SYNCHRONIZATION

1
CHAPTER 3

• SYNCHRONIZATION

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Heat Synchronization

• Controls When Groups of Normally Cycling Females
  Come Into Heat and Ovulate
• Benefits to Producers
• Beef A.I. Becomes Easier and More Timely
• Dairy Planned Breeding is Possible for Heifers
• Requires Top Management of Cattle and Conditions
  Affecting Cycling
• Choose the System That Best Fits Your Situation
• Consider Your Goals, Labor Requirements, Time and
  Program Cost

3
Benefits of Synchronization

• Opportunity to Control Group Timing of Heat
• Facilitates A.I. for Faster Genetic Improvement
• Days Needed for A.I. Can be Significantly
  Shortened
• Time Spent on Heat Detection Can be Considerably
  Reduced or Eliminated
• Scheduling Labor is Simplified Because of the
  Concentrated Period of Heat Detection and A.I.

4
Additional Advantages for Beef

• More Profitable Beef Calves Are Produced
• Cattle Can be Group Inseminated at Start of
  Breeding Season
• More Calves Born Early in Calving Season
• Calves are Older and Heavier at Weaning and
  Replacement
• Females will be Older and Heavier at 1st Breeding
• Calves Will be More Uniform Due to Similar
  Inheritance and Age

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Additional Advantages for Beef

• Greater Opportunity to Get More Females Pregnant
  During the Breeding Season
• Estrus Cycles are Advanced
• High Percentage of Cycling Cow Come Into Heat at
  Beginning of Breeding Season
• Have Two Chances to Get Female Pregnant During a
  21-25 Day Insemination Period
• Continued Use Over Several Years Helps Shorten
  Calving Season
• Strict Culling of Late Calving Cows Must be
  Practiced

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Additional Advantages for Dairy

• Convenient Way to Include Heifers in an A.I.
  program
• Improve Management by Inseminating at a
  Predetermined Date
• Know Calving Due Dates, and Incorporate them in
  Plans
• Allows for Closer Control of Calving Time
• Milk Base Can be Increased at Specific Time
• More Show Calves of Optimum Age Can be Produced,
  or Cattle Can Fit Show Dates Better

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Understanding the Estrus Cycle

• Estrus and Ovulation Can be Controlled
• Administer Prostaglandin, Progesterone, or
  Gonadotropins to Cycling Females
• Cycling Females Coming Into Heat Regularly
  Prior to Treatment
• Corpus Luteum Develops in Ovary at Ovulation Site
• Corpus Luteum Produces Progesterone
• Prepares Uterus for Pregnancy
• If NOT Pregnant CL Starts regressing 18 days Into
  the Cycle and a New Egg-Containing Follicle Begins

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Normal Estrus Cycle
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Follicular Wave Dynamics

• Estrus Cycle
• Follicular Growth Occurs in Waves and Throughout
  the Length of the Cycle
• Individual Waves are Characterized by Rapid
  Growth of Many Small Follicles
• Bovine Females are Born With All the Eggs They
  Will Ever Have
• Approximately 75,000 for Normal Females
• Eggs are Contained in Follicles Residing Deep in
  the Ovarian Tissue

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Follicular Wave Dynamics

• At Puberty Eggs Start Growing Into Mature
  Follicles
• Have Potential to Ovulate and Release an Egg
• Most Females Have 2 or 3 Waves of Growth
• At Start of Each Wave 200-600 Eggs are Recruited
  for Growth
• One Follicle is Selected
• Becomes the Dominant Follicle
• Has the Ability to Restrict Growth of Other
  Follicles

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Follicular Wave Dynamics

• Follicular Waves occurring During Early to
  Mid-Estrus Cycle
• Dominant Follicle and Subordinate Follicles
  Become Atretic, or Die
• Waves Occurring Toward End of Estrus Cycle
• Dominant Follicle Fully Develops and Ovulates

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Follicular Wave Dynamics

• Cows That Experience Two Follicular Waves
• Initiate First Wave at Day 0 and Last Until Day
  10
• Dominant and Subordinate Follicles Die or
  Degenerate
• Second Wave is Immediately Initiated
• Produces New Dominant Follicle
• Follicle Survives to the End and Ovulates
• Cows That Experience Three Follicular Waves
• Waves Last an Average of 8 Days Each
• Third Wave Develops the Dominant Follicle to
  Ovulation

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Two Follicular Wave Dynamics
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Three Follicular Wave Dynamics
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Drugs that alter the estrus cycle

• Prostaglandin
• Naturally Occurring Compound
• Essential in Normal Regulation of Reproductive
  Cycle
• Intramuscular Injection, Prescribed Only be Vets
• New Needles Prevent Possible Disease Transfer
• Correct Amount is Necessary for Proper Results
• Can be Used on All Non-Pregnant Cycling Females
• Can Cause Abortion if Used on Pregnant Cows or
  Heifers

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Drugs that alter the estrus cycle

• Prostaglandin
• Affects Developed Corpus Luteum
• Causes Premature Regression When Administered
  During Days 6-17 in Estrus Cycle
• Early in Cycle (Days 1-5) and Late in the Cycle
  (Days 18-21) Has No Effect
• Animals Should Come Into Heat at Same Time as
  Treated

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Using Prostaglandin on Beef

• Percent Cycling Females is Most Important Factor
  in Success of Synchronization Programs
• Only Effective on Regularly Cycling Females
• Heifers Must Have Ovulated Once Before Treatment
• Cows Must be Ovulating Following Calving
• Will Not Cause a Female to Begin Cycling
• Minimize Drug Costs by Recognizing Cycling
• Can Determine Through Ovarian Palpation
• May Save Drug Cost, but Adds Labor Cost for
  Palpating

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One-Injection System
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Logic of One-Injection System
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MGA and Prostaglandin
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Two-Injection System
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Logic of Two-Injection System
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Using Prostaglandin on Dairy

• The Systems Described for Beef Can be Used for
  Dairy
• Planned Breeding Programs
• Use of Prostaglandin in Dairy Synchronization
  Programs
• Not all Prostaglandin Products Have Been Cleared
  for Use on Milking Females
• Check Label Before Use

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Targeted Breeding

• Prepares Cows for Rebreeding
• Improves Pregnancy Rates in First 21 Days After
  Breeding Commences
• Ideal Time for Getting Cows Pregnant

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Targeted Breeding

• How it Works
• 17 Days Before VWP Ends
• Cows Receive First Injection of Prostaglandin
• Known as a Set-up Shot
• Dont Breed Cows on Next Detected Heat
• 2 Weeks Later
• Cows Receive Second Injection of Prostaglandin
• Known as Breeding Shot
• Should Bring Almost All Cows Into estrus
• Inseminate Cows on Standing Heat
• Non Inseminated Cows are Injected 14 Days Later
  Along With New Cows Ready for Set-up Shot

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Planned Breeding

• Using Ovarian Palpation
• Vet Can Determine if Corpus Luteum is Present
• Age of CL Affects Time Required Before Female
  Returns to Heat
• Risky to Use on Timed Breeding Program
• Heat Detection is Best Method
• Used by Many Vets When Cows Palpated Open During
  Pregnancy Examinations

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Planned Breeding

• Without Using Ovarian Palpation
• Allows Producers to Eliminate Short Calving
  Intervals
• Aids Heat Detection Problems
• Identifies Problem Cows for Early Veterinary
  Treatment

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ABS Protocol
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GnRH Based Protocols

• Use GnRH and Prostaglandin to Synchronize Estrus
  and Control Ovulation
• Effective in Mature Cows
• Less Effective in Heifers
• All Products are Prescriptions
• Must be Purchased Through Local Veterinarian
• Common GnRH Products are
• Cystorelin
• Factri
• Fertagyl

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GnRH-PG
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Ovsynch
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Co-Synch
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MGA-GnRH-PG (cows)
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MGA-GnRH-PG (heifers)
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7-11 Synch
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CIDR

• Controlled Internal Drug Release
• Intravaginal Insert Containing Progesterone
• Similar to Synchromate-B
• Non-Prescription Product
• Used in Combination with GnRH and PG
• Approved by FDA for
• Beef Cows
• Beef Heifers
• Dairy Heifers
• NOT Approved for Dairy Cows

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CIDR Insertion

• Place Device in Insert Application Gun
• CIDR Has Wings on One End
• Wings Fold Flat for Insertion Into Vagina
• Expand Against Vaginal Walls Upon Insertion
• Hold CIDR in Place During Synchronization Period
• Blue Nylons Sting is Attached to Other End
• Allows Producer to See Insert is Being Retained
• Allows for Easy Removal of Device
• At Time of Insertion GnRH is Given Intramuscularly

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CIDR Synchronization Protocol
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CIDR

• Works Regardless of Cycle Stage
• Regresses CL During Early Stages
• Prevents Ovary From Beginning New Cycle Until
  Insert is Removed
• Does Not Effect CL During Middle Stages
• By Time Insert is Removed Cow Cycles Naturally
• Offers Excellent Estrus Response in Cycling
  Females
• Can be Used in Fixed Time Insemination Program or
  on Observation of Heat

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Summary of Systems
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Common Misconceptions

• Synchronization Protocols Discussed are Not
  Miracle Drugs
• Base Your Program on Realistic Expectations
• Most Misconceptions Occur From Misinformation
  About What Drugs Can and Cannot Do

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Misconception 1

• You Can Breed Cows Earlier After Calving
• Prostaglandin Does Not Cause Cows to Come Into
  Heat Sooner After Calving
• Cows Must Go Through a Normal Recovery Period and
  Begin Cycling Before Drugs Will be Effective

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Misconception 2

• You Can Automatically Shorten the Calving Season
• Unless Strict Culling Practices are Utilized,
  Late Calvers Will ALWAYS be Late Calvers
• They Will Not Cycle in Time to be Included in
  Heat Synch Programs
• Will Concentrate More Cows at Beginning of
  Breeding Season for Eligible Cows
• More Closely Groups Calving Period

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Misconception 3

• You Wont Have to Heat Detect
• Only Works When You Select a Fixed Time
  Insemination Program
• Most Protocols Rely on Inseminating on Detection
  of Heat
• Fixed Time Programs Should Only be Used When You
  are Confident Most Females are in Heat
• Heat Detecting Helps Spot Animals Who
• Come Into Heat Early
• Come Into Heat Late
• Are Not Cycling

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Misconception 4

• By Breeding Cows in a Short Interval, They Will
  Calve in an Equally Short Interval
• This is Incorrect
• Cattle Inseminated on the Same Day Have a Calving
  Range of 10 Days From the Calving Due Date

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Which System for Your Operation?

• Determine Potential Results and Costs
• Use Feasibility Worksheets to Help
• Available From ABS
• Select Best System for Your Situation
• Advantages and Tradeoffs Must Be Weighed in Terms
  of
• Program Cost
• Time
• Facilities
• Labor Requirements

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Management Considerations

• Several Factors Influence the Outcome of Heat
  Synchronization
• Conditions Affecting Cycling
• Heat Detection
• Labor Needs During Insemination
• Facilities
• Identification
• Calving

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Conditions Affecting Cycling

• Beef Cows
• Affected by Two Factors
• Rest After Calving
• Body Condition at Calving
• The Better the Body Condition Score and the
  Longer After Calving the More Likely to Enter
  Heat
• Proper Nutrition After Calving is Important as
  Nutrient Requirement Double While Nursing

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Percent Estrus After Calving
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Conditions Affecting Cycling

• Beef First Calf Heifers
• Take Longer to Begin Cycling Than Cows
• Nutritional Intake Must Support Their Growth and
  Milk Production for Calf
• Good Nutrition Can Shorten Recovery Time
• Need Special Attention to Improve Cycling Rate
• Separate Heifers From Cows Several Months Before
  Calving
• Feed So in Moderate to Good Condition
• As Virgin Heifers, Inseminate 2 to 3 Weeks Before
  Older Cows

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Conditions Affecting Cycling

• Beef Virgin Heifers
• Three Factors Affect When Cycling Begins
• Age
• Weight
• Breed
• Most Do Not Begin Cycling Before 13 Months
• Inseminate 2 to 3 Weeks Ahead of Cows
• Provides More Time for Recovery Before Rebreeding
• Nutrition Must be Carefully Watched to Ensure
• High Percentage are Cycling
• Heifers Respond to Synchronization Drugs

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Conditions Affecting Cycling

• Dairy Heifers
• Three Factors Affect When Cycling Begins
• Age
• Weight
• Breed
• With Proper Nutrition Most Reach Puberty by 13 to
  14 Months
• Underfed Heifers Will Not Respond Well to
  Synchronization Drugs

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Heat Detection

• Amount Needed Depends on System Selected
• Must be Done Carefully as Part of Synchronization
  Program
• Many Females Exhibit Heat at Same Time
• Basic Concepts of Good Heat Detection Apply to
  Heat Synchronization

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Labor Needs

• Insemination
• Inseminator Fatigue is Common With Large Herds
• One Inseminator Can Handle 20 to 50 Cows / Day
• Semen Thawing, Preparation of Insemination
  Equipment and Record Keeping
• Should Not be Handled by Inseminator
• Working Cattle Through Facilities
• More People Needed for Better Efficiency
• Heat Detection
• People and Hours Depend on Selected System

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Facilities

• Existing Facilities Should be in Good Repair
• Needs to Withstand Pressure of More Animals in
  Shorter Time Frame
• Additional Pen Space May be Needed
• Depends on Number of Cattle Included in Program
  and Type of System Used
• When Using Fixed-Time Program Pen Must Hold All
  Animals in the Program
• See Chapter 17 For More Information

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Identification

• Good Identification Helps any Program Using Heat
  Detection
• Essential to Get Maximum Value From A.I. Program
• See Chapter 6 For More Information

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Calving Period

• Planned Breeding Programs Result in a Shorter
  Calving Period
• Helps Herd Owners Closely Observe Calving and
  Assist With Difficult Births
• Does Not Mean All Cows Will Calve in 2 to 3 Days
• Calving Generally Spans 20 Around Calving Due Date

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Summary

• Heat Synchronization Controls When Groups of
  Normally Cycling Females Come Into Heat
• Heat Cycle
• Day 1 Estrus (Heat)
• Days 2 to 4/5 Female Developing Corpus Luteum
• Days 6 to 17 CL Fully Developed
• Days 17 to 18-21 CL Regresses
• Prostaglandin Injections Can Be Used on All
  Females

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Summary

• Choose a System That Fits Your Operations Needs
  for
• Calving Times
• Financial Resources
• Labor Resources
• Operation Resources
• Available Labor
• Facilities
• Pastures
• Feeds

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Summary

• CIDRs are Newest Heat Synch Product
• Use Progesterone in Intravaginal Insert
• Recommended for Only Beef Cows and Heifer and
  Dairy Heifers
• Most Important Factor in Successful Heat Synch
• High Number of Cycling Females
• Affected by Many Factors
• Time After Calving Body Condition Score
• Age Weight
• Breed

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Question 1

• During which stage or stages of the estrous
  cycles will prostaglandin be effective?
• How does it change the cycle?

Only when a fully developed Corpus Luteum is
available.
It knocks out the CL and allows a follicle to
develop.
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Question 2

• As the percent of herd cycling increases, will
  probable drug costs per A.I. Calf decrease,
  increase or stay the same?

Decrease, because the cost is spread out over
more calves.
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Question 3

• Explain how the one-injection system safegaurds
  against treating a poor cycling herd.

By heat detecting and breeding for the 1st 6 days
I can determine the herds cycling rate by the
number detected. If 5 per day should be cycling
I should catch about 23 cows in a 100 cow herd
for it to be cycling at 80.
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Question 4

• With the two-injection system, all cycling
  animals will come into heat during the five days
  following the second injection.
• Why is this true?

Because all will be reset to the start of the
follicular stage of heat, and it take 2 to 5 days
for the cow to develop an egg.
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Question 5

• Youre using the combination two-injection system
  on your herd that involves both heat detection
  and fixed-time insemination. After the first 76
  hours of heat detection and insemination youre
  extremely disappointed with the number of females
  that have shown heat. What should you do?

Remember those early cows are on the out side of
the distribution curve, most of the cows should
be in heat at 76 to 80 hours. Breed them.
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Question 6

• To include 100 of the females in a planned
  breeding program with ovarian palpation, there
  are two times when the females can be injected
  with protaglandin.
• When are they?
• Why does the drug work at these two times?

When a CL is palpated and the cow hasnt been
bred or palpated open during a pregnancy exam.
Because there is a CL present.
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Question 7

• What advantages can you think of for using
  ovarian palpation in a dairy heifer
  synchronization program?
• For a program without ovarian palpation?

Reduce drug cost by using only on those with a
CL. Know that heifers are cycling.
Lack of skilled palpation. Less times to handle
the heifers.
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Question 8

• What is the purpose of the CIDR implant?

It stops follicle development until removed.
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Question 9

• Why can the CIDR insert be used to synchronize
  estrus without regard to previous stage of estrus
  cycle?

Because it suspends those with a CL present and
allows those with follicles developing to catch
up. Putting the entire group in the same stage
of the estrus cycle.
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Question 10

• Say, for example, your cows were in good
  condition at calving. You want to run a
  synchronization program, but you want to be sure
  at least 90 of them are cycling before
  beginning.
• How many days after the last cow calved should
  you wait before inseminating?
• What if your cows were in moderate condition
  after calving?

60 days
80 days