Sheep - AgRIS

animals. A deficiency of salt is shown first by a great craving for it. A decline in thrift follows
slowly, for under such conditions the excretion of salt almost ceases, and the small supply is
retained as long as possible. There is listlessness, a loss of appetite, and a decline in weight.
These symptoms are rapidly overcome with the restoration of salt to the diet.
Calcium and phosphorus
These two minerals are closely associated in nutrition. They are the most important mineral
constituents of the body so far as quantity is concerned. Together they make up about 70 to 75
per cent of the total mineral matter of the animal body. About 99 per cent of the calcium and 80
per cent of the phosphorus is found in the bones and the teeth. They are very important in milk
as they represent more than half of its mineral content. Hence, there is a strong need for
calcium and phosphorus in the rations of pregnant ewes, of ewes giving milk, and of growing
lambs. Mature animals that are not producing also need these minerals, for there are daily
losses from the body which must be replaced.
The supply of these minerals is adequate in various regions in the pastures and roughages,
used by sheep. But there are some regions where the supply of calcium and phosphorus in soils
has been depleted by long crop production without replenishment. Under these conditions there
is a lowered efficiency, reduced production, and cases of serious injury or even death. The
requirement of calcium is greater than that of phosphorus, but sheep are more likely to
experience a lack of phosphorus than of calcium. This is because roughages make up a large
part of the ration of sheep, and roughages contain more calcium than phosphorus. It is only
through the use of roughages of very low grade grown on poor soils that a serious deficiency of
calcium is apt to result. Inadequate amount of calcium results in weakened bones and lameness.
Rickets or ‗‗bent leg,‘‘ is a condition usually known in sheep. This because to a lack of calcium
being deposited. This may be more likely due to an accompanying lack of vitamin D necessary
for the deposition of calcium.
A lack of phosphorus is evident by symptoms similar in some respects to those due to
calcium deficiency. There is stiffness and soreness of the joints, listlessness, lack of appetite or
a deprived appetite accompanied attempts to eat bones or chew wood. Other sysntoms are
reduced growth, loss of flesh, failure to breed regularly, and poor milk production. In certain
cases the lack of milk at lambing may be due to lack of phosphorus.
As phosphorus is a part of some of the proteins, deficiency will not develop if, protein-rich
feeds are used.
Feeding extra amounts of calcium and phosphorus normally in bones of greater strength
and of denser structure, but there is very little effect on the outside diameter. The assimilation
of calcium and phosphorus depends to some extent upon the relation between the two. A ratio
of 2 to 1 is satisfactory.
Iodine
This is one of the minerals that may be deficient in rations in certain regions of the country.
About half of the idodine of the body is found in the thyroid glands of the neck. This origin is
very important in relation to health, growth and general development, and reproduction.
Deficiency symptoms are seen by lambs having very little or no wool at birth and by slight to
extreme enlargement of the thyroid gland. this condition is described by practical farmers as
‗big neck‘ or goiter. The mortality rate in such lambs is high. This can be controlled by the use
of iodine supplement, such as iodized salt.
Magnesium
Magnesium is present in the bones, fluids and tissues of the body. It is rare that sheep
experience a lack of this mineral, although, a few cases of ‗grass tetany‘ have been ascribed to
it.
Potassium
This occurs largely in muscles. Apparently no deficiencies have been found, although
some soils do not have an ample supply for large plant production.
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