May-calving dams grazed either sub-irrigated meadow or upland range from Jan. 5 to May 1 each year for 6 years. Within grazing system, dams received either no supplement or 1 lb/d of a 33% CP supplement from Jan. 5 to April 1. Dams grazing meadow in the prepartum period weighed more and had a greater body condition score prior to calving. They also tended to have greater pregnancy rates in the subsequent breeding season and tended to wean heavier calves than dams grazing upland range. Allowing May-calving dams to graze meadow in late gestation may increase herd profitability through increased dam pregnancy rates and weaned calf value. Furthermore, supplemented dams weaned heavier calves, independent of grazing system. Supplementation of May-calving dams in late gestation may be economical if the income from additional pounds of calf weaned is greater than the supplementation cost

Funston, Rick N.

Lansford, Alicia C.

Meyer, T. L., Meyer

Musgrave, Jacki A.

English

DigitalCommons@University of Nebraska

University of Nebraska - LincolnDigitalCommons@University of Nebraska - LincolnNebraska Beef Cattle Reports Animal Science Department2019Effects of Prepartum Nutrition on May-CalvingCows and ProgenyAlicia C. LansfordJacki A. MusgraveUniversity of Nebraska–Lincoln, jacki.musgrave@unl.eduT. L. Meyer MeyerRick N. FunstonUniversity of Nebraska–Lincoln, rick.funston@unl.eduFollow this and additional works at: http://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.Lansford, Alicia C.; Musgrave, Jacki A.; Meyer, T. L. Meyer; and Funston, Rick N., "Effects of Prepartum Nutrition on May-CalvingCows and Progeny" (2019). Nebraska Beef Cattle Reports. 1050.http://digitalcommons.unl.edu/animalscinbcr/10502019 Nebraska Beef Cattle Report · 9 ©  The Board Regents of the University of  Nebraska. All rights reserved.upland range (R) or sub- irrigated mead-ow (M). Within grazing treatment, cows were randomly assigned to receive either no supplement (NS) or 1 lb/d of a 33% CP supplement (S, Table 1). Grazing treatment continued for 116 ± 2 d (mean ± SD) while supplementation treatment continued for 85 ± 2 d (mean ± SD). Range sites were stocked at 0.6 AUM, whereas sub- irrigated meadow was stocked at 3 AUM.Dietary CP and TDN as a percentage of dam requirements for each treatment com-bination are presented in Table 2. Dam BW and body condition score (BCS, 1 = ema-ciated to 9 = obese) were recorded at initi-ation and conclusion of grazing treatment. After the treatment period, dams were managed as a single herd grazing upland range the remainder of the year. At par-turition, progeny birth BW, sex, and birth date were recorded. Dams were assigned a calving ease (CE) score (1 = no assistance, 2 = easy assist, 3 = difficult assist, and 4 = cae-sarian section) at parturition, with scores of 2 or greater considered dystocia.In July, dams were placed with fertile bulls at a ratio of 1:20 (bull:dam) for a 45 d breeding season. Five d after bull placement, dams were synchronized with a single PGF2α injection (5 mL i.m. Lutalyse, Zoetis, Parsippany, New Jersey). In early January, dams were diagnosed for pregnan-cy via rectal palpation or transrectal ultra-sonography and calves weaned. Calf BW was recorded at pre- breeding and weaning.Statistical AnalysisAll data were analyzed using the PROC GLIMMIX procedure of SAS (SAS Inst. Inc., Cary, NC, version 9.4). The model statement included the fixed effects of dam grazing treatment, supplementation treat-ment, and the resulting interaction. The experimental unit was considered grazing system × supplementation treatment × yr. Dam age and yr were included as a covari-ate in all analyses and were removed when P > 0.05. Data were considered significant Effects of Prepartum Nutrition on  May- Calving Cows and ProgenyAlicia C. LansfordJacki MusgraveT.L. MeyerRick N. FunstonSummary with ImplicationsMay- calving dams grazed either sub- irrigated meadow or upland range from Jan. 5 to May 1 each year for 6 years. Within grazing system, dams received either no sup-plement or 1 lb/d of a 33% CP supplement from Jan. 5 to April 1. Dams grazing mead-ow in the prepartum period weighed more and had a greater body condition score prior to calving. They also tended to have greater pregnancy rates in the subsequent breeding season and tended to wean heavier calves than dams grazing upland range. Allowing May- calving dams to graze meadow in late gestation may increase herd profitability through increased dam pregnancy rates and weaned calf value. Furthermore, supplement-ed dams weaned heavier calves, indepen-dent of grazing system. Supplementation of May- calving dams in late gestation may be economical if the income from additional pounds of calf weaned is greater than the supplementation cost.IntroductionPrevious research (2006 Nebraska Beef Cattle Report, pp. 7– 9; 2009 Nebraska Beef Cattle Report, pp. 5– 8) examined increasing dietary CP and TDN for March- calving cows in late gestation and determined no difference in rebreed pregnancy rates. Late gestation for a March- calving herd occurs when forage is dormant, low in crude protein (CP) and in vitro dry matter digestibility (IVDMD), and supplemen-tation may not have been enough to meet cow nutrient requirements. Alternately, late gestation for a May- calving herd occurs during early forage growth, where forage can meet or exceed the dam’s nutrient requirements. Furthermore, differences in forage species composition between upland range and subirrigated meadow (cool vs. warm season) result in different growth patterns and forage quality. The increased forage availability and quality during the prepartum period of a May- calving herd can affect maternal productivity, as well as progeny postnatal growth and performance. The objective of this study was to evaluate the effect of grazing system with and with-out supplementation on May- calving dam reproductive performance and progeny growth through weaning.ProcedureDam ManagementMultiparous, May- calving cows (n = 652, 928 ± 4 lb) were blocked by BW and arranged in a 2 × 2 factorial treatment at weaning in January. Dams grazed either Table 1. Nutrient analysis and composition on a DM basis of supplement provided to May- calving cows in late gestation1ItemNutrient CP, % 32.9 RUP, % CP 39.7 TDN, % 78.4Ingredient, % DM Dried distillers grains meal 52.5 Soybean meal (46.5% CP) 14.7 Vitamin and mineral package3 13.3 Wheat middlings 6.3 Sunflower meal (35% CP) 6.3 Molasses, liquid 3.7 Urea 1.6 Cull beans 1.51May- calving dams were assigned to 1 of 2 supplementation groups for 85 d: 1 lb/d of supplement (S) or no supplement (NS) beginning at weaning in January.2Calculated using the equations proposed by the NRC, 2000.3Formulated to provide 0.7 g/lb monensin (Rumensin, Elanco Animal Health).10 · 2019 Nebraska Beef Cattle Reportto dams who grazed meadow tended (P = 0.07) to have an increased birth BW (74 vs. 72 ± 0.4 lb, M vs. R). Additionally, calves born to supplemented dams had increased (P = 0.04) birth BW (74 vs. 72 ± 0.4 lb, S vs. NS). At pre- breeding, there was a tendency for a grazing system × supplement interac-tion (P = 0.09) in calf BW, with RS calves having the greatest BW, MS and MNS in-termediate, and RNS having the lowest BW. At weaning, calves born to dams grazing meadow in the prepartum period tended (P = 0.09) to have increased BW (443 vs. 436 ± 2 lb, M vs. R). Similarly, prepartum sup-plemented dams weaned heavier calves (P = 0.02; 443 vs. 434 ± 2 lb, S vs. NS). Larson et al. (2009 Nebraska Beef Cattle Report, pp. 5– 8) observed an increase in milk produc-tion for March- calving cows grazing corn residue in late gestation when compared with cows grazing winter range. It is possi-ble increased dietary nutritive value in late gestation is responsible for increased milk production and consequent calf BW.ConclusionsMay- calving dams grazing sub- irrigated meadow had increased prepartum BW and BCS. Furthermore, they tended to have increased pregnancy rates in the follow-ing breeding season and wean heavier calves. Allowing May- calving dams to graze meadow during late gestation may increase total herd profitability through increased stayability of dams and increased weaned calf value. Independent of grazing system, supplemented dams had increased prepartum BW and BCS. Progeny birth and wean BW were also increased by prepartum supplementation, with no effect on dystocia rate. The cost of supplementation provid-ed to May- calving dams in late gestation should be balanced against that additional 9 lb of calf weaned observed in the current study. This research indicates management decisions made in one segment of the beef production system may have unrealized impacts on herd profitability.Alicia C. Lansford, graduate studentJacki Musgrave, research technicianT.L. Meyer, research technicianRick N. Funston, professor, West Central Research and Extension Center, North Platte, NEcoming breeding season, with dams who increase or maintain BCS having greater pregnancy rates than dams who lose BCS. It is important to note supplemented dams in this study gained (P < 0.01) BCS over the treatment period, but NS dams did maintain condition (0.2 vs. 0.0 ± 0.03, S vs. NS).Prepartum supplementation did not affect (P = 0.48) dam rebreed pregnancy rates. Prepartum meadow grazing tended (P = 0.08) to increase subsequent pregnan-cy rates (89 vs. 85 ± 2%, M vs. R), despite no difference in prepartum BCS. Recent research has shown feeding dams a high en-ergy diet prepartum increased activation of metabolic pathways involved in triglyceride synthesis in the postpartum period (Shahzad et al., 2014, https:// doi .org /10 .1371 /journal .pone .0099757). It is possible dams grazing meadow prepartum had an altered meta-bolic response and may have been primed to better utilize nutrients in the subsequent breeding season.At parturition, dystocia rate was not affected (P ≥ 0.14) by treatment, although both grazing treatment and supplemen-tation affected calf birth BW. Calves born at P ≤ 0.05 and a tendency if P ≤ 0.10 and P > 0.05.ResultsOver the treatment period, there was a grazing system × supplement interaction (P = 0.02, Table 3) for dam BW change. Dams allotted to the MS treatment had the great-est BW gain, MNS intermediate, followed by RS dams, and RNS dams. This resulted in differences in prepartum BW between grazing treatments and supplementation treatments. Dams grazing meadow had a greater (P < 0.01) prepartum BW when compared with R dams (1,036 vs. 1,005 ± 7 lb, M vs. R). Likewise, S dams had a greater (P < 0.01) prepartum BW than NS dams (1,034 vs. 1,005 ± 7 lb, S vs. NS). Increased dam BW is likely a result of increased diet quality (Table 2).Grazing treatment did not affect (P ≥ 0.78) prepartum BCS or BCS change during treatment. Conversely, dam supple-mentation increased (P < 0.01) prepartum BCS (4.7 vs. 4.6 ± 0.03, S vs. NS). Change in BCS during the prepartum period is an indicator of pregnancy success in the up-Table 2. Predicted1 nutrient composition as a percentage of requirements in diets offered to May- calving dams in late gestation2Meadow RangeNS S NS SJanuary CP, % mid- gestation req.3 85.9 95.8 70.4 80.3 NEm, % mid- gestation req.4 96.9 99.0 118.4 120.4February CP, % late gestation req.5 139.2 146.8 73.8 82.3 NEm, % late gestation req.6 76.4 79.1 104.5 106.4March CP, % late gestation req. 251.9 255.7 153.2 159.5 NEm, % late gestation req. 143.6 143.6 143.6 143.6April CP, % late gestation req. 320.7 322.8 160.3 167.1 NEm, % late gestation req. 144.5 144.5 156.4 156.41Diet composition predicted using a computer model based on NRC, 2000 equations.2May- calving dams were arranged in a 2 × 2 factorial at weaning in January and were assigned to 1 of 2 grazing treatments: sub- irrigated meadow (M) or upland range (R) for 116 d and then to 1 of 2 supplementation treatments: 1 lb/d of 33% CP (DM) supplement (S) or no supplement (NS) for 85 d.3CP expressed as a percentage of requirement for mid- gestation multiparous dams (7.1% CP, DM; NRC, 2000).4NEm expressed as a percentage of the requirement for mid- gestation multiparous dams (0.45 Mcal/lb; NRC, 2000).5CP expressed as a percentage of requirement for late gestation multiparous dams (7.9% CP, DM; NRC, 2000).6NEm expressed as a percentage of the requirement for late gestation multiparous dams (0.50 Mcal/lb; NRC, 2000).2019 Nebraska Beef Cattle Report · 11 Table 3. Effects of late gestation nutrition1 on May- calving dam BW, BCS, and reproductive and calf performanceM RSEMP- value2     NS  S       NS S Graze Supp G × Sn 181 163 148 159Cow BW, lb Initial 926 928 935 930 9 0.62 0.87 0.75 Prepartum 1,027 1,045 983 1,021 9 < 0.01 < 0.01 0.25 BW change, lb 99ab 115a 51c 93b 6 < 0.01 < 0.01 0.02Cow BCS3 Initial 4.6 4.5 4.6 4.6 0.04 0.61 0.10 0.35 Prepartum 4.6 4.7 4.6 4.8 0.05 0.78 < 0.01 0.45 BCS change 0.0 0.2 0.0 0.2 0.04 0.58 < 0.01 0.94Dystocia, %4 0 1 1 0 1 0.96 0.95 0.15Pregnancy rate, % 90 89 82 87 3 0.08 0.48 0.37Calf BW, lb Birth 73 75 71 73 1 0.07 0.04 0.84 Pre- breed 216ab 216ab 207b 234a 9 0.58 0.11 0.09 Weaning 439 445 430 443 4 0.09 0.02 0.33a,b,cMeans within a row lacking a common superscript differ (P ≤ 0.05).1May- calving dams were arranged in a 2 × 2 factorial at weaning in January and were assigned to 1 of 2 forage types: sub- irrigated meadow (M) or upland range (R) for 116 d and then to 1 of 2 supplementation groups: 1 lb/d of 33% CP (DM) supplement (S) or no supplement (NS) for 85 d.2Graze = grazing treatment, Supp = supplementation treatment, and G × S = grazing and supplement assignment interaction.3BCS = Body condition score (1 = emaciated to 9 = obese).4At parturition a calving ease (CE) score was assigned (1 = no assistance to 4 = caesarian section). A score of 2 or greater was considered dystocia.2019 Nebraska Beef Cattle Report · 13 dam grazing treatment, supplementation treatment, and the resulting interaction. The experimental unit was considered dam treatment × year, where dam treatment consisted of the grazing system, supplemen-tation treatment, and the interaction. Dam age and year were included as a covariate in all analyses. The sex of the heifer progeny’s first calf was included as a covariate when analyzing heifer parturition data and their calf BW. Covariates were removed from the model statement when P > 0.05. Data were considered significant at P ≤ 0.05 and a tendency if P ≤ 0.10 and P > 0.05.ResultsHeifer Progeny PerformanceHeifer progeny BW, BCS, and reproduc-tive performance are presented in Table 2. Neither prebreeding BW nor percentage of heifers pubertal at the start of the breeding start of the subsequent breeding season. Pregnancy status was diagnosed in Novem-ber via transrectal ultrasonography, and BW and BCS recorded. Calves were weaned from heifers at this time.Heifer Progeny First Calf ManagementThe BW of the first calf born to heifer progeny was analyzed based on granddam pasture and supplement treatment. At par-turition, calf birth BW, sex, and birth date were recorded. Calves were vaccinated and male calves castrated at prebreeding. Calf BW was recorded at prebreeding in July and weaning in November.Statistical AnalysisAll data were analyzed using the PROC GLIMMIX procedure of SAS (SAS Inst. Inc., Cary, NC, version 9.4). The model statement included the fixed effects of were collected from heifers via coccy-geal venipuncture to determine plasma progesterone concentrations. Heifers were considered pubertal if plasma progesterone concentrations were ≥ 1.0 ng/mL at one or both time points. Heifer BW was recorded at blood collection and prebreeding BW was considered the average of these 2 time points. Heifer progeny were placed with fertile bulls at a 1:20 bull to heifer ratio for a 45 d breeding season. Heifers were synchro-nized using a single PGF2α (5 mL i.m., Lu-talyse; Zoetis Animal Health, Parisippany, NJ) 5 d after bull placement. Body weight and BCS were recorded and pregnancy di-agnosed via transrectal ultrasonography in mid- October. Two weeks prior to calving, heifer BW and BCS was recorded. A calving ease (CE) score (1 = no assistance, 2 = easy assist, 3 = difficult assist, and 4 = caesarian section) was assigned at parturition, with scores of 2 or greater considered dystocia. Body weight and BCS were recorded at the Table 2. Effect of late gestation nutrition on May- born heifer progeny BW, BCS, and reproductive performanceM RSEMP- value2NS S NS S Graze Supp G × Sn 81 76 74 79Heifer BW, lb Prebreeding (14 mo) 701 701 694 694 4 0.20 0.92 0.94 Pregnancy diagnosis (17 mo) 791 789 785 785 4 0.37 0.85 0.75 Prepartum (23 mo) 842 851 858 869 11 0.13 0.41 0.94 Prebreeding (26 mo) 873 882 884 875 9 0.78 0.96 0.31 Pregnancy diagnosis (30 mo) 864 895 891 904 13 0.13 0.06 0.42Heifer BCS3 Pregnancy diagnosis (17 mo) 5.9 5.9 5.8 5.8 0.03 0.13 0.40 0.74 Prepartum (23 mo) 5.2 5.1 5.1 5.0 0.06 0.24 0.19 0.66 Prebreeding (26 mo) 5.4ab 5.5a 5.4ab 5.2b 0.07 0.02 0.38 0.04 Pregnancy diagnosis (30 mo) 5.2b 5.5a 5.3ab 5.3ab 0.08 0.76 0.08 0.01Pubertal, %4 71 79 76 68 5 0.62 0.97 0.12Percent mature BW, %5 60 61 58 59 0.7 0.01 0.06 0.59Heifer pregnancy rate, % 78 79 72 74 5 0.29 0.81 0.88Dystocia, %6 10 17 8 28 7 0.54 0.02 0.35PPI, d7 89 89 96 95 3 0.03 0.99 0.83Primiparous cow  pregnancy rate, %84 93 74 74 8 0.02 0.35 0.361May- calving dams were arranged in a 2 × 2 factorial at weaning in January and were assigned to 1 of 2 forage types: sub- irrigated meadow (M) or upland range (R) for 116 d and then to 1 of 2 supplementation groups: 1 lb/d of 33% CP (DM) supplement (S) or no supplement (NS) for 85 d.2Graze = grazing treatment, Supp = supplementation treatment, and G × S = grazing and supplement interaction.3BCS = Body condition score (1 = emaciated to 9 = obese).4Considered pubertal if blood serum progesterone concentration > 1 ng/ml.5Percent of mature BW at 14 mo of age. Calculated using a May- herd mature cow BW of 1,172 lb.6At parturition a calving ease (CE) score was assigned (1 = no assistance to 4 = caesarian section). A score of 2 or greater was considered as dystocia.7PPI = postpartum interval. Conception date was calculated by subtracting 285 d from subsequent calving date.

Effects of Prepartum Nutrition on
May-Calving
Cows and Progeny

UNL | Libraries

University of Nebraska - Lincoln
DigitalCommons@University of Nebraska - Lincoln
Nebraska Beef Cattle Reports Animal Science Department
2019
Effects of Prepartum Nutrition on May-Calving
Cows and Progeny
Alicia C. Lansford
Jacki A. Musgrave
University of Nebraska–Lincoln, jacki.musgrave@unl.edu
T. L. Meyer Meyer
Rick N. Funston
University of Nebraska–Lincoln, rick.funston@unl.edu
Follow this and additional works at: http://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.
Lansford, Alicia C.; Musgrave, Jacki A.; Meyer, T. L. Meyer; and Funston, Rick N., "Effects of Prepartum Nutrition on May-Calving
Cows and Progeny" (2019). Nebraska Beef Cattle Reports. 1050.
http://digitalcommons.unl.edu/animalscinbcr/1050
2019 Nebraska Beef Cattle Report · 9 
©  The Board Regents of the University of  
Nebraska. All rights reserved.
upland range (R) or sub- irrigated mead-
ow (M). Within grazing treatment, cows 
were randomly assigned to receive either 
no supplement (NS) or 1 lb/d of a 33% CP 
supplement (S, Table 1). Grazing treatment 
continued for 116 ± 2 d (mean ± SD) while 
supplementation treatment continued for 
85 ± 2 d (mean ± SD). Range sites were 
stocked at 0.6 AUM, whereas sub- irrigated 
meadow was stocked at 3 AUM.
Dietary CP and TDN as a percentage of 
dam requirements for each treatment com-
bination are presented in Table 2. Dam BW 
and body condition score (BCS, 1 = ema-
ciated to 9 = obese) were recorded at initi-
ation and conclusion of grazing treatment. 
After the treatment period, dams were 
managed as a single herd grazing upland 
range the remainder of the year. At par-
turition, progeny birth BW, sex, and birth 
date were recorded. Dams were assigned a 
calving ease (CE) score (1 = no assistance, 2 
= easy assist, 3 = difficult assist, and 4 = cae-
sarian section) at parturition, with scores of 
2 or greater considered dystocia.
In July, dams were placed with fertile 
bulls at a ratio of 1:20 (bull:dam) for a 
45 d breeding season. Five d after bull 
placement, dams were synchronized with a 
single PGF2α injection (5 mL i.m. Lutalyse, 
Zoetis, Parsippany, New Jersey). In early 
January, dams were diagnosed for pregnan-
cy via rectal palpation or transrectal ultra-
sonography and calves weaned. Calf BW 
was recorded at pre- breeding and weaning.
Statistical Analysis
All data were analyzed using the PROC 
GLIMMIX procedure of SAS (SAS Inst. 
Inc., Cary, NC, version 9.4). The model 
statement included the fixed effects of dam 
grazing treatment, supplementation treat-
ment, and the resulting interaction. The 
experimental unit was considered grazing 
system × supplementation treatment × yr. 
Dam age and yr were included as a covari-
ate in all analyses and were removed when 
P > 0.05. Data were considered significant 
Effects of Prepartum Nutrition on  
May- Calving Cows and Progeny
Alicia C. Lansford
Jacki Musgrave
T.L. Meyer
Rick N. Funston
Summary with Implications
May- calving dams grazed either sub- 
irrigated meadow or upland range from Jan. 
5 to May 1 each year for 6 years. Within 
grazing system, dams received either no sup-
plement or 1 lb/d of a 33% CP supplement 
from Jan. 5 to April 1. Dams grazing mead-
ow in the prepartum period weighed more 
and had a greater body condition score prior 
to calving. They also tended to have greater 
pregnancy rates in the subsequent breeding 
season and tended to wean heavier calves 
than dams grazing upland range. Allowing 
May- calving dams to graze meadow in late 
gestation may increase herd profitability 
through increased dam pregnancy rates and 
weaned calf value. Furthermore, supplement-
ed dams weaned heavier calves, indepen-
dent of grazing system. Supplementation of 
May- calving dams in late gestation may be 
economical if the income from additional 
pounds of calf weaned is greater than the 
supplementation cost.
Introduction
Previous research (2006 Nebraska Beef 
Cattle Report, pp. 7– 9; 2009 Nebraska Beef 
Cattle Report, pp. 5– 8) examined increasing 
dietary CP and TDN for March- calving 
cows in late gestation and determined 
no difference in rebreed pregnancy rates. 
Late gestation for a March- calving herd 
occurs when forage is dormant, low in 
crude protein (CP) and in vitro dry matter 
digestibility (IVDMD), and supplemen-
tation may not have been enough to meet 
cow nutrient requirements. Alternately, late 
gestation for a May- calving herd occurs 
during early forage growth, where forage 
can meet or exceed the dam’s nutrient 
requirements. Furthermore, differences in 
forage species composition between upland 
range and subirrigated meadow (cool vs. 
warm season) result in different growth 
patterns and forage quality. The increased 
forage availability and quality during the 
prepartum period of a May- calving herd 
can affect maternal productivity, as well as 
progeny postnatal growth and performance. 
The objective of this study was to evaluate 
the effect of grazing system with and with-
out supplementation on May- calving dam 
reproductive performance and progeny 
growth through weaning.
Procedure
Dam Management
Multiparous, May- calving cows (n = 
652, 928 ± 4 lb) were blocked by BW and 
arranged in a 2 × 2 factorial treatment at 
weaning in January. Dams grazed either 
Table 1. Nutrient analysis and composition on 
a DM basis of supplement provided to May- 
calving cows in late gestation1
Item
Nutrient
 CP, % 32.9
 RUP, % CP 39.7
 TDN, % 78.4
Ingredient, % DM
 Dried distillers grains meal 52.5
 Soybean meal (46.5% CP) 14.7
 Vitamin and mineral package3 13.3
 Wheat middlings 6.3
 Sunflower meal (35% CP) 6.3
 Molasses, liquid 3.7
 Urea 1.6
 Cull beans 1.5
1May- calving dams were assigned to 1 of 2 supplementation 
groups for 85 d: 1 lb/d of supplement (S) or no supplement 
(NS) beginning at weaning in January.
2Calculated using the equations proposed by the NRC, 2000.
3Formulated to provide 0.7 g/lb monensin (Rumensin, 
Elanco Animal Health).
10 · 2019 Nebraska Beef Cattle Report
to dams who grazed meadow tended (P = 
0.07) to have an increased birth BW (74 vs. 
72 ± 0.4 lb, M vs. R). Additionally, calves 
born to supplemented dams had increased 
(P = 0.04) birth BW (74 vs. 72 ± 0.4 lb, S vs. 
NS). At pre- breeding, there was a tendency 
for a grazing system × supplement interac-
tion (P = 0.09) in calf BW, with RS calves 
having the greatest BW, MS and MNS in-
termediate, and RNS having the lowest BW. 
At weaning, calves born to dams grazing 
meadow in the prepartum period tended (P 
= 0.09) to have increased BW (443 vs. 436 
± 2 lb, M vs. R). Similarly, prepartum sup-
plemented dams weaned heavier calves (P 
= 0.02; 443 vs. 434 ± 2 lb, S vs. NS). Larson 
et al. (2009 Nebraska Beef Cattle Report, pp. 
5– 8) observed an increase in milk produc-
tion for March- calving cows grazing corn 
residue in late gestation when compared 
with cows grazing winter range. It is possi-
ble increased dietary nutritive value in late 
gestation is responsible for increased milk 
production and consequent calf BW.
Conclusions
May- calving dams grazing sub- irrigated 
meadow had increased prepartum BW and 
BCS. Furthermore, they tended to have 
increased pregnancy rates in the follow-
ing breeding season and wean heavier 
calves. Allowing May- calving dams to 
graze meadow during late gestation may 
increase total herd profitability through 
increased stayability of dams and increased 
weaned calf value. Independent of grazing 
system, supplemented dams had increased 
prepartum BW and BCS. Progeny birth and 
wean BW were also increased by prepartum 
supplementation, with no effect on dystocia 
rate. The cost of supplementation provid-
ed to May- calving dams in late gestation 
should be balanced against that additional 
9 lb of calf weaned observed in the current 
study. This research indicates management 
decisions made in one segment of the beef 
production system may have unrealized 
impacts on herd profitability.
Alicia C. Lansford, graduate student
Jacki Musgrave, research technician
T.L. Meyer, research technician
Rick N. Funston, professor, West Central 
Research and Extension Center, North 
Platte, NE
coming breeding season, with dams who 
increase or maintain BCS having greater 
pregnancy rates than dams who lose BCS. 
It is important to note supplemented dams 
in this study gained (P < 0.01) BCS over 
the treatment period, but NS dams did 
maintain condition (0.2 vs. 0.0 ± 0.03, S 
vs. NS).
Prepartum supplementation did not 
affect (P = 0.48) dam rebreed pregnancy 
rates. Prepartum meadow grazing tended 
(P = 0.08) to increase subsequent pregnan-
cy rates (89 vs. 85 ± 2%, M vs. R), despite 
no difference in prepartum BCS. Recent 
research has shown feeding dams a high en-
ergy diet prepartum increased activation of 
metabolic pathways involved in triglyceride 
synthesis in the postpartum period (Shahzad 
et al., 2014, https:// doi .org /10 .1371 /journal 
.pone .0099757). It is possible dams grazing 
meadow prepartum had an altered meta-
bolic response and may have been primed 
to better utilize nutrients in the subsequent 
breeding season.
At parturition, dystocia rate was not 
affected (P ≥ 0.14) by treatment, although 
both grazing treatment and supplemen-
tation affected calf birth BW. Calves born 
at P ≤ 0.05 and a tendency if P ≤ 0.10 and 
P > 0.05.
Results
Over the treatment period, there was a 
grazing system × supplement interaction (P 
= 0.02, Table 3) for dam BW change. Dams 
allotted to the MS treatment had the great-
est BW gain, MNS intermediate, followed 
by RS dams, and RNS dams. This resulted 
in differences in prepartum BW between 
grazing treatments and supplementation 
treatments. Dams grazing meadow had 
a greater (P < 0.01) prepartum BW when 
compared with R dams (1,036 vs. 1,005 ± 7 
lb, M vs. R). Likewise, S dams had a greater 
(P < 0.01) prepartum BW than NS dams 
(1,034 vs. 1,005 ± 7 lb, S vs. NS). Increased 
dam BW is likely a result of increased diet 
quality (Table 2).
Grazing treatment did not affect (P 
≥ 0.78) prepartum BCS or BCS change 
during treatment. Conversely, dam supple-
mentation increased (P < 0.01) prepartum 
BCS (4.7 vs. 4.6 ± 0.03, S vs. NS). Change 
in BCS during the prepartum period is an 
indicator of pregnancy success in the up-
Table 2. Predicted1 nutrient composition as a percentage of requirements in diets offered to May- 
calving dams in late gestation2
Meadow Range
NS S NS S
January
 CP, % mid- gestation req.3 85.9 95.8 70.4 80.3
 NEm, % mid- gestation req.4 96.9 99.0 118.4 120.4
February
 CP, % late gestation req.5 139.2 146.8 73.8 82.3
 NEm, % late gestation req.6 76.4 79.1 104.5 106.4
March
 CP, % late gestation req. 251.9 255.7 153.2 159.5
 NEm, % late gestation req. 143.6 143.6 143.6 143.6
April
 CP, % late gestation req. 320.7 322.8 160.3 167.1
 NEm, % late gestation req. 144.5 144.5 156.4 156.4
1Diet composition predicted using a computer model based on NRC, 2000 equations.
2May- calving dams were arranged in a 2 × 2 factorial at weaning in January and were assigned to 1 of 2 grazing treatments: sub- 
irrigated meadow (M) or upland range (R) for 116 d and then to 1 of 2 supplementation treatments: 1 lb/d of 33% CP (DM) 
supplement (S) or no supplement (NS) for 85 d.
3CP expressed as a percentage of requirement for mid- gestation multiparous dams (7.1% CP, DM; NRC, 2000).
4NEm expressed as a percentage of the requirement for mid- gestation multiparous dams (0.45 Mcal/lb; NRC, 2000).
5CP expressed as a percentage of requirement for late gestation multiparous dams (7.9% CP, DM; NRC, 2000).
6NEm expressed as a percentage of the requirement for late gestation multiparous dams (0.50 Mcal/lb; NRC, 2000).
2019 Nebraska Beef Cattle Report · 11 
Table 3. Effects of late gestation nutrition1 on May- calving dam BW, BCS, and reproductive and calf 
performance
M R
SEM
P- value2
     NS  S       NS S Graze Supp G × S
n 181 163 148 159
Cow BW, lb
 Initial 926 928 935 930 9 0.62 0.87 0.75
 Prepartum 1,027 1,045 983 1,021 9 < 0.01 < 0.01 0.25
 BW change, lb 99ab 115a 51c 93b 6 < 0.01 < 0.01 0.02
Cow BCS3
 Initial 4.6 4.5 4.6 4.6 0.04 0.61 0.10 0.35
 Prepartum 4.6 4.7 4.6 4.8 0.05 0.78 < 0.01 0.45
 BCS change 0.0 0.2 0.0 0.2 0.04 0.58 < 0.01 0.94
Dystocia, %4 0 1 1 0 1 0.96 0.95 0.15
Pregnancy rate, % 90 89 82 87 3 0.08 0.48 0.37
Calf BW, lb
 Birth 73 75 71 73 1 0.07 0.04 0.84
 Pre- breed 216ab 216ab 207b 234a 9 0.58 0.11 0.09
 Weaning 439 445 430 443 4 0.09 0.02 0.33
a,b,cMeans within a row lacking a common superscript differ (P ≤ 0.05).
1May- calving dams were arranged in a 2 × 2 factorial at weaning in January and were assigned to 1 of 2 forage types: sub- 
irrigated meadow (M) or upland range (R) for 116 d and then to 1 of 2 supplementation groups: 1 lb/d of 33% CP (DM) 
supplement (S) or no supplement (NS) for 85 d.
2Graze = grazing treatment, Supp = supplementation treatment, and G × S = grazing and supplement assignment interaction.
3BCS = Body condition score (1 = emaciated to 9 = obese).
4At parturition a calving ease (CE) score was assigned (1 = no assistance to 4 = caesarian section). A score of 2 or greater was 
considered dystocia.
2019 Nebraska Beef Cattle Report · 13 
dam grazing treatment, supplementation 
treatment, and the resulting interaction. 
The experimental unit was considered dam 
treatment × year, where dam treatment 
consisted of the grazing system, supplemen-
tation treatment, and the interaction. Dam 
age and year were included as a covariate in 
all analyses. The sex of the heifer progeny’s 
first calf was included as a covariate when 
analyzing heifer parturition data and their 
calf BW. Covariates were removed from the 
model statement when P > 0.05. Data were 
considered significant at P ≤ 0.05 and a 
tendency if P ≤ 0.10 and P > 0.05.
Results
Heifer Progeny Performance
Heifer progeny BW, BCS, and reproduc-
tive performance are presented in Table 2. 
Neither prebreeding BW nor percentage of 
heifers pubertal at the start of the breeding 
start of the subsequent breeding season. 
Pregnancy status was diagnosed in Novem-
ber via transrectal ultrasonography, and 
BW and BCS recorded. Calves were weaned 
from heifers at this time.
Heifer Progeny First Calf Management
The BW of the first calf born to heifer 
progeny was analyzed based on granddam 
pasture and supplement treatment. At par-
turition, calf birth BW, sex, and birth date 
were recorded. Calves were vaccinated and 
male calves castrated at prebreeding. Calf 
BW was recorded at prebreeding in July and 
weaning in November.
Statistical Analysis
All data were analyzed using the PROC 
GLIMMIX procedure of SAS (SAS Inst. 
Inc., Cary, NC, version 9.4). The model 
statement included the fixed effects of 
were collected from heifers via coccy-
geal venipuncture to determine plasma 
progesterone concentrations. Heifers were 
considered pubertal if plasma progesterone 
concentrations were ≥ 1.0 ng/mL at one or 
both time points. Heifer BW was recorded 
at blood collection and prebreeding BW 
was considered the average of these 2 time 
points. Heifer progeny were placed with 
fertile bulls at a 1:20 bull to heifer ratio for a 
45 d breeding season. Heifers were synchro-
nized using a single PGF2α (5 mL i.m., Lu-
talyse; Zoetis Animal Health, Parisippany, 
NJ) 5 d after bull placement. Body weight 
and BCS were recorded and pregnancy di-
agnosed via transrectal ultrasonography in 
mid- October. Two weeks prior to calving, 
heifer BW and BCS was recorded. A calving 
ease (CE) score (1 = no assistance, 2 = easy 
assist, 3 = difficult assist, and 4 = caesarian 
section) was assigned at parturition, with 
scores of 2 or greater considered dystocia. 
Body weight and BCS were recorded at the 
Table 2. Effect of late gestation nutrition on May- born heifer progeny BW, BCS, and reproductive performance
M R
SEM
P- value2
NS S NS S Graze Supp G × S
n 81 76 74 79
Heifer BW, lb
 Prebreeding (14 mo) 701 701 694 694 4 0.20 0.92 0.94
 Pregnancy diagnosis (17 mo) 791 789 785 785 4 0.37 0.85 0.75
 Prepartum (23 mo) 842 851 858 869 11 0.13 0.41 0.94
 Prebreeding (26 mo) 873 882 884 875 9 0.78 0.96 0.31
 Pregnancy diagnosis (30 mo) 864 895 891 904 13 0.13 0.06 0.42
Heifer BCS3
 Pregnancy diagnosis (17 mo) 5.9 5.9 5.8 5.8 0.03 0.13 0.40 0.74
 Prepartum (23 mo) 5.2 5.1 5.1 5.0 0.06 0.24 0.19 0.66
 Prebreeding (26 mo) 5.4ab 5.5a 5.4ab 5.2b 0.07 0.02 0.38 0.04
 Pregnancy diagnosis (30 mo) 5.2b 5.5a 5.3ab 5.3ab 0.08 0.76 0.08 0.01
Pubertal, %4 71 79 76 68 5 0.62 0.97 0.12
Percent mature BW, %5 60 61 58 59 0.7 0.01 0.06 0.59
Heifer pregnancy rate, % 78 79 72 74 5 0.29 0.81 0.88
Dystocia, %6 10 17 8 28 7 0.54 0.02 0.35
PPI, d7 89 89 96 95 3 0.03 0.99 0.83
Primiparous cow  
pregnancy rate, %
84 93 74 74 8 0.02 0.35 0.36
1May- calving dams were arranged in a 2 × 2 factorial at weaning in January and were assigned to 1 of 2 forage types: sub- irrigated meadow (M) or upland range (R) for 116 d and then to 1 of 2 
supplementation groups: 1 lb/d of 33% CP (DM) supplement (S) or no supplement (NS) for 85 d.
2Graze = grazing treatment, Supp = supplementation treatment, and G × S = grazing and supplement interaction.
3BCS = Body condition score (1 = emaciated to 9 = obese).
4Considered pubertal if blood serum progesterone concentration > 1 ng/ml.
5Percent of mature BW at 14 mo of age. Calculated using a May- herd mature cow BW of 1,172 lb.
6At parturition a calving ease (CE) score was assigned (1 = no assistance to 4 = caesarian section). A score of 2 or greater was considered as dystocia.
7PPI = postpartum interval. Conception date was calculated by subtracting 285 d from subsequent calving date.


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Effects of Prepartum Nutrition on May-Calving Cows and Progeny

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