A complementary forage system whole-farm study: forage utilisation and milk production

Abstract

Australian dairy farmers are facing decreasing availability of land and water and declining terms of trade. In this context, systems that are able to increase milk production per ha from home-grown feed, beyond the potential of pasture only, are sought. The complementary forage system (CFS), combining an area with a rotational sequence of two or three forage crops per year with an area of pasture in 35 and 65% of the farm area, respectively, was developed for this purpose. A 2-year whole-farm study with 100 milking cows on 21.5 ha evaluated the feasibility of achieving 25 t DM/ha.year of home-grown feed and converting this into 35 000 L of milk/ha.year by the implementation of such CFS. Utilisation and nutritive value of all forages and milk yields of individual cows were measured daily, body condition and bodyweight weekly, and milk composition fortnightly. Over 26 t DM/ha.year was utilised over the whole CFS farm for the 2 years of the study. This utilised forage had a mean metabolisable energy value of 10.2 MJ/kg DM and crude protein content of 20.5% DM. From this, a total yield of 27 835 L of milk/ha.year from home-grown feed was obtained, which is higher than any other whole-farm study reported in the literature. Daily pasture intake was the variable with the highest impact on milk yield, and significant differences were found in body condition and milk yield of cows calving in either autumn or spring. This study warrants further investigation to determine the environmental and economic sustainability of the implementation of the CFS.