The objective of this research paper was to estimate heritability coefficients (heritability) of growth traits in the lambs of indigenous Sjenicka Pramenka breed. The research was conducted on a sample which included 421 lambs the descendants of 15 sires and 187 sheep-dams, raised on 3 private farms in Kolubarski district, Serbia. The effect of fixed factors was studied while the values of heritability coefficients were estimated within the frame of SAS software package. A statistically highly significant (**=P<0.01) effect on studied traits had following parameters: sex, year of lambing, type of lambing, farm and method of applied reproductive technology. By means of REML method and using the sire model the values of heritability coefficients were determined for the following traits: average lamb birth weight (BW0), average lamb body weight at 30 days (BW30) and average lamb body weight at 90 days (BW90) being: 0.0355; 0.4642 and 0.3018, respectively. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. TR-31086]

The aim of this study was to examine the breeding and housing conditions and their impact on the manifestation of variability of microclimatic parameters in facilities for keeping dairy cows. The systematic measurement of microclimate parameters was performed in buildings, that is temperature ( ) and relative humidity of air (RV%) in the period from 2014 to 2020 was performed on 12 farms from 6 administrative districts in the Republic of Serbia. A total of 478328 individual hourly measurements of temperature and relative humidity of air were analyzed. The fixed model, which included factors of farm size, month, hour, and farm for the manifestation of THI with a statistically high influence of all factors involved. All surveyed farms had a high potential for the development of heat stress in June, July and August. The greatest variability of THI was between small and large accommodation farms. Medium-capacity farms had consistently the highest average THI values and potential for heat stress development.