Milk samples pertaining to first to fifth lactation from 120 native cows belonging to three districts of Assam, (India) were utilized to study the effect of location, lactation order and stage of lactation on certain physio-chemical traits of milk. The least squares mean for specific gravity, fat per cent, solids-not fat per cent, total solids per cent, protein per cent and pH in the milk of native cattle of Assam were found to be 1.027±0.0003, 5.341±0.067, 8.544±0.035, 13.885±0.07, 3.047±0.036 and 6.745±0.012 respectively. Location showed highly significant effect on fat, solids-not fat, total solids and protein per cent except on specific gravity and pH of milk. Order of lactation had nonsignificant effect on all the milk constituents under study. However, stage of lactation showed highly significant effect on fat, solids-not fat and total solids percentage and non-significant effect on specific gravity, protein content and pH in milk.
