New Zealand Journal of Agricultural Research abstracts

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Short communication

Effect of age of pre- and post-pubertal castration of bulls on growth rates and carcass quality

T. W. KNIGHT
G. P. COSGROVE
A. F. DEATH
C. B. ANDERSON

AgResearch Grasslands
Private Bag 11008
Palmerston North, New Zealand

Abstract  Groups of bulls were castrated at birth (CB), 6 months of age (C6), or 12 months of age (C12) to test the hypothesis that age at castration had no effect on subsequent liveweight or carcass weight but can be used to manipulate carcass fatness. There was no significant difference in carcass weight among the groups (287, 292, and 288 +/- 3 kg for CB, C6, and C12, respectively). Liveweight gain (LWG) from birth to 6 months was lower for CB than for C6 or C12 (1.08 +/- 0.02 kg d^-1 versus 1.15 +/- 0.02 kg d^-1 P < 0.01). For several measures of carcass fatness there was a linear trend for increasing fatness with decreasing age at castration. For example, fat depth increased (6.9, 7.7, and 9.3 +/- 0.06 mm, P < 0.05) and weight of channel fat increased (7.95, 8.64, and 9.03 +/- 0.55) for the C12, C6, and CB treatments, respectively. Varying the age of castration may be used as a tool to manipulate carcass fatness to meet market specifications.

Keywords  bulls; castration; growth rates; carcass characteristics

New Zealand Journal of Agricultural Research, 2000, Vol. 43: 585-588

0028-8233/00/4304-0585 $7.00/0 (c) The Royal Society of New Zealand 2000

PDF file of entire paper: medium quality (302K); (scanned from paper original: notes about this process)

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