NUTRITION OF LIVESTOCK

Dominion, Volume 25, Issue 223, 16 June 1932, Page 16

NUTRITION OF LIVESTOCK

Minerals Essentia I

PRACTICAL ADVICE FOR FARMERS

Prevention of Disease

(By C. V. Dayus, M.R.C.V.S., Dept, of Agriculture) The natural trend of progress in these days of intensive production is toward more rapid growth in young animals and more milk from dairy cows in a shorter space of time. However, it is obvious that if these objects are to be achieved, the food must be rich in constructive material, such as calcium and phosphorus, to meet the increased demands of development of bones and other tissues, or to compensate for the loss of such materials in milk production.

, HE ordinary constituents of ■ foodstuffs, such as protein and carbohydrate content, have received extensive publicity for many years past. It is only in more recent times that other essential constituents, among the chief being the mineral content of foodstuffs, have received the beginning of the same publicity both from veterinary research workers and other students of nutrition. Consequently it Is a decided advantage for a farmer to understand something regarding the value of minerals iu nutrition, in order that he may be in a position to provide any necessary requirements under the most efficacious and economical circumstances. The incombustible part of the animal body constitutes the ash and consists of mineral elements. The important metals are calcium, sodium, potassium, magnesium, and iron. The important non-metals arc phosphorus, chlorine, sulphur and iodine. Mineral matter is found in all the vital parts of the body, bat it at no time forms a large part, as 'it ranges only from 1.7 per cent, in a fat pig to 4.5 per cent, in the growing steer. This small proportion of mineral matter is exceedingly important in the animal body; the skeleton, for example, is composed largely of calcium, combined with phosphorus. It is significant that an animal fed on a diet free from mineral matter will die, just as an animal on complete starvation will die: its death also Is attended by painful and distressing symptoms.

The breaking down of tissue, which is continuously taking place in the annual body, involves the loss of mineral ele•inents. The building up of new tissues by the growing or pregnant animal, the secretion of milk, and the production of eggs, all necessitate the supply of relatively large quantities of mineral material. As some evidence of the value of minerals on the rate of growth, a comparison of the growth rate and the composition of the milk of the species is exceedingly interesting. A baby for example requires approximately 180 days to double its birth weight; there is 0.2 per cent, of mineral matter in human milk. A calf requires 47 days to double its birth weight; there is 0.75 per cent, of mineral matter in cow’s milk. A rabbit requires six days to double its birth weight; there is 2.5 per cent, of mineral matter in rabbit’s milk. In other words, the shorter the time required by the new-born animals of the different species to double in weight, the greater is the quantity of mineral matter, especially lime and phosphoric acid, found in the mother’s milk. These facts lay great emphasis ou the necessity of maintaining a liberal supply of mineral matter in the food of young animals as milk is replaced by other food during their early life. In the production of milk the requirements of mineral matter, especially calcium and phosphorus, is particularly high. It must be remembered that the modern animal produces anything from 5-10 times as much, as was produced by the strains from which it has been evolved. To give an example of the.drain of milk production :—-A. cow yielding 800 gallons of milk a year of average composition loses in her milk 19 per cent, more mineral matter than is contained in the entire body of a two-year-old fat. steer, weighing 12001 b. xV further example may be cited :—A cow giving -1 gallons of milk per day excretes in the milk 21b. of sugar and Joz. of calcium. Should the necessary minerals not be present in the food in adequate quantities, all the processes mentioned, together with the health of the animal, will ultimately suffer. .Sheep also require adequate mineral material, particularly calcium and phosphorus, especially for pregnant ewes and young growing iambs. Pigs frequently suffer from mineral deficiencies, through unbalanced foodstuffs and confinement in styes. A continued shortage of minerals means poor live-weight gains, and in extreme cases rickets develop. Evidence is constantly increasing which tends to show that many diseases of

farm animals owe their origin to various forms of malnutrition. The most common forms of nutritional disease are those due to a deficiency of phosphorus or calcium, particularly common in some areas of New Zealand among both cattle and sheep. In cattle the condition due to phosphorus deficiency is commonly known as Waihi disease, because it was first noticed to exist in the neighbourhood of Waihi, in North Taranaki. Animals affected become generally unthrifty and are seen to move in a painfully cramped manner. Often. creaking of joints will be heard, and a tendency to knuckling over at the fetlocks is noticed. A depraved appetite is a common development, cattle chewing bones, wood, and other foreign material. These diseases are generally much more prevalent during periods of drought, when the. percentage of phosphorus in the food becomes very strikingly reduced. Such conditions are successfully overcome by providing phosphorus-rich food, and they are very materially benefited by feeding inorganic phosphates, such as steamed bone-meal, which can readily be incorporated in mineral mixtures. The liberal use of phospliatic manures has entirely overcome Waihi disease in some areas where it was once prevalent. Calcium deficiency has been held responsible to

some degree for many bovine complaints, including increased susceptibility to tuberculosis, abortion, and .sterility. If the variety of the food of dairy cows is too limited or heavily deficient in lime, it has been shown that calves are. sometimes bori; dead or they die shortly after birth, and cows are difficult to get in calf. Temporary sterility is also more prevalent in heavy-milking cows, and as I have already mentioned, this means a heavy drain oil the mineral reserves. A disease met with sometimes in New Zealand is goitre, affecting horses, cattle, and sheep. The chief feature of the disease is an enlargement of the thyroid gland—a gland situated in the throat region. This disease is intimately connected with a deficiency of iodine, and it can be remedied by feeding salts rich in iodine. Potassium iodide is the salt commonly used, at the rate of 3 ounces per hundredweight of coarse agricultural salt. For convenience of mixing the required amount of iodide is dissolved in a small

quantity of water, and sprinkled over the salt, which is then well turned. If goitre is noticed in calves or horses it can be treated by dissolving one ounce of potassium iodide in one gallon of. water, and placing one tablespoonful of this solution daily in the food. In some cases “hairlessness has been noticed in new-born pigs. Sows have had poor litters, or the pigs are born alive, but arc so weakly that they live only a few hours. Such conditions can be prevented by giving the sows iodine throughout pregnancy. One ounce of potassium iodine is dissolved in one gallon of water. One tablespoonful of such a solution is a daily dose for a sow. . . Another malnutrition disease of interest in the North Island is “bush sickness,” occurring in both cattle and sheep, characterised by anaemia and general uuthriftiness. The condition can be prevented or cured by medicinal administration of suitable iron salts. Having frequently mentioned mineral mixtures. I must give the constituents of a desirable mixture. The base of a good mixture is coarse agricultural salt; it is an appetiser, adds to the palatability of many feeds, and also stimulates the digestive glands, and prevents digestive disturbances. To 1001 b. of salt add 501 b. of steamed bone meal, and in districts where goitre is prevalent the quantity of pottassium iodide I have already mentioned could be added. Those are the fundamental requirements, and there is little object in composing a mixture with a multitude of ingredients. Occasionally Howers of sulphur are added at the rate of 101 b., and sulphate of iron at tho rate of 41b. ... ... It must not be imagined, however, that, the use of mineral mixtures are the best means of making up mineral deficiencies. It is an artificial method, and only a second best method. . Since natural pastures constitute as far as food is concerned the mainstay in this Dominion, the best method of adding minerals is by topdressing grasslands, grading up pastures so that their mineral composition more and more closely resembles that of milk, and so that they will thus provide hay or ensilage of high mineral content for winter feeding. _ Pasture plants depend on the. soil ior their mineral requirements, which they acquire through the roots, consequently the minerals present in the plants vary according to the minerals present in the soil iu which the plant grew. Pastures deficient in minerals tend to be poor in other nutritional qualities, and evidence of this fact is often seen by. the unthrift conditions of stock,, especially young growing animals, grazing on the S' re. Food available may also be renunpalatable due to a deficiency ot mineral matter, thus affecting the appetites of the grazing stock. There is a seasonal variation in tee mineral content of pastures; the mineral content is higher in grass growing vigorously in the leafy stage. If pasture is subject to close rotational grazing or repeated mowings, so that plants are prevented from reaching maturity, the period of high mineral content is prolonged. The

mineral content is considerably lowerh! in pasture which has been allowed to become coarse and rank. The percentage of fibre in the leaves and steps of this .type of pasture is greatly increased; this , is less digestible and has a low nutritive value. But close grazing to keep pasture in tbc state of its maximum nutritive value leads to depletion of the soil mote rapidly unless continuously supplied with artificial mineral fertilisers, a practice, that is becoming increasingly popular.in New Zealand with consequent marked improvement in the grasslands and health of live stock generally. 'The importance of the enrichment of the soil by the application of mineral fertilisers is now fully appreciated, and the element in greatest demand is phosphorus. In addition to the application of mineral fertilisers to the soil, mineral licks ean be -used as a supplement in feeding stock, in fact they are very necessary on those areas where nothing is being.done, to improve or even maintain the qualitv of the pastures. Whenever there is any dan-

ger that the pasture contains too little calcium or phosphorus for health and maximum production, these mineral nutrients can lie supplied at little expense. ’Calcium may be furnished in the form or finely ground limestone, and both calcium and phosphorus are supplied by steamed bone meal. The use of expensive proprietary mineral mixtures of unknown composition is unnecessary. and generally uneconomical.