| Material Information
||The use of vitamin A in beef cattle rations
||1 folded sheet (6 p.) : ; 23 cm.
||Pace, J. E
Cunha, T. J ( Tony Joseph ), 1916-
University of Florida -- Agricultural Extension Service
||Agricultural Extension Service, University of Florida,
Agricultural Extension Service, University of Florida
||Place of Publication:
||Beef cattle -- Feeding and feeds -- Florida ( lcsh )
Vitamin A in animal nutrition -- Florida ( lcsh )
||government publication (state, provincial, terriorial, dependent) ( marcgt )
non-fiction ( marcgt )
||Statement of Responsibility:
||J.E. Pace, T.J. Cunha.
||"May, 1963"--P. 6
| Record Information
||University of Florida
||University of Florida
||All rights reserved by the source institution and holding location.
||oclc - 83878503
the use of
vitamin A in
J. E. PACE
S T. J. CUNHA
AGRICULTURAL EXTENSION SERVICE
University of Florida
THE USE OF VITAMIN A
IN BEEF CATTLE RATIONS
J. E. Pace and T. J. Cunha
During the last few years experimental work
has demonstrated that Vitamin A deficiency
in beef cattle rations is more widespread than
once realized. Rations once thought to provide
adequate amounts of this important vitamin
were either inadequate, or the cattle failed to
utilize efficiently the Carotene (Provitamin A)
present in the ration.
Beef cattle obtain Vitamin A from the in-
gestion of carotene present in feeds. Vitamin
A, as such, does not occur in feedstuffs of plant
origin. The carotene is converted into Vitamin
A in the intestinal wall of cattle.
Symptoms of Deficiency
One of the primary symptoms of Vitamin
A deficiency is night blindness. Cattle suffer-
ing from night blindness cannot see in dim
light and frequently bump into unseen objects.
Pneumonia and other respiratory ailments
accompany Vitamin A deficiency. This is due
to the fact that one of the primary functions
of Vitamin A is to keep mucous: membranes in
a healthy condition. When a deficiency of the
vitamin exists these tissues become weakened
and changed. Thus, harmful bacteria can easily
invade the body.
Other symptoms of Vitamin A deficiency
Muscular incoordination and staggering
Reduced feed intake, rate of gain and
* Convulsive seizures.
Edema or swelling, especially in the
Excessive watering of the eyes.
Lameness in the hock or knee joints.
Dry hair coat.
Decline in sexual activity in bulls.
Decrease in number of sperm produced.
Decrease in motility of sperm.
Low conception rate in breeding herd.
Birth of weak, dead or blind calves.
Why the Reappearance of Vitamin A
It is not entirely clear why Vitamin A de-
ficiency is now being recognized with rations
previously thought to be adequate in this vita-
min, but there are some possible explanations.
There is evidence that the use of higher
levels of nitrogen fertilization may be partially
responsible. High rates of nitrogen fertilization
result in high levels of nitrates in some plants.
High levels of nitrates in feedstuffs could
either interfere with the ability of the animal
to convert carotene to Vitamin A, or could
increase the need for Vitamin A-or both.
However, a high level does not always increase
the need for Vitamin A.
Cattle are not as efficient in converting caro-
tene to Vitamin A as once supposed.
Rations used for fattening cattle now contain
less roughage and thus the rations contain
Cattle are being fed at a younger age which
necessitates feeding them over a longer period
of time. As a result, the cattle are more apt to
become depleted of Vitamin A.
More corn that has been stored for longer
periods is now being fed. Storage gradually
lowers the carotene content of corn.
The thyroid gland is concerned with the con-
version of carotene into Vitamin A. Factors
such as feed, weather conditions, housing and
breeding may affect thyroid activity, and if
thyroid activity is inhibited or depressed, caro-
tene conversion is decreased.
There is a possibility that silage contains a
factor or factors that interferes with the con-
version of carotene. Cattle wintered on silage
appear to be more susceptible to Vitamin A
deficiency when placed in the feed lot.
Warm or hot weather apparently increases
the Vitamin A requirement. As more cattle
are fed during the summer months, more may
exhibit Vitamin A deficiency.
It is possible that breed or genetic differ-
ences affect the ability of cattle to convert
carotene into Vitamin A.
Recommended Feeding Levels
Steers.-Recommendations with regard to the
use of Vitamin A in beef cattle rations vary
considerably-from 5,000 to 30,000 Interna-
tional Units (I.U.) per steer daily. A good "rule
of thumb" is to feed 3,000 International Units
daily per 100 pounds of body weight. This
recommendation can be exceeded within rea-
sonable limits. Most men who feed steers allow
20,000 to 30,000 International Units of Vita-
min A per steer daily. The cost of feeding a
Vitamin A supplement is negligible.
Breeding Herd.-During the wintering per-
iod young herd replacements and pregnant cows
and heifers should be fed from 20,000 to 40,000
International Units of Vitamin A per head
daily. The higher level is recommended. 40,000
International Units per head daily will meet
the requirements of bulls. Cattle grazing green
temporary crops during the winter months
should not need additionnl Vitamin A, although
such cattle were benefited by Vitamin A sup-
plement in one trial at Belle Glade.
Newly Purchased Stocker and Feeder Cattle.
-Stress is placed on cattle when they are
moved from one ranch to another. Newly pur-
chased cattle are very susceptible to respir-
atory ailments. In addition to taking the usual
precautions, new cattle should be fed at least
100,000 International Units of Vitamin A per
head daily for the first seven days to two
weeks. After this period if no troubles have
developed, the recommended daily level for
steers may be started
Form of Vitamin A to Use
Stable Vitamin A Premixes are available in
powdered form. They do not appreciably de-
teriorate upon storage or when mixed with
other feeds. The potency of these premixes will
vary from 5,000 International Units per gram
to several hundred thousand International
Units per gram.
To insure ease of mixing and a complete
dispersion of the Vitamin A Premix in the
ration or feed, it is recommended that a sup-
plement of low potency be used. The average
cattleman and small custom feed mixer usual-
ly does not have the equipment necessary to
incorporate high potency premixes in the feed.
Should I Feed Vitamin A?
Beef cattle can store large amounts of Vita-
min A in their liver and other tissues. The
length of time that it takes an animal to be-
come depleted depends on this storage.
Young animals have a higher requirement
for Vitamin A and can become deficient much
sooner than mature animals. Borderline de-
ficiencies probably exist in many instances
Deficiencies are most apt to occur late in
winter preceded by a poor grazing season the
There is much to learn about the need for
supplementing beef cattle rations with Vitamin
A. Since the cost of adding Vitamin A to a
ration is negligible and no harm can result (if
recommendations are followed), it is recom-
mended that cattlemen give serious considera-
tion to trying Vitamin A in their cattle rations.
This applies especially to steers in dry lot, and
to growing and breeding cattle during the
wintering period when green forage is not
COOPERATIVE EXTENSION WORK IN
AGRICULTURE AND HOME ECONOMICS
(Acts of May 8 and June 30, 1914)
Agricultural Extension Service, University of Florida,
Florida State University and
United States Department of Agriculture, Cooperating
M. 0. Watkins, Director