New Zealand Journal of Agricultural Research abstracts
Grazing management of oversown tussock country
3. Effects on liveweight and wool growth of Merino wethers
B. E. ALLAN
AgResearch
P. O. Box 60
Lincoln, New Zealand
Present address: Wattie Bush, Peel Forest, RD 22, Geraldine, New Zealand
Abstract The liveweight performance, wool production, and
wool characteristics of Merino wethers under nine different grazing management
regimes for oversown tussock pasture on a steep (30deg.), south-east facing
hillside (760-930 m altitude, 500 mm annual rainfall) in New Zealand was
measured for six consecutive years. Continuous stocking, alternating (two
paddock), and rotational (six paddock) grazing were each compared at low,
medium, and high stocking rates (1.9, 3.0, and 4.1 SU/ha/year, respectively).
By the sixth year, alternating grazing at the medium stocking rate gave maximum
liveweight gain/ha. An interaction was demonstrated, with advantage to
alternating and rotational grazing over continuous stocking strengthening with
increasing stocking rate. Liveweight gain for alternating and rotational
grazing was similar at all stocking rates, showing an advantage in animal
performance over that from continuous stocking can be achieved with a minimal
amount of subdivision fencing. The advantage to alternating and rotational
grazing over continuous stocking was most obvious during late spring/early
summer, suggesting that in practical terms runholders need to consider such
management for ewes in late lactation with lambs still at foot. Wool growth/ha
increased linearly with increased stocking rate, with advantage to alternating
and rotational grazing evident at high stocking rates. In contrast to the
lowland experience with Romneys, the rate of Merino wool growth declined as the
grazing season progressed. Fibre diameter was 1.5 um less at the high than
at the low stocking rate. Practical application is discussed, with emphasis on
achieving a realistic balance between objectives to maximise wool production
and those to sustain pasture production and maintain desired animal
liveweight.
Keywords tussock grassland; oversown tussock; grazing
management; stocking rate; Merino; liveweight; wool growth
New Zealand Journal of Agricultural Research, 1997, Vol. 40: 437-447
0028-8233/97/4004-0437 $7.00/0 (c) The Royal Society of New Zealand
1997
PDF file of entire paper: medium quality (753K); (scanned from paper original: notes about this process)
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