management of young cows for maximum reproductive performance tom geary usda ars miles city, mt...
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![Page 1: Management of Young Cows for Maximum Reproductive Performance Tom Geary USDA ARS Miles City, MT 406-232-8215 tom@larrl.ars.usda.gov](https://reader035.vdocuments.us/reader035/viewer/2022062511/551944ab55034679738b462a/html5/thumbnails/1.jpg)
Management of Young Cows for Maximum Reproductive Performance
Tom GearyUSDA ARSMiles City, MT
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Troublemaker!Why?Won’t rebreedWhy?Long postpartum
anestrous intervalWhy?Insufficient energy to
reproduceWhy?
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Why? New problem? Bigger problem?
Solutions?
Overview of Presentation
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Mature Cow Size?
“My cows weigh ~ 1200 pounds” …is as big a lie as…
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Mature Cow Size?“My cows weigh ~ 1200 pounds” …is as big
a lie as…“I’ll love you just as much in the morning!”
Roy Wallace
Select Sires
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Heifer Age and Weight at Puberty
Age Weight
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% of Mature Wt @ breeding
Item 55% 65%
Pre-breeding wt 600683
Conception (21d) 30 62
Calving wt. 834 897
Calf birth wt. 71 73
Calving difficulty,% 52 29
Calf death loss,% 6 5
Heifer Development: Feeding to a Heifer Development: Feeding to a “Target Weight”“Target Weight”
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Beef Heifer/Cow Growth
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New Factors Affecting Rebreeding Performance of Young Cows
1. Mature cow size
2. Age / Weight at breeding
3. Percent of mature weight at 1st calving
4. Selection for milk
5. Heterosis
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Measures of Fertility
Pregnancy rate – percentage of cows that became pregnant out of those that were exposed to breeding.Culling Tool
Why didn’t that cow/heifer become pregnant?
Cow/Heifer
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0 10 20 30 40 50 60 70 80 90 100 110 120
Heifers3 Yr Olds
4 Yr Olds5+ Yr Olds
Day of Calving Season
Per
cen
tag
e o
f C
alve
s B
orn
Measures of Fertility
Start of Breeding
Calving Distribution
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Conception rate – percentage of cows that became pregnant out of those that were actually bred.Fertilization occurs > 95% of time.Embryo death occurs 20 – 40% of time.
Measures of Fertility
Postpartum interval (PPI) – interval from calving to re-initiation of estrous cycles.
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Effect of Cow Age on PPI
Age of Cow Days after calving40 50 60 70 80 90 100
% Cycling
5 or older 55 70 80 90 90 95 100
2-3 years 15 30 40 65 80 80 90
Increase the percentage of young cows that calve early in the calving season
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0 10 20 30 40 50 60 70 80 90 100 110 120
Heifers3 Yr Olds
4 Yr Olds5+ Yr Olds
Day of Calving Season
Per
cen
tag
e o
f C
alve
s B
orn
Calving Distribution
Start of Breeding
If heifers calve 20 d early
Calving heifers ahead of cowherd won’t solve all problems
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Effect of Calving Day during Calving Season on Subsequent Reproductive
Performance
6.99.4
12.9
17.9
26.1
0
10
20
30
40
1-20 21-40 41-60 61-80 81-100
Day Calved during Calving Season
Reproductive Failure (%)
Heifer calving season has to be short
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Conception Rate by Days Postpartum
Days Conception
Postpartum Rate 0-30 33% 31-60 58% 61-90 69% 91-120 74%Embryonic death decreases as
PPI increases.
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Goal: Short Heifer Calving Season
Develop heifers to be 65% of mature weight at breeding. Select replacements from older calves. Identify target weight and feed accordingly.
Utilize a short breeding season. Induce estrous cycles. Synchronize estrous cycles.
Fetal aging at pregnancy diagnosis.
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Reproductive Management Practices - Bull Exposure
14
2830
32
0
5
10
15
20
25
30
35
12 13 14 15
Cum
ulat
ive
Per
cent
In
crea
se in
Cyc
lic H
eife
rs
Age (months)
- Bull exposure began at 350 d of age
15 to 45 days of bull exposure may be sufficient
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Age at Pregnant at
Group puberty,d 21 days 50 days
Exposed 399 51 86
Non-exposed 439 17 81
Difference 40 34 5
Effect of Bull Exposure on Puberty Effect of Bull Exposure on Puberty and Fertility of Yearling Heifersand Fertility of Yearling Heifers
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Check heat & AI
Estrous Synchronization with AI or Natural Service for Heifers
Day
Feed MGA (.5 mg/d)
0 14 33
PGF2 $ 3.20
38
Day
Feed MGA (.5 mg/d)
0 14 33
$ 1.00
Synchronized heats
43
SubfertileEstrus
SubfertileEstrus
Synchronized heatsTurn in
Bulls
27
27
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Estrous Synchronization & Bulls
69
83
97
0
20
40
60
80
100
Per
cent
Pre
gnan
t
1st 10 Days 1st 30 Days
• Kentucky (601 Heifers)• 12 Locations
1st 50 Days(Theoretical)
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“Four have calved, we pulled em’ all!”
Calving Assistance:
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Calving Assistance
Item Late Early PPI 51 49 % in heat 82 91* Services/conception 1.24 1.15 Fall Pregnancy 78 92* Calf Vigor 1.1 1.2 Calf ADG 1.63 1.74* Calf WW 387 422*
Stage II LaborStage II Labor
After 1.5 h of stage II labor, every 30 min. delay in assistance results in a 6 day longer interval to pregnancy!!!
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At today’s diesel prices, maybe I should consider AI.
Breed Heifers AI to “Calving Ease” Proven Sires
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-20 -10 0 10 20 30 40 50 60 70 80 90 100 110 120
Heifers
3 Yr Olds4 Yr Olds
5+ Yr Olds
Day of Calving Season
Per
cen
tag
e o
f C
alve
s B
orn
Calving Distribution
Start of Breeding
Calving heifers ahead of cowherd and in a short calving season won’t solve all problems
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1.Basal Metabolism2.Activity3.Growth4.Basic Energy Reserves5.Pregnancy Maintenance6.Lactation7.Additional Energy Reserves8.Estrous Cycles and Pregnancy
Initiation9.Excess Reserves
Nutrient Partitioning in the Beef Cow
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Sort cows by BCS (or age) for winter feeding
BCS Postpartum Pregnancy @ Calving Interval % (90d) 3 89 --- 4 70 50 5 60 81 6 52 88 7 31 90
Improve Energy Availability for Reproduction
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Temporary Calf Removal Improves Reproductive Performance
After 21d Breeding Treatment Heat Pregnant Control 31% 17% 48-hr Calf Removal 62% 44% Difference 31% 27%
Provide calves dry environment with clean grass hay and water.
Pair up before returning to pasture.
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Improve Energy Utilization with Ionophores
Postpartum Interval (days) Study Ionophore Control Difference 1 30 42 12 2 59 69 10 3 67 72 5 4 65 86 21 5 92 138 46
Mean 18 daysCost: $ .014/d
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Bull Exposure for Postpartum Cows?
Decreases PPI by ~ 15 days.Bull exposure began 0 - 4 weeks after
calving for 30 days or until the start of breeding.
Bull:Cow ratio of 1:20.
Exposure to androgenized cows produces the same results.
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Hormonal Induction of Estrous Cycles
GnRH Select Synch
7-11 Synch
Progestins All progestins
are not equal
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Early & Permanent Weaning
• Decreases energy and protein demand by 30%.
• How early? 30 to 150 days
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How early to “Early Wean?” Goal: Improve reproductive performance?
Early weaning at 30 to 60 days of age.Greatest response among 1st calf heifers.
Nebraska Study:Early weaning 8 days before the start of a 42 day breeding season
8%16%26%Increased pregnancy rate
16%27%29%Increased percent in estrus
Mature Cows3 Yr Olds2 Yr OldsEarly verses normal weaning
Clemson Study: Early Normalweaned (56 d) weaned
Heifers calving within first 30 days 81% 46%
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Reproductive Benefits: Early Weaning
Normal Weaned
Early Weaned
Normal Weaned
Early Weaned
Weight, lbsat early weaning 698 680 816 832at end of breeding 746 753 922 968at normal weaning 788 875 920 1040
Conception Rate, % 59 97 83 100Calving to first estrus, days 91 73 81 46
1st Calf Heifers Mature Cows
Oklahoma Study:Early weaning (~ 50 days) in Hereford heifers or mature cows
Early weaned calves were 88 lbs heavier than normal weaned calves at the time of normal weaning!!!
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Cost Benefits: Early Weaning
Calf Diet Cost -$75.00(50 to 205 d of age)
Calf 205 d wt $57.00(+ 60 lbs @ $.95)
Cow feed savings $65 – 100(+ 1 to 1.5 BCS) +$47 - 82
Reproductive performance ???(+ 8 to 38% pregnancy rate)(earlier pregnancies)
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- 30 days
Only cows that calved at least 30 days before breeding are candidates for early weaning.
0 10 20 30 40 50 60 70 80 90 100 110 120
Heifers3 Yr Olds
4 Yr Olds5+ Yr Olds
Day of Calving Season
Per
cen
tag
e o
f C
alve
s B
orn
Practical Considerations to Early Weaning
Start of Breeding
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Heifers are ideal candidates for early weaning.
- 30 days
-20 -10 0 10 20 30 40 50 60 70 80 90 100 110 120
Heifers
3 Yr Olds4 Yr Olds
5+ Yr Olds
Day of Calving Season
Per
cen
tag
e o
f C
alve
s B
orn
Practical Considerations to Early Weaning
Start of Breeding
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Optimize Rebreeding Performance of Young Cows
Identify problem females.Manage heifers to calve early in a short
calving season.Develop to 65% of mature weight at
breeding.Induce estrous cycles.Synchronize estrus in heifers.AI heifers to calving ease proven sires.Earlier pregnancy diagnosis & fetal aging.
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Optimize Rebreeding Performance of Young Cows
Calving and postpartum management.Minimum BCS of 5 at calving.Provide early calving assistance.Provide young cows with best feed resources.Feed ionophores.Induce/synchronize estrous cycles.
Bull exposure. Hormonal. Temporary calf removal.
Early weaning.
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Questions???Questions???
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0
10
20
30
40
50
-20 -10 0 10 20 30 40 50 60 70 80 90 100 110 120
Heifers3 Yr Olds
4+ Yr Olds
Day of Calving Season
Per
cen
tag
e o
f C
alve
s B
orn
Calving Distribution Goal
Start of Breeding
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Potential Advantages of Estrous Synchronization with Natural Service
Schafer et al., 1990
171
424
184
465
150
250
350
450
550
Age Weight
NaturalSynchronized
13 days
41 lbs
Wea
ning
Age
/ W
eigh
t
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Estrous Synchronization with Natural Service for Cows
Day of Breeding Season0 7
GnRHInjection
PGFInjection
$5.00
5
Turn in Bulls
Synchronized heats
12
Select Synch Protocol
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Benefits with the Select Synch Protocol and Natural Service
4 Herds & 915 Cows5% higher pregnancy rate.
1 day earlier calving date.
10% more cows calved in first 21 days.
11 day shorter calving season.
$26.32 increase in income per cow exposed.
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Synchronization of Estrus in Cyclic Cows/heifers
$ 2.20
0 10Day
PGF2
5
Synchronized heats
Turn in Bulls
Used with 32-day breeding season at Fort Keogh with the Season of Calving herds over the past 3 years and has consistently yielded pregnancy rates > 85%.
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Early Weaning during Drought Feasible for your Operation?
Calf Diet Cost -$75.00(50 to 205 d of age)
Calf 205 d wt $57.00(+ 60 lbs @ $.95)
Cow feed savings $65 – 100(+ 1 to 1.5 BCS) +$47 - 82
Reproductive performance ???(+ 8 to 38% pregnancy rate)(earlier pregnancies)
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How early to “early wean?”Goal: Save pasture for fall grazing?
Improve calf performance?Early weaning of entire herd or younger
cows only at 3 to 5 months of age.
15 to 20% less energy required for weaned calf and cow compared to cow nursing her calf.
Cows will maintain or improve body condition going into the winter and require less supplemental feed.
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Formula for Androgenized Cows
5 Synovex H implants ~ 2 months Remove implants
Testosterone Enanthate (2000 mg) 500 mg im. + 1500 mg sc. ~ 21 days
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Reproductive Performance by RTS
RTS No.Weight
(lbs)PelvicArea
1 61 594b 152b
2 278 620c 158b
3 1103 697d 166c
4 494 733e 172d
5 728 755e 172d
EstrousResponse No. Preg. Rate
54%b 1 0%
66%c 87 79%
76%d 271 89%
83%e 184 93%
86%e 161 91%Total 2664
Logic? - $ 3/hd to identify the 2% of heifers that have only a 54% of responding to synchronization?
Separate Data Set
Total 704
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Effect of Rumensin on Puberty Effect of Rumensin on Puberty and Conception Ratesand Conception Rates
Group No. heifers % Cycling % Bred
Rumensin 24 92 55
Control 26 58 47
Treatment Age @ Puberty % PregnantHigh Roughage 383 83Rumensin +90% HR 369 96Rumensin +100% HR 369 96
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Heifer Development to Mature Cow