A deterministic dynamic model to compare different dairy breeds for farm profit in Bangladesh M K I Khan 1 , H T Blair 2 and N Lopez-Villalobos 2 1 Department of Genetics & Animal Breeding, Chittagong Veterinary and Animal Sciences University, Chittagong-4225, Bangladesh kikab1775@gmail.com (Corresponding author); 2 Institute of Veterinary, Animal and Biomedical Sciences, Massey University, Palmerston North 11 222, New Zealand Summary The aim of this study was to develop a dairy farm model to estimate profitability on an individual cow, and whole farm basis under cooperative dairying in Bangladesh. A deterministic, dynamic, model was developed by simulating herd dynamics, nutrition, and the biological and economic performance of an average farm. The energy requirements of calves and cows of different genotypes for maintenance, lactation, pregnancy, body weight gain and cow replacement were estimated. Holstein crossbreds produced comparatively higher lactation yields and profit than other genotypes. The net annual incomes for different genotypes were US$63 for Pabna cattle, US$55 for Sahiwal ´ Pabna, US$ 52 for Australian-Friesian-Sahiwal ´ Pabna, US$138 for Jersey ´ Pabna, and US$ 193 for Holstein ´ Pabna. After considering costs against revenue, the returns on the capital investment in Australian-Friesian-Sahiwal ´ Pabna, Sahiwal ´ Pabna, Pabna cattle, Jersey ´ Pabna and Holstein ´ Pabna, genotypes were 3.8%, 4.2%, 5.0%, 10. 4 % and 13.8%, respectively. The outputs of the simulation models were considered to be realistic representations of existing farms. The simulation study showed that dairy farming under cooperative dairying in Bangladesh was modestly profitable. Keywords: farm model; requirements; costs; revenues; profit Introduction A number of dairy cattle economic evaluation studies have been carried out in the tropics, but only a small number of farming activities and constraints were considered in the development of the models. For example, researchers (e.g. Kanchan & Tomar, 1984) may have only considered returns from sales of milk and manure, and the costs associated with milk production, in their economic evaluation. While in other profit function studies (e.g. Kahi et al., 2000), only returns from sales of calves, culled cows and milk sales were considered. That is, for most tropical dairy cattle economic evaluation models, some farming components that affect farm profit were missing. Therefore, the objectives of this study were to: develop a dairy farm model; estimate the profit of individual cows; estimate whole farm profit, and compare four genotypes by modelling an average Bangladesh dairy farm.