author(s)
Hemant Kumar, Seema Kumari, Ravindra Kumar Sohane, Basant Kumar and Kumar Akhilesh Mohan

abstract
A field trail was conducted at farmer’s dairy farm belonging to Purnea district of Bihar with an objective to see the effect of supplementation of bypass fat in the ration of lactating crossbred cow on economics of dairy farming. The thirty crossbred lactating cows were randomly divided into three equal groups having ten in each in such a way that the parity and average milk yield of cows of three treatment groups were almost similar. Group-I (Farmer’s practice) was fed with a basal diet without any supplement of bypass fat, groups-II and group-III were fed with basal diet supplemented with bypass fat @100g/day/animal and 150g/day/animal, respectively for 60 days. The representative samples of feed offered was subjected to dry matter determination to find out daily dry matter intake of the cows. Milk yield from individual cow was recorded daily during milking i.e. morning and evening for 60 days regularly. Milk samples were analysed daily for milk composition in lactoscan milk analyser. Analysis of variance had significance influence on almost all the economic traits under study. There was a progressive increase in all the economic traits with the increase of level of bypass fat in the diet of lactating cows. The average milk yield and 4% fat corrected milk (FCM) 11.90±0.28 and 11.35±0.21, 12.60±0.43 and 13.09±0.44 and 13.20±0.42 and 14.05±0.45 Kg/cow/day were recorded in group I, II and III, respectively. The total return/cow/day from sale of milk was found to be Rs. 340.53±6.23, 392.63±13.07 and 421.45±13.52 in group I, II and III, respectively. The corresponding net return/cow/day was Rs. 159.71±3.63, 192.75±12.09 and 212.10±16.07, respectively.