The rational management improvement of roughage production and dairy farming in Korea. 2. Optimal dairy farming for the changes of productive and economical factors
Research Reports of the Rural Development Administration, Farm Management, Agricultural Engineering, Sericulture, and Farm products Utilization 34(1): 17-24
The optimum methods for dairy farming were studied using the LP-Model in 4 systems; only dairy cows kept (purchase of replacement heifers and sale of all calves); dairy cows plus replacements from within herd and sale of surplus calves; dairy cows plus replacement from within herd, sale of surplus female calves and all male calves fattened on rice straw; and dairy cows plus replacements from within herd, sale of surplus female calves and all male calves fattened on hay (methods 1, 2, 3 and 4, respectively). Increasing milk yield from 5500 to 6000 kg per cow increased annual gross margin by 18.1, 15.4, 14.8 and 14.9% and increasing age of cows from 5 to 6 years old increased annual gross margin by 6.2, 4.6, 4.5 and 4.1%, respectively. The optimal roughage:concentrate ratio was 39.6:60.4.