The aim this study was analyse factors effecting on the milk production in select herd of the Slovak spotted breed. Data were analysed using the Statistical Analysis System version 9.3.1 and linear model with fixed effects of herdyear- season of calving, breeding type, father, number of lactation. Average of traits of milk production was 3 539.82 kg of milk, 143.59 kg of fat, 115.94 kg of proteins and 168.13 kg of lactose, 4.05 % fat, 3.28 % proteins and 4.75 % lactose. The linear model to represent coefficient determination R2 = 0.3783 for milk production with all fixed effects. The analysis by the effect was the highest effect of herd-yearsseason of calving (0.2515) than effect of number of lactation (0.1133). In assessing of individual various sources of variability on production traits had statistically most significant effect on milk production herd - year - season, father and order of lactation sources of variability P≤ 0.001. Statistically not significant impact had order of breeding type source P> 0.05. Correlation coefficients between kgs of milk and fat, kgs milk and proteins and kgs milk and lactose (r=0.90032, r= 0.97531, r= 0.98905), were statistically high significant.