THE BUSH-SICKNESS INVESTIGATION.

New Zealand Journal of Agriculture, Volume VI, Issue 4, 15 April 1913, Page 399

THE BUSH-SICKNESS INVESTIGATION.

C. J. Rbakes,

D.V.Sc., M.R.C.V.S.. and B. C. Aston, F.I.C

Some Experiments concluded.

The whole of the first series of practical experiments in . connection with this investigation, commenced over two years since, have now been concluded. These consisted of the application of various soil-dressings to small paddocks, followed by the grazing of cattle or sheep upon them. Three of these experiments must be looked upon as' having been distinctly successful so far as cattle are concerned, and . detailed particulars concerning, them will no doubt be of interest, though during their progress they . have been more than once referred to in the Journal as well as in the Annual 5 Report. Following are the particulars : .’ .. ' '

Cattle Experiment No. 1.

Land: Partially cleared bush, many stumps and fallen logs being present in the paddocks, surface-sown with grass . (principally cocksfoot) and clover. Feed : Plentiful and presenting every appearance of being of good quality. ' Paddock, 4 acres, top-dressed with superphosphate, 7 cwt. to acre good water available. Three steers, about a year and eight months old, placed in this paddock in April, 1911. Previously, on the Bth January, 1911, three steers of like class, then eighteen months old, had ’ been placed on adjoining land, not top-dressed. These had the same watersupply, and their pasture was apparently equally good, except for the lack of top-dressing, and was much less closely stocked. They, however, had a wide range of pasture, whereas the three on the topdressed paddock were limited to the 4 acres comprising it. As a matter of fact, the food became so scarce in this' paddock in August last: that these animals had to be removed to untreated land for four weeks in order to allow the grass to recover itself somewhat. These three .steers are at the time of writing (April, 1913) still alive and in .good health (see photo.), and, moreover, have grown and developed well throughout. The three control steers have all died of bush sickness, the symptoms exhibited being typical and the' clinical opinion confirmed by. post-mortem examination. The first control animal apparently exhibited the initial premonitory symptoms on the 30th April, 1911, and died on the 14th ’ February,

1912. The second exhibited the ’first premonitory symptoms on the 20th September, 1911, and died on the 25th April, 1912. The third exhibited the first premonitory symptoms on the 2nd October, 1911, and died on the 27th May, 1912. It should be further noted that these three control steers had not grown or developed, even before exhibiting any • symptoms, in the same normal manner as had the three on the top-dressed paddock. Rock salt was supplied to all alike,.

Experiments Nos. 2 and 3.

Paddock of cleared and grassed bush land about 5 acres in - area, which had been reploughed and sown down with English grasses and clover, manured with Malden Island guano, 10 cwt. per acre. Two

steers, about twenty-one months old, were placed on this paddock in July, 1911. • These animals have remained there throughout, showing no signs whatever of bush ‘ sickness, and v growing and developing in , a normal and natural way. One of these had two attacks of some form of ’indigestion, each of which threw it back temporarily, but on . both occasions a good recovery was made without treatment. . These animalswere transferred to the Mamaku Experimental .. Farm in - January last, being still in excellent . health. Since going on to the experimental farm they have remained well.. Two ewes were also placed in . thispaddock on the same date as the steers, but one of these unfortunately died as the result of an accident seven months afterwards. The second

lived and remained healthy for sixteen months, when it was worried by a dog. Neither suffered from bush sickness. Another experiment was carried out in an immediately adjoining paddock of similar land on the same farm. This was a small piece of land, slightly under 2 acres in area,, which was ploughed and sown down in English grasses and clover, and manured with blood and bone manure, 7 cwt. to the acre. One steer, about twenty-one months old, was placed on it on the 12th July, 1911, . and remained in perfect health and growing, well until January last, when it was removed to the Government farm. ; This animal has kept in good condition through the experiment, and when removed showed every sign of perfect health,and, moreover, since going on to the farm it has still remained healthy. Two ewes were also placed in this paddock on the 7th July, 1911. One died as . the result of an accident on the-26th February, 1912 ; the other was killed by a dog in November, 1912. Neither had developed bush -sickness. No control cattle were used .in these two experiments, but the farm is well known to be affected with bush : sickness,. the owner generally having found it necessary not to run young cattle on it for more . than eight or nine-months at a time without a . change, . ,

That the . soil - treatment given here did. not entirely ■ prevent the development of bush sickness was shown by the fact ■ that of three lambs born of the ewes running in- these paddocks with the steers (one ewe proved barren), two out of three died of bush-sickness.' All three . lambs were born about the 15th June, 1911. The deaths , from bush sickness occurred on the following dates : Ist January, 1912, and 30th March, 1912. The third lamb remained . healthy until fifteen months after birth, when it, with its dam,' was-killed by being worried by a dog. Lambs are much more susceptible to the development of bush sickness than are any other animals, becoming. victims of ~ it on only slightly affected land whereon cattle and older sheep will remain free from it. It was unfortunate that these experiments, so far as sheep and lambs were concerned, were incomplete owing, to accident. ‘ It is proposed in the next issue of the Journal to. give full particulars of each individual 'experiment in this series, \ including those which proved indecisive. The subdivision of the Mamaku Experimental and Demonstration Farm is now about completed. It has . been stocked, and all arrangements are well underway for commencing practical dairy-farming on it next season. ' ■

*lt is to be noted that the above quantities of fertilizers are large, and are not necessarily those which would be adopted in farming practice. •