form comprised 79.6 percent, 77.9
percent, and 100 percent in the barley, corn and oat trials, respectively. The rolled form was rejected in the oat trial and comprised
20.4 percent and 22.1 percent of the total intake in the barley
and corn trials, respectively. The whole form was rejected in all
three trials.
Nine common commercial concentrates were offered ad libitum,
cafeteria style in various combinations, to the deer in a series of
trials. Consumption rates indicated that corn, wheat and soybean
meal were preferred by the deer with barley and oats being selected in
limited amounts. Beet pulp, cottonseed meal, linseed meal, and peas
were rejected by the deer if given a choice of more preferred feedstuffs,
but, if not given a choice then they would consume limited
amounts of these.
Two palatability studies were conducted whereby browse plants
that were considered to be highly palatable to deer were fed in combination
with a cereal grain considered to be of low palatability. The
relative intake of the browse-grain mixture was compared to the intake
of the grain alone. The browse-grain mixtures were mountain
mahogany-oats and blackberry-barley. With one exception, there was
uniform rejection of treatments containing browse. The deer were
able to detect browse in the feedstuffs at levels of 1 percent browse.
Two levels of blackberry leaves (1 and 5 percent) and 3 levels of
mahogany (1, 5 and 10 percent) all resulted in marked rejection. One
mule deer was used in the mahogany-oat trial and there is some indication that this deer may have preferred the mixture. All of the
other data which were taken from black-tailed deer indicate that low
levels of dried mountain mahogany and blackberry in oats and barley,
respectively, will decrease intake.
The effects of abrupt dietary changes on mule deer and black-tailed
deer, following periods of malnutrition were investigated. Four
separate trials were conducted. These were, (1) changing five mule
deer fawns from a browse diet to alfalfa ad libitum, (2) changing one
mule deer from alfalfa to a complete concentrate ration ad libitum,
(3) changing one mule deer from alfalfa to a green grass diet ad
libitum, and (4) changing 18 black-tailed deer and two mule deer from
grass hay to high protein diets. A total of three deer died after these
dietary changes, but the ensuing necropsies did not reveal conclusive
evidence that would indicate that any of the deer died as a result of the
ration changes. Diarrhea was prevalent in the high protein ad libitum
rations.
Mule deer were observed while using feeding stations in Eastern
Oregon during a severe winter. Rumen contents were taken and body
condition was determined by necropsy on 16 deer that died at the feeding
site and from 11 live deer that were sacrificed and which had
access to the feeders. The results indicated that all deer to die on the
feeding site died of starvation. The ingesta from the deer had high
acid detergent fiber and cellulose levels, both of which were significantly related to lowered in vitro dry matter digestibility of
the rumen samples. There was a significant negative correlation
between body condition and in vitro dry matter digestibility of the
rumen contents.
Two herds of mule deer were artificially fed during a severe
winter in Eastern Oregon. Two rations were fed to the deer without
causing severe digestive upset, although one of the rations, containing
45 percent soybean meal, caused the deer to develop diarrhea for a
brief period. Feed cost estimations indicated that it costs $0.07 and
$0.11 per deer-day for the two rations fed during this study. It is
suggested that creep feeders may offer a method of feeding fawns
separate from adults which would make more economical use of the
feed. A possible advantage of winter feeding is discussed.
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