Abstract

There is increasing interest in the use of alternative forages to improve animal performance and reduce nitrogen (N) leaching on farms. A system-scale field trial, which included 20 hydrologically isolated drainage plots (800 m2 /plot) was carried out at Massey University’s ‘Keeble’ farm to investigate the effects of forage type on ewe and lamb performance and the quantity of N lost in drainage. Four forage types (treatments) were studied: perennial ryegrass/white clover (RGWC), plantain/WC (PWC), Italian ryegrass/WC (IRWC) and swedes (Brassica). The forage types were included as ~24% area of a self-contained farmlet, with the remaining area (~76%) being RGWC. Ewes were weighed at mating, pre-lambing and weaning, and lambs were weighed at weaning. Drainage (mm) from each plot was measured using a tipping-bucket flow meter and sub-samples of water were analysed for nitrate-N, ammonium-N and total-N losses. The forage types had no effect (P>0.05) on ewe or lamb live weight at any occasion. The average nitrate-N losses for RGWC (0.77 kg N ha-1), PWC (0.45 kg N ha-1) and IRWC (0.56 kg N ha-1) treatments did not differ (P>0.05) and was lower than the brassica treatment (6.36 kg N ha-1).

S, Maheswaran, LM Cranston, JP Millner, DJ Horne, JA Hanly, PR Kenyon, and PD Kemp

New Zealand Journal of Animal Science and Production, Volume 81, Online, 146-152, 2021