Seasonal variations in pasture quality on New Zealand sheep and
beef farms
A.J. LITHERLAND, S.J.R. WOODWARD, D.R. STEVENS, D.B. McDOUGAL,
C.J. BOOM, T.L. KNIGHT AND M.G. LAMBERT AND M.G. LAMBERT
AgResearch Limited, Private Bag 11008, Palmerston North
NZSAP 2002 Abstract No. 35
Proceedings of the New Zealand Society of Animal Production 62:
138-142
Nineteen sheep and beef farmers in the Waikato, Tararua,
Canterbury and Southland regions collected two pre-grazing pasture
samples offered to either lambs or bulls once every month from autumn
2000 to autumn 2001. One sample of pasture on offer was collected to
ground level and the other was hand plucked to represent pasture
selected by animals. The samples were analysed by NIRS for chemical
composition and dissected into morphological components. Energy
concentration of herbage was lowest in autumn and highest in spring.
Energy concentrations of offered pasture were 8.1, 9.2, 7.6 and 10.0
MJME/kg DM in autumn and 10.3, 11.6, 10.8 and 11.4 MJME/kg DM in spring
in Waikato, Tararua, Canterbury and Southland, respectively.
Crude-protein, fibre and soluble-carbohydrate concentrations reflected
the changes in ME. Variations in dead material and reproductive stem
were the main causes of changes in ME. Predicted liveweight gain of
350-kg bulls grazing pasture with a pre- and post-grazing herbage mass
of 2500 and 1500 kgDM/ha respectively, were 0.4, 0.8, 0.0, and 1.1 kg/d
in autumn, and 1.2, 1.5, 1.4 and 1.6 kg/d in spring, for Waikato,
Tararua, Canterbury and Southland regions, respectively. It is concluded
that high animal performance in summer and autumn may not be achieved in
summer-warm regions without the addition of high-quality forages or
supplements.
Keywords: NZSAPAB;
pasture; metabolisable energy; crude protein; farm; sheep;
cattle; seasonal pattern
Last Updated 30/07/2002
