- Mohair production and reproduction of Angora and Angora x Boer goat genotype does
|Last update: November 22, 2010 02:01:16 PM|
MOHAIR PRODUCTION AND REPRODUCTION OF ANGORA AND
ANGORA X BOER GOAT GENOTYPE DOES
Grootfontein Agricultural Development Institute, Private Bag X529, Middelburg (EC), 5900, South Africa
Email: Gretha Snyman
A project aimed at developing an easy care, hardy goat, with a relatively high reproductive ability and good carcass characteristics, and which will also produce good quality mohair, free from kemp and medullated fibres, was initiated at the Jansenville Experimental Station in South Africa in 1988. Two genotypes, viz. a 75 % Angora goat : 25 % Boer goat (G1) and a 87.5 % Angora goat : 12.5 % Boer goat genotype (G2) were subsequently established. The objective of this paper is to evaluate mohair production and reproduction performance of the does of these two established genotypes against that of pure bred Angora goat does.
Production data collected on the breeding does (G1 = 898 does; G2 = 798 does; Angora = 468 does) from 1995 to 2001 include body weight, fleece weight, clean yield percentage, clean fleece weight, fibre diameter and staple length. Two mathematical models were fitted to the data. The first included fixed effects due to genotype, year, age of the doe and a genotype x year interaction, as well as residual error. The second model, fitted only to data from G1- and G2-does, included a fixed effect for generation and a genotype x generation interaction as well.
Reproduction data collected from does from 1991 to 2001 included number of does mated, number of does kidding, number of kids born and number of kids weaned. Differences between genotypes with regard to the percentage of does that kidded, percentage of kids born per doe mated or kidded, survival rate of kids from birth till weaning and percentage of kids weaned per doe mated, were tested for significance with the Chi-square-procedure of SAS. For the analyses of variance of total weight of kids weaned per doe per year, the mathematical model included fixed effects due to genotype, year and age of doe, as well as residual error.
Significant differences between genotypes were observed for all production traits. G1-does had the highest body weight (42.3±0.2 kg), followed by G2-does (37.6±0.2 kg) and Angora does (33.6±0.3). Angora does produced the heaviest fleeces (3.39±0.04 kg/year), compared to the G2 (3.24±0.03 kg/year) and G1 (2.85±0.03 kg/year) does. Mohair fibre diameter of the G1-does (35.6±0.1 µm) was finer (P<0.01) than those of the G2 (36.1±0.0 µm) and Angora does (36.0±0.1 µm) respectively. The only significant effect of generation of the doe was on body weight, where 3rd generation G2-does were heavier than their 2nd and 1st generation counterparts.
With the exception of kid survival rate, significant differences were observed in all reproductive traits among does of the three genotypes, where G1-does performed the best, followed by the G2-does and then the Angora does. The following reproductive performances were recorded for G1-, G2- and Angora does respectively: 82.0 %, 77.7 % and 70.4 % does kidded per 100 does mated; 141.3 %, 115.0 % and 119.7 % kids born per 100 does kidded (fecundity); 115.9 %, 89.4 % and 84.3 % kids born per 100 does mated; 94.0 %, 71.2 % and 65.1 % kids weaned per 100 does mated. Kid survival rate from birth to weaning was 83.3 %, 81.9 % and 78.5 % for the respective genotypes, while total weight of kids weaned per doe per year (P<0.01) was 16.3±0.5 kg, 13.6±0.5 kg and 7.1±0.7 kg for G1-, G2- and Angora does respectively.
This study showed that by utilizing Boer and Angora goat genetics, it was possible to breed a robust mohair producing genotype, which is able to produce and reproduce under extensive conditions without any supplementary feeding.