DETERMINING THE GENETIC PARAMETERS OF MERINO SHEEP AND POSSIBLE APPLICATIONS IN THE TROPICS AND SUBTROPICS
OLGA SLANÁ, IVAN ŠÁDA, FRANTISEK VOHRADSKÝ
Abstract
For the development of the performance characteristics
of local sheep breeds in the countries of the tropical and subtropical regions
it is important to work out adequate procedures of analysing the genetic parameters
which are essential for effective selection. The paper evaluates the variations
of five performance indicators in a complete population of year-old breeding
lambs of both sexes (n — 744) born in 1986. Eight internal and external environmental
factors were used to assess the performance characteristics and the her stability
coefficients. The genotypic and phenotypic correlations were assessed on their
basis.
The following mean values of performance characteristics were recorded in the
group of animals tested: grease wool 4. 9 kg, pure wool 2.8 kg, wool rendement
58.3 %, mean fleece fineness 25.6 microns, and live weight 59.4 kg. The internal
and external environmental effects were statistically significant in all the
characteristics studied, except for the effect of the age of the sire and the
age of the dam. The effect of the month of birth upon wool rendement was also
insignificant.
A high heritability coefficient was recorded in the rendement and mean fineness
of fleece (h2 = 0.693 and 0.582), high values of genetic correlation were recorded
in the relationships of greasy wool + pure wool (RG = 0.645)f pure wool + rendement
and mean fineness (PG = 0. 761 and 0. 773} and rendement + mean fineness (RG
~ 0.669. A weak negative correlation was recorded in the relationship of wool
rendement + live weight (RG = - O. 119) * The analysis was conducted as a model
application to breeding sheep populations in tropical and subtropical countries.
Key words:
genetic parameters, heritability, Mutton Merino