New Zealand Journal of Agricultural Research abstracts
Effect of sward surface height on herbage intake and performance of finishing
beef cattle
C. E. REALINI
J. HODGSON
Institute of Natural Resources
Massey University
Private Bag 11222
Palmerston North, New Zealand
S. T. MORRIS
Institute of Veterinary, Animal and Biomedical
Sciences
Massey University
Private Bag 11222
Palmerston North, New Zealand
R. W. PURCHAS
Institute of Food, Nutrition and Human Health
Massey University
Private Bag 11222
Palmerston North, New Zealand
Abstract This study examined the effects of contrasting sward
surface height (SSH) on the herbage intake, ingestive behaviour, and
performance of steers grazing perennial ryegrass (Lolium perenne)/white
clover (Trifolium repens) pastures in New Zealand during summer, and the
influence of this initial treatment contrast on subsequent cattle performance
under common grazing conditions during early autumn. Twenty-four Angus-cross
steers, 26 months old and with an initial liveweight of 522 +/- 7.6 kg, were
continuously stocked on swards maintained at SSH of 5 and 10 cm (L versus H)
from 18 November 1996. Six steers from each treatment were slaughtered on 4
March and the remaining animals were grazed for another 5 weeks on common
pastures until the final slaughter on 8 April 1997.
Herbage intake (estimated by the n-alkane technique) and liveweight
gain over the SSH contrast period, and carcass weight at first slaughter, were
higher for steers grazed at 10 cm than for those grazed at 5 cm (7.5 +/- 0.21
versus 5.0 +/- 0.18 and 7.8 +/- 0.38 versus 5.0 +/- 0.33 kg DM d-1
from two intake estimates, P < 0.05 for each comparison; 1.10 +/-
0.23 versus 0.32 +/- 0.21 kg d-1, P < 0.01; and 332 +/-
10.6 versus 287 +/- 7.5 kg, P < 0.05, respectively). SSH did not
affect carcass or meat quality characteristics. Liveweight and carcass weight
gain per hectare were 71% and 43% greater (318 versus 186 kg and 166 versus 116
kg over 105 days) for steers grazing at 10 cm despite the lower stocking rate
(2.86 versus 5.80 steers ha-1) maintained by the tall swards.
Significant differences in carcass weight were still evident at the end of the
compensatory period between the steer groups originally on treatments H and L
(335 +/- 9.4 versus 297 +/- 9.4 kg, P < 0.05).
These results suggest that maintaining a sward height of 10 cm offers
advantages in terms of individual animal output and output per hectare compared
with grazing at 5 cm, and that compensatory growth does not seem to be an
important phenomenon in heavy (over 500 kg liveweight) finishing steers.
Keywords sward height; herbage intake; grazing behaviour;
n-alkanes; liveweight; carcass; meat quality; compensatory growth; beef
cattle
New Zealand Journal of Agricultural Research, 1999, Vol. 42: 155-164
0028-8233/99/4202-0155 $7.00/0 (c) The Royal Society of New Zealand
1999
PDF file of entire paper: medium quality (847K); (scanned from paper original: notes about this process)
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