Frothy bloat may occur in cattle on a wide variety of feeds. It has been observed on green feeds, including clovers, lucerne and other legumes, ryegrass, young green corn, chou moellier and cabbages. It also occurs in grain fed animals under American “dry-lot” con- ‘ditions. In this country, where the great majority of cases of bloat occur on rapidly growing clover, frothy bloat appears to be the prevalent form.
Since Australian workers demonstrated the essentiality of dietary cobalt some 20 years ago great progress has been made in the diagnosis and, control of a wasting disease of cattle and sheep now known to be due to a deficiency of cobalt in feed. In New Zealand the routine examination of animal livers for cobalt content has, with reservations to be discussed, proved a useful diagnostic aid. It has been shown that cobalt deficiency disease is usually assocliated with specific soil types low in cobalt, and so it has been possible to define cobalt deficient areas in broad outline (Fig. 1). Areas are defined in terms of cobalt available from the soil through the plant to the animal. The following criteria are used. Severe Deficiency: Prior to the advent of cobalt supplementation, sheep of all ages, and in places cattle, sickened and died. Mild to Moderate Deficiency: Mainly young sheep affected, but at times and in places mature sheep possibly unthrifty to a mild degree. Marginal or Suspected Deficiency: At times and in places young sheep may develop cobalt deficiency disease. Areas distinguished on the map are necessarily arbitrarily defined. For example land classified as mildly to moderately deficient will include areas where cobalt deficiency is at best only suspected; at present much of the land tentatively classified as marginally or suspected deficient is probably healthy.
You are in sunny Hawkes Bay, the word “sunny” having become synonymous with the name Hawkes Bay, and there is justification for this when one examines the sunshine records for the district. This city of Napier enjoys an average of 2,420 hours of sunshine per annum which, if you look at it on a daily basis, is equivalent to just over 6% hours of sunshine per day for every day of the year. Lying to the south-east of the North Island as it does, and protected from the prevailing westerly winds by the Ruahine Ranges on its western boundary, and to a more limited extent from the southerly winds by the hills to the ‘south, it escapes much of the cloud that districts to the west of the ranges experience.
Some 700 members and farmers attended the field day held on the property of the late Mr H. M. Glasebrook, Washpool Station, Maraekakaho. During a trip around the farm with stops at points of interest selected speakers gave short addresses.
At the 1947 Conference of the ‘New Zealand Grassland Association at Palmerston North a considerable amount of interest was shown in a short paper by a young Manawatu hill country farmer as part of a symposium on “Pasture Grazing Management.” In the paper a system of sheep grazing management very different from that commonly practised on our hill country by sheep farmers was described, and the results in increased carrying capacity of the farm for the comparatively short time the new grazing method had been in operation were given. The possibilities of the change in grazing management in promoting the improvement of hill country’ pastures, both in production and in composition, in the control and suppression of weeds, and the better and easier management of a hill country ewe flock, were also discussed. It is now proposed to briefly review the new grazing management as applied to this same farm over the past eleven years and give also the experience and results of a few only. of the many younger hill country farmers wha have adopted the same or similar methods of grazing management. These latter without exception have been influenced and assisted by the methods and results of the .Manawatu farmer; which have been brought to them through the extension service of the Department of Agriculture.
In the past the farmer in Hawkes Bay regarded weeds as a natural hazard. As such he accepted them. With the development of selective weedkillers.there is at least a straw for him to clutch at. In a 1954 survey the most important problems listed for Hawkes Bay were the pasture weeds, barley grass, thistles, blackberry and gorse, and the crop weeds in lucerne, red clover, brassicas, small seed crops and peas. The list also included over 20 other prevalent weeds, docks, weeds in drains, etc. In this paper I intend discussing the more important problems for which chemical weedkillers are of value.
But for the fortuitous appearance of a hitherto unknown scale insect of the Eriococcus genus on manuka, in the Geraldine District of Canterbury in the mid 1930’s, this paper may well have been titled “Manuka- the problem weed of the Hawkes Bay hill. country.” We might have been telling of a losing battle fought on farms and stations against a persistent and relentless foe; of properties verging on bankruptcy and abandonment, because of the difficulty of securing. labour and finance for cutting and control.
Probably everyone present here today is familiar with the story of the 1931 Napier earthquake, but I wonder if it is equally well known that the Ahuriri Lagoon Reclamation owes its origin to this same disaster.
Rickets is common in New Zealand lambs which are grazing on winter greenfeeds, the incidence being highest on cereal crops, lowest on brassicas, while ryegrasies appear to lie between these extremes in rachitogenic potency. The disease is more common in the milder seasons which favour good growth during late autumn find early winter. The presence of a rachitogenie substance in greenfeeds was first postulated by Fitch, and the results of subsequent work has not only confirmed his opinion but indicated that carotene, the main plant carotenoid precursor of vitamin A, is the main factor involved. The rachitogenic properties of vitamin A or its precursors have been described recently, and it is apparent that the higher the vitamin A uptake the greater will be the vitamin D requirement of the animal.
The talk delivered at the Grassland Conference was a summary of the following paper, which has recently been published in the New Zealand Journal of Science and Technology
At the outset it must be made clear that this paper is largely based on John Hancock’s extensive grazing behaviour studies at Ruakura. More recently I have had the opportunity of carrying out further observations on grazing cattle. A brief review of these, of Hancock’s earlier work, and a number of related overseas reports form the basis of this paper.
Dr. McMeekan was to have given this paper, but has not been able to do so owing to his absence overseas. It has fallen upon me to describe the work he has been carrying out at Ruakura to obtain factual information on the relative merits of the break and paddock systems of grazing dairy cows during the main growing season.
The New Zealand farmer who breeds pigs tends to place either too much emphasis upon the value of pasture, with rather dire effects, or too little, with the result that he deprives himself of a valuable addition to his basic feed supply. In this paper an attempt will be made to assess the value of pasture in the New Zealand pig keeping economy over the whole production cycle from the mating of the sow to the marketing of the finished product.
The overdrilling of pastures is a mechanical method of placing the seed, and usually the fertiliser also, directly into the soil, as distinct from the accepted practice of broadcasting on the pasture surface with or without previous surface cultivation.
During the past six years trials have been carried out at Invermay Research Station with the trace elements molybdenum, vanadium, boron, copper and cobalt.
Of the recent developments in agricultural science few have been more important than those following the discovery of the essential nature of certain trace ele- .ments for plants and animals. This is particularly true of Australasia where large areas of land have been found to be deficient in one or more of these essential trace elements.
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