In a commercial feedyard trial, 242
Holstein steer calves averaging 378 lb were
used to compare effects of six alternative
implant programs, consisting of sequential use
of Synovex-S® or a combination of estradiol
and trenbolone acetate (Revalor-S® or Finaplix-
S® plus Synovex-S®), on feedlot performance
and carcass characteristics. The calves were
implanted three times at 78- to 90-day intervals
while on feed an average of 252 days. The
combination implant increased (P<.05) gain
by .13 to .21 lb per day in all three implant
periods compared to Synovex alone. Total
feedlot gain was increased in direct relation to
the number of times steers received the
combination implant. However, marbling
score and the percentage of carcasses grading
USDA Choice tended to be reduced with
repeated use of Revalor or Finaplix.
