MINERALS IN STOCK FOOD

Hawera Star, Volume LI, 20 June 1931, Page 14

MINERALS IN STOCK FOOD

GREAT RESULTS REPORTED. Remarkable increases in the yield of milk and wool, and in the growth rate of lambs, obtained both by feeding small amounts of minerals to stool and by using mineral fertilisers, are recorded in a report just published by the Economic Advisory Council on “The Mineral Content of Natural Pastures. 1 ' The results of these experiments, which were carried out during the last two years in Kenya, apply equally to wide areas of natural pastures, in South Africa, Australia, New Zealand, Rhodesia and other parts of the Empire.

Minerals, it is now known, are found in pastures as well as in mines. Scientists have shown that a deficiency of minerals in the herbage causes serious diseases and lowers vitality in stock. These experiments prove that the addition of minerals will increase the yield and improve the health of animals grazing on pastures where the deficiency is not so marked as to cause disease.

An Empire wide scheme for tackling the mineral deficiencies problems was launched in 1926, centred at the Rowett Research Institute in Aberdeen, and the Empire Marketing Board met the costs by grants totalling £25,000. In 1928 the Kenya Government handed over its experimental stock farm at Naivasbn for the investigation described in the report. Tt was carried out co-operatively by Rowett Institute scientistst working in Kenya and by Kenya agricultural and vetinary officers. Valuable work within the scope of the scheme has been done in Australia, New Zealand, and Rhodesia. The pioneer research which made possible this Empire-wide investigation, was largely carried out -at Ondersteport, in South Africa. The whole inquiry is, therefore, a remarkable example of Empire team-work. The Kenya tests show that common salt alone, used ns a fertiliser, increased the yield of the most deficient pastimes by 25 per cent. Nitrogen and phosphates actually raised the yield of herbage by 400 per cent. Grazinganimals showed a definite preference for the fertilised plots.

“EAT MORE MINERALS.” Direct feeding of minerals to the animals , had equally remarkable, results. A mineral supplement increased

the milk yield of dairy cows by 30 per cent., speeded up the rate of growth of lambs by 10 per cent., and added 10 per cent, on to the fleece weight of sheep. The feeding of minerals to dairy cows had such a good effect on the cow’s health that an animal receiving minerals could be told at a glance, even at a distance, by its sleek and glossy coat, and its condition from the “control” cows, with thenstaring coats and thin, anaemic look. The calves of tlie mineral-fed group were considerably larger and stronger at birth. The mixture used consisted of two-thirds bone meal, one-third salt, and a trace of potassium iodide. Each cow was given about 2oz a gallon of milk.

Sheep received the same mixture. The quantity of the wool was increased without any apparent loss of quality. This is an important point, because m Australia it has been found that where pastures are improved by using phosphate manures, the weight of the fleece is increased but, at the same time, tlie quality deteriorates. Feeding experiments carried out m the rich pastures of Navaisha gave no significant increase in the growth of lambs or the yield of milk. It is only on poor pastures that mineral supplements give marked results. Recent work at the Waite Institute in Australia has shown that the ti (inspiration of plants (i.e. the evaporation of water from the leaves) is greater on phosphorus-poor soils than on those rich in this element. This suggests that phosphatic fertilisers would notu ally tend to conserve moisture in times of drought. . , ~ The story of “Nakuruitis, ’ a wasting disease of cattle grazing in the Na.kuru district of Kenya, is told m this report. Iron salts, which make up tor the lack of iron in tlie Nakuru district grazing, have been found to prevent. the disease altogether. A very similar disease, “bush-sickness, uhic-> occurs in New Zealand, was discovered in 1918 by New Zealand .workers ,to S due to lack of. iron and is being largely eliminated in the same wav.