Everglades Station Mimeo 63-17 April, 1963
BALANCING PASTURES WITH PROPER FEED SUPPLEMENTS a
Herbert L. Chapman, Jr.
Everglades Experiment Station
The basic feed for any cattle operation in Florida should be pasture.
This raises three questions.
1. What are the nutritional requirements of beef cattle;
2. How much is furnished by pasture?
3. How can nutrients not furnished by pasture best be supplied?
Factors affecting nutritional requirements of beef cattle.
The nutritional requirements of beef cattle are affected by age, sex, con-
dition of the animal, stage of life cycle, purpose for which the animal is
being kept, genetic potential of the animal and the level of disease and para-
sites present. Cattle have a minimum nutritional requirement to maintain
normal body functions, even though they do not gain weight, have a calf or
give milk. If the minimum needs of water, protein, minerals, carbohydrates and
fats are not provided the animal will supply its needs by depleting its body
tissues. This necessitates the use of properly-balanced supplemental feed and
mineral mixtures for cattle grazing pastures lacking in the required nutrients.
When the animal uses its body stores of nutrients there will be a loss of body
weight, lowered reproduction, poorer weaning weights, and the usual deficiency
symptoms in muscles, bone and blood tissue.
Maintenance requirements for many nutrients are roughly related to animal
size. The rate of gain will directly effect the amount of nutrients needed.
There will be a greater need by cows for many nutrients the last 2 months of
pregnancy and first 4 months of lactation. (Failure to have these available
will result in thin cows, thin calves, breeding failures and possibly deaths.)
Some animals have the ability to utilize available nutrients more efficiently
than others and will need less feed to gain weight. The presence of disease
or parasites will place an additional stress on the animal and may reduce
utilization of available nutrients. All of these'factorp ae important.
Generally, the major nutrients that cattlemn inF rida should be con-
cerned about in supplemental feeds are proteini''ngy (carbohydrates and fats),
phosphorus, copper, cobalt and Vitamin A.
a/ Prepared for presentation at 1963 Vegetable and Pasture Field Day,
Indian River Field Laboratory, Fort Pierce, Florida.
Suggested rules-of-thumb for estimating needed levels of various nutrients.
The exact requirement of beef cattle for the various nutrients will vary,
as already mentioned, with age and condition of the animal, as well as other
factors. It is difficult to make a blanket statement that will apply to all
conditions. However, the suggested "rules-of-thumb" listed below have been
cited from or calculated from research reports (1, 2, 3) and will be satis-
factory in most cases. It should be emphasized that these are offered to be
used as a guide and may require slight modifications under each individual set
1. Total digestible nutrients (daily needs):
(a) Maintenance of growing animals:
Body weight (Ibs) T.D.N. (Ibs)
(b) Gain 3.5 pounds per pound of animal gain
(c) Pregnant cows 10.0 pounds
(d) Nursing cows 16.8 pounds
2. Digestible protein (daily needs)
(a) Fattening cattle 0.2 percent of body weight
(b) Nursing cows 0.15 percent of body weight
(c) Pregnant females 0.10 percent of body weight
(d) Calves and yearlings to gain 1.0 lb/day 0.13 to 0.15 percent
of body weight
(a) Should be a minimum 0.20 percent P in fattening rations and
forages, on dry matter basis.
(b) For maintenance, 0.02 times body weight, stated as grams.
(a) Organic soils 1/8 gram/animal/day
5. Cobalt .07 to .10 milligrams/100 pounds of body weight
6. Vitamin A 2,000 to 3,000 I.U./100 pounds of body weight where it
is suspected to be needed.
Nutritional adequacy of permanent forages.
The nutritional quality of permanent forages is affected by type of soil,
type of forage, fertilization program, degree of grazing, maturity of forage,
amount of rainfall and season of the year. For example, differences exist in
the chemical composition of pasture grasses on organic soils and mineral soils.
Generally, the crude protein of well-managed grass on organic soil will seldom
fall below 10 percent on a dry matter basis. On mineral soils unless grasses
are provided heavy nitrogen application or planted with legumes the crude pro-
tein will more often be less than 10 percent and this will decrease sharply in
fall and winter months. Differences in mineral analyses also exist between
grasses grown on the two types of soils.
Differences exist in the productivity of grasses, both on organic and
mineral soils. Also legumes have a different productivity. Grass-legume mix-
tures, on sandy soils, generally will provide an increase in amount of avail-
able dry matter, crude protein and phosphorus per acre, resulting in greater
production per cow, than will grass alone.
Carrying capacity of permanent grasses is greatly reduced during
fall and winter months, both on organic and mineral soils. If cattle are not to
be penalized during this period inventories must be reduced or supplemental feed
provided. Changes in plant maturity coincide with the fall and winter months
and unless nitrogen application or legumes are used on mineral soils the protein
content of the grass will decrease, fiber content will increase and total
digestible nutrients will decrease. Unless supplemental nitrogen is provided
the protein content of permanent grasses on mineral soil should be conr:~.dered
nearly undigestible in the fall and winter months. Grass pastures on ,organic
soils, if not severely damaged by cold, drowth or excessive rainfall, will not
have as large a change in chemical composition as those on mineral coils. How-
ever, carrying capacities will be reduced 60 to 65 percent. Under extreme con-
ditions protein and energy may both be limiting factors on organic soils but
generally it would appear that energy is the most important to consider in a
supplemental feed for cattle.
The nutritive value of pasture forages is difficult to assess. Chemical
analyses of the forage can be used as an index. Another factor to consider is
the leaf-stem ratio. The digestibility of the forage is closely related to the
ratio of leaf to stem.. More leaf than stem usually indicaies a relatively
high digestibility. More stem than leaf usually indicates low digestibility.
Supplemental feeds to use.
Factors affecting the choice of supplemental feed to use include type of
supplemental feed, type of forage and physical facilities available and also
the relative price of feed and cattle.
Protein supplements that can be used include cottonseed meal, soybean
oil meal and peanut oil meal. Energy feeds that are available in Florida, in-
clude dried citrus pulp, blackstrap molasses, citrus molasses, corn, ground
snapped corn and sorghum grain. Other ingredients can be shipped in but it is
often more economical to utilize locally-produced feeds. It may be more econ-
omical to utilize a single material or it may be more desirable to use a com-
bination of ingredients. This will depend upon the adequacy of pasture forage,
costs of the feeds, the relative price of the cattle and whether feed additives
are to be administered.
In south Florida, dried citrus pulp, blackstrap molasses and ground snapped
corn have each been used as the only feed for beef cattle. Properly balancing
these ingredients will increase gain but also increases feed costs. A few
rations that have been used successfully on pastures in south Florida are pre-
sented below. A number of modifications may be made to these suggestions and a
satisfactory pasture supplement provided. Advantage should be taken of cost as
well as nutritional factors when designing a supplemental feed for beef cattle.
Supplemental feeds should usually include Vitamin A, stilbestrol and adequate
Examples of concentrate feeds that have been
used successfully on good pasture.
Protein TDN Rations
Ingredient 1 2 3 4 5 6
Ground snapped corn 7.5 69 45 30 85 40 30 80
Dried citrus pulp 6.0 75 40 30 40 25
Corn, (c(Cracked, rolled or ground) 8.7 80 25 25
Cottonseed meal, (41L ) a/ 41.0 72 15 15 15 18 18 18
Molasses (cane or citrus) b/
Urea-262 2 2 2
Total 100 100 100 100 100 10
a/ Soybean oil meal and cottonseed oil meal can be used interchangeably in
b/ Molasses may be added up to 15 percent of ration, substituted for ground
snapped corn, dried citrus pulp, etc.
Suggested pasture supplemental feeding programs
(1) Replacement heifers.
(a) On organic soil, and on grass-legume pastures on mineral soil -
3 to 5 pounds daily of a high energy feed, with a 12 to 14 percent
crude protein during late fall and winter.
(b) On sandy soil same feeding schedule of a high-energy supplement
having a minimum of 18 to 20 crude protein, or 1 pound of a 40
percent supplement plus 3 to 4 pounds of a high energy feed.
(2) Stockers. The type of program followed will affect the supplemental
feeding program required. It is suggested that weanling steers should
not be on inventory for more than 12 months and yearling steers for
not more than 6 to 8 months. If the entire period is spent on pasture
it will be necessary to supplement pasture with 0.8 to 1.0 percent of
the animals weight as supplemental feed. On good pasture on organic
soil and grass-legume mixtures on sandy soils, protein level need not
exceed 12 percent. On grass pastures on mineral soil it may be
necessary to increase the protein content of the supplemental feed to
approximately 18 to 20 percent during fall and winter months. The
supplemental feed should be high in total digestible nutrients.
(3) Brood cows.
(a) Organic soil feed 3 to 5 pounds of a high energy feed daily
from November 15 until bulls are removed. If bulls are left in
all year feed from approximately November 15 to April 15. The
protein level need not exceed 10 percent. If a supplement is
used on grass-legume pastures on sandy soils the same type is
(b) Sandy soils, without legumes feed 3 to 5 pounds daily of a 18
to 20% supplement, or 2 to 3 pounds of a high energy feed plus
1 to 2 pounds of a 40 percent protein supplement.
1. Brody, S. Bioenergetics and growth. Reinhold Publishing Corp.,
2. Maynard, L. A. and J. K. Loosli. Animal nutrition, 4th Edition.
McGraw Hill Book Co., Inc. New York. 1956.
3. National Academy of Sciences. Nutrient requirement of domestic
animals. Number 4. Nutrient requirement of beef cattle. 1958.
EES Mimeo 63-17