The effect of the level of application of selection and breeding criteria as factors of sustainable sheep production on productive traits of sheep in extensive rearing system

Abstract

For the purpose of realization of the project of development of sustainable sheep production systems, in this paper, the major influences on production parameters of sheep in conditions of Stara Planina Mountain are investigated. Using the knowledge of gene effects, with good breeding programs, it is possible to realize, with more or less success, planned annual genetic progress of traits which are of interest to the breeders. This relates first of all on gain of lambs and milk yield in sheep. As already known, traits of body development and milk production vary depending on the factors of hereditary nature, but also factors of the environment. Therefore, the level of application of selection-breeding criteria is of great practical importance, which is confirmed also in this paper, and level of significance was statistically confirmed. Also, for complete creation of the program of improvement of sheep milk and meat production it is important to be aware of the effect of the breed itself, as well as of type of birth on production parameters, which was taken into consideration during investigation, processing and presentation of data in this paper. Obtained results show that majority of observed factors had significant effect on realized production of sheep. .