A commercial feedlot experiment was conducted using 1,558 heifers to evaluate the effects of implant programs on finishing heifers. Implanting with Synovex Plus increased ADG and hot carcass weight compared to heifers implanted with Revalor-H or Finaplix- H and fed MGA. Heifers implanted with either Synovex Plus or Revalor-H had increased DMI compared to heifers implanted with Finaplix-H. Marbling score was influenced by each of the implant treatments, being highest for Finaplix-H followed by Revalor-H and Synovex Plus

Dicke, Bill

Macken, Casey

Milton, Todd

English

UNL | Libraries

University of Nebraska - Lincoln 
DigitalCommons@University of Nebraska - Lincoln 
Nebraska Beef Cattle Reports Animal Science Department 
January 2002 
Implant Programs for Feedlot Heifers using Synovex® Plus™, 
Revalor®-H, or Finaplix®-H with MGA 
Casey Macken 
University of Nebraska-Lincoln 
Todd Milton 
University of Nebraska-Lincoln 
Bill Dicke 
University of Nebraska-Lincoln 
Follow this and additional works at: https://digitalcommons.unl.edu/animalscinbcr 
 Part of the Animal Sciences Commons 
Macken, Casey; Milton, Todd; and Dicke, Bill, "Implant Programs for Feedlot Heifers using Synovex® 
Plus™, Revalor®-H, or Finaplix®-H with MGA" (2002). Nebraska Beef Cattle Reports. 273. 
https://digitalcommons.unl.edu/animalscinbcr/273 
This Article is brought to you for free and open access by the Animal Science Department at 
DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Nebraska Beef Cattle 
Reports by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. 
Page 31 — 2002 Nebraska Beef Report
The prevalence of fecal shedding
of a detectable level of E. coli O157:H7
within a given group of feedlot cattle
varied widely over the feeding period
and the variability in prevalence was a
function of changes in both incidence
and duration of fecal shedding.
E. coli O157:H7 appeared to be ubiq-
uitous to this group of cattle since the
organism was recovered at least once
from each animal and the organism was
detected from at least one animal every
week of the study. It is interesting that
the range of prevalence for cattle shed-
ding E. coli O157:H7 in this longitudinal
study was nearly identical to the range of
prevalence we previously observed in a
cross-sectional study of commercial
feedlot cattle (2001 Beef Report, pp. 81-
84). Identifying the factors that explain
the difference between groups of cattle
with high or low prevalence may be
useful for devising a control strategy on
farms to enhance food safety. Some of
those factors may vary with time just
as the prevalence of shedding does.
Additional studies are in progress to
identify time-dependent factors that
explain fecal shedding of E. coli O157:H7
by feedlot cattle.
1Spring Younts, graduate student; David
Smith, assistant professor, Veterinary and
Biomedical Sciences, Lincoln; Jeffrey Folmer,
research technician, Animal Science, Lincoln;
Rodney Moxley, professor, Susanne Hinkley,
research assistant professor, Veterinary and
Biomedical Sciences, Lincoln; Jeff Gray, USDA,
ARS, ARRU, Athens, Ga.; Laura Hungerford,
associate professor, Margaret Khaitsa, post-
doctorate researcher, Veterinary and Biomedical
Sciences, Lincoln; Terry Klopfenstein, professor,
Animal Science, Lincoln.
Implant Programs for Feedlot Heifers using
Synovex® PlusTM, Revalor®-H, or Finaplix®-H
with MGA
(Continued on next page)
Casey Macken
Todd Milton
Bill Dicke1
Implanting feedlot heifers with
Synovex Plus increases ADG and
hot carcass weight but decreases
grade compared to heifers implanted
with Revalor-H or Finaplix-H and
fed MGA.
Summary
A commercial feedlot experiment was
conducted using 1,558 heifers to evalu-
ate the effects of implant programs on
finishing heifers. Implanting with
Synovex Plus increased ADG and hot
carcass weight compared to heifers
implanted with Revalor-H or Finaplix-
H and fed MGA. Heifers implanted with
either Synovex Plus or Revalor-H had
increased DMI compared to heifers
implanted with Finaplix-H. Marbling
score was influenced by each of the
implant treatments, being highest for
Finaplix-H followed by Revalor-H and
Synovex Plus.
Introduction
In finishing heifer implant programs,
the final implant (administered approxi-
mately 100 days prior to harvest) gener-
ally contains trenbolone acetate (TBA)
or a combination of estradiol (E2) and
TBA. Along with these implants
melengestrol acetate (MGA) can be fed
to enhance the activity of TBA. Implants
commercially available that contain TBA
or the combination of E2 and TBA are
Finaplix-H (200 mg of TBA), Revalor-
H (14 mg of E2 and 140 mg of TBA), and
Synovex Plus (28 mg of estradiol ben-
zoate (20 mg of E2) and 200 mg of TBA).
Within these implants, dosage, combi-
nation of hormones, and carrier of active
ingredients differ and may alter growth
promoting activity. Objectives of this
trial were to compare performance, car-
cass characteristics, and feeding eco-
nomics in heifers implanted with
Finaplix-H, Revalor-H, or Synovex Plus
and fed MGA.
Procedure
The experiment was conducted be-
tween the dates of Jan. 11, 2000 and
Aug. 3, 2000 using 1,558 heifers (761
lb) in a randomized block design. Heif-
ers were kept separate by truckload fol-
lowing unloading and were weighed.
Heifers from the separate truckloads were
randomly assigned to one of three im-
plant programs, one by one, using a gate
sort into one of three arrival pens and
then assigned to one of 18 home pens
(six replications/treatment). Treatments
were heifers terminally implanted with
1) Finaplix-H, 2) Revalor-H, or 3)
Synovex Plus with all treatments receiv-
ing MGA supplementation. The finish-
ing diet was formulated to provide 0.4
mg of MGA/head/d. Within a block, all
heifers arrived at the feedyard at the
same time. After sorting, pens were re-
weighed, processed, and moved to their
home pen. During processing, heifers
were vaccinated for viral diseases
(BoviShield® 4, Pfizer Inc,), treated for
internal and external parasites
(Dectomax®, Pfizer Inc,), implanted
with Ralgro®, and given a lot tag for
identification.
Heifers were reimplanted with their
respective treatment of Finaplix-H,
Revalor-H, or Synovex Plus following
2002 Nebraska Beef Report — Page 32
45 (range 35 to 58 days) days on feed.
Heifers were exposed to their final
implant for an average of 95 days
across replications (range 84 to 108).
Heifers were not fed MGA in the
adaptation diets (first 18 to 20 days on
feed). The final diet contained 48.0%
steam-flaked corn, 27.0% dry-rolled
corn, 9.0% supplement, 7.5% alfalfa
hay, 5.5% corn steep liquor, and 3.0%
fat, and was formulated to contain
13.7% CP, 7.0% crude fat, 0.77% Ca,
and 0.37% P. Heifers were fed an aver-
age of 139 days (range 127 to 166).
Initial weights were determined by
prorating each arrival treatment pen
weight back to the total of the group of
heifers within block and adjusted to pay
weight. For example, shrink (positive or
negative depending upon the source of
cattle) would be applied to the cumula-
tive off-truck weight of all heifers within
a block to determine pay weight for the
entire group. The weight of individual
pens, after heifers were sorted into
arrival treatment pens, was divided by
the cumulative weight of all three arrival
treatment pens. The total pay weight for
the entire group was multiplied by this
percentage to calculate the initial start-
ing (pay weight) weight for each home
treatment pen. Final live weights were
determined on a treatment pen just prior
to shipment, and shrunk 4%. Final live
weights were obtained under identical
weighing conditions for each treatment
pen within a block. Carcass weights also
were used and adjusted to a common
dressing percentage of 63% to calculate
daily gain and feed conversion on a
carcass-adjusted basis.
All pens within a block were har-
vested under identical conditions. Hot
carcass weights were recorded on the
day of harvest. Carcass fat thickness,
marbling score, KPH fat, longissimus
muscle area, and USDA quality grade
were recorded following a 24- to 48-
hour chill.
The economic influence of the
implant treatments was determined
using the ration cost at the feedyard
during the period the experiment was
conducted. The ration cost used in the
analysis includes markup. Nonfeed
costs (medicine, processing, etc.) were
calculated for each pen of heifers in
Table 1. Effect of implant strategy on performance and carcass characteristics in
finishing heifers.
Implant Strategya
PLUS REV FIN
Item MGA MGA MGA SEMb
Number of pens 6 6 6
Number of heifers 523 519 516
Days on feed 139 139 139
Initial weight 760 761 760 3.0
Final weightc 1250d 1235e 1232e 4.2
Dry matter intake 20.3d 20.1d 19.5e 0.2
Daily gain, lb 3.52f 3.39g 3.38g 0.05
Feed/gain 5.76 5.94 5.77 0.09
Carcass weight, lb 787d 778e 776e 2.7
12th rib fat, in. 0.53 0.54 0.54 0.01
Longissimus muscle area, sq. in. 14.5f 14.2f 14.0g 0.1
Calculated yield grade 2.6 2.7 2.7 0.1
Marbling scorei 5.26f 5.38g 5.48h 0.04
Quality grade distribution, %
Prime 1.9 1.4 2.8 0.5
Upper 2/3 Choice 16.1d 21.7e 24.0e 3.2
Low Choice 37.1 42.4 40.5 3.1
Select 41.8f 29.8g 25.9g 2.9
Standard 3.1 1.4 1.4 0.7
Dark cutters, % 1.2 2.0 0.0 0.8
aPLUS = Synovex Plus, REV = Revalor-H, and FIN = Finaplix-H.
bSEM = Standard error of the mean.
cFinal weight calculated as hot carcass weight divided by .63 (common dressing percentage).
d,eMeans within a row with different superscripts differ (P < .10).
f,g,hMeans within a row with different superscripts differ (P < .05).
iMarbling score: 4.0 = Slight; 4.5 = Slight 50; 5.0 = Small; 5.5 Small 50; etc.
Table 2. Effects of implant program on feeding economics of finishing heifers.
Implant Strategya
PLUS REV FIN
Item MGA MGA MGA SEMb
Ration costc, $/ton 131.50 131.50 131.50
Cost of feed, $/head 185.36d 183.59d 178.27e 1.6
Total feeding cost, $/head 194.24d 192.95d 187.32e 1.6
Cost of gain, $/cwt 39.74 41.09 39.85 0.65
Carcass pricef, $/cwt 107.56d 108.62de 109.51e 0.5
Profit(loss)g, $/head
Live basis 62.77 54.15 61.73 5.0
Dressed basis 86.91 76.42 81.11 4.7
Carcass merit basis 59.90 58.19 70.37 5.3
aPLUS MGA = Synovex Plus fed MGA, REV MGA = Revalor-H fed MGA, and FIN MGA =
Finaplix-H fed MGA.
bSEM = Standard error of the mean.
cIncludes feed mark-up.
d,eMeans within a row with different superscripts differ (P < .05).
fCalculated using a $111/cwt carcass base price: discounts = $10, Select; $20, Standard; $15, yield
grade 4 and 5; $30, dark cutter; premiums = $8, Prime; $3, upper 2/3 Choice; $3, yield grades 1 and 2.
gInitial animal cost = $78/cwt; animal returns based on $70/cwt live price, $111/cwt carcass price, or
calculated carcass value, respectively, interest not included.
the experiment and averaged. This
average nonfeed cost was applied to
each pen of heifers for calculation of
cost of gain and net return. Final
heifer value was calculated by using a
live price, dressed price, or a carcass-
merit price based on individual heifer
carcass value. Carcass value was calcu-
lated based on USDA quality grade,
calculated yield grade, carcass weight
and nonconformance (i.e. dark cutters).
A carcass base price of $111/cwt was
used for low Choice, yield grade 3 car-
casses weighing 550 to 950 lb. Dis-
counts were calculated as: $10, Select;
$20, Standard; $30, dark cutters; $25,
Page 33 — 2002 Nebraska Beef Report
light (<550 lb) and heavy (>950 lb)
carcasses; and $15, yield grades 4 and 5.
Premiums were calculated as: $8, Prime;
$3, upper 2/3 Choice; and $3, yield
grades 1 and 2.
Performance, carcass, and economic
data were analyzed as a randomized
block design using SAS. Least squares
means were separated using the Least
Significance Difference method when a
significant (P < 0.10) F-test was de-
tected. Variables were considered sig-
nificant when probability values less than
0.10 were obtained.
Results
Data are presented with deads and
chronics removed from the analysis. Feed
intake and total head days were adjusted
on a pen basis when deaths occurred or
chronic cattle were sold before their
home pen was. Feed intake and head
days were adjusted one day prior to the
removal of the animal from the pen as
either a dead or chronic.
Effects of implant programs on per-
formance of finishing heifers implanted
with Finaplix-H, Revalor-H, or Synovex
Plus supplemented with MGA are shown
in Table 1. Dry matter intake was higher
(P < 0.05) for heifers implanted with
Synovex Plus or Revalor-H compared
with those implanted with Finaplix-H.
On a carcass-adjusted basis, heifers im-
planted with Synovex Plus as the final
implant gained 4.2% (P< 0.10) faster
than heifers implanted with Revalor-H
or Finaplix-H as the final implant. This
resulted in 17 lb heavier (P < 0.05)
carcass-adjusted final weight for
Synovex Plus heifers compared to
Revalor-H and Finaplix-H heifers.
Carcass-adjusted daily gain of heifers
implanted with Revalor-H or Finaplix-H
was similar. Live performance daily gain,
final weight, and feed conversion were
similar among implant treatments.
Carcass characteristics are presented
in Table 1. Hot carcass weight was 10 lb
or 11 lb heavier (P < 0.05) for heifers
implanted with Synovex Plus compared
with heifers implanted with Revalor-H
or Finaplix-H, respectively. Hot carcass
weight was similar for heifers implanted
with Revalor-H or Finaplix-H. Dressing
percentage tended (P = 0.13) to be sig-
nificant among treatments. Longissimus
muscle area was larger (P < 0.05) for
heifers implanted with Synovex Plus
compared with Finaplix-H, with Revalor-
H being intermediate. Twelfth rib fat
thickness and KPH fat were similar
among treatments. Calculated yield grade
was similar among treatments. Marbling
score was lower (P < 0.10) for heifers
implanted with Synovex Plus compared
to those implanted with either Revalor-
H or Finaplix-H. Revalor-H implanted
heifers had a lower marbling score than
Finaplix-H heifers. The percentage of
carcasses grading USDA upper 2/3
Choice was lower (P < 0.05) and per-
centage of carcasses grading USDA Se-
lect was higher (P < 0.10) for heifers
implanted with Synovex Plus compared
to those heifers implanted with Revalor-
H or Finaplix-H. Carcasses grading
USDA Standard and the incidence of
dark cutting carcasses were similar
among treatments.
A summary of the economic analysis
is provided in Table 2. Cost of gain was
similar among treatments. Cost of feed
and total feeding cost were (P < 0.05)
less for those heifers implanted with
Finaplix-H compared to heifers im-
planted with Synovex Plus or Revalor-H
which is due to the decreased intake of
Finaplix-H implanted heifers. Carcass
price, calculated on individual carcasses
using a grid for premiums and discounts
as discussed previously in this report, for
heifers implanted with Finaplix-H were
higher (P < 0.05) compared to those
heifers implanted with Synovex Plus,
while Revalor-H implanted heifers were
intermediate. Net return on a dressed
basis price tended to be improved (P =
0.15) by $10.49 per head for those heif-
ers implanted with Synovex Plus com-
pared to Revalor-H. Net return on a
carcass-merit basis tended to be im-
proved (P = 0.20) by $10.47 or $12.18
per head for those heifers implanted with
Finaplix-H compared to Synovex Plus
or Revalor-H, respectively.
These data suggest implanting with
Synovex Plus increases ADG and hot
carcass weight compared to implanting
with Revalor-H or Finaplix-H when
MGA is fed. When MGA is fed, mar-
bling score decreases with Synovex Plus
compared to Revalor-H or Finaplix-H
implants. Finally, implanting with
Revalor-H decreases marbling compared
to Finaplix-H. Part of the data from this
experiment has been pooled with data
from two other experiments reported in
the following report (2002 Nebraska
Beef Report pp. 34-35).
1Casey Macken, research technician; Todd
Milton, former assistant professor, Animal Science,
Lincoln; Bill Dicke, Cattlemen’s Consulting,
Lincoln.


Implant Programs for Feedlot Heifers using Synovex® Plus™, Revalor®-H, or Finaplix®-H with MGA

DigitalCommons@University of Nebraska

University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln Nebraska Beef Cattle Reports Animal Science Department January 2002 Implant Programs for Feedlot Heifers using Synovex® Plus™, Revalor®-H, or Finaplix®-H with MGA Casey Macken University of Nebraska-Lincoln Todd Milton University of Nebraska-Lincoln Bill Dicke University of Nebraska-Lincoln Follow this and additional works at: https://digitalcommons.unl.edu/animalscinbcr  Part of the Animal Sciences Commons Macken, Casey; Milton, Todd; and Dicke, Bill, "Implant Programs for Feedlot Heifers using Synovex® Plus™, Revalor®-H, or Finaplix®-H with MGA" (2002). Nebraska Beef Cattle Reports. 273. https://digitalcommons.unl.edu/animalscinbcr/273 This Article is brought to you for free and open access by the Animal Science Department at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Nebraska Beef Cattle Reports by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. Page 31 — 2002 Nebraska Beef ReportThe prevalence of fecal sheddingof a detectable level of E. coli O157:H7within a given group of feedlot cattlevaried widely over the feeding periodand the variability in prevalence was afunction of changes in both incidenceand duration of fecal shedding.E. coli O157:H7 appeared to be ubiq-uitous to this group of cattle since theorganism was recovered at least oncefrom each animal and the organism wasdetected from at least one animal everyweek of the study. It is interesting thatthe range of prevalence for cattle shed-ding E. coli O157:H7 in this longitudinalstudy was nearly identical to the range ofprevalence we previously observed in across-sectional study of commercialfeedlot cattle (2001 Beef Report, pp. 81-84). Identifying the factors that explainthe difference between groups of cattlewith high or low prevalence may beuseful for devising a control strategy onfarms to enhance food safety. Some ofthose factors may vary with time justas the prevalence of shedding does.Additional studies are in progress toidentify time-dependent factors thatexplain fecal shedding of E. coli O157:H7by feedlot cattle.1Spring Younts, graduate student; DavidSmith, assistant professor, Veterinary andBiomedical Sciences, Lincoln; Jeffrey Folmer,research technician, Animal Science, Lincoln;Rodney Moxley, professor, Susanne Hinkley,research assistant professor, Veterinary andBiomedical Sciences, Lincoln; Jeff Gray, USDA,ARS, ARRU, Athens, Ga.; Laura Hungerford,associate professor, Margaret Khaitsa, post-doctorate researcher, Veterinary and BiomedicalSciences, Lincoln; Terry Klopfenstein, professor,Animal Science, Lincoln.Implant Programs for Feedlot Heifers usingSynovex® PlusTM, Revalor®-H, or Finaplix®-Hwith MGA(Continued on next page)Casey MackenTodd MiltonBill Dicke1Implanting feedlot heifers withSynovex Plus increases ADG andhot carcass weight but decreasesgrade compared to heifers implantedwith Revalor-H or Finaplix-H andfed MGA.SummaryA commercial feedlot experiment wasconducted using 1,558 heifers to evalu-ate the effects of implant programs onfinishing heifers. Implanting withSynovex Plus increased ADG and hotcarcass weight compared to heifersimplanted with Revalor-H or Finaplix-H and fed MGA. Heifers implanted witheither Synovex Plus or Revalor-H hadincreased DMI compared to heifersimplanted with Finaplix-H. Marblingscore was influenced by each of theimplant treatments, being highest forFinaplix-H followed by Revalor-H andSynovex Plus.IntroductionIn finishing heifer implant programs,the final implant (administered approxi-mately 100 days prior to harvest) gener-ally contains trenbolone acetate (TBA)or a combination of estradiol (E2) andTBA. Along with these implantsmelengestrol acetate (MGA) can be fedto enhance the activity of TBA. Implantscommercially available that contain TBAor the combination of E2 and TBA areFinaplix-H (200 mg of TBA), Revalor-H (14 mg of E2 and 140 mg of TBA), andSynovex Plus (28 mg of estradiol ben-zoate (20 mg of E2) and 200 mg of TBA).Within these implants, dosage, combi-nation of hormones, and carrier of activeingredients differ and may alter growthpromoting activity. Objectives of thistrial were to compare performance, car-cass characteristics, and feeding eco-nomics in heifers implanted withFinaplix-H, Revalor-H, or Synovex Plusand fed MGA.ProcedureThe experiment was conducted be-tween the dates of Jan. 11, 2000 andAug. 3, 2000 using 1,558 heifers (761lb) in a randomized block design. Heif-ers were kept separate by truckload fol-lowing unloading and were weighed.Heifers from the separate truckloads wererandomly assigned to one of three im-plant programs, one by one, using a gatesort into one of three arrival pens andthen assigned to one of 18 home pens(six replications/treatment). Treatmentswere heifers terminally implanted with1) Finaplix-H, 2) Revalor-H, or 3)Synovex Plus with all treatments receiv-ing MGA supplementation. The finish-ing diet was formulated to provide 0.4mg of MGA/head/d. Within a block, allheifers arrived at the feedyard at thesame time. After sorting, pens were re-weighed, processed, and moved to theirhome pen. During processing, heiferswere vaccinated for viral diseases(BoviShield® 4, Pfizer Inc,), treated forinternal and external parasites(Dectomax®, Pfizer Inc,), implantedwith Ralgro®, and given a lot tag foridentification.Heifers were reimplanted with theirrespective treatment of Finaplix-H,Revalor-H, or Synovex Plus following2002 Nebraska Beef Report — Page 3245 (range 35 to 58 days) days on feed.Heifers were exposed to their finalimplant for an average of 95 daysacross replications (range 84 to 108).Heifers were not fed MGA in theadaptation diets (first 18 to 20 days onfeed). The final diet contained 48.0%steam-flaked corn, 27.0% dry-rolledcorn, 9.0% supplement, 7.5% alfalfahay, 5.5% corn steep liquor, and 3.0%fat, and was formulated to contain13.7% CP, 7.0% crude fat, 0.77% Ca,and 0.37% P. Heifers were fed an aver-age of 139 days (range 127 to 166).Initial weights were determined byprorating each arrival treatment penweight back to the total of the group ofheifers within block and adjusted to payweight. For example, shrink (positive ornegative depending upon the source ofcattle) would be applied to the cumula-tive off-truck weight of all heifers withina block to determine pay weight for theentire group. The weight of individualpens, after heifers were sorted intoarrival treatment pens, was divided bythe cumulative weight of all three arrivaltreatment pens. The total pay weight forthe entire group was multiplied by thispercentage to calculate the initial start-ing (pay weight) weight for each hometreatment pen. Final live weights weredetermined on a treatment pen just priorto shipment, and shrunk 4%. Final liveweights were obtained under identicalweighing conditions for each treatmentpen within a block. Carcass weights alsowere used and adjusted to a commondressing percentage of 63% to calculatedaily gain and feed conversion on acarcass-adjusted basis.All pens within a block were har-vested under identical conditions. Hotcarcass weights were recorded on theday of harvest. Carcass fat thickness,marbling score, KPH fat, longissimusmuscle area, and USDA quality gradewere recorded following a 24- to 48-hour chill.The economic influence of theimplant treatments was determinedusing the ration cost at the feedyardduring the period the experiment wasconducted. The ration cost used in theanalysis includes markup. Nonfeedcosts (medicine, processing, etc.) werecalculated for each pen of heifers inTable 1. Effect of implant strategy on performance and carcass characteristics infinishing heifers.Implant StrategyaPLUS REV FINItem MGA MGA MGA SEMbNumber of pens 6 6 6Number of heifers 523 519 516Days on feed 139 139 139Initial weight 760 761 760 3.0Final weightc 1250d 1235e 1232e 4.2Dry matter intake 20.3d 20.1d 19.5e 0.2Daily gain, lb 3.52f 3.39g 3.38g 0.05Feed/gain 5.76 5.94 5.77 0.09Carcass weight, lb 787d 778e 776e 2.712th rib fat, in. 0.53 0.54 0.54 0.01Longissimus muscle area, sq. in. 14.5f 14.2f 14.0g 0.1Calculated yield grade 2.6 2.7 2.7 0.1Marbling scorei 5.26f 5.38g 5.48h 0.04Quality grade distribution, %Prime 1.9 1.4 2.8 0.5Upper 2/3 Choice 16.1d 21.7e 24.0e 3.2Low Choice 37.1 42.4 40.5 3.1Select 41.8f 29.8g 25.9g 2.9Standard 3.1 1.4 1.4 0.7Dark cutters, % 1.2 2.0 0.0 0.8aPLUS = Synovex Plus, REV = Revalor-H, and FIN = Finaplix-H.bSEM = Standard error of the mean.cFinal weight calculated as hot carcass weight divided by .63 (common dressing percentage).d,eMeans within a row with different superscripts differ (P < .10).f,g,hMeans within a row with different superscripts differ (P < .05).iMarbling score: 4.0 = Slight; 4.5 = Slight 50; 5.0 = Small; 5.5 Small 50; etc.Table 2. Effects of implant program on feeding economics of finishing heifers.Implant StrategyaPLUS REV FINItem MGA MGA MGA SEMbRation costc, $/ton 131.50 131.50 131.50Cost of feed, $/head 185.36d 183.59d 178.27e 1.6Total feeding cost, $/head 194.24d 192.95d 187.32e 1.6Cost of gain, $/cwt 39.74 41.09 39.85 0.65Carcass pricef, $/cwt 107.56d 108.62de 109.51e 0.5Profit(loss)g, $/headLive basis 62.77 54.15 61.73 5.0Dressed basis 86.91 76.42 81.11 4.7Carcass merit basis 59.90 58.19 70.37 5.3aPLUS MGA = Synovex Plus fed MGA, REV MGA = Revalor-H fed MGA, and FIN MGA =Finaplix-H fed MGA.bSEM = Standard error of the mean.cIncludes feed mark-up.d,eMeans within a row with different superscripts differ (P < .05).fCalculated using a $111/cwt carcass base price: discounts = $10, Select; $20, Standard; $15, yieldgrade 4 and 5; $30, dark cutter; premiums = $8, Prime; $3, upper 2/3 Choice; $3, yield grades 1 and 2.gInitial animal cost = $78/cwt; animal returns based on $70/cwt live price, $111/cwt carcass price, orcalculated carcass value, respectively, interest not included.the experiment and averaged. Thisaverage nonfeed cost was applied toeach pen of heifers for calculation ofcost of gain and net return. Finalheifer value was calculated by using alive price, dressed price, or a carcass-merit price based on individual heifercarcass value. Carcass value was calcu-lated based on USDA quality grade,calculated yield grade, carcass weightand nonconformance (i.e. dark cutters).A carcass base price of $111/cwt wasused for low Choice, yield grade 3 car-casses weighing 550 to 950 lb. Dis-counts were calculated as: $10, Select;$20, Standard; $30, dark cutters; $25,Page 33 — 2002 Nebraska Beef Reportlight (<550 lb) and heavy (>950 lb)carcasses; and $15, yield grades 4 and 5.Premiums were calculated as: $8, Prime;$3, upper 2/3 Choice; and $3, yieldgrades 1 and 2.Performance, carcass, and economicdata were analyzed as a randomizedblock design using SAS. Least squaresmeans were separated using the LeastSignificance Difference method when asignificant (P < 0.10) F-test was de-tected. Variables were considered sig-nificant when probability values less than0.10 were obtained.ResultsData are presented with deads andchronics removed from the analysis. Feedintake and total head days were adjustedon a pen basis when deaths occurred orchronic cattle were sold before theirhome pen was. Feed intake and headdays were adjusted one day prior to theremoval of the animal from the pen aseither a dead or chronic.Effects of implant programs on per-formance of finishing heifers implantedwith Finaplix-H, Revalor-H, or SynovexPlus supplemented with MGA are shownin Table 1. Dry matter intake was higher(P < 0.05) for heifers implanted withSynovex Plus or Revalor-H comparedwith those implanted with Finaplix-H.On a carcass-adjusted basis, heifers im-planted with Synovex Plus as the finalimplant gained 4.2% (P< 0.10) fasterthan heifers implanted with Revalor-Hor Finaplix-H as the final implant. Thisresulted in 17 lb heavier (P < 0.05)carcass-adjusted final weight forSynovex Plus heifers compared toRevalor-H and Finaplix-H heifers.Carcass-adjusted daily gain of heifersimplanted with Revalor-H or Finaplix-Hwas similar. Live performance daily gain,final weight, and feed conversion weresimilar among implant treatments.Carcass characteristics are presentedin Table 1. Hot carcass weight was 10 lbor 11 lb heavier (P < 0.05) for heifersimplanted with Synovex Plus comparedwith heifers implanted with Revalor-Hor Finaplix-H, respectively. Hot carcassweight was similar for heifers implantedwith Revalor-H or Finaplix-H. Dressingpercentage tended (P = 0.13) to be sig-nificant among treatments. Longissimusmuscle area was larger (P < 0.05) forheifers implanted with Synovex Pluscompared with Finaplix-H, with Revalor-H being intermediate. Twelfth rib fatthickness and KPH fat were similaramong treatments. Calculated yield gradewas similar among treatments. Marblingscore was lower (P < 0.10) for heifersimplanted with Synovex Plus comparedto those implanted with either Revalor-H or Finaplix-H. Revalor-H implantedheifers had a lower marbling score thanFinaplix-H heifers. The percentage ofcarcasses grading USDA upper 2/3Choice was lower (P < 0.05) and per-centage of carcasses grading USDA Se-lect was higher (P < 0.10) for heifersimplanted with Synovex Plus comparedto those heifers implanted with Revalor-H or Finaplix-H. Carcasses gradingUSDA Standard and the incidence ofdark cutting carcasses were similaramong treatments.A summary of the economic analysisis provided in Table 2. Cost of gain wassimilar among treatments. Cost of feedand total feeding cost were (P < 0.05)less for those heifers implanted withFinaplix-H compared to heifers im-planted with Synovex Plus or Revalor-Hwhich is due to the decreased intake ofFinaplix-H implanted heifers. Carcassprice, calculated on individual carcassesusing a grid for premiums and discountsas discussed previously in this report, forheifers implanted with Finaplix-H werehigher (P < 0.05) compared to thoseheifers implanted with Synovex Plus,while Revalor-H implanted heifers wereintermediate. Net return on a dressedbasis price tended to be improved (P =0.15) by $10.49 per head for those heif-ers implanted with Synovex Plus com-pared to Revalor-H. Net return on acarcass-merit basis tended to be im-proved (P = 0.20) by $10.47 or $12.18per head for those heifers implanted withFinaplix-H compared to Synovex Plusor Revalor-H, respectively.These data suggest implanting withSynovex Plus increases ADG and hotcarcass weight compared to implantingwith Revalor-H or Finaplix-H whenMGA is fed. When MGA is fed, mar-bling score decreases with Synovex Pluscompared to Revalor-H or Finaplix-Himplants. Finally, implanting withRevalor-H decreases marbling comparedto Finaplix-H. Part of the data from thisexperiment has been pooled with datafrom two other experiments reported inthe following report (2002 NebraskaBeef Report pp. 34-35).1Casey Macken, research technician; ToddMilton, former assistant professor, Animal Science,Lincoln; Bill Dicke, Cattlemen’s Consulting,Lincoln.

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Implant Programs for Feedlot Heifers using Synovex® Plus™, Revalor®-H, or Finaplix®-H with MGA

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