Abstract

Perennial ryegrass (RG) and Matua prairie grass swards of low (LMPG) and high (HMPG) pre-grazing herbage masses were compared in 8 grazing trials (2-3 weeks) during early spring, late spring, summer and autumn (1987/88 and 1988/89) to assess their feeding values. Pre- grazing masses were approximately 3000, 4000 and 5500kg DM/ha for RG, LMPG and HMPG treatments, respectively. Friesian cows (8 per treatment) were allowed 50 kg DM/cow/d. Mean concentrations of N (% in OM) and OMD (%) for RG, LMPG and HMPG herbage were 2.7, 2.6, 2.3 (s.e.lsm 0.04, P<0.001); and 74.7, 73.1 and 70.7 (s.e. 0.18, P<0.001), respectively, HMPG values were lowest during all seasons and were influenced by high compositions of dead material, low leaf:stem ratios and low compositions of clover in the swards. Daily yields of milk and protein on RG swards were 3% higher (P<0.05) than LMPG yields, and 11 and 13% higher (P<0.001), respectively than those of HMPG swards. Milkfat yields were similar on RG and LMPG swards, but were 11% lower (P<0.001) on the HMPG treatment. The results indicate that leafy prairie grass and leafy ryegrass swards have similar feeding and productive values. Further research is needed on Matua's persistence under grazing.

PGC, Douch

Proceedings of the New Zealand Society of Animal Production, Volume 50, , 229-236, 1990