Thoroughbred Early Breeding

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Thoroughbred Early Breeding

• Courtney Blohm, Jessica Laux, Kourtney Kuba

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Background - The problem

• Ten thoroughbred breeding mares from prestigious
  racing farms have been booked to be bred to Whata
  Studleyman.
• Whata Studleyman can only do a limited booking
  since he is training for races in March.
• The mare owners are interested in producing
  racing foals they all want their mares bred one
  week before or after February 15.
• The stallion owner signed all 10 breeding
  contracts and now you are legally responsible for
  breeding the mares within this two week period.
• The mares will all arrive on January 15 and have
  been under lights since December 1. The Jockey
  Club does not allow the use of artificial
  insemination.

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The drugs of choice

• The drugs we will be using will be Regu-Mate, a
  progesterone, and lutalyse, a prostaglandin
• The mares are already receiving light treatment.

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How to get a mare pregnant

• The Regu-Mate (progesterone) is given once daily
  for 9-14 days to the mares.
• The lutalyse (prostaglandin) will be administered
  the on the same day as the last day of Regu-mate.
  
• The mares should come into heat within 2-3 days
  and ovulate within 5-11 days (avg 8-9 days).

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Regu-Mate

• Oral drug
• progesterone
• Works on the uterine endometrium, mammary gland,
  hypothalamus
• Acts as an agonist, has the same effect as
  natural progesterone, behaves as a steroid with
  nuclear receptors
• Negative feedback on gonadotopin secretion
• Used to hasten mares through the spring
  transition in cyclicity

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Lutalyse

• Injectible prostaglandin
• Works on luteal cells
• Binds to the PGF receptor in the plasma membrane
  of a luteal cell
• Has Ca second messenger hormone action
• Initiates regression on the CL

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Possible Problems

• The reproductive state of the horse affects the
  ability of the treatment to work because the
  horse is a seasonal breeder.
• The amount of sunlight a mare receives affects
  her estrus cycle and ovulation.
• If you give the drug regu-mate during the winter
  it won't have any effect on the ovulation of the
  mare.
• The drug is most effective in the spring or
  summer when the mares are receiving the needed
  light to induce their reproductive cycle actions

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Did it work?

• To determine if the mare is in estrus, look for
  teasing behavior when the mare is presented with
  a stallion.
• If the treatment regime works, the mare should
  present signs of estrus, and will have a normal
  estrus cycle within five to 11 days after the
  treatment stops.

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How much time is this going to take?

• Labor needs will not be high. Someone will need
  to inject lutalyse and feed regu-mate.
• Regu-mate will need to be given daily for 9-14
  days and lutalyse on a one-time basis, and this
  will not be very labor intensive with ten horses.
  
• At parturition, it will be the owners' of the
  female horses responsibility to monitor the
  pregnancy and birth of the foal.