FEEDING EXPERIMENTS

Taranaki Daily News, 10 June 1931, Page 16

FEEDING EXPERIMENTS

MINERALS FOR LIVE STOQK REMARKABLE RESULTS GAINED. TRIUMPH OF EMPIRE TEAM WORK. ■(From a Special Correspondent.) London, May 1. 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 stock and by using mineral fertilisers, are recorded in a report just published by the Economic Advisory Council on “The Mineral Content of Natural Pastures.” 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. POWER OF COMMON SALT. 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 192 S the Kenya Government handed over its experimental stock farm at Naivasha for the investigation described in the report. It -was carried out co-operatively by Rowett Institute scientists working in Kenya and by Kenya agricultural and veterinary 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 Onderstepoort in South Africa. The whole inquiry is, therefore, a remarkable example of Empire team work. The Kenya tests show that common salt alone, used as a fertiliser, increased the yield of the most deficient pastures by 25 per cent. Nitrogen and phosphates actually raised the yield of herbage by 400 per cent. Grazing animals 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. Four centres in Kenya—Naivasha, Molo, Nakuru and the Athi Plains—were selected for experiments. In general, all pastures were deficient in sodium and chlorine (the constituents of common salt) compared with good British pastures, and all except Naivasha were also low in phosphorus. At Molo the deficiency in phosphorus was as great as in parts of South Africa, where it causes disease in cattle. The feeding of minerals to dairy cows had such a good effect on the cows’ 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 their staring coats and thin, anaemic look. STRONGER CALVES. The calves of the 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 2 ounces per gallon of milk. Sheep received the same mixture. The quality of the wool was increased without any apparent loss of quality. This is an important point, because in Australia it has been found that where pastures are improved by using phosphatic manures the weight of the fleece is increased, but at the same time the quality deteriorates. Feeding experiments carried out in the rich pastures of Naivasha 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. YIELD OF PASTURES DOUBLED. < Dr. J. B. Orr, Director of the Rowett Institute, believes that there are vast areas throughout Africa, Australia and other parts of the Empire where the yield of the animals grazing over them could be very greatly increased by the large-scale application of these Kenya results. It has even been stated that a combination of fertilisers, mineral supplements and improved pedigree grasses could double the carrying capacity of the Empire’s grasslands. Each part of the Empire, of course, has a different aspect of the question to grapple with. Dr. Orr’s team has shown that mineral deficiencies are, broadly speaking, of two kinds. Where hot, dry weather brings droughts, as in parts of Kenya, South Africa and Australia, phosphorus is the missing element, whereas in areas of high rainfall such as Scotland and the Falkland Islands the shortage is generally of calcium. In enya soils, the report says, “phosphorus appears to be the limiting factor for the growth of good pasture.” The application of .phosphorus not only increases the bulk of the pastures, but tends to keep them green and succulent in times of drought. AUSTRALIA AND NEW ZEALAND. Recent work at the Waite Institute in Australia has shown that the transpiration of plants —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 actually tend to conserve moisture in times of drought. The story of “Nakuruitis,” a wasting disease of cattle grazing in the Nakuiu district of Kenya, is told in this report. Iron salts, which make up for the lack of iron in the Nakuru district crazing, have been found ■to pievent the disease altogether. A very similar disease, “bush-sickness,” which occurs in New Zealand, was discovered iu 1918 by New Zealand workers to be due to lack of iron, and is being largely eliminated in the same way.