72
ABSTBACTS
reduced level throughout. The treatment did not effect the proportions of butter
fat and non-fatty solids in the milk. There was some effect on the heart rate but in
general the cows showed no other symptoms indicative of Hyper thyroidism. Loss in
body weight was directly proportional to the dose administered. This loss in weight
gradually disappeared. There was no significant effect on the health of the animals
or on their reproductive activity. Long continued use of thyroactive materials
is not recommended. The probable role of thyroxine in augmenting the milk yield
has
been discussed. [S. K. De.]
Comparative Nutrition of Farm Animals. H. R. GUILBERT and J. K. LOOSLI (1951)
J, Anim. Sci. 10, 22-41
T HE present report on the comparative nutrition of farm animals was under-
taken by the authors in view of the discrepancies, pointed out by Maynard
in the feeding standards for livestock recommended by the Committee on the Animal
Nutrition of the National Research Council, in 1942.
The relevant literature, and the concepts contributing to the procedure adopted
by the authors, have been reviewed. The concept of physiologically equivalent
age has been used to compare the recommended nutritional requirements of different
species of animals that fit with the physiologically equivalent age curve.
The total feed capacities of the different species are in general, proportional
to the fractional power of bodyweight as the maintenance requirement and the
basal heat production. There is no fundamental difference in the efficiency of feed
utilization for growth, that depends on body size as such. There are no differences
in the recommended dietary allowances for protein, calcium, phosphorus for different
species but the ratio of these nutrients to energy intake changes with advancing age.
The recommended requirements for thiamine, riboflavin, niacin, and pantothenic
acid, indicated a constant direct relation with intake of energy irrespective of the
different stages of development, and is consistent with their function in enzyme
systems associated directly or indirectly with the metabolic rate. It is also pointed
out that the vitamin requirements of vitamin A and carotene are directly propor-
tional to the bodyweight in mammals. This applies to poultry, as well, but the
requirement is somewhat higher than mammals. The existing knowledge about
the nutritional requirements of vitamin D, would point out to a lack of any relation
either with the body weight or feed consumption.
The generalized recommended nutritional requirements for farm animals, as a
per cent of the total digestible nutrients in relation to per cent mature weight, is
presented, which with the existing knowledge or the results of future research is
capable of being translated into suitable feeding standards for practical use.
The authors suggested an investigation into the feasibility of expressing the
relationship of the various nutrients with the metabolizable energy rather than with
the total digestible nutrients in order to bring the data for ruminants and non-
ruminants into closer accord. The field of comparative nutrition is fertile and there
is ample scope for studying the similarities, which are more likely to be more pro-
nounced, than differences, that exist among the different species of farm animals.
[V. N. M.]
MGIPC—M—28 AR/52 6—12-52—830