MINERAL REQUIREMENTS OF ANIMALS.

Otago Witness, Issue 3764, 4 May 1926, Page 12

MINERAL REQUIREMENTS OF ANIMALS.

The mortality among fat lambs which has occurred in various parts of Otago, and which was referred to at a special meeting of the Otago Provincial Executive of the New Zealand Farmers’ Union, arrests attention. The veterinarians of the Department of Agriculture have failed to satisfy producers that the deaths occurred as the result of certain causes which suggested remedial measures failed to eliminate. It is acknowledged that fatty kidney is the immediate cause of death. It was pointed out by one speaker at the meeting that in places where there was no fatty kidney five years ago the disease existed to-day, though the conditions were exactly similar. It was also suggested that certain kinds of weeds might cause death by effecting changes in the liver. The mortality occurred on both old and new pastures, but was at its worst on the older established pastures. The problem is one which in the interests of fat lamb-raisers should be determined as soon as possible. Little, however, can be done until next season, as the trouble occurs at the time when there is a flush of grass or feed of some sort. Late lambs were not affected. This mortality among fat lambs is no new thing, losses having been experienced in a similar manner years ago. The death rat. was checked by frequently changing the feeding grounds. As no class of stock gives more rapid returns for the cost of feeding than fat lambs, it is suggested that care should be expended before they are born. Wellfed ewes produce lambs already heavy in weight and capable of making rapid progress. Again, the feeding of the ewe on “ right lines ” gives the suckling lanA every opportunity to develop its full powers C? growth. Such a lamb is in a sense fully equipped for taking a vast amount of food with no harmful results; and it is reasonable to -suppose that the “ balance ” of the food for both ewes and lambs is a matter worthy of more consideration than most producers give it. Authorities on matters of nutrition are more and more emphasising the desirability of obtaining the food of animals from as many sources as possible, and of supplementing these with small quantities of accessories, such as minerals, without which the ration cannot be regarded as complete. It would be interesting to learn whether the death rate among lambs was apparent on farms where top-dress-ing of grass lands was practised. The depletion of minerals in the course of time from our sorely-tried pastures and arable lands has been very great. Pasture grasses are known to vary in their mineral content according to the composition of the soil upon which they are grown. Almost 85 per cent, of the ash of bones is calcium phosphate. Hence, quantitatively, the most urgent need for mineral matter by farm animals is for calcium and phosphorus. It has been estimated that over 80 per cent, of the mineral matter retained in the bodies of growing animals is calcium and phos- ■ pliorus. It is natural, - therefore, that the calcium and phosphorus requirements of animals and the calcium and phosphorus content of farm feeds should receive the most attention in experiments concerned with the mineral requirements of farm animals. It may be stated as a general proposition that the leguminous roughages are adequate sources of calcium and phosphorus except, possibly, under conditions of excessive demands for boncmaking materials, as with high-producing dairy cows. Yet how many areas are practically devoid of leguminous plants? The point we wish to make is that, although apparently the conditions are similar to-day to those of years ago, they are not so, and seeing that, say, 95 per cent, of the ills which Bheep were heir to come from the land it is suggested that its covering is not conducive for the proper growth and development of fattening animals. Minerals are essential in the animal as well as in the land. If there were no minerals in the land there could be none in the animal, with consequent evil results. Dr Orr and his colleagues at the Rowett Research Institute proved that the mineral content of the diet has a profound influence on the health, rate of growth, etc., of farm animals. As we all know sheep unconfined and grazing as they please vary

their feeding ground, and there is no mineral deficiency or excess; there are no deaths as a result of, say, venal congestion. Confine these same sheep on an ill-balanced ration for any length of time and there is trouble. Dr Orr points out that disturbances in nutrition due to deficiency of minerals in natural pastures would be liable to occur: (a) When animals accustomed to wide ranging are restricted to a limited area, (b) When animals reared on cultivated pasture, and characterised by a rapid rate of growth, are transferred to a natural pasture which contains markedly less of one or more mineral elements than the pasture on which the type has been evolved, (c) When over a long period pasture has been depleted in those mineral elements which are used as constructive materials in growth, as when animals reared on the pastures are sold off without any measures being taken to restore to the soil minerals equivalent to those carried off in the bodies of the animals. In the report of the meeting to which reference has been made it is stated that Dr Reakes says that “ the mortality in lambs was confined to definitely ascertained breeds of sheep—Leicester and Romney cross. This is a startling statement, and conflicts with our own experience. While it is conceivable that longwools and British shortwools and their crosSC**- And some more than others, owing ’to their, ancestry, might make better play with succulent feed (although lacking in some essential ifiineral) than crossbreds with a big dash of mcrmQ blood, it is questionable whether any one breed, is immune if placed under, so to speak, “foreign” conditions.