Ryegrasses with increased water soluble carbohydrate: evaluating the potential for grazing dairy cows in New Zealand

Abstract

An elevated concentration of water soluble carbohydrate (WSC) in grasses may increase the availability of readily degradable energy, increase milk production and improve the efficiency of nitrogen utilisation. Two ryegrasses with elevated WSC, a tetraploid Italian (IRG) and a diploid perennial selected for higher WSC (HSG), were compared against a standard diploid perennial (STG) during spring 2004 and 2005, and autumn 2006 and 2007. Groups of cows (n=20) grazed each grass type for periods of 6 weeks in spring and 2 weeks in autumn. During spring, the 'high' WSC grasses were 20-40 g/kg DM higher in concentration of WSC than the standard (P