Anti-Müllerian Hormone (AMH) has been associated with follicle number and age of the ovary. Therefore, our hypothesiswas that AMH was a biomarker for both follicle number and ovarian function in the beef cow. Ovaries were collected by flank laparotomy. The number of follicles increased as cows aged from 1.5 to 6 years and began to decrease thereafter; however, the size of the ovary continued to increase with advanced age. Expression of the AMH gene increased with increasing follicle number in 2-year-old beef cows. These results suggest that heifers with larger ovaries will have greater numbers of follicles and greater productivity, allowing them to stay in the production herd longer. AMH could be used to identify heifers of high reproductive potential at a very young age

Beavers, Kevin A

Bergman, Jeffrey W.

Clopton, Debra T.

Cupp, Andrea S.

Cushman, Robert A

Moline, Karl V.

Pohlmeier, William E

Slattery, Rachael G

Smith, Jacqueline

Wood, Jennifer R

English

DigitalCommons@University of Nebraska

University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln Nebraska Beef Cattle Reports Animal Science Department 2010 Reproductive Aging Influences Ovarian Function in Beef Cows Robert A. Cushman University of Nebraska-Lincoln, Bob.Cushman@ars.usda.gov Jennifer R. Wood University of Nebraska-Lincoln, jwood5@unl.edu Rachael G. Slattery University of Nebraska-Lincoln Debra T. Clopton University of Nebraska-Lincoln, dclopton1@unl.edu Jacqueline Smith University of Nebraska-Lincoln, jsmith19@unl.edu See next page for additional authors Follow this and additional works at: https://digitalcommons.unl.edu/animalscinbcr  Part of the Animal Sciences Commons Cushman, Robert A.; Wood, Jennifer R.; Slattery, Rachael G.; Clopton, Debra T.; Smith, Jacqueline; Beavers, Kevin A.; Pohlmeier, William E.; Bergman, Jeffrey W.; Moline, Karl V.; and Cupp, Andrea S., "Reproductive Aging Influences Ovarian Function in Beef Cows" (2010). Nebraska Beef Cattle Reports. 558. https://digitalcommons.unl.edu/animalscinbcr/558 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. Authors Robert A. Cushman, Jennifer R. Wood, Rachael G. Slattery, Debra T. Clopton, Jacqueline Smith, Kevin A. Beavers, William E. Pohlmeier, Jeffrey W. Bergman, Karl V. Moline, and Andrea S. Cupp This article is available at DigitalCommons@University of Nebraska - Lincoln: https://digitalcommons.unl.edu/animalscinbcr/558 © The Board of Regents of the University of Nebraska.  All rights reserved. 2010 Nebraska Beef Report  — Page 17 Reproductive Aging Influences Ovarian Functionin Beef CowsRobert A. CushmanJennifer R. WoodRacheal G. SlatteryDebra T. CloptonJacqueline SmithKevin A. BeaversWilliam E. PohlmeierJeff W. BergmanKarl V. MolineAndrea S. Cupp1SummaryAnti-Müllerian Hormone (AMH) has been associated with follicle num-ber and age of the ovary. Therefore, our hypothesis was that AMH was a biomarker for both follicle number and ovarian function in the beef cow. Ova-ries were collected by flank laparotomy.  The number of follicles increased as cows aged from 1.5 to 6 years and began to decrease thereafter; however, the size of the ovary continued to increase with advanced age. Expression of the AMH gene increased with increasing follicle number in 2-year-old beef cows. These results suggest that heifers with larger ovaries will have greater numbers of follicles and greater productivity, allow-ing them to stay in the production herd longer. AMH could be used to identify heifers of high reproductive potential at a very young age.IntroductionFertility declines in mammalian females as they age, mainly due to depletion of the number of follicles in the ovary. Early studies demonstrated that Hereford heifers were born with approximately 100,000 follicles in their combined ovaries, but there was a great deal of variation among heifers in the number of follicles in their ovaries at birth. Low follicle number is associated with decreased heifer pregnancy rate, poor oocyte quality, decreased superovulatory response, impaired corpus luteum function, and increased ovulation failure in beef cows. Anti-Müllerian Hormone is a growth factor that has been demonstrated to be both a bio-logical and genetic marker of ovarian function and follicle numbers in other mammalian females. Therefore, we hypothesized that AMH could act as a biomarker and genetic marker of fol-licle number in beef cows.ProcedureAll procedures were approved by the Animal Care and Use Com-mittee (IACUC) at the University of Nebraska–Lincoln. Beef cows (n = 37) ranging in age from 1.5 to 11 years were injected with Lutalyse, and ovaries were removed by flank lapa-rotomy (incision in the flank through the side to excise the ovaries) 36 hours later to obtain dominant follicles prior to ovulation. Ovaries were weighed, measured for length and height, and all visible surface follicles were count-ed. The outer cortical region of the ovary that contains the follicles was dissected and a representative piece was frozen for genomic analysis.ResultsThe number of follicles was greater in mature cows than in cows less than 3 years of age; however, beyond 6 years of age, follicle numbers declined (Figure 1). Interestingly, although follicle numbers declined, ovarian size continued to increase in cows of advanced age (Table 1). In general, larger ovaries were associated with Table 1.  Influence of age on ovarian traits in beef cows.  AgeTrait 1.5 - 2 yr 3 - 6 yr 7 - 11 yr P-valueNo. of cows 25 248Ovarian weight (g)1 11.8 + 0.9 4 17.2 + 1.05 22.5 + 1.66 0.0001Ovarian length (mm)2 28.1 + 0.94 31.2 + 0.95 33.0 + 1.56 0.008Ovarian height (mm)3 19.6 + 0.64 21.3 + 0.65 24.0 + 1.06 0.0011Sum of the weight of the combined ovaries.2Average length of the left and right ovary within a cow.3Average height of the left and right ovary within a cow.4,5,6Within a row, means with different superscripts are different.6050403020100Follicle Number 1.5 - 2 yr 3 - 6 yr 7 - 11 yrAgeababFigure 1. Influence of age on surface follicle numbers in the bovine ovary. Follicle numbers were greater in mature cows than in heifers, and began to decrease in cows of advanced age (P = 0.04). Page 18 — 2010 Nebraska Beef Report  © The Board of Regents of the University of Nebraska.  All rights reserved.numbers and ovarian dysfunction. The results of the present study sug-gest AMH may be a genetic marker of follicle number and ovarian func-tion in the beef cow as well, and DNA sequencing efforts have begun. Genetic markers would be useful for identifying heifers of high reproduc-tive potential at a young age, before ultrasonography is viable. This would allow culling decisions to be made before time and resources were wasted on heifers with low reproductive potential. 1Robert A. Cushman, physiologist, Jennifer R. Wood, assistant professor, Racheal G. Slattery, graduate student, Debra T. Clopton, research analyst, Jacqueline Smith, research analyst. Kevin A. Beavers, technician, U.S. Meat Animal Research Center (USMARC); William E. Pohlmeier, technician, Karl V. Moline, cow/calf manager, Jeff  W. Bergman, agriculture technician, Andrea S. Cupp, associate professor, Animal Science, University of Nebraska, Lincoln, Neb.Figure 2. Relationship between relative level of AMH gene expression and follicle numbers in the ovarian cortex of the 2-year-old beef cow. As the number of follicles increased, the amount of AMH RNA increased (P = 0.01). 7006005004003002001000Anti-Mullerian Hormone RNA 0 10 20 30 40 50 60 70Follicle Numbery = 7.1207x = 18.782R2 = 0.5386increased follicle numbers in heifers. These results suggest that cows that are productive to an advanced age have larger ovaries and larger numbers of follicles than do heifers. This would explain why ovarian size appears to be increasing as follicle number is beginning to decrease.Within the ovarian cortex of 2-year-old cows, AMH gene expres-sion increased as follicle numbers increased (Figure 2). Similar results have been observed in rodents, pri-mates, and women. Additionally, polymorphisms in the human AMH gene have been associated with follicle 

Reproductive Aging Influences Ovarian Function in Beef Cows

UNL | Libraries

University of Nebraska - Lincoln 
DigitalCommons@University of Nebraska - Lincoln 
Nebraska Beef Cattle Reports Animal Science Department 
2010 
Reproductive Aging Influences Ovarian Function in Beef Cows 
Robert A. Cushman 
University of Nebraska-Lincoln, Bob.Cushman@ars.usda.gov 
Jennifer R. Wood 
University of Nebraska-Lincoln, jwood5@unl.edu 
Rachael G. Slattery 
University of Nebraska-Lincoln 
Debra T. Clopton 
University of Nebraska-Lincoln, dclopton1@unl.edu 
Jacqueline Smith 
University of Nebraska-Lincoln, jsmith19@unl.edu 
See next page for additional authors 
Follow this and additional works at: https://digitalcommons.unl.edu/animalscinbcr 
 Part of the Animal Sciences Commons 
Cushman, Robert A.; Wood, Jennifer R.; Slattery, Rachael G.; Clopton, Debra T.; Smith, Jacqueline; Beavers, 
Kevin A.; Pohlmeier, William E.; Bergman, Jeffrey W.; Moline, Karl V.; and Cupp, Andrea S., "Reproductive 
Aging Influences Ovarian Function in Beef Cows" (2010). Nebraska Beef Cattle Reports. 558. 
https://digitalcommons.unl.edu/animalscinbcr/558 
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. 
Authors 
Robert A. Cushman, Jennifer R. Wood, Rachael G. Slattery, Debra T. Clopton, Jacqueline Smith, Kevin A. 
Beavers, William E. Pohlmeier, Jeffrey W. Bergman, Karl V. Moline, and Andrea S. Cupp 
This article is available at DigitalCommons@University of Nebraska - Lincoln: https://digitalcommons.unl.edu/
animalscinbcr/558 
© The Board of Regents of the University of Nebraska.  All rights reserved. 2010 Nebraska Beef Report  — Page 17 
Reproductive Aging Influences Ovarian Function
in Beef Cows
Robert A. Cushman
Jennifer R. Wood
Racheal G. Slattery
Debra T. Clopton
Jacqueline Smith
Kevin A. Beavers
William E. Pohlmeier
Jeff W. Bergman
Karl V. Moline
Andrea S. Cupp1
Summary
Anti-Müllerian Hormone (AMH) 
has been associated with follicle num-
ber and age of the ovary. Therefore, 
our hypothesis was that AMH was a 
biomarker for both follicle number and 
ovarian function in the beef cow. Ova-
ries were collected by flank laparotomy.  
The number of follicles increased as cows 
aged from 1.5 to 6 years and began to 
decrease thereafter; however, the size 
of the ovary continued to increase with 
advanced age. Expression of the AMH 
gene increased with increasing follicle 
number in 2-year-old beef cows. These 
results suggest that heifers with larger 
ovaries will have greater numbers of 
follicles and greater productivity, allow-
ing them to stay in the production herd 
longer. AMH could be used to identify 
heifers of high reproductive potential at 
a very young age.
Introduction
Fertility declines in mammalian 
females as they age, mainly due to 
depletion of the number of follicles in 
the ovary. Early studies demonstrated 
that Hereford heifers were born with 
approximately 100,000 follicles in 
their combined ovaries, but there 
was a great deal of variation among 
heifers in the number of follicles in 
their ovaries at birth. Low follicle 
number is associated with decreased 
heifer pregnancy rate, poor oocyte 
quality, decreased superovulatory 
response, impaired corpus luteum 
function, and increased ovulation 
failure in beef cows. Anti-Müllerian 
Hormone is a growth factor that has 
been demonstrated to be both a bio-
logical and genetic marker of ovarian 
function and follicle numbers in other 
mammalian females. Therefore, we 
hypothesized that AMH could act as a 
biomarker and genetic marker of fol-
licle number in beef cows.
Procedure
All procedures were approved 
by the Animal Care and Use Com-
mittee (IACUC) at the University 
of Nebraska–Lincoln. Beef cows (n 
= 37) ranging in age from 1.5 to 11 
years were injected with Lutalyse, and 
ovaries were removed by flank lapa-
rotomy (incision in the flank through 
the side to excise the ovaries) 36 hours 
later to obtain dominant follicles prior 
to ovulation. Ovaries were weighed, 
measured for length and height, and 
all visible surface follicles were count-
ed. The outer cortical region of the 
ovary that contains the follicles was 
dissected and a representative piece 
was frozen for genomic analysis.
Results
The number of follicles was greater 
in mature cows than in cows less than 
3 years of age; however, beyond 6 
years of age, follicle numbers declined 
(Figure 1). Interestingly, although 
follicle numbers declined, ovarian 
size continued to increase in cows of 
advanced age (Table 1). In general, 
larger ovaries were associated with 
Table 1.  Influence of age on ovarian traits in beef cows.
  Age
Trait 1.5 - 2 yr 3 - 6 yr 7 - 11 yr P-value
No. of cows 25 248
Ovarian weight (g)1 11.8 + 0.9 4 17.2 + 1.05 22.5 + 1.66 0.0001
Ovarian length (mm)2 28.1 + 0.94 31.2 + 0.95 33.0 + 1.56 0.008
Ovarian height (mm)3 19.6 + 0.64 21.3 + 0.65 24.0 + 1.06 0.001
1Sum of the weight of the combined ovaries.
2Average length of the left and right ovary within a cow.
3Average height of the left and right ovary within a cow.
4,5,6Within a row, means with different superscripts are different.
60
50
40
30
20
10
0
Fo
lli
cl
e 
N
um
be
r
 1.5 - 2 yr 3 - 6 yr 7 - 11 yr
Age
a
b
ab
Figure 1. Influence of age on surface follicle numbers in the bovine ovary. Follicle numbers were 
greater in mature cows than in heifers, and began to decrease in cows of advanced age 
(P = 0.04). 
Page 18 — 2010 Nebraska Beef Report  © The Board of Regents of the University of Nebraska.  All rights reserved.
numbers and ovarian dysfunction. 
The results of the present study sug-
gest AMH may be a genetic marker 
of follicle number and ovarian func-
tion in the beef cow as well, and 
DNA sequencing efforts have begun. 
Genetic markers would be useful for 
identifying heifers of high reproduc-
tive potential at a young age, before 
ultrasonography is viable. This would 
allow culling decisions to be made 
before time and resources were wasted 
on heifers with low reproductive 
potential. 
1Robert A. Cushman, physiologist, Jennifer 
R. Wood, assistant professor, Racheal G. 
Slattery, graduate student, Debra T. Clopton, 
research analyst, Jacqueline Smith, research 
analyst. Kevin A. Beavers, technician, U.S. Meat 
Animal Research Center (USMARC); William 
E. Pohlmeier, technician, Karl V. Moline, cow/
calf manager, Jeff  W. Bergman, agriculture 
technician, Andrea S. Cupp, associate professor, 
Animal Science, University of Nebraska, Lincoln, 
Neb.
Figure 2. Relationship between relative level of AMH gene expression and follicle numbers in the 
ovarian cortex of the 2-year-old beef cow. As the number of follicles increased, the amount 
of AMH RNA increased (P = 0.01). 
700
600
500
400
300
200
100
0
A
n
ti
-M
ul
le
ri
an
 H
or
m
on
e 
R
N
A
 0 10 20 30 40 50 60 70
Follicle Number
y = 7.1207x = 18.782
R2 = 0.5386
increased follicle numbers in heifers. 
These results suggest that cows 
that are productive to an advanced 
age have larger ovaries and larger 
numbers of follicles than do heifers. 
This would explain why ovarian size 
appears to be increasing as follicle 
number is beginning to decrease.
Within the ovarian cortex of 
2-year-old cows, AMH gene expres-
sion increased as follicle numbers 
increased (Figure 2). Similar results 
have been observed in rodents, pri-
mates, and women. Additionally, 
polymorphisms in the human AMH 
gene have been associated with follicle 


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Reproductive Aging Influences Ovarian Function in Beef Cows

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