A. J.
MACDONALD
245
Hatchability.
Two White Leghorn cockerels
were kept in each of the pens and were moved
to each pen in rotation at weekly intervals. Eggs
from each group were set every week for a period
of eight weeks in a forced-draught electric in-
cubator run at a temperature of 99.5—99.75°F.
Details of the hatching results are given in
Table IV.
Group IV gave a somewhat higher percentage
of fertile eggs but lower hatchability of fertile
eggs than the other three groups.
Mortality. The general health of the birds
remained fairly good throughout, but many of
the birds moulted during periods three to seven.
During the course of the experiment, Group III
maintained slightly better body weight than the
other three groups. The average body weight
of the birds in Group I-IV over the whole ex-
periment showed an increase of 9.3 oz., 7.9 oz.,
14.8 oz. and 11.0 oz. respectively.
Over the
period of 40 weeks the mortality percentages in
Group I-IV were 18.0, 12.0, 8.0 and 8.0
respectively.
DISCUSSION
The results obtained are broadly in very close
agreement with those already reported by
Macdonald and Bose [1943] and they prove that
a supplement of common salt has little or no
beneficial value in laying rations, containing
only 10 per cent total protein. This result is
somewhat surprising in view of the known value
of salt in cereal laying rations, but in this parti-
cular instance the protein content of the ration
was lower than normal and it is probable that
the limiting factor in this case was deficiency of
protein and not deficiency of salt.
Further-
more, during the whole experiment the feeding
of liberal amounts of green food, which is a
fairly good source of both sodium and chlorine,
tended to make good the deficiency of salt in
the cereal ration.
The addition of separated milk and meat offal
had a very marked influence on egg production
and somewhat improved egg size. Though the
milk ration over a period of 40 weeks gave
slightly better egg production than the meat
offal ration, the difference in egg production was
not significant. Both the separated milk and
the meat offal rations gave significantly better
egg production than the two low protein rations.
There was no significant difference in egg size
between Groups I and II either for any period
or over the whole experiment. Both groups III
and IV produced significantly heavier eggs
than Groups I and II for the whole period and
during most of the ten periods.
Though the
average egg size for Group III was somewhat
greater than that of Group IV, it is not possible
without further experimental work, to draw con-
clusion in regard to the significance of these
differences. It is interesting to note that, with
the onset of warmer weather in March and April
(period 10), the egg size fell very considerably
in Groups I, II and IV, whereas the corres-
ponding drop was very small in Group III. During
this period there was a marked reduction in food
consumption in all the groups and this probably
was responsible for the lowering of the egg size.
In the case of Group III, however, the drop in
consumption had less effect on the birds pro-
bably because they had been regularly con-
suming greater amounts of food than the other
groups. The average consumption per bird in
Group III during period 10 was still as high
as the average consumption by the other groups
prior to the drop in consumption. The birds
in Group IV consumed somewhat more food
than those in Groups I and II but less than
those in Group III. Despite the greater food
consumption per bird, Groups III and IV made
significantly better utilization of the food con-
sumed than Groups I and II.
In order to test the suitability of the rations
for breeders, incubation trials were carried out.
Group IV, on the meat offal diet, gave slightly
higher fertility than the other three rations.
The percentage of dead germs and the per-
centage hatechability to fertile eggs in Group IV
was significantly less than that for Groups II
and III. Group I gave somewhat lower hatch-
ability than Groups II and III but better hatch-
ability than Group IV.
SUMMARY
1. Under semi-intensive conditions, a cereal
diet (protein content 10 per cent) in conjunction
with liberal amounts of green food and calcium
is unsatisfactory for laying fowls.
2. Under semi-intensive conditions there is
no value in adding common salt to a low protein
laying diet composed of cereals plus liberal
amounts of green food and calcium.
3. Separated milk is a very valuable protein
supplement for laying and breeding birds.
4. Meat offal is a good protein supplement for
laying birds but gives lower hatchability than a
supplement of separated milk.
REFERENCE
Macdonald, A, J. and Bose, S. (1943), Indian J. vet. Sci
13, 150-6