A comparison of two systems of organic milk production

The physical and financial performance of two systems of organic milk production have been studied to determine the effect of either increasing the level of self-sufficiency in home-grown feeds and sustainability of the system (Self-sufficient system) or maintaining a higher stocking density by importing concentrate inputs (Imported-feed system). The results presented are from the first year of the study. In the self-sufficient system increasing the level of self-sufficiency to 99.2% was achieved by establishing a crop rotation based on both forage and grain production, leading to an average crop yield of 8,070 Scandinavian Feed Units/ha and a stocking density of 1.44 livestock units/ha. Milk production was 5,407 kg/cow and 6,709 kg/ha from an input of 0.4 t of concentrates per cow. Of the total feed energy requirements for the dairy herd 90% was provided by forage. In the imported-feed system an all-forage rotation was established with purchased concentrate feeds (energy and protein sources) imported to balance the nutritive quality of the home-grown forage. The average crop yield was 9,280 Scandinavian Feed Units/ha and the stocking density 1.67 livestock units/ha. Concentrate inputs were 1.3 t/cow and milk production 6,093 kg/cow and 9,232 kg/ha, significantly higher when compared with the yields from the self-sufficient System. Feeding a low quantity of concentrate feed in the self-sufficient system increased the production of milk from forage to 4,441 kg/cow compared with 2,950 kg/cow in the system based on imported concentrate feed. The utilisation of home-grown feed sources for energy production, calculated as UME (Utilised Metabolisable Energy) values was significantly higher from the dairy cows in the self-sufficient system (84.8 GJ UME/ha) compared with those in the imported-feed system (58.8 GJ UME/ha).