Tips for a Successful Synchronization
Program
Kacie McCarthy, PhD Beef Cow-Calf Specialist
January 28, 2021
Outline
• Long term benefits of estrus synchronization
• Synchronization tools available
• Protocols available
• Associated costs for different protocols
Producer Question
Do you utilize synchronization in your herd?
YES or NO
Less than 8% of the beef
cattle in the U.S. are artificially
inseminated
(NAHMS, 2007)
According to NAHMS (2007)
The #1 reason why producers don’t use
AI or estrous synchronization:
“Time and Labor”
WHY so few?
(NAHMS, 2007)
Only 7.6% of U.S. beef operations use artificial
insemination
Only 7.9% of U.S. beef operations use estrous
synchronization
Reasons for NOT using Estrous Synchronization
39.1 16.8 10.5 17.2 14.1 2.3 0 5 10 15 20 25 30 35 40 45
Labor/Time Cost Lack of FacilitiesTo Difficult/Complicated Other Does Not Work
P e rc e n t o f O p e ra ti o n s (NAHMS, 2007)
1
2
3
4
5
6
Percentage of Heifers and Cows Bred or Intended to be Bred
for calving (in 2007)
79.2 3.9 12.4 4.5 94.2 1.1 4.1 0.6 0 10 20 30 40 50 60 70 80 90 100
Only exposed to bulls Only artificially inseminated Both artificially inseminated and exposed to bulls
Brought on bred females Heifers Cows
NAHMS:APHIS, 2009
Estrous Synchronization in Bull Breeding Herds
• Suitable step towards
–Altering the calving season –Decreasing the breeding season length –Initiating noncycling cows to start cycling
• Has the potential to impact a greater number of producers
–Greater than 90% of producers do not utilize AI in their current management systems
The ideal synchronization protocol:
• A high number of females respond to the treatment.
• Protocol does not negatively impact fertility - high conception
rates.
• Estrus in all females occurs at a specific time after treatment
-no estrus detection needed.
• Females are gathered only a few times for treatment/breeding.
• Could be used on cyclic and non-cyclic females.
What’s needed to implement an estrous
synchronization program:
• Well planned program • Fertile females
–BCS/Nutrition –Healthy/disease free • Good working facility:
–Pens, chute, alley, feed bunks • Accurate records/females with ID • People trained in detecting
Potential Advantages of Estrous Synchronization
programs:
• Concentrate the breeding season – Concentrates calving period – More uniform calf crop
– Allows more uniform management of cows – Concentrates labor
• Makes AI programs practical by reducing time a labor for heat detection • Allows use of superior bulls via AI or natural service
• Been shown to produce calves that were on average 13 d older and 21 lb heavier than nonsynchronized females (Schafer et al., 1990)
Long Term Benefits
7
8
Improving Longevity and Genetic Merit of Replacement
Females
• Heifers that calve earlier in their first calving season stay in the herd longer and produce more lbs of calf during their lifetime than heifers calving later
(Lesmeister et al., 1973)
• Research from Nebraska clearly demonstrates the value of heifer conceiving in the first 21 days of the breeding season (Cushman et al., 2013)
Cushman et al., 2013
Effect of Artificial Insemination or Natural Service on
Heifer Performance
681 429 92 661 418 87 0 100 200 300 400 500 600 700 800Yearling Wt Age at 1st AI (d) PPI (d)
Heifer Performance
AI NS
(French et al., 2013)
AI = 871 heifers NS = 302 heifers
Effect of Artificial Insemination or Natural Service on
Calf Performance
82 463 186 2,364 5.2 79 452 188 1,398 3 0 500 1000 1500 2000 2500Birth Wt (lb) Weaning Wt (lb) Age at weaning (d) Lifetime weight
weaned (lb) Lifetime calves weaned
Calf Performance AI NS (French et al., 2013)
699 lbs
2 calves
AI = 4,530 calves NS = 909 calvesImpact of TAI on % of Cows Calving
18 22 20 15 7 7 3 3 1 4 6 16 25 21 10 9 4 2 1 7 0 5 10 15 20 25 30 1 to 10 11 to 20 21 to 30 31 to 40 41 to 50 51 to 60 61 to 70 71 to 80 81+ NC % o f p re gn an t c o ws ca lv in g
Days of Calving Season TAI Control * * **** ** **
TAI = CO-Synch + CIDR * = P < 0.01
** = P < 0.05 (Rodgers et al., 2012)
Impact of TAI on Calving and Weaning
20.9 23.2 16.4 17.5 4.6 3 2.7 1.5 6.7 17.7 28.7 25.2 7.8 1.8 2.8 2 0 5 10 15 20 25 30 35 1 to 10 11 to 20 21 to 30 31 to 40 41 to 50 51 to 60 61 to 70 > 70 % o f ca lv e s b o rn
Days of Calving Season TAI Control
TAI = CO-Synch + CIDR
(Rodgers et al., 2012) 44.1%
vs. 24.4%
Impact of TAI on Calving and Weaning
Treatment
Item
Control
TAI
No. of cows
615
582
Weaning rate, %
78
84
Weaning weight, lb
387 ± 8
a425 ± 8
babMeans within row differ (P < 0.01)
(Rodgers et al., 2012)
38 lbs
$49/cow
13
14
15
16
17
18
Beef Reproductive Task Force
https://beefrepro.org/ https://beefrepro.org/resources/
Synchronization protocols
Estrous synchronization calendar
http://www.iowabeefcenter.org/ estrus_synch.html https://beefrepro.org/resources/
AI Cowculator
https://beefrepro.org/resources/19
20
21
22
Breeding Cost Cow-Q-Lator
https://farm.unl.edu/breeding-cost-calculatorEstrous Synchronization
What does synchronization
really mean?
To manipulate the cow’s estrous cycle to where
all cows within the herd will be cycling at the
same time
What are the Main Hormones in Beef
Reproduction?
• GnRH –Release of FSH, LH • FSH –Development of follicles • LH –Ovulation • Estradiol– Behaviors, characteristics, prepare tract
• Progesterone
– Maintenance of Pregnancy, prevention of estrus/ovulation
• Prostaglandin F2a
– Lysing of CL, smooth muscle contractions
Bovine Estrous Cycle
0 2 4 6 8 10 12 14 16 18 20 0 Es tr us Es tr us
Day of the Estrous Cycle
(R. Rasby Notes) Es tr us Es tr us
Day of the Estrous Cycle
Bovine Follicular Waves
Three Wave Model
Ovulation Ovulation 0 2 4 6 8 10 12 14 16 18 20 0 (R. Rasby Notes)
25
26
27
28
29
30
Keys to Synchronization Success
• Heifers 13 to 15 months at breeding
• Cow at least 50 days post-partum; BCS = 5
• IF synchronizing using MGA (heifers only)
–Plenty of bunk space
–Feed MGA when cattle are hungry
• Vaccinations current – work with veterinarian
• CIDR’s – cut strings to 2” - better retention
If Natural Service is used with Estrous
Synchronization:
• Bulls undergo a BSE
– Minimum scrotal circumference 34 cm as yearling bulls – recommend using 2-yr-old or older use older bulls
• Bull to female ratio 1:15 or 1:20
• Need at least two bulls
– Preferred - two bulls with the heifers at one time
• If you use 1 bull in with the females in a two bull rotation – need constant monitoring
Main Hormones used in Estrous
Synchronization
Prostaglandin
F
2aGnRH
Progestins
•
PG causes CL regression
• No effect on anestrous cattle
• No induction of estrous cyclicity = No Jump-start
• Only effective during Days 6 (6 days after
estrus) to 16 of the estrous cycle
Prostaglandin F
2a(PG)
Lauderdale, 1972
0 2 4 6 8 10 12 14 16 18 20 0 Day of the Estrous Cycle
PG regresses CL NO NO YES
Prostaglandin F
2a(PG)
Es tr us Es tr usProstaglandin Products
• Lutalyse
• Etrumate
• Prostamate
• estroPLAN
• In-Synch
31
32
33
34
• GnRH – single injection to beef females at random stages of their estrous cycle:
– Will result in an LH surge that will lead to:
• Ovulation (lyses) or luteinization of large (> 10 mm) healthy follicles without females exhibiting estrus
– This will initiate follicle “turn-over” or a new follicular wave
– Prostaglandins will regress GnRH-induced CL 7 days later – Can induce estrous cycles in anestrous females that are close to cycling
= Jump Start
Gonadotropin Releasing Hormone
(GnRH)
Ovulation
Without Estrus
LH Surge
• GnRH stimulates surge release of LH that triggers ovulation without estrus
• If cattle have large, healthy follicles, ovulation will be induced approximately 24 to 30 hours after GnRH injection without estrous behavior
GnRH Injection
… 2-4 hours … … 20-30 hours …
How Does GnRH Induce Ovulation?
GnRH, LH surge, and Ovulation
GnRH Products
• Cystorelin
• Factrel
• OvaCyst
• Fertagyl
Progestins
•
Progestins:
–Will block ovulation
–Can induce estrous cycles in anestrous females that
are close to cycling =
Jump StartProgestin Products
• CIDR
• Controlled Internal Drug
Release
• MGA
• Melengesterol acetate
CIDRs can stimulate estrous cycle
Lamb et al., 2001
37
38
39
40
Synchronization protocols
Heat Detection AI Protocols
What is Heat?
• Heat: Short period of receptivity of open cows
and heifers
– 8-18 hour period
Heat Detection
• Standing Heat **
• Receptive to other females mounting
• Secondary Characteristics
– Mounting other cows – Roughened tail head – Friendly – Nervous/Restless – Clear mucus from vagina – Swollen vulva
– Blood mucus → Was in heat ABS Global, 2017
Heat Detection:
• Commitment of TIME
• Check at least 2x daily
–20 to 30 minutes each check period
• Know the signs
–Most accurate is a standing female being ridden
• Some research: 60%-70% occur at night • Some last 8 hr (25%) some last 16 hr (65%) • Typically will last 12-18 hours
–May want to combine visual with an aid (Estrotect patches etc.)
Heat Detection Aids
• Tail Chalking • ESTRU$-ALERT Detectors
– Friction activated
• Kamar Heatmount Detectors • Estrotect Patches • Pedometers
– Activity
• HeatWatch System
– Pressure sensitive
• Chin Ball Markers
– Used on surgically altered bulls
• Androgenized Animals
– Females injected/implanted with testosterone • Male-like behaviors
ABS Global, 2017
43
44
HeatWatch II System (base station, access point, software)
$ 3,950.00 Repeater $ 945.00 Monitors $ 49.00 Patches (HeatWatch II or HeatWatch) $ 3.75
Fixed-Time AI (FTAI)
What does fixed-time AI mean?
Where all cows will be synchronized to be bred at the
same time
–Theoretically ovulating at the same time
Costs Associated with Estrous Synchronization
and Artificial Insemination
Conception Rates (%) to a 5-day AI Period or a
Single Timed Insemination*
Range Typical Range Typical
MGA+PGF 40-70 60 40-60 55 MGA Select 40-65 60 40-65 60 Select Synch 40-65 35-55 50 Co-Synch* 60 30-55 50 Co-Synch +CIDR* 30-80 50 30-70 50 CIDR-PGF7 40-80 50 35-60 50 7-11 Synch 30-55 35-65 2 x PGF 30-65 50 20-45 40 Heifers Cows
Johnson, 2004 Applied Reproductive Strategies in Beef Cattle
CR = Percentage of females pregnant of those detected in estrus and AI’ed.
Breeding System Costs for a Herd Size
of 100 Head
System Days Worked Preg Rate, %
to AI Total LaborHours No. of Bulls Cost ($) per Pregnancy
Natural Service 4 35 MGA/PG 6 50 67 2 41 MGA Select 7 50 72 2 45 Select Synch 9 50 82 2 46 7-11 Synch 8 50 77 2 48 MGA-Select +TAI 3 50 47 2 51 CIDR + PG d6 8 50 77 2 52 Select Synch + CIDR 7 50 72 2 55 CoSynch + CIDR 3 50 47 2 61
Johnson, 2004 Applied Reproductive Strategies in Beef Cattle Purchase price of bull = $2500
Cost per pregnancy - doesn’t include cost of females that didn’t become pregnant to AI, semen and drug cost not included, so cost are really higher than this.
49
50
51
52
Artificial Insemination Costs
Item Cost per unit,$
Semen 14.00/straw Prostaglandin 2.54/dose GnRH 3.21/dose CIDR 8.00/dose Supplies 0.50/insemination Fixed Costsa 175.00
aSeman tank, carrying case, pipette gun, thaw box, and liquid nitrogen Johnson, 2004 Applied Reproductive Strategies in Beef Cattle
Pregnancy In Synchronized Heifers Bred AI
or Natural Service
Item AI Natural Service No. of heifers 80 80 Heifers in estrus, % In 6 day 94 96 Pregnancy, % In 6 day 58 71 In 30 day 70 83
MGA for 14 days, PG 16 days post MGA Plugge et al, Nebraska
Summary
• Nutrition, Body Condition, and Post Partum Interval are all critical for a successful synch program
• You decide when your cows get pregnant
– Allows for genetic improvement – More cows pregnant earlier – More calves born earlier – More pounds born earlier
• Heifers born early in the calving season have greater lifetime productivity • Number of synchronization tools to help
