NationalLibraryOfScotland/medical-history-of-british-india huggingface dataset:
NOTE
Far Eastern Association of Tropical Medicine
10TH CONGRESS
THE Tenth Congress of the Far Eastern Association of Tropical Medicine
will be held at Hanoi (Address " Igesante ", Hanoi, Indochine) from the
24th to 30th November, 1938.
All licensed Medical, Dental and Veterinary practitioners are eligible
for membership. The membership fee for the period 1934-38 is £3 (or
Rs. 40-2-0) and should be paid to the Local Provincial Secretaries of the
Far Eastern Association of Tropical Medicine, to whom the names of members
in their areas should be submitted. The members are also requested to in-
form the Local Secretaries whether they propose attending the Congress.
The titles of any papers which it is proposed to place before the Congress
should be submitted to the Local Secretaries at an early date. Arrange-
ments will be made for the reading at the Congress of any paper submitted
by a member who is unable to attend.
The Ninth Congress held at Nanking in 1934 decided that sections on
Food Problems and Sanitary Measures with reference to Sewage and Garbage
Disposal should also be added to the programme of the Tenth Congress.
Further information may be obtained from the Local Provincial Sec-
retaries or from Lt.-Col. G. Covell, M.D., D.P.H., D.T.M. & H., F.R.E.S.,
I.M.S., Director, Malaria Institute of India, and Local Secretary of the Far
Eastern Association of Tropical Medicine for Government of India, Kasauli,
Punjab, or the Honorary General Secretary, Far Eastern Association of
Tropical Medicine, Parapattan 10, Batavia (Centrum) Java.
( 163 )
L
CORRIGENDA
The Indian Journal of Veterinary Science and Animal Husbandry, Vol. VIII,
Part I, (March, 1938).
Page 36, Table II, 5th, 6th and 8th columns—
For ' 100 ' read ' <100 '.
Page 37, Table III, 4th column—
For ' 50 ' read ' <50 '.
Page 38, Table IV, 6th column, last figure—
For ' 25 ' read ' <25 '.
Page 39, Table V, 3rd, 4th, 5th and 6th columns—
For ' 50 ' read ' <50 '.
( 164 )
PUBLICATIONS OF THE IMPERIAL COUNCIL
OF AGRICULTURAL RESEARCH, INDIA
[Prices are inclusive of packing and Indian postage]
1. Agriculture and Live-stock in India
ICAR. 1
A bi-monthly journal of agriculture and animal husbandry for the general
reader interested in agriculture or live-stock in India or the Tropics.
(Established 1931. Published in January, March, May,
July,
September and November. Prepayable subscription Rs. 6 or 9s.
9d. per annum. Price per part Rs. 2 or 3s. 6d.). Volumes I to VII complete
are available.
2. The Indian Journal of Agricultural Science
ICAR. 5
A bi-monthly scientific journal of agriculture and the allied sciences mainly
devoted to the publication of the results of original research and field
experiments. (Established 1931. Published in February, April, June,
August, October and December. Prepayable subscription Rs. 15 or
24s. per annum. Price per part Rs. 3 or 5s. 3d.). Volumes I to VII
complete are available.
3. The Indian Journal of Veterinary Science and Animal Husbandry
ICAR. 6
A quarterly journal for the publication of scientific matter relating to the
health, nutrition and breeding of live-stock. (Established 1931. Pub-
lished in March, June, September and December. Prepayable subscrip-
tion Rs. 6 or 9s. 9d. Price per part Rs. 2 or 3s. 6d.). Volumes I to VII
complete are available.
4. Scientific Monographs of the Imperial Council of Agricultural Research
ICAR. 10.1
ICAR. 10.2
ICAR. 10.3
ICAR. 10.4
ICAR. 10.5
ICAR. 10.6
No. 1. The Fungi of India, By E. J. Butler, C.I.E., D.Sc., M.B., F.R.S ,
and G. R. Bisby, Ph. D. (1931). Price Rs. 6-12-0 or 11s.
No. 2. Life-histories of Indian Microlepidoptera, Second Series : Alucitidæ
(Pterophoridæ, Tortricina and Gelechiadæ), By T. Bainbrigge Fletcher,
R.N., F.L.S., F.E.S., F.Z.S. (1932). Price Rs. 3-4-0 or 5s. 6d.
No. 3. The Open Pan System of White-Sugar Manufacture, By R. C. Srivas¬
tava, B.Sc. (1935, 2nd edition.) Price Rs. 3-2-0 or 5s. 6d.
No. 4. Life-histories of Indian Microlepidoptera: Cosmopterygidæ to
Neopseustidæ, By T. Bainbrigge Fletcher, R.N., F.L.S., F.E.S., F.Z.S.
(1933). Price Rs. 4-8-0 or 7s. 6d.
No. 5. The Bombay Grasses, By E. J. Blatter, S. J., Ph. D., F.L.S. and C.
McCann, F.L.S. Illustrated by R. K. Bhide. (1935). Price Rs. 20-12-0
or 32s. 6d.
No. 6. Helminth Parasites of the Domesticated Animals in India, By G. D.
Bhalerao, M.Sc. (1935). Price Rs. 7-12-0 or 13s. 3d.
( 165 )
166
I.
C. A. R. PUBLICATIONS
ICAR. 10.7
ICAR. 10.8
ICAR. 10.9
ICAR. 10.10
ICAR. 10.11
ICAR. 10.12
No. 7. Influence of Manures on the Wilt Disease of Cajanus indicus Spreng
and the Isolation of Types Resistant to the Disease, By W. McRae,
M.A., D.Sc. (Edin.), F.L.S. and F. J. F. Shaw, D.Sc. (Lond.), A.R.C.S.,
F.L.S. (1933). Price Rs. 2-4-0 or 4s. 3d.
No. 8. The Silk Industry of Japan with Notes on Observations in the United
States of America, England, France and Italy, By C. C. Ghosh, B.A.,
F.E.S. (1933). Price Rs. 4 or 6s. 9d.
No. 9. Mechanical Cultivation in India. A History of the Large-scale
Experiments carried out by Burmah-Shell Oil Storage and Distribut-
ing Company of India, Ltd., By C. P. G. Wade. (1935). Price Rs.
3-14-0 or 6s. 6d.
No. 10. The Spotted Boll-Worms of Cotton in South Gujarat, By B. P.
Deshpande and N. T. Nadkarny, B.Ag. (1936). Price Rs. 5-14-0
or 9s. 6d.
No. 11. Investigations on the Course and Distribution of the Nerves supply-
ing Levator anguli scapuli and Rhomboideus muscles and the form-
ation of the Phrenic Nerve in the Ox, with Observations on certain
Anatomical Deviations, By H. N. Chelva Ayyangar, G.M.V.C. (1937).
Price Rs. 4-10-0 or 7s. 9d.
No. 12. The Fungi of India. Supplement I. By B. B. Mundkur. (In the
Press.)
5. Miscellaneous Bulletins of the Imperial Council of Agricultural Research
ICAR. 8.1
ICAR. 8.2
ICAR. 8.3
ICAR. 8.4
ICAR. 8.5
ICAR. 8.6
ICAR. 8.7
ICAR. 8.8
ICAR 8.9
ICAR. 8.10
ICAR. 8.11
No. 1. List of Publications on Indian Entomology, 1930, By the Imperial
Entomologist, Pusa. (1934). Price As. 14 or 1s. 6d.
No. 2. List of Publications on Indian Entomology, 1931, By the Imperial
Entomologist, Pusa. (1934). Price As. 8 or l0d.
No. 3. List of Publications on Indian Entomology, 1932, By the Imperial
Entomologist, Pusa. (1934). Price As. 12 or 1s. 3d.
No. 4. Host Plant Index of Indo-Ceylonese Coccidae, By S. Ramachandran,
L.Ag. and T. V. Ramakrishna Ayyar, B.A., Ph.D., F.Z.S. (1934).
Price Rs. 1-10-0 or 2s. 9d.
No. 5. List of Publications on Indian Entomology, 1933, compiled by the
Imperial Entomologist, Pusa. (1935). Price As. 9 or 1s.
No. 6. Bee-keeping, By C. C. Ghosh, B.A., F.E.S. (3rd Edition.) (1936).
Price Rs. 1-14-0 or 3s. 3d.
No. 7. List of Publications on Indian Entomology, 1934, compiled by the
Imperial Entomologist, Pusa. (1935). Price Rs. 1-2-0 or 2s.
No. 8. Selected Clinical Articles, Part I, By G. K. Sharma, G.P.V.C. and
R. L. Kaura, B.V.Sc., M.R.C.V.S. (1936). Price As. 8 or l0d.
No. 9. Statistical Methods and their Application to Agronomy : A biblio-
graphy, By K. K. Guha Roy. (1936). Price Rs. 2-2-0 or 4s.
No. 10. Diseases of Sugarcane and Methods for their Control, By L S.
Subramaniam. (1936). Price Rs. 1-14 or 3s. 3d.
No. 11. Tables of Standard Errors of Mendelian Ratios, compiled by Swarn
Singh Purewal, M.Sc., Ph.D. (Cornell) and P. Krishna Rao, L. Ag.
(1936). Price As. 12 or 1s. 3d.
I. C. A. R.
PUBLICATIONS
167
ICAR. 8.12
ICAR. 8.13
ICAR. 8.14
ICAR. 8.15
ICAR. 8.15
ICAR. 8.17
ICAR. 8.18
ICAR. 8.19
ICAR. 8.20
ICAR. 8.21
No. 12. List of Publications on the Botany of Indian Crops, Part II, for
the period 1928-32, By R. D. Bose. (1936). Price Rs. 3-6-0 or 6s. 9d.
No. 13. Two New Statistical Tables based upon Fisher's ' t ', By M. Vaidya-
nathan, (1936). Price As. 6 or 8d.
No. 14. List of Publications on Indian Entomology (1935), compiled by
the Imperial Entomologist, Pusa. (1937). Price Re. 1-4-0 or 2s.
No. 15. Selected Clinical Articles, Part II, By G.K. Sharma,
G.P.V.C.,
R. L. Kaura. B.V.Sc., M.R.C.V.S., S. Ganapathy Iyer, G.M.V.C.,
G. S. Khan, B.Sc. and S. Mangrulkar, M.Sc., M.R.C.V.S., D.T.V.M.
(EDIN.) (1937). Price Re. 1-4 or 2s.
No. 16. Indian Grazing Conditions and the Mineral Contents of some
Indian Fodders by P. E. Lander, M.A., D.Sc., F.I.C., I.A.S. (1937).
Price Rs. 3-14 or 6s. 9d.
No. 17. A Brief Survey of some of the Important Breeds of Cattle in India
by Col. Sir Arthur Olver, C.B., C.M.G., F.R.C.V.S., F.N.I. (1938)
Price Rs. 2 or 3s. 6d.
No. 18. Milk Records of Cattle in Approved Dairy Farms in India by
K. P. R. Kartha. (In the Press.)
No. 19. A Preliminary Annotated List of the Fruit Pests of the North¬
West Frontier Province by Hem Singh Pruthi, M.Sc., Ph.D. (Cantab.),
F.N.I., and H. N. Batra, B.Sc., Assoc. I. A. R. I. (In the Press.)
No. 20. Report on an Enquiry into the Cultivation of Cloves in India by
A. K. Yegna Narayana Iyer, M.A. (Cantab.), Dip. Agri. (In the Press.)
No. 21. Investigations on the Cold Storage of Mangoes by Dr. G. S. Cheema,
Dr. D. V. Karmarkar, M.Sc., Ph.D., A.I.I.Sc., and Mr. B. M. Joshi,
M.Sc. (In the Press.)
6. Annual Report of the Imperial Council of Agricultural Research
ICAR. 12.31
ICAR. 12.32
ICAR. 12.33
ICAR. 12.34
ICAR. 12.35
ICAR. 12.36
ICAR. 12.37
Annual Report of the Imperial Council of Agricultural Research for the
years 1929-30 and 1930-31. Price As. 12 or 1s. 3d.
Annual Report of the Imperial Council of Agricultural Research for the year
1931-32. Price As. 6 or 8d.
Annual Report of the Imperial Council of Agricultural Research for the year
1932-33. Price As. 6 or 8d. (Out of stock.)
Annual Report of the Imperial Council of Agricultural Research for the year
1933-34. Price Re. 1-8-0 or 2s. 6d.
Annual Report of the Imperial Council of Agricultural Research for the year
1934-35. Price Re. 1 or 1s. 9d.
Annual Report of the Imperial Council of Agricultural Research for the year
1935-36. Price As. 14 or 1s. 6d.
Annual Report of the Imperial Council of Agricultural Research for the year
1936-37. Price Re. 1-2-0 or 2s.
7. Agriculture and Animal Husbandry in India (called Review of Agricul-
tural Operations in India up to 1933)
ICAR. 9.29
Review of Agricultural Operations in India, 1928-29. Price Rs. 3-2-0 or
5s. 6d. (Out of stock.)
168
I. C. A. R. PUBLICATIONS
ICAR. 9.31
ICAR. 9.33
ICAR. 13-1-35
ICAR. 13-2-35
ICAR. 13.36
Review of Agricultural Operations in India, 1929-31. Price Rs. 5 or 8s.
3d.
Review of Agricultural Operations in India, 1931-33. Price Rs. 5-12-0 or
9s. 6d.
Agriculture and Animal Husbandry in India, 1933-34 and 1934-35—
Part I.—Crop Production. Price Rs. 4-14-0 or 8s.
Part II.—Animal Husbandry. Price Re. 1 or 1s. 9d.
Agriculture and Animal Husbandry in India, 1935-36. Price Rs. 4-10 or 7s. 9d.
8. Proceedings of the Board of Agriculture and Animal Husbandry
ICAR. 2
ICAR. 3
Proceedings of the First Meeting of the Animal Husbandry Wing of the Board
of Agriculture and Animal Husbandry held at New Delhi from the 20th to 23rd
February 1933, with Appendices. Price Rs. 5-14-0 or 9s. 6d.
Proceedings of the First Meeting of the Crops and Soils Wing of the Board of
Agriculture and Animal Husbandry in India held at Delhi from the 25th
February to the 2nd March 1935, with Appendices. Price Rs. 6 or 9s. 9d.
9. Miscellaneous Publications
VRI. 1
ARI.7.187
ICAR. 16
ICAR. 7
ICAR. 18
A Description of the Imperial Institute of Veterinary Research, Muktesar, and
its Sub-station, the Imperial Veterinary Serum Institute, Izatnagar, By F.
Ware, F.R.C.V.S. Price Rs. 1-4-0 or 2s.
The Production of Cigarette Tobacco by Flue-curing, By F. J. F. Shaw, C.I.E.,
D.Sc., A.R.C.S., F.L.S. and Kashi Ram. Imp. Inst. Agri. Res. Pusa Bull.
No. 187. Reprinted (1935). Price Re. 1 or 1s. 9d.
A Handbook of Statistics for use in Plant Breeding and Agricultural Problems,
By F. J. F. Shaw, C.I.E., D. Sc., A.R.C.S., F.L.S. Price Rs. 4-6-0 or 7s. 3d.
Report on the Work of the Imperial Council of Agricultural Research in Apply-
ing Sciences to Crop Production in India, By Sir John Russell, D Sc.,
F.R.S. Price Re. 1-14 or 3s. 3d.
Report on the Development of the Cattle and Dairy Industries of India, By
Norman C. Wright, M.A., D.Sc., Ph.D. Price Re. 1-8-0 or 2s. 6d.
Copies of the above publications can be had from —
The Manager of Publications, Civil Lines, Delhi and from any of the Agents, a list of
whom will be found on the inside page of the front cover.
Purchasers not residing in Asia, Africa and Australia should apply to the High Com-
missioner for India, India House, Aldwych, London. Prices include Indian
postage and packing.
Note.—When indenting please give only the symbol preceding the name of the publica-
tion.
ORIGINAL ARTICLES
THE PROBLEM OF VITAMIN-A DEFICIENCY IN THE
DIET OF FARM ANIMALS *
BY
K. C. SEN, D.Sc.
Officer-in-Charge
AND
P. A. SESHAN, B.A.
Assistant, Animal Nutrition Section, Imperial Veterinary Research Institute,
Izatnagar, U. P.
(Received for publication on 25th May 1938)
INTRODUCTION
THE discovery of the fact that the proper growth, health and reproduc-
tion of an animal involved other factors than a sufficiency of calories and
protein has shifted the centre of interest in nutritional studies from quantity
to quality. Among these accessory constituents of food, vitamin-A occupies
a most important place. Although this substance has now become deter-
minable by chemical and spectroscopical methods, our knowledge with regard
to the requirements of the various animals and the conditions favourable
to its proper utilization is so limited that the adequacy or inadequacy of
a diet has to be judged by clinical observations only.
The symptoms characteristic of avitaminosis-A are more or less well-
defined. It would, however, be interesting to notice some recent cases on
record. Fed on over-ripe timothy hay as sole roughage in addition to a
mixture containing yellow corn meal, linseed meal, soya bean meal and wheat
bran for about twelve months, four cows, negative to contagious abortion,
consistently failed to have normal calves [Converse and Meigs, 1931]. A
ration for pigs made up of white corn, buckwheat middlings, tankage and
minerals or white corn, oats, linseed oil meal, tankage and minerals resulted
in serious eye troubles, paralysis, respiratory trouble and convulsions [Long-
well and Weakley, Jr., 1932]. A sow on a vitamin-A deficient diet gave
birth to a litter of eleven pigs, all without eyeballs [Hale, 1933]. When the
mother had received a diet short in vitamin-A content before mating and
during the first thirty days of gestation, three litters of pigs were born with-
* Paper read before the Section of Veterinary Research of the Indian Science Congress,
held in Calcutta, January, 1938.
( 169 )
170
Vitamin-A Deficiency in the Diet of Farm Animals
out eyeballs or with very serious eye defects [Hale, 1935]. It was shown that
on a low vitamin-A diet, female rats were affected by a prolongation of the
gestation period, with death of foetus in utero and failure of the mechanism
of parturition, despite an abundant supply of vitamin-E [Mason, 1934, 1935].
Rabbits, guinea-pigs and albino rats developed xerophthalmia on a diet low
in vitamin-A content while one monkey out of twenty-seven developed typical
xerophthalmia with keratomalacia in both eyes [Hetler, 1934]. An adverse
effect on the prostate was seen in eight pre-puberal rats aged thirty days and
eight post-puberal ones aged 100 days all receiving a vitamin-A deficient diet.
The change was taken to indicate a failure in the secretion of the male sex
hormone. In five extreme cases of human malnutrition similar changes
were also observed [Moore and Mark, 1936]. On a ration consisting of white
corn ninety parts, fish meal seven and mineral mixture five, pigs, kept in sunlight
but with no pasture, ceased to grow after 150 days and developed muscular in¬
co-ordination with spasms, lameness, lachrymation, blindness due to ulcera
tion, inflammation and congestion of the intestinal tracts and finally succumb
ed. White corn in the diet introduced a vitamin-A deficiency, since rats fed
on it developed ophthalmia, lost weight and died even when the diet was
irradiated and supplemented with five per cent yeast. Rat experiments and
bone analysis showed that the diet was sufficient in vitamins B l , B 2 and D
[Hostetler et al, 1935].
All the disorders mentioned above are both curable and preventable
by an adequate supply of vitamin-A. The liver being the store house for
this material in the animal body, the best sources of vitamin-A must neces
sarily be the livers themselves or their extracts properly concentrated.
Escarole, cod-liver oil, halibut liver oil and " vogan " are some of such con
centrates. While these may be important as therapeutic doses for curative
purposes, to include them in the regular dietary of animals would not be a
practical proposition. Various investigations have, therefore, been carried
out to determine the suitability or otherwise of different vegetables and
plants as vitamin-A supplements.
CAROTENE AS THE SOURCE OF VITAMIN-A IN PLANTS
It is generally known that while vitamin-A as such is not available in
plants, all green leaved or yellow rooted vegetables or plants contain various
quantities of carotene, the precursor of vitamin-A, particularly in the earlier
stages of growth. It has also been shown in an investigation on fifty-nine
plant carotenes that while β-carotene was the main constituent in all cases,
α-carotene was also present in quantities varying from traces to about thirty-
five per cent of the total carotene content [Mackinney, 1935]. The carotene in
these plant sources is also convertible into vitamin-A in the animal system.
It was noticed that while swine, sheep, goats and rats almost completely
converted their carotene in the feed into the colourless vitamin-A before storage
or secretion, cattle were capable of conserving and secreting their vitamin-A
K. C. SEN AND P. A.
SESHAN
173
Govt. Agric. Chem. Coimbatore, 1932-33). Vegetables had their carotene
content markedly increased by a fertilization of the soil with nitrogen, phos
phate and potash. Irradiation by neon light of parsley, chive and spinach
increased their yield and vitamin-A content [Pfutzer and Pfaff, 1935].
Several attempts have been made to estimate the carotene content of
some of the commoner pasture plants in their fresh green stage. Timothy
grass contained 200±13 Sherman units per grm. of fresh material, red top
308±10, smooth brome grass 396±27, alfalfa 269±17, white blossom sweet
clover 242±19 and 500±30 respectively in the second and first years, orchard
grass 275±13 and meadow fescu 250±13. Based on these results it has
been advised that dairymen could select any mixture of pasture plants adapted
to their particular climatic and soil conditions without any risk of producing
a vitamin-A deficiency [Woods, et al, 1935, 1935-a, 1935-b]. In making an
estimate of the vitamins in the diet of pigs, the vitamin-A contents of air¬
dried rye grass and sun-cured pasture hay have been put down as 3,500 and
1,000 international units per 100 grm. [Cunningham, 1936].
VITAMIN-A REQUIREMENT OF ANIMALS
We have so far concerned ourselves with avitaminosis-A and the possible
sources through which it can be averted in so far as it relates to animal nutri
tion. The effect of providing the animal with its normal requirement of
vitamin-A would just enable the animal to have its proper health, growth
and production. It is, therefore, desirable to obtain an idea as to the require
ments of the various animals for carotene or vitamin-A for prophylactic and
curative purposes.
To prevent and cure xerophthalmia in rats on a vitamin-A deficient
diet, it was found sufficient to give a daily dose of 0.5 to 1.0 γ of three different
specimens of carotene. Other workers found that 2 to 5 γ were necessary
[Polak and Stokvis, 1931]. As a result of studies on thirty-one puppies,
depleted of vitamin-A by feeding, it was shown that 114 U. S. P. units per
100 grm. of body weight were required before any appreciable storage could
occur [Frohring, 1935]. The requirements of the fowl per unit of body weight
was observed to be more than that of the rat for growth and maintenance.
Depleted birds of about 400 grm. weight required about 0.05 mg. of caro
tene daily, while fowls weighing 2,000 grm. had to be given 0.5 mg. For
prophylactic purposes slightly smaller quantities might be sufficient. White
Leghorns required thirty-three Sherman units per pound of live weight every
day for maintenance and 6.3 units to produce one unit of vitamin-A in
the egg yolk, the yolk in an average egg weighing fifteen grm., each grm. of
which would contain twenty units of vitamin-A [Cruickshank, 1935].
Pigs on the other hand have been found to require only small quantities
of vitamin-A. On a vitamin-A free diet they continued in normal health till
the third litter. Pigs born at this stage failed to thrive on the same deficient
diet. But young ones born to normally fed parents grew up in proper condi
tion to the fattening stage, even on a vitamin-A free diet. Green fodder or
174
Vitamin-A Deficiency in the Diet of Farm Animals
yellow maize was deemed a sufficient vitamin-A supplement, any further
additions of vitamin-A concentrates to the ration being of no additional
benefit [Sheehy, 1932]. It has, however, been pointed out that a 100 lb.
pig should have the equivalent of four mg. carotene daily in its diet to satisfy
its vitamin-A requirements for maintenance and normal growth [Dunlop,
1935].
In an investigation into the minimum vitamin-A requirements of cattle,
it was noticed that animals receiving a small daily ration of cod-liver oil or
alfalfa meal for two years showed scarcely any storage, the total reserve of
the body being estimated at 200 mg. of carotene and vitamin-A. It was
also determined that the rate of depletion of this reserve was about 9 to 11
γ per kg. of body weight per day. For animals depleted till night blind
ness had set in, the minimum daily dose to enable them to have a normal
health and growth was found to be 26 to 33 γ per day per kg. of live weight
[Guilbert and Hart, 1935]. On this basis the approximate requirement of a
1,000 lb. bullock worked out to be 11.7 to 14.85 mg. of pure β-carotene
per day. Besides the above mentioned maintenance requirement, cows
would have to secrete large amounts daily in their milk. The vitamin-A
value of the best grade of cows' milk was found to be 1,500 rat units per quart.
It was also observed that only less than five per cent of the carotene content
of the food was transmitted through the milk [Russell, 1933]. In another
experiment it was recorded that the cows' milk contained 2,500 to 1,600 inter
national units per quart and that more than 3.5 per cent of the feed carotene
was never present in the milk [Russell et al, 1935]. A biological estimation
of the vitamin-A content of whole milk showed it to be about 454 international
units per pint [Cunningham, 1936]. When the carotene or vitamin-A inges
tion was low, cows secreted 3.3 per cent of the intake through its milk and
when on carotene rich feed 1.3 per cent only [Garry et al, 1936].
STORAGE AND UTILIZATION OF VITAMIN-A
Having considered the vitamin-A requirements of animals for main
tenance, growth and health, it is natural to suppose that the excess amount
in the feed of the animals would be stored in the system for use in produc
tive purposes. This takes us on to the question of the animals' capacity
to store and the mechanism through which they eliminate this constituent.
It has been found that of the total amount fed to a horse about 70 to 80
per cent of the carotene and 55 to 64 per cent of the xanthophyll were excret
ed in the faeces. An examination of the dung pigments showed that they
remained unchanged by the digestive process [Zechmeister and Tuzson,
1934]. Another experiment showed that the vitamin-A excess was mainly
excreted in the urine as a degradation product, giving it an increased iodine
value [Santos Ruis, 1935].
Quantities of vitamin-A in the feed which escaped elimination through
either of these channels should have found their way into the store of the
body, namely, the liver, which is also the seat of carotene metabolism. An