ANIMAL NUTRITION

Taranaki Daily News, 2 September 1933, Page 22 (Supplement)

ANIMAL NUTRITION

INFLUENCE OF MINERALS PHOSPHATE STARVATION. PROBLEM OF BUSH SICK LAND. (By Mr. W. Alexander, Agricultural Adviser, Kempthorne, Prosser and Co.’s New Zealand Drug Co. Ltd.) Throughout the world increasing attention is being paid to the part played by minerals in the maintenance of health in live stock; we no longer accept the law of the survival of the fittest as being applicable to modem requirements. The concentration of live stock in comparatively small areas with a high carrying capacity, has brought out weaknesses that call for attention if carrying capacity and production are to be maintained. In the literature published from time to time by research institutions can be found some outstanding and classical examples of malnutrition amongst’ live stock running under natural conditions over large areas of country. In South Africa for instance a form of malnutrition, the outward signs of which are a wasting away and a ravenous appetite for old bones and decaying carcases, has been definitely identified as phosphate starvation. In the Falkland Islands a great deal of trouble in the rearing of live stock has been experienced. In a report on this problem, following a close investigation on the spot, the late Mr. Munro stated that the rearing of lambs was a difficult business and deaths taking place up to weaning time left- less than 50 per cent, of the lambs dropped. It is also on record that thoroughbred horses imported into the islands have, in the course of two or three generations, gone right back to pony size—the reason given being that the naturally low mineral content of the native pastures is noj capable of sustaining other .than undersized stock. In many other countries of the world nutritional problems have arisen and always it has happened that a shortage of one or more essential minerals is the underlying cause.

NEW ZEALAND PROBLEMS. Here in New Zealand we have our own peculiar problems of which perhaps the most widely-known are the bushsick problems of the pumice lands and the iodine deficient areas in the Lakes district of Central Otago. In the case of the bush-sick areas it is considered that a deficiency of iron in the soil and in the pasture is responsible for most of the trouble with stock. There certainly is a deficiency of iron in most of these soils, but there are also deficiencies of lime and phosphate sufficient in themselves to cause trouble, especially on areas that have been developed and carry a fairly heavy concentration of stock. In Central Otago where troubles have been experienced lambs have been born with, or have quickly developed, enlarged glands and joints, and this condition is traceable to a shortage of iodine in the food and consequently in the system. It is of interest to consider here that the absence of the very minute quantity of iodine required by an animal, especially a lamb, can have such a harmful effect on its development. The main function of iodine seems to be in assisting the animal to assimilate the minerals—calcium and phosphate—that would otherwise pass right through the system. The areas of land in this Dominion that are associated with malnutrition problems such as bush-sickness and iodine deficiency are fairly well defined and not of very great extent, moreover, they ■ are not areas with a great concentration of stock, consequently, looked at from a national point of view, they do not represent a very great loss, although it is recognised that from the point of view of the farmers concerned the losses are serious.

NATIONAL LOSS.

We have, however, right throughout the Dominion, a form of malnutrition that represents a serious loss both national and individual, but which unfortunately has been given very little concentrated attention. I refer here to that case of malnutrition that has as its outward signs—sterility, abortion, milkfever, etc., and which in some districts of New Zealand amounts to 25 per cent, of the dairy cattle population. It would be difficult to make even a rough estimate of what this particular form of malnutrition is costing this Dominion every year, but the sum must be enormous. It should be a duty on the shoulders of everyone interested in agriculture to endeavour to do something towards eliminating this almost universal and costly form of malnutrition. It is comparatively easy to trace the development of this state of affairs from the earliest days of settlement up to the present day. When and where the stock-carrying capacity of the country was low and the grazing areas at their disposal extensive, troubles were few and far between; indeed, nature’s own law of “the survival of the fittest” was accepted as inevitable. .As the land became more closely settled grazing areas became more confined and every effort was made to increase carrying capacity. With every advance made in these directions settlers were increasing the risks associated with keeping live stock merely by hastening the day when the natural resources of the soil became insufficient to completely meet the requirements of such stock. This state of affairs was most pronounced in the more or less specialised dairying districts where the concentration of stock was and still is greatest. To meet the position of heavy stocking and the race for increased production, recourse was made to artificial fertilisers and there is not the least doubt that the use of such fertilisers, especially superphosphate, had a marvellous effect in consolidating what had been gained and in even still further increasing carrying capacity. Further progress followed the study of pasture mixtures and the laying down of better quality, more permanent grasses whilst investigations into pasture management problems resulted in increased production and better utilisation of feed. Now, having reached what appears to be a maximum carrying capacity, farmers are faced with troubles of one sort or another that between them reduce the productive capacity of the herd and consequently the nett income from the farm. Amongst the causes responsible for that 25 per cent, herd wastage, we find temporary sterility, slips, milk fever, mammitis, etc., a series of troubles due, at least in. part, to some form of malnutrition. By being deprived of some essential mineral element in their food, cattle have a lowered resistance to diseases, bacterial and otherwise, that should pass them by.

EFFECT ON BREEDING. As an example of how a deficiency of certain minerals in their diet may affect the breeding capacity of live stock, let me quote from, a recent report on some research work carried out at the California Agricultural Experiment Station: The report reads:—“Tire normal functioning of sex activity, particularly in the case of dairy cattle, as the milk production is entirely dependent thereon, belongs to one of the most important spheres of animal breeding and rearing. By means of numerous experiments it has been ascertained that an adequate content of mineral nutrients such as phosphoric acid and lime in particular,

arc indispensable for the healthy growth of grazing cattle and that a phosphoric acid deficiency may give rise to the appearance of a serious cattle disease. After reporting in detail the result of a series of four somewhat complicated experiments on breeding capacity, the report concludes with the statement that. “From these investigations it is possible to realise the importance of an adequate fertilisation of meadows and pastures with phosphoric acid, as it exerts a decisive influence not only on the growth of cattle and milk yield but also on the normal cycles of sex activity which are so important to animal breeding and milk production. It has been ascertained that only 50 per cent, of one to two-year-old heifers which have been grazing on pastures deficient in nutrients have the same amount of blood serum as animals receiving normal fodder and that these heifers have less phosphoric acid in their blood than cows, whilst in the case of normal feeding the phosphoric acid content of the blood ,of heifers is higher than that of cows.” NEED FOR COMPLETE MINERALS. The outstanding need in our agricultural world to-day is an adequate supply of complete minerals to live stock, especially heavy producing cows; it is only by paying attention to this question that we can hope to reduce the appalling wastage that now takes place in a majority ofi the herds in the Dominion. It is not sufficient to have plenty of grass unless that grass contains the essential minerals in adequate supply and in the correct balance to meet, all the requirements of stock. The question arises as to how this ideal standard may be realised. Fortunately, the work} at large contains extensive reserves of'all the minerals at present known to be essential and the cost of these minerals is noi really beyond the purchasing capacity of the man on the land. Realising that the correct and natural means of getting minerals to stock is through their food, we have developed the practice of topdressing pastures and fertilising fodder crops in such a way that pastures and crops may take up what they require The mineral content of the soil is generally reflected in the mineral content of the crops and pastures growing thereon and this in turn is reflected in the condition of the stock grazing thereon. If the available lime present in the soil is below normal so will it be with the pasture. In the same way deficiencies of phosphoric acid, potash, iron, etc., go right through from the soil to the stock. Direct evidence of the effect on pastures of mineral fertilisers applied to the soil is contained in a report published recently in the Journal of the American Society of Agronomy. In this report we read that “the phosphoric acid content of pasture grass was increased by means of superphosphate to a particularly noticeable extent —actually on an average by 60 per cent. If in addition to superphosphate, lime or potash was applied, a further moderate increase in the phosphoric acid content of pasture grass was noticeable, the potash content rising at the same time. As to the proportion of lime and phosphoric acid the following was ascertained. When omitting superphosphate in the course of fertilisation, the lime content of pasture grasses was very small. The clover on the plot fertilised with nitrogen, lime and potash showed a low lime content. Superphosphate applied alone and in conjunction with lune and potash, however, increased the lime content of the plants on all plots to a considerable degree.”

PUT MINERALS THROUGH THE FOOD

It is quite obvious from these experiments and also many others carried out much nearer home that the application of mineral fertilisers to the soil is the safest, most economical and easiest means of increasing the mineral content of pastures. That being the case it becomes of the utmost importance that farmers should exercise care and selection in the purchase of topdressing manures. It may not be sufficient to top-dress with supei alone and it certainly is not sufficient if the Soil concerned happens to be deficient in lime and potash. Under dairying conditions there is a heavy drain upon the lime, phosphate and potash contents of the soil and if trouble with stock is to be avoided then each of these elements should be returned, to the soil. Correct manuring, especially for autumn and early winter, under dairying conditions would be first a dressing of finely ground limestone at the rate of from 5 to lOcwt. per acre to be followed later by a dressing of from 2i to 3cwt. of super and i to lewt. of 30 per cent, potash salts per acre. The minerals represented by such treatment are phosphate, calcium, sulphur, potassium, chlorine, sodium, all of which are essential to the well-being of stock. The use of lime and complete manures constitute the only sound method whereby a heavy concentration of stock can be sustained in a perfectly healthy condition. Cost is an. important factor in determining the type of fertiliser a farmer uses, but that is not always a determination, especially when considerations such as price per ton take precedence. It may be that a high priced fertiliser such as potash salts is condemned because of the price per ton, whereas if the cost per acre of land treated was the chief consideration, it would be more freely used. Because a farmer cannot do the whole of his property well is no reason why he should not do some of it well.

A practice that is growing in favour with many farmers is that of having what is conveniently called “hospital paddocks,” that is, two or three handy sized paddocks that are well limed and top-dressed perhaps twice a year with complete fertilisers. Stock are given access to these paddocks at regular intervals as that should such a thing as a deficiency exist on any of the remaining grassland, it can be completely offset by the adequate supply of minerals on the hospital paddocks. These paddocks are most useful for running young stock in from time to time more especially as they approach that stage where they are mated for the more serious phase of life. LICKS SUPPLEMENT FERTILISERS. There are, of course, other ways of administering minerals to animals. The use of stock licks has become very popular, so much so that the sale of licks and lick mixtures has developed into an extensive business. I do not believe that licks can ever satisfactorily take ths place of minerals assimilated in the natural process of consumption and digestion of food, but there Is no doubting the fact that they do serve a most useful purpose. Whereas minerals applied to the land take time to get through to stock, the minerals taken in from lick mixtures are more immediate in their action.

It may be on account of the more rapid action of minerals fed direct that some farmers prefer to use them that way rather than top-dress. In this connection it must be borne in mind that if there is a deficiency of lime in the soil no amount of lime administered to stock in the lick form will have the least influence in making good the deficiency in the soil. It may be possible to keep stock in a fairly satisfactory condition by the use of mineral licks, but licks in themselves will never remove an actual source of danger in the land. Licks should be regarded first of all as a means of supplementing the mineral resources of pastures and secondly as a means of hastening the effect of cbmplete fertilisation of crops and pastures Lick mixtures designed to supply such ingredients as calcium, phosphate, iron, chlorin?, sulphur, etc., are easily put together and the cost is low. A very, useful all-round mixture is one consisting

of equal parts of finely ground carbonate of lime, bonechar, limonite and salt. If thought necessary potassium iodide at the rate of 2 or 3oz. per cwt. of mixture can be added, but even without the potassium iodide, stock will benefit by free access to such a mixture. To meet the particular requirements of areas known to be deficient in certain minerals, special mineral fertiliser and lick mixtures can be put up but such cases are really remote when competed with the almost universal requirement of lime, phosphates and potash which is a feature of Auckland province soils. I heard recently of a traveller for a line of veterinary remedies making quite a good thing out of the sate of a product with an attractive name but which consisted almost wholly of lime-water. Again just a few days ago I was told of a dairy farmer giving his cows Fellowes Syrup to keep them right. No doubt these are extreme cases, cases which show earnest efforts to cope with a situation that appears to be full, of difficulties but which really is the natural - outcome of depleted fertility. Unfortunately too many men. are content to let matters drift; they are fully alive to the annual loss and inconvenience due to cows failing to come in, to acute attacks of mammitis, and to the difficulty of getting the herd production figures up to a satisfactory level. We have gone on far too long judging top-dressing results by mere weight of crop grown without regard to quality, but a dangerously increasing incidence of stock troubles forces us back to a realisation that out only hope for the future lies in manuring along with which should go the elimination of herd wastage through causes other than deaths. SUBDIVISION OF FARMS. MUST NOT BE OVERDONE. (By “Tainui.”) While advocating the subdivision of farms into reasonably small paddocks to assist in the proper utilisation of the pastures, which is an important feature of pasture management, Mr. J. M. Smith,of the Fields Division of the Agricultural Department, expressed the opinion at Kaimata the other night that it was possible for subdivision to be overdone. If the paddocks were made too small and were overcrowded some of the more timid cows were apt to suffer through being constantly driven away by the other cows and prevented from securing sufficient feed. He considered that the pad docks should be of such a size as would suit the herd, based on a maximum of not more than 10 to the acre. That would mean iha'FTor a herd of 60 cows the paddocks should not be less than six acres. CONTROL OF GORSE. A PARASITE DISCOVERED. A possible means of preventing the spread of gorse, which has already rendered much good land in New Zealand unworkable, is suggested by the results of researches by Dr. W. Maldwyn Davies in England, according to a note in a recent number of Nature, the well-known scientific weekly published in London. A possible solution lies in the introduction of a weevil, Apion Ulicis, which has been found to destroy the fertility of the gorse plants. , In July in England many gorse pods harbour this insect enemy which has just passed into the pupal stage before emerging as the weevil, Apion Ulicis. During this month the adults make their appearance; and, although they do little damage to the gorse bushes, the destruction caused in the larval stage within the pods seriously affects the fertility of the plants and their chances of spreading. Dr. Davies foimd, from investigation of pods gathered throughout the length of Britain, that the number of pods infected varied from 0 per cent., which was rare, to 92 per cent., and that 50 per cent, and more was common.. A considerable proportion of pods had' their entire contents destroyed by the larvae. The point of this investigation was in far-off New Zealand, where Demwin had observed gorse plants in 1835, and when the ravages of the plant had been badly felt. There _ was a possibility that the introduction of such a parasite might solve the problem of New Zealand’s unwanted gorse, as the introduction of the cochineal insects had been a solution of the problem of Australia’s prickly pear. Experiments had shown that the Apion Ulicis was unlikely to attack any other leguminous plant.