128
Common Diseases of Young Calves
inflammatory changes followed by an opacity in the eye (Plate XI, fig. 2).
Sometimes these calves also develop convulsive fits which may be associated
with vitamin A deficiency.
The occurrence of congenital blindness in calves can be successfully pre-
vented by including green fodder or two or four ounces of cod-liver oil in the
daily ration of cows especially during pregnancy.
(ii) Pica.—A large quantity of calcium and phosphorus is required for
growth of the foetus inside the uterus and a similar quantity is also passed out
from the cow's body in the milk. She, therefore, requires plenty of these
minerals in her food during pregnancy and the lactation period in order to cope
with this demand and to make up any losses in the bones which act as body
reserves for these minerals. If the demand on these body reserves is too large
and the losses are not made good, the cow as well as her milk yield suffers,
and the calves may be born weak or dead. Such cows may even fail to breed
or may abort. Calves require plenty of calcium and phosphorus for bone
development and it is, therefore, essential to provide them with a sufficient
quantity of these minerals in the diet. If by any means calves suffer from a
lack of phosphorus they generally develop pica. It may also be caused by an
insufficiency of sodium salts.
Affected calves have a tendency to lick and to gnaw almost any foreign
object which they come across, e.g. wood, earth, soiled litter and even excreta.
Their appetite for normal food is very capricious. They become uneasy and
depressed and lose condition. They show intermittent tympany and irregu-
lar bowels. If left untreated they become thin and wasted and die from
malnutrition and exhaustion after a period of suffering which may last for
several months. They lick one another and by so doing considerable quantity
of hair may accumulate in the rumen, the constant movement of which may
convert it into a ball or a short cylinder. Sometimes salts may deposit on a
hair ball giving it a highly polished surface (Plate XI, fig. 3). On account of
the changing position of these balls intermittent flatulence or impaction may
result.
The best method of preventing this disease is to supply plenty of calcium,
phosphorus and sodium in the diet of the cows during pregnancy and to the
calves after birth. Calves that are fed on liberal amounts of milk will receive
enough calcium and phosphorus from this food. To compensate any deficiency
of these minerals the best method is to leave a mineral mixture consisting
of 200 lbs. of bone-meal, for the supply of calcium and phosphorus, and 150
lb. of common salt, for the supply of sodium, contained in a box protected
from rain in the calf-pens and cow-sheds so that they may eat it as they need.
The digestive disturbances may be treated by giving castor oil (2-4 ounces)
followed by digestive tonics like gentian (1-2 drachms), ginger (1-2 drachms)
and nux vomica (10-20 grains). When a hair ball is suspected, treatment is
not satisfactory as the condition is likely to prove fatal sooner or later.
(iii) Rickets.—This is a disease of young animals caused by faulty nutri-
tion and is characterized by constitutional debility, together with enlargement
of the ends of the long bones and a diminution in their resistance. There is a
deficiency of lime salts and an excess of organic matter in the affected bones.
The quantity of lime salts, which form the framework of the bone, limits the