Abstract

Pasture growth and quality, and lamb growth rates were measured on a conventional grass based trial unit of 87.8 ha and a high legume unit of 85.1 ha, established to investigate climate-risk management strategies within high stocking rate dryland sheep farming systems. There was no difference between the units in total pasture production with a pasture utilization of 71.7% and 74.3% on the grass and legume units, respectively. Metabolisable energy values remained close to, or above, the target values throughout the growing season. Preweaning lamb growth rates averaged 304 g/day on both units. There were significant differences between singles (342 g/day), twins (300 g/day) and triplets (254 g/day) and between lambs from first cycle (294 g/day) and main mob ewes (315 g/day). There were some differences in lamb growth rates between different pastures types but these were not consistent between years. Post-weaning growth rates averaged 137 g/day with significant differences attributable to litter size, mob and year. Growth from birth to sale averaged 295 g/day, slightly less than the target of 300 g/day. Thus high lamb growth rates are possible on a range of pasture types on dryland at low pasture covers of high quality.

AC, Bywater, CM Logan, GR Edwards, and JR Sedcole

Proceedings of the New Zealand Society of Animal Production, Volume 71, Invercargill, 103-108, 2011