Not AvailableThis study was done to test the effect of Azolla as supplemental feed on the milk production and economics under field conditions with 106 farmers in Chitradurga district of Karnataka. Azolla production units of 6 x 4 feet size were established in 11 villages spread across Hiriyur, Challakere and Hosadurga taluks of Karnataka state. The Azolla samples were collected from different villages and their nutrient content was analyzed.700 grams of Azolla was fed to the cows daily and milk yield was continuously recorded for 70 days. The dry matter content of Azolla varied between 4.2 and 5.6% and the crude protein from 19.1 to 22.3%. Azolla supplementation for 60 days improved the mean daily milk production from each cow by half a litre, and the returns by Rs.9.60. The higher milk yield was most probably due to supplementation of protein and essential amino acids through Azolla. This low cost supplementation of Azolla can improve the mean returns from single cow (through additional milk yield) by Rs.240 per month in the villages. The ICBR was calculated to be 1: 3.97, indicating the high economic utility of using Azolla for regular supplemental feeding.ICA