Influence of birth type on body weight of lambs from birth to weaning in various strains of sheep Pramenka

The dynamics of increasing of bodyweight of lambs is conditioned by genetic factors, environmental factors and their interaction. The aim of this work was study variability of bodyweight of lambs related to type of birth of lambs in sheep genotype of four different strains of pramenka type and four growth stage: at the birth time, at the 30, 60 and 90 days of age after birth. For this investigation used lambs of four strains (Svrljiški, Pirotski, Sjeniĉki, Šarplaninski) of sheep type Pramenka (450 lambs per strain) for study dinamics of bodyweight at the time of birth, 30, 60 and 90 days after birth during three years of experiment (2011-2013). The results showed that the bodyweight of lambs born singles was higher than bodyweight of lambs born twins in studied four sheep genotypes i.e. Pirotski (4.00 kg : 3.40 kg), Svrljiški (3.90 kg : 3.79 kg), Sjeniĉki (3.73 kg : 3.61 kg), Šarplaninski (3.81 kg : 3.74 kg). The differences of bodyweight between lambs born singles and twins was significant for genotypes Pirot pramenka and Svrljig pramenka, on the level of significance for Sjenica pramenka and was not significant in Šarplanina pramenka. At the age of 30 days, the influence of birth type on the bodyweight of lambs was not statistically significant in any of the examined strains. The difference of bodyweight between singles and twins was statistically significant at the 60 days old of lambs in Svrljig pramenka and in lambs at 90 days old of Svrljig pramenka. On the base of results is established that type of born associated with significant differences of bodyweight at the birht time expressed later at the 60 and 90 day old lambs

PHENOTYPIC AND MOLECULAR PREDICTION AND SELECTION OF DOMESTIC ANIMALS

Environmental factors are always present, it is difficult to reliably determine the value of an animal's genotype. The fact that genotypes are not passed from generation to generation, but numerous genes that exhibit average effects in relation to the mean value of the population also complicated genotype assessment. In order to estimate the genotype of an individual as accurately as possible, we must apply a series of procedures that collectively at the end of the journey can give us a clearer picture of what we are looking for. The basis of selection work is the assessment of the breeding value of domestic animals on the basis of which the selection of individuals or groups for further reproduction and use in production. With the development of computer technology, statistical software was obtained, which enabled faster and more reliable data processing and assessment of breeding value, using linear models. From the first ideas of DNA molecule analysis for that purpose until today, many procedures have been applied and improved and many genetic markers and methods have been discovered, so that in practical terms it is necessary to accept a common platform called genomic selection. Genomic selection - is a powerful tool for future use. Currently, the efficiency of genomic selection is limited by various interactions between the locus of quantitative traits, the variability of quantitative traits, and the influence of environmental factors. However, research results in many countries have confirmed that the use of standard statistical methods together with genomic selection increases reliability in predicting the breeding values of animals