Abstract :
Central performance testing of meat goats has increased in popularity recently, but minimum
test duration has not been ascertained to assess accurately performance traits. This
study was conducted to determine the minimum length of time required for accurate evaluation
of growing Boer bucks for ADG, dry matter intake (DMI), DMI/BW0.75, and feed
efficiency as assessed by ADG:feed intake and residual feed intake. Data were collected
from 425 bucks enrolled in Langston University tests lasting 84 days from 2000 to 2009.
Bucks averaged 111 ± 25 days of age and 27 ± 8 kg BW at the beginning of the test, consumed
a pelletized 50% concentrate diet ad libitum, and were weighed weekly. Daily feed intake
was determined with Calan gates (American Calan, Inc., Northwood, NH) or automated
MK3 FIRE feeders (Feed Intake Recording Equipment, Osborne Industries Inc., Osborne,
KS). Weekly data of five performance traits were analyzed using the MIXED procedure of
SAS with a repeated-measures model. Residual variance relative to that at 84 days (%) for
the goats fed with Calan gates was 358, 293, 235, 193, 153, 127, 116, and 107% for ADG,
184, 173, 161, 149, 136, 123, 113, and 106% for DMI, 374, 317, 256, 203, 161, 137, 118, and
107% for DMI/BW0.75, 445, 320, 225, 162, 135, 124, 111, and 105% for ADG:feed intake, and
174, 154, 143, 128, 113, 107, 103, and 102% for residual feed intake at 28, 35, 42, 49, 56, 63,
70, and 77 d, respectively. Residual variance relative to that at 84 days (%) for the goats fed
with FIRE was 286, 221, 192, 174, 154, 134, 125, and 110% for ADG, 111, 113, 111, 112, 111,
107, 106, and 105% for DMI, 176, 155, 144, 130, 120, 110, 110, and 110% for DMI/BW0.75,
373, 258, 216, 171, 134, 119, 114, and 106% for ADG:feed intake, and 114, 101, 103, 95, 94,
92, 98, and 103% for residual feed intake at 28, 35, 42, 49, 56, 63, 70, and 77 d, respectively.
Under either Calan gates or FIRE feeding conditions, the duration of Boer buck performance
tests could be decreased from the standard 84 to 63 days with little loss in accuracy
