Estrus Synchronization

1
Estrus Synchronization
2
Estrous Cycle

• GnRH
• FSH
• Estrogen
• LH
• PGF2a

3
The cycle

• GnRH stimulates the AP to release FSH
• FSH acts on the ovary to begin follicular
  development
• Follicle grows until mature and estrogen inhibits
  FSH
• This causes the AP to release LH
• LH acts on the follicle bursting the blister and
  causing ovulation

4
The cycle cont.

• Spot on the ovary becomes the CL
• CL produces progesterone maintaining pregnancy
• On day 14 if the uterus does not detect and
  embryo then it releases PGF2a
• PGF2a destroys the CL and the cycle begins again

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Synchronization

• Estrous synchronization gives many producers the
  opportunity to capture the economic benefits of
  artificial insemination (AI).
• Because AI involves a substantial investment of
  labor and time, most commercial farms or ranches
  will not utilize this technology unless this
  investment can be confined to a period of less
  than 5 to 7 days.
• To make the labor requirements of AI compatible,
  the estrous cycle must be synchronized so that a
  high percentage of treated females show a
  fertile, closely synchronized estrus.

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Why synchronize

• Because the estrous cycle is 21 days long, you
  can only expect to catch about 1/3 of the cycling
  animals in heat during the first week of the
  breeding period if you dont use estrus
  synchronization.
• Regardless of whether the animals are inseminated
  naturally or artificially, you can only expect 65
  to 70 of them to conceive to a given
  insemination.
• Thus, after a week of breeding to natural heats,
  only 21 of the eligible animals could possibly
  be pregnant

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Why synchronize

• Many estrus synchronization protocols can induce
  75 to 90 of the cycling animals to display
  estrus within a 5 day period.
• Additionally, many protocols can induce a fertile
  heat in as much as 50 of the anestrous cows.

8
Using Prostaglandins

• One shot method inject PGF2a, heat detect and
  breed within 7 days
• Two shot method
• Option 1 inject PGF2a, heat detect and breed
  within 7 days, inject again on day 14, heat
  detect and breed within 7 days
• Option 2 inject PGF2a, then again on day 14,
  heat detect and breed

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GnRH based

• Give an injection of GnRH on day 0
• Begin detecting heat on day 6
• Day 7 give injection of PGF2a
• On day 10 inject anything that has not shown
  estrus with GnRH and AI

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MGA

• Feed additive to control estrus
• Feed at .5mg/hd/d for 14 days
• Inject with GnRH 12 days after last feeding of
  MGA
• Inject with PGF2a 7 days later
• Used mainly for heifers in the feedlot

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CIDR

• Insert CIDR and inject with GnRH on day 0
• Day 6 inject with PGF2a
• Remove CIDR on day 7 and begin heat detection
• Should breed 48 hrs after removal of CIDR

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Synchronization in swine

• Boar exposure
• Lutylase
• PG 600

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Boar exposure

• When sows or gilts are put together and exposed
  to a boar everyday their cycle will synchronize
  with each other.
• Also helps bring them into heat

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Lutylase PG 600

• Lutylase acts the same as does in cattle
• PG 600 is combination of PMSG and HCG
• Given in combination with lutylase will give
  stronger heats and better conception
• We use these two with boar exposure to
  synchronize our sows