The aim of this study was to investigate the effects of monthly air temperature and rainfall variations on the reproductive performance and lambing distribution of the Jezersko-Solčava breed in northwestern Croatia during 7 years period from 2010 until 2016. At 11 medium-scale sheep farms, the sheep were kept on a pasture in a semi-intensive environment with access to the stables. The anomalies of rainfall observed on a monthly basis during monitoring were statistically significant. Non-parametric test showed that the percentages of lambing differ among the months during the year (P = 0.0001). By using regression analysis, it was found that the percentages of pregnant sheep were linearly associated with the sequential number of the month. The seasonal distribution of lambings were 53.85% of ewes delivered in winter (n = 1296), 21.13% in spring (n = 509), 8.91% in summer (n = 215) and 16.11% in autumn (n = 387). Sexual activity was lowest during spring and early summer (from March to May) with a peak from the end of July to October. The conception rate during year 2011 was significantly lower (89.74%), and the litter size was the lowest (1.05) than in other years of the observation. Average conception rate was 92.85% and average litter size 1.21. Despite being a seasonally polyoestrous, the distribution of matings and lambings of this breed of sheep was not uniform throughout the seasons. There were established a positive or negative correlations between the air temperature and rainfall precipitation variations with tested reproductive performances of Jezersko-Solčava breed sheep in the Northwestern part of Croatia.
Keywords: Air temperature; Jezersko-Solčava breed; Lambing distribution; Rainfall.