A. J. MACDONALD 217
The percentage protein consumption figures
for group 1, ranging from 10.6 in period 1 to 10.4
in period 5, were very much lower than those in
the other four groups. The figures for groups 3 and
4 were very similar in the different periods, being
at their maximum during periods 1 and 2 and at
their minimum during the later part of the experi-
ment. In group 2 the percentages of protein
consumed were 15.7 per cent in period 1, 14.1
in period 2, 15.8 in period 3 and 13.6 in periods
4 and 5. Group 5 consumed higher levels of pro-
tein throughout than group 2, especially during
periods 1—3.
Mortality. Table V gives a statement of the
mortality percentages in the different groups from
0.20 weeks.
TABLE V
Mortality percentages (0-20 weeks)
Group
Percentage mortality
1
7.2
2
8.7
3
8.7
4
5.8
5
2.9
The mortality percentages which ranged from
2.9 to 8.7 may be regarded as satisfactory for all
the groups. The birds in Group 1 never handled
as well or appeared as thrifty as those in the other
groups, but nevertheless they maintained a com-
paratively good health record. The birds in
groups 3 and 4 were always more backward in
appearance than those in groups 2 and 5, but
maintained normal health. The birds in groups
2 and 5 were better feathered and always had a
more robust appearance and a better bloom than
those in the other groups.
DISCUSSION
The rate of growth of the birds in group 1
receiving a supplement of salt only was very much
slower than that of the birds in the other groups
receiving protein-rich supplements. The slow rate
of growth in group 1 was most marked from 0-8
weeks, i.e. during the period when the protein
requirements for growth are at their maximum.
During the period of 0-8 weeks, the food utilization
figures were also much higher for group 1 than in
groups 2—5 which were receiving protein supple-
ments. However, the rate of growth in this experi-
ment, with a ration containing a supplement of
salt, was very much better than that obtained in a
previous experiment carried out by Macdonald
[1941] in which no salt was included in the ration.
In the previous experiment with cereals without
salt, the food utilization figures were much less
satisfactory and the mortality was excessively
high, whereas in this experiment the mortality
(7.2 per cent) was normal. It would, therefore,
appear that the addition of salt to cereal rations
has a very beneficial effect, even when the protein
content is below 11 per cent. This finding is in
close agreement with the results of Prentice
and Baskett [1932] and Prentice [1933], who found
that the addition of a mineral mixture containing
salt to cereal rations materially improved the rate
of growth in chicks, decreased the units of food
per unit of liveweight gain and decreased mortali-
ty. In other experiments,
Robertson, Orr,
Prentice and Macdonald [1930] found that salt was
essential in rations where the protein was entirely
of vegetable origin. Though more controlled
work is necessary before final conclusions can be
drawn, it would appear that villagers who feed
cereals only to young chicks could improve their
chick rearing results by adding salt to the ration
of the birds.
The additions of soya bean meal and earthnut
meal in conjunction with salt gave fairly good
results, but the figures obtained were not so
satisfactory as regards the rates of growth from
0-20 weeks or the food utilization during the early
stages of growth. Though numerous workers
have shown the value of soya bean meal in the
ration of chickens, the author has not seen any
references of similar work with earthnut meal.
In this experiment earthnut meal gave results
as good as those obtained with soya bean
meal. Though the results with these two vege-
table proteins were not so satisfactory as those
with separated milk or meat offal, they could
both be used with considerable success when-
ever animal proteins are expensive or difficult
to obtain. As earthnut meal is generally much
cheaper than soya bean meal, it should normally
be used in preference to soya bean meal in chicken
rations.
Though numerous reports are available on the
value of meat meals and meat and bone meals,
the author has not come across any data in regard
to the value of meat offal in the ration of chickens.
In this experiment the meat offal ration gave some-
what better growth results during certain parts
of the experiment and more economic food utiliza-
tion during period 1 than the separated milk ra-
tion. No final conclusions in regard to the relative
values of separated milk and meat offal in the
ration of chickens can be made until further tests
have been carried out. In this experiment, owing
to daily variations in the compositions of the meat
offal and milk, the birds on the former rations
received somewhat higher levels of protein through-
out and it is possible that this might have had
some bearing on the results obtained. Further,
the results may have been affected by the method