Milksolids production and farm profitability from different combinations of perennial ryegrass and white clover cultivars: Progress report 2001-2003

Abstract

2001/2002 and 2002/2003 were the final two seasons of a replicated dairy farm systems trial designed to evaluate the effects of progress in perennial ryegrass and white clover breeding programmes on whole farm productivity and profitability (Economic Farm Surplus, EFS). All the pastures were sown in late autumn 1998. There were four treatments with all combinations of 1980's (80R), and late 1990's (98R) ryegrasses, and 1960's (60C) and late 1990's (98C) white c lover s, each replicated two times in a randomised block design giving eight 4 ha, self-contained farmlets stocked with three Friesian cows/ha and rotationally grazed. In agreement with the first two years of the trial, the last two seasons have demonstrated no major benefit in terms of either milksolids (MS) production or EFS to sowing different combinations of perennial ryegrass and only a small advantage in one season (2001/2002) to sowing new (98C) white clover cultivars. There were no effects of ryegrass or clover cultivar type on total dry matter (DM) production during the last two seasons but, as observed during the first two seasons of the trial, there were differences in the distribution of pasture growth through the year with old ryegrass (80R) treatments having more pasture growth during spring. During 2001/2002 and 2002/2003 the clover content of the swards was determined more strongly by clover type than by the type of companion ryegrass, in contrast to events during the first two seasons of the trial. Thus clover type, rather than a ryegrass x clover interaction, had a small effect on MS production and EFS during 2001/2002, but not 2002/2003, due to significantly higher clover content in both the new clover (98C) treatments than the old clover (60C) treatments. Any differences between ryegrass or white clover cultivars in terms of lower DM production at certain times of the year, and consequent small differences in total DM production and pasture quality caused only minor differences in EFS between treatments because effective farm management decisions compensated for these effects. Keywords: cultivars, dairying, economic farm surplus, milksolids, perennial ryegrass, white clover