UN SDG
Livestock Studies 1972, Vol 12, Num, 3     (Pages: 022-038)
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Possibilities of using skin follicle characteristics in the improvement of mohair production and mohair characteristics

B. Cahit YALÇIN

- Skin samples obtained from 5-5.5 month old single born male kds raised in 6 years (1966 – 1971) in the Angora goat flock kept at Lalahan Animal Breeding Research Institute, near Ankara, have been histologically examined in order to study the possibilities of using skin follicle characteristics in the improvement of important fleece characteristics. For this purpose, mean values for primary (nP), secondary (nS) and total (nP + nS) number of follicles in 1 mm2 skin area and average number of secondaries per primary follicle (S/P ratio) have been determined; heritabilities for these follicle charac-teristics have been estimated and phenotypic and genetic correlations between follicle and first year fleece characteristics have been calculated. Heritability estimates were obtained by paternal half-sib correlation method, using the records of 383 single born male kids sired by 78 bucks; sire groups having less than 3 progeny were excluded. Correlation analyses were performend on the records of 356 kids surviving to the first shearing (at about one year old), by the use of between and within sire variance and covariance components. Both the heritability and correlation analyses were carried out on within year basis.

Mean values for nP, nS, nP + nS and S/P in 6 years ranged between 1.50-2.41, 15.51-18.91, 17.01-21.33 and 7.91-10.30, respectively; overall means were 1.88, 17.07, 18.96 and 9.16 in the same order. Differences between years were significant for all characteristics (P<0.01). Heritabilities estimated for these characteristics were found to be 0.23, 0.36, 0.32 and 0.49 in the above order; heritability estimates obtained after eleminating the effects on follicle characteristics of weight of kid at sampling by covariance analysis were 0.24, 0.38, 0.34 and 0.52, respectively. Phenotypic correlations of nP, nS and nP + nS with greasy mohair production were close to zero, those with staple length and fiber diameter were negative and those with density score (obtained on live animal) were pozitive. Phenotypic correlations between S/P ratio and the above fleece characteristics were also found close to zero. Althought the correlations between follicle numbers (nS and nP + nS) and density score, staple length and fiber diameter were statistically significant (P<0.05 and 0.01), they all had low values (between + 0.19 and – 0.20). Genetic correlations of nP, nS and nP + nS with staple length were negative but those with the other fleece characteristics were pozitive. Genetic correlations of S/P ratio with mohair production and density score were positive, while those with staple mength and fiber diameter were negative. In general, genetic correlations were larger than the phenotypic ones, but only those between follicle numbers (nS and nP + nS) and staple mength (- 0.57 and – 0.58) respectively; (P<0.05), and that between S/P ratio and fiber diameter (- 0.84; P<0.01) were statistically significant.

The above results show that, fairly rapid increases in nS, nP + nS and S/P ratio, and therefore in fiber density, can be obtained through selection, but because of the strong negative genetic correlations between first two characteristics and staple mength as well as between S/P ratio and fiber diameter, increases due to selecting for these follicle characteristics will be accompanied by only small increases in greasy mohair production; on the other hand, any increase in S/P ratio will result in the finer fleece production. Keywords :