- Evaluation of a genetically fine haired Angora goat flock
|Last update: November 25, 2010 08:28:21 AM|
EVALUATION OF A GENETICALLY FINE HAIRED ANGORA GOAT FLOCK
M. A. Snyman & P. J. Griessel
Grootfontein Agricultural Development Institute, Private Bag X529, Middelburg (EC), 5900
In 1988, a project which involved the establishment and evaluation of a genetically fine mohair flock, was initiated at the Angora Goat Experimental Station near Jansenville in the Eastern Cape Province of South Africa. The aim of this project was to breed a goat which produces fine mohair, without sacrificing body weight, but still conforms to the breed standards set for South African Angora goats. The performance of the established fine hair flock is evaluated against that of a control flock, which was run together with the fine hair flock for the duration of the project. Body weight, fleece trait and conformation trait data, collected on kids born from 1994 till 1998 in the fine hair (n=1120) and control flocks (n=710), were analysed with least‑squares mean methods. Data collected on ewes present in the flocks from 1993 till 1999 included body weight, fleece weight, fibre diameter, clean yield percentage and staple length. Reproduction data collected on the ewe flock from 1988 to 1999 comprised records from 419 fine hair and 301 control flock ewes. BLUP of breeding values were estimated for body weight, fleece weight and fibre diameter measured at 18 months of age and for the subjectively assessed traits, style, character and evenness of fleece. Body weights of fine hair kids were significantly higher than those of control flock kids from weaning till 18 months of age. Fibre diameter of the fine hair kids was finer (P<0.01) than that recorded for the control flock kids at all ages, the difference being larger for the ewe than the ram kids. Fine hair ewe and ram kids produced hair that was respectively 2.31 µm and 1.47 µm finer than that produced by control flock kids at 14 months of age. Fleece weight of the fine hair kids was generally lower than that produced by the control flock kids. Young goats from the fine hair flock produced fleeces of better style and more ideal in character than those of the control flock (P<0.01). Evenness of fleece was better in the fine hair goats than in the control flock goats. There was no significant difference in body weight between ewes in the fine hair and control flocks. Fine hair ewes produced 0.36 kg less hair per year, which was 2.55 µm finer than the hair produced by the control flock ewes. Genetic trends in the fine hair and control flocks showed that for all traits, with the exception of fibre diameter, the control flock goats remained genetically constant throughout the duration of the project. Positive trends were obtained in the fine hair flock for body weight, style, character and evenness of fleece, while significant negative trends were recorded for fibre diameter and fleece weight. At the end of the experimental period, fine hair young goats were heavier and produced less, but finer mohair of better style and character, which was more even, than the control flock goats. During the third shearing at 14 months of age, 56.7 % of kids in the fine flock produced fleeces with a fibre diameter below 28.0 µm (fine kid hair), compared to 22.2 % in the control flock. Furthermore, 57.9 % of the kids in the control flock produced young goat and coarser hair (> 30 µm), compared to 21.3 % in the fine hair flock. A similar trend is evident for the ewe flock, where 68.9 % of ewes in the fine hair flock produced kid or young goat fleeces (<34 µm), 25.2 % produced fine adult hair (34 to 36 µm), and only 5.9 % produced coarse adult hair (> 36 µm). In the control flock 50% of the ewes produced coarse to over coarse adult mohair. The results of the study suggest that genetic selection for reduced fibre diameter, while maintaining or improving body weight, can be effective in South African Angora goats. In a selection programme aimed at decreasing fibre diameter in Angora goats, fleece weight should also be considered to prevent it from decreasing too much. One of the most important results of this study is that a larger proportion of fleeces from the fine hair goats could be classed into the finer, higher value classes, compared to those produced by the control flock goats. This could have a large impact on the financial return from mohair produced by the fine hair flock.