New Zealand Journal of Agricultural Research abstracts
Pasture management to minimise the detrimental effects
of pre-lamb shearing
M. H. HUSAIN
S. T. MORRIS*
S. N. MCCUTCHEON
Department of Animal Science
Massey University
Palmerston North, New Zealand
W. J. PARKER
Department of Agricultural and Horticultural Systems Management
Massey University
Palmerston North, New Zealand
Abstract The purpose of this study was to examine whether the
performance of pre-lamb shorn sheep is influenced by pasture allowance in the
immediate post-shearing period and whether the relationship between performance
and pasture allowance differs according to whether the ewes are shorn by
standard comb or cover comb. The trial was replicated across two years to allow
for climatic variations between years. Fifty-four ewes were used in each year
in a 3 x 3 x 2 factorial design with three shearing treatments (standard comb,
cover comb, and unshorn), three sward surface height (SSH) treatments (nominal
3, 5, and 7 cm), and two pregnancy status treatments (single and twin). Rectal
temperatures of standard comb or cover comb ewes were significantly lower (P
< 0.05) than those of unshorn ewes on day 2 following shearing (S2), and
on S4, S8, and S20. Pasture allowance, however, did not affect rectal
temperatures of shorn ewes. There was an interaction (P < 0.05)
between shearing treatment and SSH. Thus, liveweight gains during the period
from pregnancy day 115 (P115) to P135 were 275, 613, and 4518 g; 1557, 2314,
and 3997 g; and 3623, 2894, and 3997 g for standard comb, cover comb, and
unshorn (control) ewes set-stocked on 3, 5, and 7 cm SSH, respectively. There
was no interaction between shearing treatment and SSH for lamb birth weight,
but the birth weights of lambs born to standard comb ewes (4.9 +/- 0.1 kg) were
significantly greater (P < 0.05) than those of lambs born to unshorn
ewes (4.3 +/- 0.1 kg). There were no effects of shearing treatment or SSH on
lamb weaning weight, ewe wool growth rate or mean fibre diameter. Likewise,
there were no effects of shearing treatment or SSH on ewe organic matter intake
(OMI), except on the second day following shearing when the OMIs of ewes
set-stocked on 3 cm (941 +/- 147 g) were significantly (P < 0.05)
lower than those of ewes grazing 5 cm (1628 +/- 101 g) or 7 cm (1349 +/- 135 g)
SSH pasture. The results suggest that hypothermia, as determined by rectal
temperatures and induced by pre-lamb shearing, cannot be avoided by pasture
management, provided SSH exceeds 3 cm. This reflects the fact that, in the
period immediately after shearing, ewes do not increase feed intake when
provided with increased pasture allowances.
Keywords sheep; pre-lamb shearing; herbage intake; sward
height
New Zealand Journal of Agricultural Research, 1997, Vol. 40: 489-496
0028-8233/97/4004-0489 $7.00/0 (c) The Royal Society of New Zealand
1997
PDF file of entire paper: medium quality (621K); (scanned from paper original: notes about this process)
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