111 Present address: 1 Veterinary Officer (shandilyavet @gmail.com), Government Sheep Breeding Farm, Pipalkoti, Chamoli, Uttarakhand. 2 Senior Scientist (anuchatterjee @gmail.com), 3 Principal Scientist (dr.pkroy@rediffmail.com). Organic dairy farming is gaining importance in the world to obtain organic milk for better human health. It includes feeding and rearing of animals on organic feed and fodder grown without use of pesticides and chemical fertilizers, the creation of compatible environment for production, health management following organic norms. Indian traditional animal husbandry system has potential for conversion to organic animal husbandry system considering the large livestock population which are well adapted to local situations and mixed – crop livestock farming (Chander and Mukherjee 2005). In general, the conversions of organic milk production system possess a more or less relevant decrease in milk production, which is at least partially recovered when the new system is well established (Vaarst et al. 2003). The percentage of organic milk production shows an increasing trend on global basis. With the growing awareness among the educated and economically sound class of people in India, there is a good scope for production and marketing Indian Journal of Animal Sciences 85 (11): 1263–1266, November 2015/Article Productive and reproductive performance of cows reared under organic vis-à-vis conventional management system in West Bengal S K SHANDILYA 1 , A CHATTERJEE 2 and P K ROY 3 National Dairy Research Institute, Eastern Regional Station, Kalyani, West Bengal 741 235 India Received: 12 May 2015; Accepted: 13 May 2015 ABSTRACT The study was conducted on 24 Jersey × Tharparkar / Red Sindhi cows maintained at the Institute farm to find the impact of organic dairy farming on milk production, milk composition and reproductive performance of cows and compared with the performance of cows reared under conventional management system. Cows under first year organic production management system (OPMS) had significantly higher yield than the performance of cows under third year OPMS. The differences between first and second year and between second and third year performance was not significant. There was a decrease in milk production in the second year and thereafter reduction rate was very low in the third year. Production and reproduction traits were not affected by the management systems (organic and conventional). The 3-year performance data revealed that the 305-day milk yield was slightly higher for cows maintained under conventional management system than the performance of cows maintained under organic management system (2,488.75 kg vs. 2,392.47 kg). Reproductive performance was better in the organic group than the conventional group. The cows maintained under organic management system had significantly higher fat % (5.25±0.08%) than the cows maintained under conventional management system (4.72±0.11%). Significantly higher protein% was observed for the cows maintained under conventional management system (3.76±0.04%) as compared to the cows maintained under organic management system (3.28±0.03%). The cows under organic management had lower SNF % and higher total solid % than the cows maintained under conventional management. However, the differences were statistically nonsignificant. The results indicated better reproductive performance and higher fat % in organically managed cows than conventional. Key words: Milk composition, Milk production, Organic dairy farming, Reproductive performance of organic milk in urban areas. Keeping this in view, the present study was undertaken to find out the impact of organic dairy farming on milk parameters and reproductive performance of cows. MATERIALS AND METHODS The study was conducted on 24 medium to high yielding Jersey × Tharparkar / Red Sindhi crossbred cows of first to third parity, calving normally, spread over a period of 4 years (2008 – 2011) and maintained at NDRI, Kalyani farm. Out of 24 cows, 12 cows were selected randomly and maintained under organic management system. The rest 12 cows were kept under conventional management system. Information regarding production and reproduction parameters was collected from both groups of cows. The cows were maintained in the loose housing system under group feeding. For each cow, milk yield, lactation length, date of calving, date of first AI, date of conception, number of AI/conception and date of dry were recorded for generating the data like 305 day milk yield, total milk yield, lactation length, milk yield per day of lactation length, calving interval, milk yield per day of calving interval, days from calving to first service and service period.