Weaned heifers grazed corn residue, upland range, or were fed 1 of 2 drylot diets differing in energy. Heifer development diets did not impact their resulting AI or final pregnancy rates. Cost per pregnant heifer was similar among treatments. A subset of AI- pregnant heifers was placed in a Calan Broadbent individual feeding system during late gestation. As a pregnant heifer, feed efficiency was not impacted by development system. These results indicate producers may utilize their most readily available and/or cost- effective feed resources with no detriment to pregnancy rates or feed efficiency as first- calf heifers

Funston, Richard N.

Kirby, Mike

Meyer, Tonya L.

Nielson, Hazy Rae

Springman, Shelby A.

Teichert, Jim

English

DigitalCommons@University of Nebraska

University of Nebraska - LincolnDigitalCommons@University of Nebraska - LincolnNebraska Beef Cattle Reports Animal Science Department2017Effect of Heifer Development System onReproduction and Subsequent Gain as a PregnantHeiferShelby A. SpringmanUniversity of Nebraska-Lincoln, shelby.springman@huskers.unl.eduHazy Rae NielsonUniversity of Nebraska-Lincoln, hnielson21@gmail.comTonya L. MeyerUniversity of Nebraska - Lincoln, tl.meyer@live.comMike KirbyUniversity of Nebraska-LincolnJim TeichertUniversity of Nebraska-LincolnSee next page for additional authorsFollow this and additional works at: https://digitalcommons.unl.edu/animalscinbcrPart of the Large or Food Animal and Equine Medicine Commons, Meat Science Commons, andthe Veterinary Preventive Medicine, Epidemiology, and Public Health CommonsThis Article is brought to you for free and open access by the Animal Science Department at DigitalCommons@University of Nebraska - Lincoln. It hasbeen accepted for inclusion in Nebraska Beef Cattle Reports by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln.Springman, Shelby A.; Nielson, Hazy Rae; Meyer, Tonya L.; Kirby, Mike; Teichert, Jim; and Funston, Richard N., "Effect of HeiferDevelopment System on Reproduction and Subsequent Gain as a Pregnant Heifer" (2017). Nebraska Beef Cattle Reports. 1007.https://digitalcommons.unl.edu/animalscinbcr/1007AuthorsShelby A. Springman, Hazy Rae Nielson, Tonya L. Meyer, Mike Kirby, Jim Teichert, and Richard N. FunstonThis article is available at DigitalCommons@University of Nebraska - Lincoln: https://digitalcommons.unl.edu/animalscinbcr/10072017 Nebraska Beef Cattle Report · 5 ©  Th e Board Regents of the University of Nebraska. All rights reserved.of deep snow. All heifers were managed together in a drylot during estrus synchro-nization and AI.Prior to estrus synchronization, 2 blood samples were collected 10 d apart to deter-mine plasma progesterone concentration. Heifers with greater than 1 ng/mL at either collection were considered pubertal. Heifers were synchronized using the melengestrol acetate- prostaglandin F2α (MGA- PG) proto-col. Heat detection aids (Estrotect, Rockway Inc., Spring Valley, WI) were applied at PG injection (Lutalyse, Zoetis, Florham Park, NJ). Heifers in standing estrus were AI 12 h later. Heifers not expressing estrus received a PG injection 6 d following the fi rst PG injection and placed with bulls. Remaining heifers were combined with the non- AI heifers and bulls 10 d following AI on range at a 1:50 bull to heifer ratio for 60 d. Pregnancy diagnosis was conducted via transrectal ultrasonography (ReproScan, Beaverton, OR) 45 d following AI. Forty- fi ve d aft er bull removal a second pregnancy diagnosis determined fi nal pregnancy rate.Pregnant Heifer Feed Effi  ciencyIn mid- October, following fi nal preg-nancy diagnosis, a subset of AI- pregnant heifers from each treatment (RANGE, n = 36; CR, n = 46; DLHI, n = 48; DLLO, n = 23) were placed in a Calan Broadbent indi-vidual feeding system. Heifers were allowed a 20 d acclimation period before beginning a 90 d trial at approximately gestational d 170. Heifers were off ered ad libitum hay (7.9% CP); individual amounts off ered were recorded daily and orts collected weekly.decrease DMI in the mature cow. Under-standing the long term eff ects of heifer development on cow effi  ciency will allow producers to make better management deci-sions. Whether a diff erence lies in behavioral eff ects, or previous diet quality, mature cow intake as a result of development systems, have the potential to impact beef producers’ profi tability. Th erefore, objectives of the current study were to determine if post- weaning heifer development system aff ected ADG, pregnancy rates, and subsequent feed effi  ciency as a pregnant heifer.ProcedurePost- Weaning DevelopmentA 4- yr study conducted at the West Central Research and Extension Cen-ter (WCREC), North Platte, NE utilized Angus- based crossbred, spring born heifers. In Yr 1, weaned heifers grazed corn residue (CR, n = 50) or were fed in a drylot (DLHI, n = 50). In Yr 2, 3, and 4, heifers grazed CR (n = 75), upland range (RANGE; n = 75), or were fed 1 of 2 drylot diets (Table 1) diff er-ing in energy, high (DLHI, n = 75) or low (DLLO, n = 75). Heifers developed on CR (n = 125) grazed corn residue from mid- November through mid- February and then grazed winter range until estrus synchro-nization. RANGE heifers (n = 75) grazed winter range from mid- November until estrus synchronization. While grazing corn residue or winter range, heifers received the equivalent of 1 lb.hd- 1.d- 1 of a 29% CP, dried distillers grain- based supplement contain-ing monensin, with hay provided in times Shelby A. SpringmanHazy R. NielsonT. L. MeyerMike KirbyJim TeichertRick N. FunstonSummary with ImplicationsWeaned heifers grazed corn residue, upland range, or were fed 1 of 2 drylot diets diff ering in energy. Heifer development diets did not impact their resulting AI or fi nal pregnancy rates. Cost per pregnant heifer was similar among treatments. A subset of AI- pregnant heifers was placed in a Calan Broadbent individual feeding system during late gestation. As a pregnant heifer, feed effi  ciency was not impacted by development system. Th ese results indicate producers may utilize their most readily available and/or cost- eff ective feed resources with no detri-ment to pregnancy rates or feed effi  ciency as fi rst- calf heifers.IntroductionRetaining and developing replacement heifers presents one of the largest expens-es to the cow- calf producer. Developing heifers to a lower target BW than previously recommended has been shown to reduce costs, without reducing pregnancy rate. Previous research comparing corn residue and drylot systems has found heifers in the drylot gained more during the development period than heifers grazing corn residue (2013 Nebraska Beef Report, pp. 5– 7). However, heifers developed on corn residue experienced increased post- AI ADG while on summer range compared with heifers developed in confi nement, possibly due to compensatory gain or retained learned graz-ing behavior. Greater eff ort has been made to select heifers with higher feed- effi  ciency. However, selecting for greater effi  ciency may  Eff ect of Heifer Development System on Reproduction and Subsequent Gain as a Pregnant HeiferTable 1. Drylot diet composition (DM basis) off ered to replacement heifersIngredient, % DLHI1 DLLO2Hay 74 83Wet CGF 21 12Heifer supplement3 5 51 DLHI = heifers in Yr 1, 2, 3, and 4 received a high- energy diet in the drylot for 170 d.2 DLLO = heifers in Yr 2, 3, and 4 received a low- energy diet in the drylot for 170 d.3 Supplement = dry rolled corn (81.35% of supplement, DM basis), limestone (11.11%), iodized salt (5.55%), trace mix (1.39%), Rumensin- 90 (0.37%), and Vitamins A- D- E (0.22%).6 · 2017 Nebraska Beef Cattle ReportEconomic AnalysisDue to price fl uctuations during the experiment (2010– 2014), an average 5 yr price was used for economic analysis. Heifer value was obtained for the wk heifers were received. Pasture values were calculat-ed as half the cost of a cow- calf pair in the Southwest region of Nebraska and obtained from the Nebraska Farm Real Estate Market Highlights. Wet corn gluten prices were obtained from the USDA- AMS for the third wk in September using Kansas City values. Hay prices were obtained for the third wk of September in the Platte Valley from the Nebraska and Iowa Hay report. Actual supplement costs, both drylot and cube, were used. Other expenses included interest (6.5% of heifer value), vaccine, yardage, trucking for CR heifers, breeding expenses, and other miscellaneous expenses. Cull val-ues of non- pregnant heifers were obtained for the wk of fi nal pregnancy diagnosis. Th e value of one, non- pregnant heifer was divided by 1 minus pregnancy rate to deter-mine the value of cull heifers per pregnant heifer. Th is value was subtracted from the total development cost. Finally, the adjusted development cost was divided by pregnan-cy rate to determine the net cost of one pregnant heifer.Statistical AnalysisTreatments were the specifi c heifer development system where CR and DLHI were replicated for 4 yr and RANGE and DLLO were replicated for 3 yr. Treat-ment group within year was considered the experimental unit, with development treatment fi tted as a fi xed eff ect. Data were analyzed using the GLIMMIX procedure of SAS (SAS Inst. Inc., Cary NC). Pregnancy analyses included AI technician as a ran-dom eff ect. Pregnant heifer feed effi  ciency analyses included pen as a random eff ect. A P- value ≤ 0.05 was considered signifi cant.ResultsPost Weaning Development TreatmentHeifers had a similar initial BW (P = 0.88, 518 ± 11 lb, Table 2). During develop-ment, ADG was greater (P = 0.01) for DLHI heifers (1.57 ± 0.11 lb/d) compared with RANGE and CR (0.97 and 0.86 ± 0.11 lb/d, respectively). Diff erences in ADG resulted Table 2. Eff ect of development system on heifer gain and reproductive performanceItem RANGE1 CR2 DLHI3 DLLO4 SEM P- valuen 75 125 125 75Initial BW, lb 516 520 518 516 11 0.88Post- development BW5, lb664b 659b 763a 708a,b 18 < 0.01Development ADG, lb 0.97b 0.86b 1.57a 1.26a,b 0.11 0.01Pre- breeding BW, lb 714b 725b 820a 765a,b 20 0.01Percent of mature, % 59b 60b 67a 63a,b 2 0.01Pubertal status, % 28 41 86 77 10 0.20Synchronization ADG, lb1.57 1.79 1.52 1.72 0.24 0.20AI pregnancy diagnosis BW, lb802b 818b 873a 829a,b 13 0.02Final pregnancy diagnosis BW, lb941 941 985 952 24 0.13Breeding ADG6, lb 1.68a,b 1.76a 1.01c 1.26b,c 0.22 < 0.01AI pregnancy, % 67 63 61 49 7 0.39Final pregnancy, % 84 90 91 91 5 0.59Calved in fi rst 21 d, % 81a 69ab 70ab 53b 12 0.021 RANGE = heifers were off ered the equivalent of 0.99 lb . hd- 1 . d- 1 while grazing winter range for 170 d before entering the drylot for estrus synchronization and AI.2 CR = heifers were off ered the equivalent of 0.99 lb . hd- 1 . d- 1 while grazing corn residue for 90 d and winter range for 80 d before entering the drylot for estrus synchronization and AI.3 DLHI = heifers were developed in the drylot for 170 d and through estrus synchronization and AI on a high- energy diet.4 DLLO = in Yr 2, 3, and 4 heifers received a low- energy diet in the drylot for 170 d through estrus synchronization and AI.5 BW at the time of blood collection.6 ADG in the period between prebreeding and fi rst pregnancy diagnosis.a,b,c Means in a row with diff erent superscripts are diff erent (P ≤ 0.05).Table 3. Eff ects of heifer development system on pregnant heifer feed effi  ciencyItem RANGE1 CR2 DLHI3 DLLO4 SEM P- valuen 36 46 48 23Initial BW, lb 994 1,008 1,041 1,023 22 0.35Mid BW, lb 1,032 1,052 1,085 1,063 20 0.25Final BW, lb 1,076 1,096 1,127 1,107 31 0.24DMI, lb 21.47 21.98 22.44 22.05 1.68 0.27ADG, lb 0.84 0.99 0.95 0.90 0.37 0.36RFI5 0.094 0.091 - 0.056 - 0.074 0.160 0.61F:G 21.4 18.2 21.1 21.3 4.8 0.381 RANGE = heifers were off ered the equivalent of 0.99 lb . hd- 1 . d- 1 while grazing winter range for 170 d before entering the drylot for estrus synchronization and AI.2 CR = heifers were off ered the equivalent of 0.99 lb . hd- 1 . d- 1 while grazing corn residue for 90 d and winter range for 80 d before entering the drylot for estrus synchronization and AI.3 DLHI = heifers were developed in the drylot for 170 d and through estrus synchronization and AI on a high- energy diet.4 DLLO = heifers received a low- energy diet in the drylot for 170 d through estrus synchronization and AI.5 RFI = Residual Feed Intake2017 Nebraska Beef Cattle Report · 7 greatest cull heifer value. Th ese data diff er from previous studies that reported similar cull heifer value on intensive and extensive heifer development (2010 Nebraska Beef Report, pp. 8– 10). Numerically higher fi nal pregnancy rates resulted in lower cull value for DLHI and DLLO heifers. Net cost per pregnant heifer was similar (P = 0.99) among treatments using 5 yr average prices. Th is contradicts previously reported data suggesting extensive development reduced (P = 0.01) cost by $45 per pregnant heifer (2010 Nebraska Beef Report, pp. 8– 10). Diff erences may be due to the extreme price fl uctuation in the years this experiment was conducted.Shelby A. Springman, graduate studentHazy R. Nielson, former graduate studentT.L. Meyer, research technicianMike Kirby, research technicianJim Teichert, beef herdsmanRick N. Funston, professor, University of Nebraska- Lincoln West Central Research and Extension Center, North Platte, Neb.Th is may cut feed costs, but reproductive performance could be compromised. Some research has found heifers selected for high feed effi  ciency had lower pregnancy (P = 0.09) and calving (P = 0.05) rates than low effi  ciency contemporaries. In the current study, development treatment did not impact feed effi  ciency as a pregnant fi rst calf heifer. Future studies investigating how heifer development system impacts lifetime feed effi  ciency are needed.Economic AnalysisHeifers began development with the same value and receiving diet expense. Diet cost was diff erent (P < 0.01) among treatments with the exception of RANGE and CR, which had similar (P = 0.56) treatment costs. Th e most expensive diet, DLHI, and the mean of the 2 least expen-sive diets, RANGE and CR, indicated a $41 diff erence. Summer pasture and additional expenses were similar across treatments. Due to numerical diff erences in pregnancy rates and BW at pregnancy diagnosis, cull heifer value was diff erent (P < 0.01) among treatments where RANGE heifers, with the numerically lowest pregnancy rate, had the in a similar trend in post- treatment BW; DLHI heifers were heavier than RANGE and CR heifers (P < 0.01) but similar to DLLO heifers. At pre- breeding, percent of mature BW was greater (P = 0.01) for DLHI heifers compared with RANGE and CR heifers. Many measures were similar among treatments (P ≤ 0.20), including pubertal status prior to synchronization, ADG from AI to fi rst pregnancy diagnosis, AI preg-nancy rate and fi nal pregnancy rate. Body weight at the fi rst pregnancy diagnosis was greatest (P = 0.02) for DLHI heifers com-pared with other treatments. Th e propor-tion of heifers that calved within the fi rst 21 d was greater for RANGE heifers compared with DLLO heifers (P = 0.02).Pregnant Heifer Feed Effi  ciencyIn the feed effi  ciency trial (Table 3), initial and fi nal BW were similar (P > 0.24). Both DMI (P = 0.27) and residual feed in-take (RFI; P = 0.61) did not diff er between treatments. Th ere was no diff erence (P ≥ 0.33) in ADG or F:G. Recent emphasis on genetic selection for feed effi  cient cattle to optimize feedlot profi t has led to the idea of increased feed effi  ciency in the cow herd. Table 4. Economic analysis (5 yr avg, 2010 to 2014) of heifer development systemsItem RANGE1 CR2 DLHI3 DLLO4 SEM P- valueHeifer value, $/heifer 876 876 877 877 138 1.00Feed cost:Receiving diet,5 $/heifer 32 32 32 32 3.43 1.00Treatment diet, $/heifer 113a 109a 152b 137c 4.87 < 0.01Summer pasture,6 $/heifer 68 68 68 68 3.69 1.00Other expenses,7 $/heifer 311 319 311 311 8.96 0.91Total development cost 1,401 1,404 1,440 1,425 152 0.99Less: cull heifer value 228a 127b 100b,c 69c 19 < 0.01Net cost 1,173 1,277 1,340 1,356 137 0.77Net cost per pregnant heifer, $ 1,420 1,413 1,447 1,432 150 1.001 RANGE = heifers were off ered the equivalent of 0.99 lb . hd- 1 . d- 1 while grazing winter range for 170 d before entering the drylot for estrus synchronization and AI.2 CR = heifers were off ered the equivalent of 0.99 lb . hd- 1 . d- 1 while grazing corn residue for 90 d and winter range for 80 d before entering the drylot for estrus synchronization and AI.3 DLHI = heifers were developed in the drylot for 170 d and through estrus synchronization and AI on a high- energy diet.4 DLLO = heifers received a low- energy diet in the drylot for 170 d through estrus synchronization and AI.5 Heifers received a common receiving diet for 30 d prior to the initiation of the treatments.6 Summer pasture was calculated as half the cost of a cow- calf pair.7 Other expenses included breeding expense, interest (6.5% of heifer value), yardage, trucking for heifers on CR, vaccinations and other miscellaneous health expenses.a,b,c Means in a row with diff erent superscripts are diff erent (P ≤ 0.05).

Effect of Heifer Development System on Reproduction and Subsequent Gain as a Pregnant Heifer

UNL | Libraries

University of Nebraska - Lincoln
DigitalCommons@University of Nebraska - Lincoln
Nebraska Beef Cattle Reports Animal Science Department
2017
Effect of Heifer Development System on
Reproduction and Subsequent Gain as a Pregnant
Heifer
Shelby A. Springman
University of Nebraska-Lincoln, shelby.springman@huskers.unl.edu
Hazy Rae Nielson
University of Nebraska-Lincoln, hnielson21@gmail.com
Tonya L. Meyer
University of Nebraska - Lincoln, tl.meyer@live.com
Mike Kirby
University of Nebraska-Lincoln
Jim Teichert
University of Nebraska-Lincoln
See next page for additional authors
Follow this and additional works at: https://digitalcommons.unl.edu/animalscinbcr
Part of the Large or Food Animal and Equine Medicine Commons, Meat Science Commons, and
the Veterinary Preventive Medicine, Epidemiology, and Public Health Commons
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.
Springman, Shelby A.; Nielson, Hazy Rae; Meyer, Tonya L.; Kirby, Mike; Teichert, Jim; and Funston, Richard N., "Effect of Heifer
Development System on Reproduction and Subsequent Gain as a Pregnant Heifer" (2017). Nebraska Beef Cattle Reports. 1007.
https://digitalcommons.unl.edu/animalscinbcr/1007
Authors
Shelby A. Springman, Hazy Rae Nielson, Tonya L. Meyer, Mike Kirby, Jim Teichert, and Richard N. Funston
This article is available at DigitalCommons@University of Nebraska - Lincoln: https://digitalcommons.unl.edu/animalscinbcr/1007
2017 Nebraska Beef Cattle Report · 5 
©  Th e Board Regents of the University of 
Nebraska. All rights reserved.
of deep snow. All heifers were managed 
together in a drylot during estrus synchro-
nization and AI.
Prior to estrus synchronization, 2 blood 
samples were collected 10 d apart to deter-
mine plasma progesterone concentration. 
Heifers with greater than 1 ng/mL at either 
collection were considered pubertal. Heifers 
were synchronized using the melengestrol 
acetate- prostaglandin F2α (MGA- PG) proto-
col. Heat detection aids (Estrotect, Rockway 
Inc., Spring Valley, WI) were applied at 
PG injection (Lutalyse, Zoetis, Florham 
Park, NJ). Heifers in standing estrus were 
AI 12 h later. Heifers not expressing estrus 
received a PG injection 6 d following the 
fi rst PG injection and placed with bulls. 
Remaining heifers were combined with the 
non- AI heifers and bulls 10 d following AI 
on range at a 1:50 bull to heifer ratio for 60 
d. Pregnancy diagnosis was conducted via 
transrectal ultrasonography (ReproScan, 
Beaverton, OR) 45 d following AI. Forty- 
fi ve d aft er bull removal a second pregnancy 
diagnosis determined fi nal pregnancy rate.
Pregnant Heifer Feed Effi  ciency
In mid- October, following fi nal preg-
nancy diagnosis, a subset of AI- pregnant 
heifers from each treatment (RANGE, n = 
36; CR, n = 46; DLHI, n = 48; DLLO, n = 
23) were placed in a Calan Broadbent indi-
vidual feeding system. Heifers were allowed 
a 20 d acclimation period before beginning 
a 90 d trial at approximately gestational d 
170. Heifers were off ered ad libitum hay 
(7.9% CP); individual amounts off ered were 
recorded daily and orts collected weekly.
decrease DMI in the mature cow. Under-
standing the long term eff ects of heifer 
development on cow effi  ciency will allow 
producers to make better management deci-
sions. Whether a diff erence lies in behavioral 
eff ects, or previous diet quality, mature cow 
intake as a result of development systems, 
have the potential to impact beef producers’ 
profi tability. Th erefore, objectives of the 
current study were to determine if post- 
weaning heifer development system aff ected 
ADG, pregnancy rates, and subsequent feed 
effi  ciency as a pregnant heifer.
Procedure
Post- Weaning Development
A 4- yr study conducted at the West 
Central Research and Extension Cen-
ter (WCREC), North Platte, NE utilized 
Angus- based crossbred, spring born heifers. 
In Yr 1, weaned heifers grazed corn residue 
(CR, n = 50) or were fed in a drylot (DLHI, 
n = 50). In Yr 2, 3, and 4, heifers grazed CR 
(n = 75), upland range (RANGE; n = 75), or 
were fed 1 of 2 drylot diets (Table 1) diff er-
ing in energy, high (DLHI, n = 75) or low 
(DLLO, n = 75). Heifers developed on CR 
(n = 125) grazed corn residue from mid- 
November through mid- February and then 
grazed winter range until estrus synchro-
nization. RANGE heifers (n = 75) grazed 
winter range from mid- November until 
estrus synchronization. While grazing corn 
residue or winter range, heifers received the 
equivalent of 1 lb.hd- 1.d- 1 of a 29% CP, dried 
distillers grain- based supplement contain-
ing monensin, with hay provided in times 
Shelby A. Springman
Hazy R. Nielson
T. L. Meyer
Mike Kirby
Jim Teichert
Rick N. Funston
Summary with Implications
Weaned heifers grazed corn residue, 
upland range, or were fed 1 of 2 drylot diets 
diff ering in energy. Heifer development diets 
did not impact their resulting AI or fi nal 
pregnancy rates. Cost per pregnant heifer 
was similar among treatments. A subset of 
AI- pregnant heifers was placed in a Calan 
Broadbent individual feeding system during 
late gestation. As a pregnant heifer, feed 
effi  ciency was not impacted by development 
system. Th ese results indicate producers may 
utilize their most readily available and/or 
cost- eff ective feed resources with no detri-
ment to pregnancy rates or feed effi  ciency as 
fi rst- calf heifers.
Introduction
Retaining and developing replacement 
heifers presents one of the largest expens-
es to the cow- calf producer. Developing 
heifers to a lower target BW than previously 
recommended has been shown to reduce 
costs, without reducing pregnancy rate. 
Previous research comparing corn residue 
and drylot systems has found heifers in the 
drylot gained more during the development 
period than heifers grazing corn residue 
(2013 Nebraska Beef Report, pp. 5– 7). 
However, heifers developed on corn residue 
experienced increased post- AI ADG while 
on summer range compared with heifers 
developed in confi nement, possibly due to 
compensatory gain or retained learned graz-
ing behavior. Greater eff ort has been made 
to select heifers with higher feed- effi  ciency. 
However, selecting for greater effi  ciency may 
 Eff ect of Heifer Development System on Reproduction and 
Subsequent Gain as a Pregnant Heifer
Table 1. Drylot diet composition (DM basis) off ered to replacement heifers
Ingredient, % DLHI1 DLLO2
Hay 74 83
Wet CGF 21 12
Heifer supplement3 5 5
1 DLHI = heifers in Yr 1, 2, 3, and 4 received a high- energy diet in the drylot for 170 d.
2 DLLO = heifers in Yr 2, 3, and 4 received a low- energy diet in the drylot for 170 d.
3 Supplement = dry rolled corn (81.35% of supplement, DM basis), limestone (11.11%), iodized salt (5.55%), trace mix (1.39%), 
Rumensin- 90 (0.37%), and Vitamins A- D- E (0.22%).
6 · 2017 Nebraska Beef Cattle Report
Economic Analysis
Due to price fl uctuations during the 
experiment (2010– 2014), an average 5 
yr price was used for economic analysis. 
Heifer value was obtained for the wk heifers 
were received. Pasture values were calculat-
ed as half the cost of a cow- calf pair in the 
Southwest region of Nebraska and obtained 
from the Nebraska Farm Real Estate Market 
Highlights. Wet corn gluten prices were 
obtained from the USDA- AMS for the third 
wk in September using Kansas City values. 
Hay prices were obtained for the third wk 
of September in the Platte Valley from the 
Nebraska and Iowa Hay report. Actual 
supplement costs, both drylot and cube, 
were used. Other expenses included interest 
(6.5% of heifer value), vaccine, yardage, 
trucking for CR heifers, breeding expenses, 
and other miscellaneous expenses. Cull val-
ues of non- pregnant heifers were obtained 
for the wk of fi nal pregnancy diagnosis. 
Th e value of one, non- pregnant heifer was 
divided by 1 minus pregnancy rate to deter-
mine the value of cull heifers per pregnant 
heifer. Th is value was subtracted from the 
total development cost. Finally, the adjusted 
development cost was divided by pregnan-
cy rate to determine the net cost of one 
pregnant heifer.
Statistical Analysis
Treatments were the specifi c heifer 
development system where CR and DLHI 
were replicated for 4 yr and RANGE and 
DLLO were replicated for 3 yr. Treat-
ment group within year was considered 
the experimental unit, with development 
treatment fi tted as a fi xed eff ect. Data were 
analyzed using the GLIMMIX procedure of 
SAS (SAS Inst. Inc., Cary NC). Pregnancy 
analyses included AI technician as a ran-
dom eff ect. Pregnant heifer feed effi  ciency 
analyses included pen as a random eff ect. A 
P- value ≤ 0.05 was considered signifi cant.
Results
Post Weaning Development Treatment
Heifers had a similar initial BW (P = 
0.88, 518 ± 11 lb, Table 2). During develop-
ment, ADG was greater (P = 0.01) for DLHI 
heifers (1.57 ± 0.11 lb/d) compared with 
RANGE and CR (0.97 and 0.86 ± 0.11 lb/d, 
respectively). Diff erences in ADG resulted 
Table 2. Eff ect of development system on heifer gain and reproductive performance
Item RANGE1 CR2 DLHI3 DLLO4 SEM P- value
n 75 125 125 75
Initial BW, lb 516 520 518 516 11 0.88
Post- development 
BW5, lb
664b 659b 763a 708a,b 18 < 0.01
Development ADG, lb 0.97b 0.86b 1.57a 1.26a,b 0.11 0.01
Pre- breeding BW, lb 714b 725b 820a 765a,b 20 0.01
Percent of mature, % 59b 60b 67a 63a,b 2 0.01
Pubertal status, % 28 41 86 77 10 0.20
Synchronization 
ADG, lb
1.57 1.79 1.52 1.72 0.24 0.20
AI pregnancy diagnosis 
BW, lb
802b 818b 873a 829a,b 13 0.02
Final pregnancy 
diagnosis BW, lb
941 941 985 952 24 0.13
Breeding ADG6, lb 1.68a,b 1.76a 1.01c 1.26b,c 0.22 < 0.01
AI pregnancy, % 67 63 61 49 7 0.39
Final pregnancy, % 84 90 91 91 5 0.59
Calved in fi rst 21 d, % 81a 69ab 70ab 53b 12 0.02
1 RANGE = heifers were off ered the equivalent of 0.99 lb . hd- 1 . d- 1 while grazing winter range for 170 d before entering the drylot 
for estrus synchronization and AI.
2 CR = heifers were off ered the equivalent of 0.99 lb . hd- 1 . d- 1 while grazing corn residue for 90 d and winter range for 80 d before 
entering the drylot for estrus synchronization and AI.
3 DLHI = heifers were developed in the drylot for 170 d and through estrus synchronization and AI on a high- energy diet.
4 DLLO = in Yr 2, 3, and 4 heifers received a low- energy diet in the drylot for 170 d through estrus synchronization and AI.
5 BW at the time of blood collection.
6 ADG in the period between prebreeding and fi rst pregnancy diagnosis.
a,b,c Means in a row with diff erent superscripts are diff erent (P ≤ 0.05).
Table 3. Eff ects of heifer development system on pregnant heifer feed effi  ciency
Item RANGE1 CR2 DLHI3 DLLO4 SEM P- value
n 36 46 48 23
Initial BW, lb 994 1,008 1,041 1,023 22 0.35
Mid BW, lb 1,032 1,052 1,085 1,063 20 0.25
Final BW, lb 1,076 1,096 1,127 1,107 31 0.24
DMI, lb 21.47 21.98 22.44 22.05 1.68 0.27
ADG, lb 0.84 0.99 0.95 0.90 0.37 0.36
RFI5 0.094 0.091 - 0.056 - 0.074 0.160 0.61
F:G 21.4 18.2 21.1 21.3 4.8 0.38
1 RANGE = heifers were off ered the equivalent of 0.99 lb . hd- 1 . d- 1 while grazing winter range for 170 d before entering the drylot 
for estrus synchronization and AI.
2 CR = heifers were off ered the equivalent of 0.99 lb . hd- 1 . d- 1 while grazing corn residue for 90 d and winter range for 80 d before 
entering the drylot for estrus synchronization and AI.
3 DLHI = heifers were developed in the drylot for 170 d and through estrus synchronization and AI on a high- energy diet.
4 DLLO = heifers received a low- energy diet in the drylot for 170 d through estrus synchronization and AI.
5 RFI = Residual Feed Intake
2017 Nebraska Beef Cattle Report · 7 
greatest cull heifer value. Th ese data diff er 
from previous studies that reported similar 
cull heifer value on intensive and extensive 
heifer development (2010 Nebraska Beef 
Report, pp. 8– 10). Numerically higher 
fi nal pregnancy rates resulted in lower cull 
value for DLHI and DLLO heifers. Net cost 
per pregnant heifer was similar (P = 0.99) 
among treatments using 5 yr average prices. 
Th is contradicts previously reported data 
suggesting extensive development reduced 
(P = 0.01) cost by $45 per pregnant heifer 
(2010 Nebraska Beef Report, pp. 8– 10). 
Diff erences may be due to the extreme price 
fl uctuation in the years this experiment was 
conducted.
Shelby A. Springman, graduate student
Hazy R. Nielson, former graduate student
T.L. Meyer, research technician
Mike Kirby, research technician
Jim Teichert, beef herdsman
Rick N. Funston, professor, University of 
Nebraska- Lincoln West Central Research 
and Extension Center, North Platte, Neb.
Th is may cut feed costs, but reproductive 
performance could be compromised. Some 
research has found heifers selected for high 
feed effi  ciency had lower pregnancy (P = 
0.09) and calving (P = 0.05) rates than low 
effi  ciency contemporaries. In the current 
study, development treatment did not 
impact feed effi  ciency as a pregnant fi rst 
calf heifer. Future studies investigating how 
heifer development system impacts lifetime 
feed effi  ciency are needed.
Economic Analysis
Heifers began development with the 
same value and receiving diet expense. 
Diet cost was diff erent (P < 0.01) among 
treatments with the exception of RANGE 
and CR, which had similar (P = 0.56) 
treatment costs. Th e most expensive diet, 
DLHI, and the mean of the 2 least expen-
sive diets, RANGE and CR, indicated a $41 
diff erence. Summer pasture and additional 
expenses were similar across treatments. 
Due to numerical diff erences in pregnancy 
rates and BW at pregnancy diagnosis, cull 
heifer value was diff erent (P < 0.01) among 
treatments where RANGE heifers, with the 
numerically lowest pregnancy rate, had the 
in a similar trend in post- treatment BW; 
DLHI heifers were heavier than RANGE 
and CR heifers (P < 0.01) but similar to 
DLLO heifers. At pre- breeding, percent of 
mature BW was greater (P = 0.01) for DLHI 
heifers compared with RANGE and CR 
heifers. Many measures were similar among 
treatments (P ≤ 0.20), including pubertal 
status prior to synchronization, ADG from 
AI to fi rst pregnancy diagnosis, AI preg-
nancy rate and fi nal pregnancy rate. Body 
weight at the fi rst pregnancy diagnosis was 
greatest (P = 0.02) for DLHI heifers com-
pared with other treatments. Th e propor-
tion of heifers that calved within the fi rst 21 
d was greater for RANGE heifers compared 
with DLLO heifers (P = 0.02).
Pregnant Heifer Feed Effi  ciency
In the feed effi  ciency trial (Table 3), 
initial and fi nal BW were similar (P > 0.24). 
Both DMI (P = 0.27) and residual feed in-
take (RFI; P = 0.61) did not diff er between 
treatments. Th ere was no diff erence (P ≥ 
0.33) in ADG or F:G. Recent emphasis on 
genetic selection for feed effi  cient cattle to 
optimize feedlot profi t has led to the idea of 
increased feed effi  ciency in the cow herd. 
Table 4. Economic analysis (5 yr avg, 2010 to 2014) of heifer development systems
Item RANGE1 CR2 DLHI3 DLLO4 SEM P- value
Heifer value, $/heifer 876 876 877 877 138 1.00
Feed cost:
Receiving diet,5 $/heifer 32 32 32 32 3.43 1.00
Treatment diet, $/heifer 113a 109a 152b 137c 4.87 < 0.01
Summer pasture,6 $/heifer 68 68 68 68 3.69 1.00
Other expenses,7 $/heifer 311 319 311 311 8.96 0.91
Total development cost 1,401 1,404 1,440 1,425 152 0.99
Less: cull heifer value 228a 127b 100b,c 69c 19 < 0.01
Net cost 1,173 1,277 1,340 1,356 137 0.77
Net cost per pregnant heifer, $ 1,420 1,413 1,447 1,432 150 1.00
1 RANGE = heifers were off ered the equivalent of 0.99 lb . hd- 1 . d- 1 while grazing winter range for 170 d before entering the drylot 
for estrus synchronization and AI.
2 CR = heifers were off ered the equivalent of 0.99 lb . hd- 1 . d- 1 while grazing corn residue for 90 d and winter range for 80 d before 
entering the drylot for estrus synchronization and AI.
3 DLHI = heifers were developed in the drylot for 170 d and through estrus synchronization and AI on a high- energy diet.
4 DLLO = heifers received a low- energy diet in the drylot for 170 d through estrus synchronization and AI.
5 Heifers received a common receiving diet for 30 d prior to the initiation of the treatments.
6 Summer pasture was calculated as half the cost of a cow- calf pair.
7 Other expenses included breeding expense, interest (6.5% of heifer value), yardage, trucking for heifers on CR, vaccinations and 
other miscellaneous health expenses.
a,b,c Means in a row with diff erent superscripts are diff erent (P ≤ 0.05).


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Effect of Heifer Development System on Reproduction and Subsequent Gain as a Pregnant Heifer

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