A. J. MACDONALD 197
43 and 25 per cent respectively. At 26 weeks the average egg production
per bird in Group 1 was 2.8 for the Leghorns and 5.0 for the Rhodes. The
corresponding figures in Group 2 were 0.9 for the Leghorns and 0.8 for the
Rhodes. There were no significant differences in the weights of the eggs
produced by the birds in the two groups.
DISCUSSION
The rate of growth and general health of the birds on the basal diet sup-
plemented with separated milk only to drink from 1 to 10 weeks and separated
milk and water to drink from 10 to 24 weeks were very satisfactory through-
out all the stages of the experiment. As the level of the protein in the food
consumed was very much lower than the accepted standard of 18-20 per cent,
this experiment in conjunction with previous experiments [Macdonald, 1941]
demonstrates that chickens can be reared very successfully on rations con-
taining 12-13 per cent protein when separated milk is fed as the sole protein-
rich supplement. As the protein percentages in the food consumed by the
birds up to 16 weeks on the earthnut cake mash were higher for each period
than those consumed by the birds on the separated milk ration, it is obvious
that the lower rate of growth of the birds on the earthnut meal mash could
not have been due primarily to a low protein level. The better growth results
from 1 to 16 weeks with the birds on the separated milk diet cannot be attri-
buted to any single factor in the milk and are probably due to the high biolo-
gical value of the milk proteins, its richness in vitamins, especially the growth-
promoting factor, and its well-balanced mineral content.
The better growth results from 16 to 24 weeks obtained with the birds on
the basal ration supplemented with 10 per cent earthnut meal and 1 per cent
common salt in the mash are quite a natural phenomenon, for birds that are
retarded in growth by inferior diets during the early stages of growth tend
to grow faster during the later stages of growth than birds which had been
previously fed on more adequate rations. At 24 weeks, there were no signi-
ficant differences between the respective weights of either the quick-matur-
ing Leghorns or desi pullets in the two groups under test, but in the case of the
slower maturing Rhode Island Reds, the birds in the ' milk fed group' were
significantly heavier than those in the ' earthnut group '.
Over the whole experiment the birds fed on the milk diet made slightly
better utilization of their food, for the average food consumption per bird
was a shade lower, whilst the average final weights were higher for all the
three breeds. The somewhat lower efficiency of food utilization on the part
of the ' milk-fed group ' during the latter part of the experiment is quite
normal, for birds that are well fed during early life, make poor utilization of
their food during the later stages of growth as compared with birds which
have been less well fed during the early stages of growth.
CONCLUSIONS
(1) During the early stages of growth (1-10 weeks), a ration of cereals
supplemented by liberal amounts of green food and calcium along with separt-
ed milk only to drink gave normal growth results, low mortality and efficient
food utilization.
C 2