The relative digestibilities of the cellulose of 
alfalfa and timothy, determined when the fistu- 
lated deer was on a diet of natural food in an- 
other phase of the study, are also shown in 
table 6. In that phase, the deer was allowed to 
roam freely and to eat ad libitum in the wood- 
lot surrounding the deer pens. This phase was 
begun in the fall when much leafy browse was 
available, and continued until after frost, when 
some acorns had fallen. Alfalfa hay was made 
available to supplement the diminishing supply 
of browse after frost. Nylon bag samples of 
red maple and black cherry browse, and of the 
alfalfa and timothy mentioned above, were sus- 
pended in the rumen for 48-hour digestion pe- 
riods. Two trials were run on each forage, in 
separate series, so that several days elapsed be- 
tween duplicate trials on a given sample. 
Values in table 7 represent means of the dupli- 
eate trials. It is apparent from the results 
(table 7) that in both species of browse the 
percentage of cellulose digestion is directly re- 
lated to the percentage of crude protein, and is 
inversely related to cellulose content. 
TABLE 7.—Composition and digestibility 
of browse samples, using the nylon bag 
method, and with deer on a natural diet 
Item Twig Crude Cellulose Cellulose 
section protein digested 
Inches Percent Percent Percent 
Red maple ______ 1-2 6.72 30.3 49.2 
Dome aoe 2-3 6.06 31.2 43.6 
DOVES isa 0 3-6 5.65 37.1 30.4 
Dor 22 te 256-9 4.94 41.1 17.8 
Do 29-112 4.62 41.8 17.0 
Black cherry __ Bud 17.38 13.7 52.3 
Do 
es Ses ta oe 0-1 14.40 21.0 34.0 
Dore ss eee 1-2 11.74 22 31.1 
Dobe Be Nee He 2-3 10.21 30.0 27.1 
Do 3-6 7.45 32.7 19.3 
Dose I= 6-9 5.86 37.4 16.3 
DD) Opa ee OLD, 4.91 41.3 13.2 
Tmothy.“hay= =o. = 2.2. eee Dues 51.7 
AU ialtatehayar teow 228 ke knee 60.7 
SUMMARY 
Determination of the nutritive values of for- 
age species is only one task in a research pro- 
cess that can lead to scientific management of 
the game food resource on a unit of game 
range. 
Available literature relating to nutrient 
composition of deer forage species reveals a 
lack of data from which to determine relation- 
ships useful in computing or predicting nutri- 
tive value or carrying capacity of deer range 
units. 
Reports of studies of the digestibility of for- 
age species indicate the importance of develop- 
ing small-scale laboratory tests for evaluating 
forages used by wild ruminants. Since many 
forage samples are to be evaluated, the meth- 
ods to be developed must permit rapid determi- 
nation of the chemical characteristics of small 
samples which represent nutritive value (di- 
gestibility) with a reasonable degree of confi- 
dence. 
Crude protein content may be an important 
index of the feeding value of forages. The 
crude protein content of black cherry and red 
maple browse was determined for plants grow- 
ing under different conditions. Differences in 
crude protein content due to geographical loca- 
tion or to origin of growth on the plant— 
(terminal vs. lateral twigs) appeared to be 
slight. There was a rather definite pattern of 
distribution of crude protein in twigs, the 
highest level occurring in the bud, with a sharp 
reduction to the first l-inch section of twig. 
The level declined gradually with each suc- 
ceeding section of the current annual growth. 
The level of crude protein increased in the 
distal portions of dormant twigs as the growing 
season approached. 
It was determined that the digestive capaci- 
ties of sheep and deer were similar enough to 
justify the use of sheep to represent both 
animals in digestion trials that are needed to 
establish relationships between actual nutritive 
values and small-sample evaluations. 
The in vivo nylon bag technique appears sat- 
isfactory for determining relative digestibility 
of forage samples, and it shows promise as an 
intermediate step in the calibration of other 
methods involving only chemical analysis of 
the forage. 
LITERATURE CITED 
Adams, R. S., Moore, J. H., Kesler, E. M., and Stevens, 
G. Z 
1964. New relationships used in estimating TDN 
content of forages from chemical composi- 
tion. J. Dairy Sci. 47: 1471. 
Alkon, Philip U. 
1961. Nutrition and acceptability values of hard- 
wood slash as deer browse. J. Wildlife Man- 
age. 25: 77-81. 
Bratzler, J. W. 
1951. A metabolism crate for use with sheep. J. Ani- 
mal Sci. 10: 542-601. 
Cowan, R. L., Hartsook, E. W., Whelan, J. B., Long, T. 
A., and Wetzel, R. S. 
1968. A cage for metabolism and radioisotope stud- 
ies with deer. J. Wildlife Manage. In press. 
Dewitt, James B., and Darby, James V., Jr. 
1955. Changes in nutritive value of browse plants 
following forest fires. J. Wildllife Manage. 
19: 65-70. 
Dietz, Donald R., Udall, R. H., and Yeager, Lee E. 
1962. Chemical composition and digestibility by mule 
deer of selected forage species, Cache la 
Poudre Range, Colorado, Col. Game and 
Dep. Tech. Publication 14, 89 pp. 
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