ABSTRACT
In this paper effects of major factors of genetic and paragenetic nature on milk yield of
existing sheep populations are investigated. Mathematical procedures for evaluation of genetic
and phenotypic parameters and anticipation of genetic values, today, are mainly based on
different linear and non-linear concepts, therefore it is necessary to accept the reality that there is
no absolute accuracy.
Results of the investigation have shown that there are positive and negative deviations in
monitored traits depending on the population, season, order of lactation, type of birth and litter
size. Considering that, sheep milk has decisive role in production of cheese. Results obtained in
this research can be used as indicator for more efficient projection of improvement programmes
in order to increase the production of milk and cheese.