Crossbred heifers (n=19) were used to determine the effects of feeding Cu, Co, Mn and Zn in amounts greater than recommended by the NRC on ovarian function. Heifers were fed hay ad libitum and individually fed a control (n=9) or trace mineral (n=10) supplement for 109 days. Dry-matter intake, average daily gain, day luteal phase began, length of luteal phase, daily mean progesterone production, follicular phase estradiol production and first wave dominant follicle size were not affected by mineral supplementation. However, heifers in the treatment group had fewer large follicles during the early portion of the estrous cycle

Brink, Dennis R.

Kinder, Jim

Moravek, Tony

Rasby, Richard J.

Story, Chuck

English

DigitalCommons@University of Nebraska

University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln Nebraska Beef Cattle Reports Animal Science Department 1-1-1999 Trace Mineral Supplementation and Ovarian and Luteal Function in Pubertal Heifers Chuck Story University of Nebraska - Linocln Richard J. Rasby University of Nebraska-Lincoln, rrasby1@unl.edu Dennis R. Brink University of Nebraska-Lincoln, dbrink1@unl.edu Jim Kinder University of Nebraska-Lincoln, kinder.15@osu.edu Tony Moravek University of Nebraska-Lincoln Follow this and additional works at: https://digitalcommons.unl.edu/animalscinbcr  Part of the Animal Sciences Commons Story, Chuck; Rasby, Richard J.; Brink, Dennis R.; Kinder, Jim; and Moravek, Tony, "Trace Mineral Supplementation and Ovarian and Luteal Function in Pubertal Heifers" (1999). Nebraska Beef Cattle Reports. 423. https://digitalcommons.unl.edu/animalscinbcr/423 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. 1999 Nebraska Beef Report — Page 10Trace Mineral Supplementation and Ovarian and Luteal Function in Pubertal Heifersby either established NRC requirements,feed tag recommendations or by the pro-ducer based on past experience. Recent research suggests reduced reproductive performance of two-year-old cows when trace minerals were fed in amounts above NRC recommendations (1997 Nebraska Beef Report, pp. 15-17) after -ological characteristic or mechanism was implicated as the cause of this decrease in reproductive performance. Therefore, the objective of this study was to evaluate effects of feeding greater than recom-mended amounts of Cu, Co, Mn and Zn on number and size of ovarian follicles during the early part of the estrous cycle, size of the largest ovarian follicle, luteal phase progesterone (P4) production, length of the luteal phase and estradiol production during the follicular phase of the estrous cycle.ProcedureNineteen Angus x MARC II post-pu-bertal heifers (680 lbs) were randomly assigned to either a control (CON, n = 9) or treatment (TRT, n = 10) group based on weight and age. Beginning on day zero of the supplementation period, heifers were fed grass hay free choice and individually fed 4.0 lbs of dry-rolled corn and 1.3 lbs of either a control or treatment supplement. This feeding program continued through day 109. The diets were formulated to provide the mineral concentrations listed in Table 1 each day, and the nutrients needed for heifers to gain 1.5 lb/day. Weekly group hay and daily individual supplement refusals were monitored to characterize DM intake.Liver biopsy samples were taken on days -1 and 65 of the experiment. Liver samples were analyzed for Cu, Mn and Zn concentrations (the day before treat-ments were imposed).Heifers were synchronized to begin an estrous cycle on approximately day 66 of the experiment by using two in-jections of prostaglandin given 11 days apart. Beginning on day 66, jugular vein samples were collected twice daily (a.m. and p.m.) for the next 21 days and ana-lyzed for concentration of progesterone (P4). Length of the luteal phase, was determined during this time (the time in the estrus cycle when progesterone is produced due to the presence of a func-the luteal phase was when concentration of P4 in plasma exceeded .5 ng/ml and the last day of the luteal phase was when concentration of P4 in plasma fell below Chuck StoryRick RasbyDennis BrinkJim KinderTony Moravek1Cu, Co, Mn and Zn supplemented at high levels do not affect blood progesterone or estradiol concentra-tions or luteal phase characteristics, but supplemented heifers have fewer large follicles.SummaryCrossbred heifers (n=19) were used to determine the effects of feeding Cu, Co, Mn and Zn in amounts greater than recommended by the NRC on ovarian function. Heifers were fed hay ad libitum and individually fed a control (n=9) or trace mineral (n=10) supplement for 109 days. Dry-matter intake, average daily gain, day luteal phase began, length of luteal phase, daily mean progesterone production, follicular phase estradiol -licle size were not affected by mineral supplementation. However, heifers in the treatment group had fewer large follicles during the early portion of the estrous cycle.IntroductionTrace minerals are commonly included in rations for developing re-placement heifers. Amount of trace min-erals supplemented is often determinedTable 1. Amounts of Cu, Co, Mn and Zn in ration per daya based on dry-matter intake and feed nutrient analysis.Rationmg/hd/day  NRCNutrient Control Treatmentb RecommendedCu 45 269 84Co .92 20 .84Mn 673 946 168Zn 120 551 252aRation and NRC recommended mineral concentra-tions based on 18.4 lbs. of dry-matter intake.bDaily mineral intake provided from the supple-ment fed to treatment heifers: 235 mg Cu, 19.4 mg Co, 315 mg Mn, 470 mg Zn.Page 11 — 1999 Nebraska Beef ReportTable 3. Reproductive characteristics of heifers by treatment group.Control SE Treatment SEDay luteal phase began 5 .5 5.5 .5Length of luteal phase, days 15.27 .63 14.05 .59Mean daily luteal phaseP4 concentration, ng/ml 3.36 .28 2.91 .26Size of largest follicle, mm 13.4 .8 14.0 .8Number of large folliclesa 3.2a .2 2.6b .2Mean sample estradiolconcentration, pg/ml .58 .27 1.05 .26abMeans within a row with different supercripts are different (P < .10).Table 2. Liver biopsy tissue analysisa.Group Control   TreatmentDay   DayNutrient -1b 65 SE -1b 65 SECu, mg/kg 236 146 124 432 193 113Mn, mg/kg 7.8 7.5 .4 7.2 7.0 .3Zn, mg/kg 150c 94d 7 129c 94d 7aConcentrations reported on a dry-weight basis.bDay -1 indicates the liver tissue samples were taken before any treatments were imposed.cdMeans within a row with different superscripts are different (P < .01)..5 ng/ml. The mean daily progesterone production during the luteal phase was also determined.Ovarian follicular development was monitored using ultrasonography daily from day 66 to day 73 and every other day from day 74 through day 87. To study the follicular phase of the estrous cycle, heifers were once again synchronized using two injections of prostaglandin given 11 days apart so estrus occurred on approximately day 96 of the experiment. On the morning of day 106, all ovarian follicles > 5 mm were ablated via transvaginal follicular aspiration. Beginning approximately 12 hours post-ablation, jugular blood samples were collected every six hours for approximately 72 hours to monitor the amount of estradiol in blood. Heif-ers were weighed throughout the trial to monitor weight gain.ResultsAverage heifer weights at the be-ginning of the trial were not different between groups and averaged 673 lbs for heifers in the TRT group and 688 lbs for the CON heifers. Weights at the end of the trial for heifers in the TRT and CON groups were not different and averaged 841 lb and 850 lb, respectively. Mineral supplementation did not affect DM intake or ADG which were 18.37 lb/day, 1.54 lb/day and 18.38 lb/day, 1.49 lb/day for heifers in the CON and TRT groups, respectively.Liver concentrations of Cu, Mn and Zn were not different between CON and TRT heifers on day -1 or 65 of the experiment (Table 2.). However, liver biopsy samples indicated a numerical decrease in Cu and Mn concentrations in both CON and TRT heifers between day -1 and day 65. In addition, there was a decrease (P < .01) in Zn between day -1 and day 65 of the experiment in heifers of both groups (Table 2.). The decrease in liver Cu, Mn and Zn concen-trations within both groups is not fully understood. There appears to be large variations in liver mineral concentrations among individual animals as indicated by the standard error associated with the means. As the animal grows, vital organs (liver, kidneys, spleen, heart) also increase in size. The increase in mass of the organs may have a diluting effect of mineral concentrations in the liver. Because blood volume is a function of body weight, blood volume increases as the animal increases in body size, potentially causing liver concentrations of minerals to decrease.The beginning day of the luteal phase of the estrous cycle for the CON and TRT groups was not affected by mineral supplementation (Table 3.). Luteal phase length was not affected by mineral supplementation and was 15.3 +.6 days for the CON group and 14.1 + .6 days for the TRT group. Mean daily P4production during the luteal phase was also similar for CON and TRT heifers (Table 3.). Furthermore, between days 14 and 16, which is when pregnancy is recognized by the uterus, there was no difference in daily mean P4 production between the CON (4.85 + .55 ng/ml) and TRT (4.26 + .53 ng/ml) heifers.The size of the largest follicle during the early portion of the estrous cycle was not different between the CON and TRT groups. However, TRT heifers had fewer follicles (2.6 + .2) greater than 8mm compared to the CON heifers (3.2 + .2; P < .10). Finally, mean sample estradiol concentration in blood was not different between the CON and the TRT groups (Table 3.).Supplementation of Cu, Co, Mn and Zn at amounts greater than NRC has been shown to decrease female reproduc-tive performance (1997 Nebraska Beef Report, pp. 15-17). Our study indicates supplementing Cu, Co, Mn and Zn at amounts in excess of NRC recommen-dations does not affect the physiological characteristics at the ovarian level which are important for reproductive success in cattle. However, supplemented heif-ers had fewer large follicles. How this impacts subsequent reproductive perfor-mance is not understood.1Chuck Story, graduate student; Rick Rasby, associate professor; Dennis Brink, Jim Kinder, pro-fessors, Animal Science, Lincoln; Tony Moravek, former undergraduate student.

Trace Mineral Supplementation and Ovarian and Luteal Function in Pubertal Heifers

UNL | Libraries

University of Nebraska - Lincoln 
DigitalCommons@University of Nebraska - Lincoln 
Nebraska Beef Cattle Reports Animal Science Department 
1-1-1999 
Trace Mineral Supplementation and Ovarian and Luteal Function 
in Pubertal Heifers 
Chuck Story 
University of Nebraska - Linocln 
Richard J. Rasby 
University of Nebraska-Lincoln, rrasby1@unl.edu 
Dennis R. Brink 
University of Nebraska-Lincoln, dbrink1@unl.edu 
Jim Kinder 
University of Nebraska-Lincoln, kinder.15@osu.edu 
Tony Moravek 
University of Nebraska-Lincoln 
Follow this and additional works at: https://digitalcommons.unl.edu/animalscinbcr 
 Part of the Animal Sciences Commons 
Story, Chuck; Rasby, Richard J.; Brink, Dennis R.; Kinder, Jim; and Moravek, Tony, "Trace Mineral 
Supplementation and Ovarian and Luteal Function in Pubertal Heifers" (1999). Nebraska Beef Cattle 
Reports. 423. 
https://digitalcommons.unl.edu/animalscinbcr/423 
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. 
1999 Nebraska Beef Report — Page 10
Trace Mineral Supplementation and Ovarian 
and Luteal Function in Pubertal Heifers
by either established NRC requirements,
feed tag recommendations or by the pro-
ducer based on past experience. Recent 
research suggests reduced reproductive 
performance of two-year-old cows when 
trace minerals were fed in amounts 
above NRC recommendations (1997 
Nebraska Beef Report, pp. 15-17) after 
-
ological characteristic or mechanism was 
implicated as the cause of this decrease 
in reproductive performance. Therefore, 
the objective of this study was to evaluate 
effects of feeding greater than recom-
mended amounts of Cu, Co, Mn and Zn 
on number and size of ovarian follicles 
during the early part of the estrous cycle, 
size of the largest ovarian follicle, luteal 
phase progesterone (P4) production, 
length of the luteal phase and estradiol 
production during the follicular phase 
of the estrous cycle.
Procedure
Nineteen Angus x MARC II post-pu-
bertal heifers (680 lbs) were randomly 
assigned to either a control (CON, n 
= 9) or treatment (TRT, n = 10) group 
based on weight and age. Beginning 
on day zero of the supplementation 
period, heifers were fed grass hay free 
choice and individually fed 4.0 lbs of 
dry-rolled corn and 1.3 lbs of either a 
control or treatment supplement. This 
feeding program continued through 
day 109. The diets were formulated to 
provide the mineral concentrations listed 
in Table 1 each day, and the nutrients 
needed for heifers to gain 1.5 lb/day. 
Weekly group hay and daily individual 
supplement refusals were monitored to 
characterize DM intake.
Liver biopsy samples were taken on 
days -1 and 65 of the experiment. Liver 
samples were analyzed for Cu, Mn and 
Zn concentrations (the day before treat-
ments were imposed).
Heifers were synchronized to begin 
an estrous cycle on approximately day 
66 of the experiment by using two in-
jections of prostaglandin given 11 days 
apart. Beginning on day 66, jugular vein 
samples were collected twice daily (a.m. 
and p.m.) for the next 21 days and ana-
lyzed for concentration of progesterone 
(P4). Length of the luteal phase, was 
determined during this time (the time 
in the estrus cycle when progesterone is 
produced due to the presence of a func-
the luteal phase was when concentration 
of P4 in plasma exceeded .5 ng/ml and 
the last day of the luteal phase was when 
concentration of P4 in plasma fell below 
Chuck Story
Rick Rasby
Dennis Brink
Jim Kinder
Tony Moravek1
Cu, Co, Mn and Zn supplemented 
at high levels do not affect blood 
progesterone or estradiol concentra-
tions or luteal phase characteristics, 
but supplemented heifers have fewer 
large follicles.
Summary
Crossbred heifers (n=19) were used 
to determine the effects of feeding Cu, 
Co, Mn and Zn in amounts greater than 
recommended by the NRC on ovarian 
function. Heifers were fed hay ad libitum 
and individually fed a control (n=9) or 
trace mineral (n=10) supplement for 109 
days. Dry-matter intake, average daily 
gain, day luteal phase began, length of 
luteal phase, daily mean progesterone 
production, follicular phase estradiol 
-
licle size were not affected by mineral 
supplementation. However, heifers in 
the treatment group had fewer large 
follicles during the early portion of the 
estrous cycle.
Introduction
Trace minerals are commonly 
included in rations for developing re-
placement heifers. Amount of trace min-
erals supplemented is often determined
Table 1. Amounts of Cu, Co, Mn and Zn in 
ration per daya based on dry-matter 
intake and feed nutrient analysis.
Ration
mg/hd/day
  NRC
Nutrient Control Treatmentb Recommended
Cu 45 269 84
Co .92 20 .84
Mn 673 946 168
Zn 120 551 252
aRation and NRC recommended mineral concentra-
tions based on 18.4 lbs. of dry-matter intake.
bDaily mineral intake provided from the supple-
ment fed to treatment heifers: 235 mg Cu, 19.4 
mg Co, 315 mg Mn, 470 mg Zn.
Page 11 — 1999 Nebraska Beef Report
Table 3. Reproductive characteristics of heifers by treatment group.
Control SE Treatment SE
Day luteal phase began 5 .5 5.5 .5
Length of luteal phase, days 15.27 .63 14.05 .59
Mean daily luteal phase
P4 concentration, ng/ml 3.36 .28 2.91 .26
Size of largest follicle, mm 13.4 .8 14.0 .8
Number of large folliclesa 3.2a .2 2.6b .2
Mean sample estradiol
concentration, pg/ml .58 .27 1.05 .26
abMeans within a row with different supercripts are different (P < .10).
Table 2. Liver biopsy tissue analysisa.
Group Control   Treatment
Day   Day
Nutrient -1b 65 SE -1b 65 SE
Cu, mg/kg 236 146 124 432 193 113
Mn, mg/kg 7.8 7.5 .4 7.2 7.0 .3
Zn, mg/kg 150c 94d 7 129c 94d 7
aConcentrations reported on a dry-weight basis.
bDay -1 indicates the liver tissue samples were taken before any treatments were imposed.
cdMeans within a row with different superscripts are different (P < .01).
.5 ng/ml. The mean daily progesterone 
production during the luteal phase was 
also determined.
Ovarian follicular development 
was monitored using ultrasonography 
daily from day 66 to day 73 and every 
other day from day 74 through day 87. 
To study the follicular phase of the 
estrous cycle, heifers were once again 
synchronized using two injections of 
prostaglandin given 11 days apart so 
estrus occurred on approximately day 
96 of the experiment. On the morning 
of day 106, all ovarian follicles > 5 mm 
were ablated via transvaginal follicular 
aspiration. Beginning approximately 
12 hours post-ablation, jugular blood 
samples were collected every six hours 
for approximately 72 hours to monitor 
the amount of estradiol in blood. Heif-
ers were weighed throughout the trial to 
monitor weight gain.
Results
Average heifer weights at the be-
ginning of the trial were not different 
between groups and averaged 673 lbs 
for heifers in the TRT group and 688 
lbs for the CON heifers. Weights at the 
end of the trial for heifers in the TRT 
and CON groups were not different and 
averaged 841 lb and 850 lb, respectively. 
Mineral supplementation did not affect 
DM intake or ADG which were 18.37 
lb/day, 1.54 lb/day and 18.38 lb/day, 1.49 
lb/day for heifers in the CON and TRT 
groups, respectively.
Liver concentrations of Cu, Mn and 
Zn were not different between CON 
and TRT heifers on day -1 or 65 of the 
experiment (Table 2.). However, liver 
biopsy samples indicated a numerical 
decrease in Cu and Mn concentrations 
in both CON and TRT heifers between 
day -1 and day 65. In addition, there 
was a decrease (P < .01) in Zn between 
day -1 and day 65 of the experiment in 
heifers of both groups (Table 2.). The 
decrease in liver Cu, Mn and Zn concen-
trations within both groups is not fully 
understood. There appears to be large 
variations in liver mineral concentrations 
among individual animals as indicated 
by the standard error associated with 
the means. As the animal grows, vital 
organs (liver, kidneys, spleen, heart) also 
increase in size. The increase in mass of 
the organs may have a diluting effect 
of mineral concentrations in the liver. 
Because blood volume is a function of 
body weight, blood volume increases 
as the animal increases in body size, 
potentially causing liver concentrations 
of minerals to decrease.
The beginning day of the luteal 
phase of the estrous cycle for the CON 
and TRT groups was not affected by 
mineral supplementation (Table 3.). 
Luteal phase length was not affected by 
mineral supplementation and was 15.3 +
.6 days for the CON group and 14.1 + .6 
days for the TRT group. Mean daily P4
production during the luteal phase was 
also similar for CON and TRT heifers 
(Table 3.). Furthermore, between days 
14 and 16, which is when pregnancy is 
recognized by the uterus, there was no 
difference in daily mean P4 production 
between the CON (4.85 + .55 ng/ml) and 
TRT (4.26 + .53 ng/ml) heifers.
The size of the largest follicle during 
the early portion of the estrous cycle was 
not different between the CON and TRT 
groups. However, TRT heifers had fewer 
follicles (2.6 + .2) greater than 8mm 
compared to the CON heifers (3.2 + .2; 
P < .10). Finally, mean sample estradiol 
concentration in blood was not different 
between the CON and the TRT groups 
(Table 3.).
Supplementation of Cu, Co, Mn and 
Zn at amounts greater than NRC has 
been shown to decrease female reproduc-
tive performance (1997 Nebraska Beef 
Report, pp. 15-17). Our study indicates 
supplementing Cu, Co, Mn and Zn at 
amounts in excess of NRC recommen-
dations does not affect the physiological 
characteristics at the ovarian level which 
are important for reproductive success 
in cattle. However, supplemented heif-
ers had fewer large follicles. How this 
impacts subsequent reproductive perfor-
mance is not understood.
1Chuck Story, graduate student; Rick Rasby, 
associate professor; Dennis Brink, Jim Kinder, pro-
fessors, Animal Science, Lincoln; Tony Moravek, 
former undergraduate student.


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Trace Mineral Supplementation and Ovarian and Luteal Function in Pubertal Heifers

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