Supplementing Range Forage 
WELDON O. SHEPHERD and RALPH H. HUGHES? 
Supplementing the range diet in order to 
better meet the nutritional requirements of 
livestock is one approach to more effective use 
of available range forage. Theoretically, deter- 
mining supplemental needs should involve 
straightforward calculation of balanced diets 
based on composition of the forage and on nu- 
trient standards developed by the Committee 
on Animal Nutrition of the National Academy 
of Sciences-National Research Council (193, 
1964) by Morrison (1954) and others. How- 
ever, on rangelands, the approach is compli- 
cated by extremely heterogeneous and variable 
forages, and is limited by a lack of nutritional 
information, including digestibility of range 
forages. 
Supplementation varies considerably in the 
United States in relation to regional climate 
and the associated differences in forage quality 
and livestock management. In the semiarid 
West, range soils generally are capable of sup- 
porting plants that provide high-quality forage 
during the growing season. Deficiencies may 
occur as forage matures, and these can be im- 
portant to growing animals. The clearest need 
for supplemental feeding in the West is on dor- 
mant, winter range. Substitute feeds required 
during emergencies, such as snowstorms and 
severe droughts, will not be considered as sup- 
plements in this discussion. 
The situation is quite different on pineland 
ranges of the humid South (including the 
Southeast, as used in this paper) where rela- 
tively infertile soils produce forage of limited 
quality. Nutritional levels vary seasonally, but 
deficiencies prevail most of the year. Supple- 
mentation and other practical means of provid- 
ing an adequate, yearlong diet for livestock are 
especially needed to effectively utilize range re- 
sources. 
This paper discusses several aspects of sup- 
plementing range forage to meet the nutri- 
tional levels required for commercial livestock 
production. Economic aspects (i.e., costs vs. re- 
turns) are not treated directly, but supplemen- 
tation questions are considered essentially 
economic. 
PRACTICAL CONSIDERATIONS 
Range grazing is generally an extensive live- 
stock operation based on low-cost feed; supple- 
mental feeding on range is essentially an econ- 
* Respectively, Principal Range Scientist-and Range 
Scientist, Fort Myers, Fla. The project at Ft. Myers is 
maintained by the Southeastern Forest Experiment Sta- 
tion. Headquarters for the station is at Asheville, N.C. 
omic question to be decided by balancing costs 
against additional production (Stoddart and 
Smith 1955; Cook and Harris 1968). Although 
range diets may not be optimum, supplemental 
feeding has been economical only in special cir- 
cumstances which involve minor portions of 
the total animal diet. Aside from emergency 
periods requiring substitute feeds, these special 
circumstances include protein and mineral im- 
balances that prevent animals from effectively 
using digestible nutrients. 
Type of Operation 
Throughout the United States, livestock op- 
erations have been adapted to the quality of 
available range resources in order to reduce 
needs for expensive supplementation. Produc- 
ing grass-fat beef or lambs requires a ration 
containing about 8 percent digestible protein 
and 65 percent total digestible nutrients 
(TDN); yearling cattle make normal growth 
on 5 to 7 percent digestible protein and about 
50 percent TDN; cows nursing calves need 
about 5 percent digestible protein and 60 per- 
cent TDN; mature, pregnant cows need 4.5 
percent digestible protein and 50 vercent TDN 
(NAS-NRC 1963). Thus, a cow-calf operation, 
in which calves are sold when weaned at the 
end of the best grazing period, has been consid- 
ered the most practical period for utilizing 
range of limited quality much of the time, be- 
cause mature, nonlactating animals subsist on 
low-quality range better than do growing ani- 
mals with higher nutritional requirements. 
Southern ranges are used almost entirely in 
cow-calf operations. In the West, practical al- 
ternatives include production of stocker and 
feeder or even grass-fat livestock, depending 
largely on the nutritional level of available 
range forage. Alternatives might be increased 
with development of new supplemental feeding 
methods, but other approaches to coping with 
limited forage quality continue to warrant con- 
sideration. 
Minimizing Supplement Needs 
Where possible, adjusting the grazing period 
to coincide with the growth period of main for- 
age plants optimizes diet quality and minimizes 
need for supplementation. In the mountainous 
West, shifting livestock seasonally to ranges 
having different growth periods associated 
with elevation results in optimum use of for- 
age. In other regions, some opportunities exist 
for beneficial adjustment of grazing season 
among range types, such as between tobosa 
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