Background: The production traits are quantitative traits governed by polygenic inheritance and influenced by non-genetic factors. The present study was under taken to study the effect of sire and some non-genetic factors on production traits of frieswal cattle under field progeny testing. 
 
Methods: The study utilized data spanning nine years (2013-2021) on frieswal cattle maintained under the field progeny testing (FPT) programme at the Pantnagar centre of AICRP on progeny testing. Traits analyzed included FL305-DMY, TDPY, FP and FLL. Data were classified by year and season of calving. Statistical analysis was performed using SPSS (version 20) and the mixed model least squares and maximum likelihood programme to assess the effects of non-genetic factors. 
 
Result: The overall means of 3086.28&plusmn;14.86, 12.87&plusmn;0.07, 3.48&plusmn;0.01 and310.55&plusmn;0.40 with CV% of 19.95, 18.97, 11.68 and 4.47, respectively, for First lactation 305-days milk yield (FL305-DMY), Test day peak yield (TDPY), Fat percentage (FP) and First lactation length (FLL). The effect of sire and period was highly significant (P&lt;0.01) on all the traits under study whereas effect of season was non-significant on all the traits under study. The study revealed that the Frieswal herd under the under field progeny testing is performing well with the moderate performance status compared to other cattle genetic resource of country. Also, the prevailing microclimatic conditions of Uttarakhand, with respect feed and fodder availability influence reproduction performance. Further, these cattle are well adapted to the seasonal environmental fluctuation of area. 
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Estimation of Least Squares Means and Non-genetic Factors for Production Traits in Frieswal Cattle under Field Progeny Testing