The effect of paragenetic factors on milk yield of sheep

Abstract

Selection of sheep according to milk yield is increasingly present especially in Mediterranean countries due to production of high quality cheeses, for instance hard cheese. This demands knowledge of genetic parameters of milk yield traits, as well as of the effect of paragenetic factors. Investigation of these paragenctic factors was objective of this paper. Investigations were carried out in the region of Stara planina mountain on population of Pirot Pramenka sheep breed. The effect of year, lactation, type of birth and number of offspring on milk yield was investigated. It was established that the effect of year as paragenetic factor varied from not significant to significant. Lactation had significant effect on milk yield since the lowest value for the milk quantity was registered in the first and the highest in third lactation. Type of birth had no significant influence on investigated trait. The size of litter had significant influence on milk yield since higher quantity of milk was established in case of sheep with twins compared to ship with single offspring.