Wool samples from 47 Barki yearlings were taken from five positions during two years to study the variability in the fleece, the cause of variability and associations between different fleece traits. Statistical analysis has indicated the following significant points.An antero-posterior gradient occurred in the different traits under study. When medullation was discarded, though it was of a low magnitude (3-9%), a reduction of 5-89% in the mean fibre diameter and of 18-33% in its standard deviation occurred.The position most representative of the whole fleece varied with the trait. It is recommended to take three sampling positions forming a triangle, withers, mid-side and hip, to represent the Barki fleece.The animals contributed the major part in the variability of mean fibre diameter (.X^), the standard deviation of fibre diameter (s.D-i), percentage medullation, mean fibre diameter after discarding the medullated fibres (X 2 ), the standard deviation of fibre diameter after discarding the medullated fibres (S.D. 2 ), the contribution of medullation to the total variability, percentage fine fibres and percentage coarse fibres. The positions were the main contributor to the variability of percentage kemp fibres, staple length, medullation index and to a certain extent to that of the kemp score. The year played a significant part in the variability except for X 2 and S.D. 2 .The highest correlations with the standard deviation of fibre diameter were those of H lt percentage medullation and kemp score. These three variables when considered separately accounted for 0-47, 0-35 and 0-31 respectively of the variability in S.D.Equations were obtained to predict the standard deviation from both the mean fibre diameter and the percentage medullation and to predict the mean fibre diameter from the staple length and the kemp score. The coefficient of determination of the first set of equations ranged from 0-47 to 0-56 while that of the second set ranged between 0-07 and 0-51 for different positions. INTRODUCTIONdifferent characters and to study the cause of variability. Such information may indicate a Because of their uniformity, synthetic fibres possible way of improving this type of wool and represent a source of great competition to wool, of assigning it to its most suitable category for a fact which emphasizes the importance of reduc-industry, ing the variability in the natural product.The fleece of Barki sheep (Fahmy et al 1969) MATERIALS AND METHODS has a relatively high variability in wool fibre diameter. In an earlier study (R. A. Guirgis, Forty-seven yearling Barki sheep were used, unpublished) the mean fibre diameter was 33-94 fi 28 in 1969 and 19 in 1970, and wool samples were with a coefficient of variation of 46-11%, when taken from five positions (Guirgis, 1967): three samples were taken from different lots of fleeces, dorsal positions -withers, back and hip -and two However, no information is available on how the lateral positions -mid-side and breech. The traits variability in fleece traits is affected by ...

A study of fibre-type arrays in relation to kemp succession in Kerry, Cheviot-cross and Swaledale lambs has been carried out. It is found that:1. There is a general association between HH grade and array such that higher grades tend to have stronger arrays.

SUMMARYA study was carried out during three successive years from 1970 to 1972 on different wool types. Breed groups involved were Merino (M), coarse-wool Barki sheep and five of their crosses. Traits studied were greasy-fleece weight, clean-fleece weight, kemp score and means of staple length and fibre diameter in the whole fleece.The heaviest greasy fleeces were produced by ¾ followed by ⅝ M. Total average greasy fleece weight of the crosses was 3·43 kg. There was a general trend of increase in greasy fleece weight with increasing Merino proportion.The total average percentage clean yield of the crosses was 42·2, and ½ M and ¾ M produced the heaviest clean fleeces. The total average clean fleece weight of the crosses was 1·44 kg. Skirting the fleeces caused a reduction in the within-fleece variability of staple length and diameter. Percentages reduction for staple length were 10·3, 9·6 and 14·6 and those for fibre diameter were 2·4, 5·0 and 9·5 in Barki, crosses and Merino respectively.Barki had the coarsest diameter and the whole fleece of ¾ M showed the finest mean diameter of the crosses. The within-staple variability in distribution of fibre diameter was high in Barki and throughout the crosses. The average percentage medullated fibres was highest in Barki and decreased throughout the series of crosses. The ¼ M had the highest frequency medullated fibres of the crosses.The longest mean staple in the crosses was produced by ¼ M. The within-fleece variability in staple length was generally low. In the crosses, the variability assumed slightly higher values than those of the parental breeds.Kemp production was mainly contributed from the dorsal line, particularly from the back and hip.As regards some wool and mutton characteristics, ⅝ M might be considered the most suitable cross-bred type.With increasing Merino contribution in the crosses, the mean fibre diameter showed a decreasing trend, but a high within-staple variability was maintained throughout the crosses. Inter se mating, in most of the crosses, produced animals that showed relatively more uniformity between fleeces than either both or one of the crosses. Inter se mating of the different cross-bred types with selection of the desired uniformity in length and diameter would be recommended.

SUMMARYData were collected from 549 Barki and Merino cross sheep during 1967, 1968 and 1969 to study the relation between kemp production and body vigour. The study also included the staple length and greasy fleece weight. The results showed that:Age had a marked effect on the traits studied. Whereas kemp frequency (score) declined slightly as age proceeded, showing a significant reduction in the seventh shearing season, the staple length and fleece weight decreased after the second shearing season.Differences due to sex, year and breed occurred, though the pattern differed in the different traits.Kemp showed a highly significant correlation with birth and weaning weights, as indicating the animal vigour, and was negatively correlated with fleece weight.Staple length was negatively correlated with birth and weaning weights and positively correlated with fleece weight.Fleece weight was positively correlated to birth and weaning weights and negatively correlated to kemp score.Kemp score in the Barki sheep was shown to be quite repeatablo (repeatability = 0·5).

SUMMARYA study using 1150 lambs to estimate genetic and phenotypic parameters of some weight and fleece traits was carried out on coarse-wool Barki sheep. The weight traits were birth, weaning, yearling weights and daily gains whereas fleece traits included kemp score, staple length and greasy-fleece weight.Heritability estimates of weight traits were within the range 0·25–0·30. Those of fleece traits were 0·16, 0·21 and 0·43. The repeatability estimates of fleece traits were 0·18, 0·38 and 0·53 for staple length, greasy-fleece weight and kemp score respectively.Phenotypic correlations between body weight and fleece traits were mostly positive. Genetic correlations between greasy-fleece weight and body weights were mostly positive and of medium values. Those between kemp score and body weights were mostly negative, ranging from medium-high to high.