EVALUATION OF BREEDING VALUE OF YOUTH KARAKUL SHEEP AFTER THE COMPLEX SELECTION INDICES

I. Buzu

Abstract
   The aim of the research was to reveal the methodological principles and to elaborate the formulas for evaluating the breed value of youth Karakul sheep according to the complex selection indices. The scientific researches were carried out on a batch of youth Moldavian Karakul sheep of the National Institute of Animal Husbandry and Veterinary Medicine from village Maximovca, Anenii Noi. The complex selection indices for youth Karakul sheep was built on the basis of three selected morpho-productive characters: furskin quality, expressed in points; own body mass (kg) and mother's milk production (kg). The complex selection indices of youth were built according to the formula I_cs=(M_fp ∙ C_fap)+(M_fmc ∙ C_famc)+(M_fpl ∙ C_fapl), where: I_cs – complex selection indices of youth;M_fp – the phenotypic size of the furskin quality; C_fap - coefficient of aggregate phenotype of furskin quality; M_fmc - the phenotypic size of the body mass of the youth; C_famc - coefficient of aggregate phenotype of body mass; M_fpl - the phenotypic size of the mother's milk production; C_fapl - coefficient of aggregate phenotype of milk production of ewe-mothers. Scientific research has shown that for the assessment of sheep youth's breeding value according to the comlex selection indices it was necessary to establish the race standard after all three selected morpho-productive characters. Subsequently, the coefficients of the aggregate phenotype for each selected character were determined. As a result, it has been found that the determination of Karakul sheep youth's breeding value according to the complex selection indices is one of the most objective and effective methods, because it contains both phenotypic and genotypic elements of appreciation. The complex selection indices for youth sheep can be determined at any age, from birth to adult age. Determining the breeding value of Karakul lamb after complex selection indices is of scientific and practical importance because they are often marketed at early ages. The specificity of determining the aggregate phenotype coefficient for body mass is a particularity of the principles of construction of the complex selection indeces of youth Karakul sheep. The size of the aggregate phenotype coefficient of body mass in youth sheep varies according to the standard of body mass not only at standard ages but also at intermediate ages.