EVALUATION OF THE LIVE WEIGHT AND PURE WOOL PRODUCTION FOR SHEEPS AT THE AGE OF ONE-YEAR BY MEANS OF THE ANIMAL-MODEL

Utilization of the animal model should bring an important precise definition of breeding value estimation and improvement of the prerequisites for an increase in selection efficiency. Utilization of all available information on efficiency of ancestors and siblings and inclusion of repeatability of the observed properties were the priorities of this model. During the spot evaluation the class for efficiency was layed down on the basis of objectively determined live weight and pure wool production at the age of one year and it was joined with the class for fleece and exterior classifications. From synthesis of these data the final class is determined and it is a certain type of index. For the population observed we used this method in comparison with evaluation of the same properties by the animal model using the information from pedigree. Variability of properties and differences at population evaluation by the spot system presented in comparison with the animal model utilization were evaluated. We were finding out, whether the information on breeding value is more accurate and whether it can establish conditions for improvement of the efficiency of selection in the sheep population. The analysis of efficiency of the ,,Sumavka'' (S) sheep breed population and synthetic group of cross-breds with the different share of genes from the Romney Marsh sheep breed (Kent - K), Romanov sheep breed (R), Finnish sheep breed (F), Improved Wallachian sheep breed (ZV) and Texel sheep breed (T) was carried out. The population had been observed over the years 1988, 1989 and 1990. Totally 925 individuals were evaluated, out of which the efficiency is known for 515 individuals. The following indicators were evaluated: live weight, pure wool production and mean fineness at the age of one year. The analysis of the final breeding class, determined by the index of the basis of spot evaluation, was carried out. Steady effects on efficiency at the age of one year (genotype, litter size, dam age and the year and month of birth) were considered. All relations were used for numerical expression of estimation of breeding values of the individuals. Estimation was carried out individually for particular observed properties. Solving the problem is performed by the iterative method and statistical significances of particular effects are not known therefore. For all individuals both with efficiency measured and in pedigree an order in estimated breeding value for weight, pure wool and the class, determined by the spot evaluation at the age of one year, was laid down. Correlations among the indicators were calculated. Live weight at the age of one year was 42.65 kg and the average pure wool production was 3.11 kg (Tab. I). Standard deviation for both properties proves higher variability, which establishes conditions for efficient selection. The average of mean fineness - 37.61 mum expresses predominance of the initial breed. The individuals of similar type as the initial domestic breed, which is evidently the most suitable for the given environment, seem to be in the process of hybrid individuals selection also included into breeding. In this respect a natural selection could be of any effect, too. Found out differences in the live weight among the levels of steady effects were relatively small and they were approximately 7.81 % of the average weight, in the pure wool even only 6.11 %. The highest differences were found out in the mean fineness, they were 15.46 % there. Crossbreds with fertile breeds and the Texel breed reached the highest values in the live weight and the group of S x KJ crossbreds was the second. In pure wool shearing a group with the share of fertile and K breeds was manifested as the best and the initial S population was the weakest. In the mean fineness the highest values were found out for the group with smaller share of fertile breeds and the K breed. The initial S population had more crude wool. The deviations in the class correspond in an order with deviations of the genotypes in the mean fineness, but pure wool and live weight have the different order than the class determined by the index. Also a litter size had an effect on the differences in live weight and pure wool production. Singletons were heavier and they manifested higher pure wool shearing, mean wool fineness was higher comparing to the twins. The effect of dam's age was negligible for the indicators observed. The highest production values were found out in the progeny of three to four years old dams. For older and younger dams the live weight and pure wool of progenies decreased. Only in the mean fineness with the increased age of dams a finer assortment was gradually recorded. Besides the age also an effect of the year when a dam was born was considered and it can better express changing environment and genetic trend. The results indicate that some, however insignificant, differences actually exist. They were manifested in the live weight more markedly than in pure wool, but a trend in both properties was equal, Lay-out of breeding values, determined by the animal model, is besides pure wool considerably irregular and a higher part of individuals obtained negative breeding values. Variability for all the properties observed is adequate. Found correlations between utility properties and the class determined by the index were low and negative (class - live weight r = -0.089, class - pure wool r = -0.298, class-mean fineness r = -0.066). On the contrary the correlation among utility properties were higher, significant and positive (live weight - pure wool r = 0.554, pure wool - mean fineness r = 0.463). It is obvious that also another indefinable factors have an effect on the complex evaluation during the spot evaluation. Proper efficiency considers this evaluation only little. The class laid down from the efficiency spot evaluation and on the basis of visual classification is of a low conclusiveness, which can cause the differences between estimated and factual selection effect. The animal model utilization during the process of evaluation contributes to an objective utilization of complex information on the proper efficiency, parental and relationships efficiencies at simultaneous elimination of random and systematic errors.