F. C. MINETT
135
DISCUSSION
Calf mortality figures. The first question that may be put is what should be considered a ' normal
death-rate in cow calves. Lovell and Bradford Hill [1940], in the article mentioned above, state that
in 335 milk-recorded and thus somewhat selected herds in England and Wales out of 12,544 female
calves born alive, 693 (5.5 per cent) died before the age of six months. If calves of both sexes are
included, and still-births or abortions added. then of 27.970 pregnancies 14.9 per cent failed to produce
a calf surviving to the age of six months. They found the death-rate in Scotland to be significantly
higher, viz. 158 (11.4 per cent) out of 1,383 females born. This figure is not as high as that given by
Jordan [193,3] in another enquiry in Ayrshire (Scotland), who found that of 78,4 females born, 169
(21 .6 per cent) died. The death-rates of calves born in the spring of two consecutive years were 24
and 27 per cent compared with only 8 per cent for calves born in the autumn, the difference being
ributed by Jordan to the extra green food consumed by the pregnant cows during the summer.
In the observations of Lovell and Bradford Hill, the mortality in calves born alive showed a seasonal
swing, being significantly higher in the first half than in the second half of the year. There is an
advantage in allowing calves to take the colostrum naturally from the mother compared with feeding
it from the bucket. In the females, nearly half the deaths took place in the first week of life and
three-quarters of them in the first month, and the probable cause of death in most cases was ' white
scours '. The following figures from the United States, referring to calves of both, sexes, may be
noted. Wing [1933] gives figures relating to forty years' (1889 to 1928) working in the University
herd at Cornell. Of 644 conceptions during this period, there were 120 (18.6 per cent) which died at
or before birth, and 61 (9.5 per cent) which died within-three months. Slack and Harrison [quoted
by Savage and McCay, 1942] add figures for the Cornell herd for the years, 1932-42. From 1,352
conceptions, there were 169 (12.5 per cent) which died at or before birth, and 144 (10.7 per cent,—
range 3 to 19 per cent in different years), which died later, usually from pneumonia and digestive
troubles.
Position at, Secunderabad and Airfield. In India, I am aware of practically no authoritative
figures for calf mortality. Fundamentally, there seems to be no reason why the mortality in cow
calves in India should be higher than anywhere else. In practice, however, it will probably be found
to be higher, because the climatic conditions are often extreme and because methods of calf-rearing
are often primitive. In the two groups of cow calves considered in this work the rates are high,
viz. 24-27 per cent for calves dying after birth. What the rates may be for abortions and still-births
we have no knowledge. These rates for calves born alive on well-managed farms compare very un-
favourably with most of the figures quoted above, being four or five times the English figure of 5.5 per-
cent and over twice the American figures, though the latter are for calves of both, sexes. While the
figures involved are not comparable in magnitude, the reasons for this difference are worthy of thought.
At Secunderabad, the death-rate in the cow calves is swollen by the relatively high prevalence of
pneumonia. At Airfield, pneumonia and intestinal troubles are equally responsible for the high
rate. Comparing Secunderabad and Airfield, at the former, deaths from pneumonia were significantly
higher than at Airfield, while at Airfield the proportion of intestinal troubles was significantly higher
than at Secundcrabad. With buffalo calves at Secunderabad, intestinal troubles were the outstanding
cause of the. high death-rate.
The high incidence of pneumonia in cow calves at Secunderabad may be ascribed to vitamin-A
deficiency. There are three particular reasons for this conclusion : (I) The amount of green fodder
available has been small; as mentioned above, green fodder has been fed. to the milking herd but
not to the dry stock. It seems clear that the cows were not getting enough carotene at the time when
it is most needed, i.e. towards the end of the gestation period, hence the vitamin-A content of their
colostrum must have been very low. (2) Stewart and McCallum [1938] showed that an important
predisposing cause of white scours, navel-ill and joint-ill is a deficiency of vitamin-A in the colostrum.
The same is true of calf pneumonia. (3) The air temperatures in the winter at Secunderabad are
such that chilling is unlikely to be common.
There was unfortunately no opportunity for vitamin estimations on the colostrum or on the blood
of the calves, nor have any bacteriological investigations been made. Apart from the pneumonia,