Abstract

Plantain is a productive and persistent pasture species known for its capacity to feed livestock over summer, but there has been limited research published on grazing management and lamb production from Tonic plantain in summer without irrigation. Farmlet scale (individual plots ranged from 0.44 – 0.75 ha over the three years), randomised and replicated experiments, with grazing lambs on pure swards of Tonic plantain were undertaken over three summers. The treatments were sward height at pre- and post-grazing and stocking rate. Study one was in a wet summer and the plantain was not water-stressed, whereas in study two, it was mainly dry and the plantain was regularly under stress, and in study three, the summer rainfall was erratic, resulting in a period of water stress at the beginning of the experiment. The average daily weight gains (ADG) of the lambs ranged from 81 to 219 g/day across the three studies. The highest ADGs were when soil moisture was not limiting plantain growth and post-grazing sward height was greater than 5 cm (approximately 1500 kg DM/ha). The crude protein concentration of plantain was low (156 -175 g/kg DM) when plants were water stressed and high (236 g/kg DM) when rainfall was adequate. It was concluded ADG of lambs grazing Tonic plantain in summer was greatest when pre- and post-grazing sward heights were 8 and 5 cm, respectively (2000 and 1500 kg DM/ha herbage mass) and the plantain was not water stressed. It is recommended that Tonic plantain be sown with pasture legumes to increase its feeding value and crude protein concentration.

PD, Kemp, PR Kenyon, ST Morris, T Johnston, H Appleton, and HK Best

Proceedings of the New Zealand Society of Animal Production, Volume 74, Napier, 94-101, 2014