H.—34.

returns. Exploratory work on these aspects of wool-production, their inter-relationships with each other and with the environment, their inheritance, and their possible association with mutton conformation and breed type in the Romney has been commenced. The results obtained are treated under the following heads : — (a) Medullatio.n Research. Investigations on the measurement and recording of medullation in Romney fleeces, commenced some years ago and interrupted from 1935 to 1938, have been resumed with a detailed study of sampling and grading technique, sources of error, and a general survey of environmental factors affecting the manifestation of medullation. In addition, a search has been made of records accumulated by the Massey Agricultural College Fleece Testing Department with a view to obtaining information relating to the intensity of the inheritance of this important wool characteristic, thus enabling the cost, in power of selection, of breeding for freedom from medullation, to be estimated. Statistical analyses of the available records revealed that data could be collected by different observers without introducing error. Errors arising through the sampling of fleeces were found not to influence the grading of a sheep by more than one grade, which was not very serious, and sampling at five points in the fleece gave results substantially as correct as when six samples were chosen. It has been found that seasonal influences have played a greater part in the occurrence of medullation than was suspected, and 40 per cent, of the total medullation may be attributed to season and 60 per cent, to the individuality of the animal. To get a true measure of the variations duo to the individuality of sheep it is essential that these be maintained under precisely the same conditions. No clear evidence has yet been secured to indicate whether medullation is inherited. In a flock comprised of animals whose fleeces show little medullation, improvement is likely to be very slow ; indeed, so slow as not to justify attention being devoted to improvement. If, however, rams showing a high degree of freedom from medullation are used with low-testing ewes, their progeny will show sufficient improvement in their fleece characters to make the effort economically sound. The presence of halo hairs in the wool of the lamb is no indication of the degree of medullation which will occur in the mature fleece, nor can the claim that medullated fleeces are the heaviest be substantiated. Nevertheless, there is evidence that seasons of heavy average fleece weight are those also in which the degree of medullation increases. Some breeders claim that medullation is associated with big sheep, but an analysis of data collected did not support this, though it revealed a strong relationship between body weight and fleece weight. Another claim that medullation is associated with the strong constitution necessary for hill-country sheep was tested out in a flock of 700 Romney ewe hoggets and could not be substantiated. (b) Halo Hair Investigations. Analyses of records of data derived from the fleece coats of some 700 lambs show that simple selection against halo hairs would be almost immediately effective in reducing the amount of medullation. The results also show that the wool characters of the britch areas are the most strongly inherited. (c) Fleece Weight and Quality Investigations. Examination of fleece weights in a flock showed that the standard deviation for weight of fleece within count groups was of the order of 1-25 lb., which is surprisingly high. Now, as the fleece weight of any sheep remains fairly constant in successive years, and therefore, if the young ewe flock was culled on account of fleece weight, the average of the flock would fairly steadily increase, and, seeing that fleece weight is a fairly strong hereditary character, with the use of progeny-tested rams it would be possible, within a comparatively short period, to increase the average fleece weight by as much as 2 lb. per sheep. Considerable attention, therefore, is being paid to fleece weight, at the present time, in order to determine what relationships, if any, exist between other fleece characters such as count, general character, length of staple, medullation, age of sheep, and environmental conditions. Such information, when available, will enable an accurate forecast to be made of the effect of intensive selection for any one character, such as fleece weight, on the remainder of the fleece. (d) Yield-determination Investigations. Although prices are quoted for wool as so much per pound in the grease, these are calculated from the estimated clean scoured yield. To determine the yield of a fleece is almost as important, therefore, as to determine the weight of a fleece and, with the temporary assistance of Mr. J. Godfrey, attempts are being made to secure a micro-method for determining yield which can be applied to samples cut for medullation estimation. If this work is successful we will be in the position to place in the hands of the breeders the means whereby complete recording of the wool quantity and quality ca,n be achieved and, if these be utilized in practice, there seems to be no reason why the spectacular improvements effected by the dairy breeder should not be duplicated in the sheep industry. (e) Relationships between Wool Characters and Body Conformation. Even for hill-country farms the importance of wool in the production of total gross income is only of the order of 50 per cent., the remainder being made up from the sale of surplus stock. Since returns from the sale of surplus stock are dependent in large measure on characteristics of the animal apart from its wool, it is necessary that wool characters be considered in relation to mutton conformation and breed type. If correlations between fleece and carcass exist they must manifestly be of importance in any programme designed to promote increased returns. From investigations on the connection between mutton and wool characters, there would appear to be a tendency for animals graded in higher classes for mutton conformation on the hind quarter to carry fleeces of higher grade and quality.

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