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Calculating Zenyatta's foaling date

edited January 23 in General
I was curious about equine gestation length (horse pregnancy). And I found this nifty little calculator (http://duncity.net/horses/foalingcalc.htm) doing some research I discovered Zenny was confirmed to be 37 days in foal on June 14 2013 (source:http://www.bloodhorse.com/horse-racing/articles/78892/zenyatta-confirmed-in-foal-to-war-front) there is 37 days between May 8, 2013 and June 14, 2013. Therefore Zenny was last bred May 8, 2013. (However mares are usually bred more than once for better chances of the mare catching. So she may have been bred prior to this date.) Now back to research; because on the calculator it asks, "how many days was the mare in foal before giving birth?" We have to know that information. So, she was confirmed to be 60 days in foal to Tapit on June 21, 2012 and 60 days from June 21st is April 22. So for her Tapit baby Zenny was probably bred April 22, 2012. So now we know she was bred April 22, 2012 and she delivered April 1, 2013. Therefore she delivered at 344 days. Which means that Zennys most likely foaling date this year is April 17, 2014. Using the foaling calculator I was also able to figure out that she is 260 days in foal (technically horses can deliver anywhere from 320 days to 362 days, and if you watch mare stare you know can occasionally go over a year in foal.) However, it is also possible for mares to foal at 300 days so I would say the countdown to Z14 should begin March 4, 2014.
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Comments

  • Yes I was bored, am contagious and cant go to class today
  • edited January 23
    This is really interesting according to the foaling calculator website:Research has shown that 70% of all mares may repeat their first pregnancy cycle regardless of whether it is a filly or colt. For Zenny's first foal she foaled at 342 days 4/01/2011- 3/8/2012. Second foal was 344 days as described above.
  • Between March 4 - April 17.....Thank you for your effort on this.
  • no problem it was fun!
  • edited January 24
    All this time we thought Zenny was going to have a late April-Early May foal...that's why there was a discussion to let Zenny rest for the 2015 foaling season due to having a late foal due date for 2015 of May-June. This is especially since come 1/1/16, her 2015 foal would be considered a year old. A 2015 foal would be at a disadvantage to the other babies born earlier.

    They don't tend to cover mares right during the foal (heat) cycle...covering doesn't take as well and they have to allow time for her body to heal and prevent infections that can occur if bred too soon. They have to wait a few more weeks for her next (heat) cycle. Anyway...that's what I been hearing and reading. :o)

    Therefore each subsequent foaling will be later and later into the foaling season.
  • march 4 is possible but based on the research saying 70% of mares follow the same pattern with subsequent foals April 15-18 is probably the most likely... are there any other mares you would like me to calculate? this can be tricky as not everyone gives out notices when a mare is confirmed in foal, and when they do the dates are tricky as well.
  • edited January 23

    All this time we thought Zenny was going to have a late April-Early May foal...that's why there was a discussion to let Zenny rest for the 2015 foaling season due to having a late foal due date for 2015 of May-June. This is especially since come 1/1/16, her 2015 foal would be considered a year old. A 2015 foal would be at a disadvantage to the other babies born earlier.

    They don't tend to cover mares right during the foal cycle...covering doesn't take as well and they have to allow time for her body to heal and prevent infections that can occur if bred too soon. They have to wait a few more weeks for her next cycle. Anyway...that's what I been hearing and reading. :o)

    if she is bred in May 2014 based on what appears to be her cycle she would foal in April 2015. if bred June 2014 she would foal in may 2015. The Mosses appear to like to breed her May 8 as that is when she has been bred for previous foals with the exception of her first due to her miscarriage.
  • Wow! Thanks for all your research and calculating to produce a due date! I can't wait for 14Z!
  • Forgive me for being dim but.....What you are saying is, If she has her foal mid April or sooner she can be bred in May for a 2015 foal ? If that turns out to be the case then 2015 would the year she would not be bred (?).
  • Thanks EriNC. Very interesting.
  • KayJay said:

    Forgive me for being dim but.....What you are saying is, If she has her foal mid April or sooner she can be bred in May for a 2015 foal ? If that turns out to be the case then 2015 would the year she would not be bred (?).

    It would still depend on when she foals, as she could still foal in April of 2015.
  • Thanks Pepper for the explanation. I was still stuck in the "skipping a year to get an earlier due date" conversation. : /
  • I would say 2016 would be the year she wouldnt be bred.
  • edited January 24
    Great work EriNC! Appreciate all your hardwork in researching!
          I think this article helps explain the breeding cycle for broodmares from Lanes End "Ask the Experts"...This is where I mentioned that each year, the mare (Zenny) will foal later and later each time. They don't breed a mare until 27-30 days after she's foaled...gestation period usually averages more than 11 months. Let's see if the Mosses will decide to breed her for a 2015 foal or let her rest a year to get her back into an earlier foaling date in 2016. I know Zenny herself was a slow developing foal so that might weigh in on the Mosses decision whether or not to breed her in 2014. :oD
    http://www.zenyatta.com/experts/ask-the-experts-7
  • Great work EriNC! Appreciate all your hardwork in researching!
          I think this article helps explain the breeding cycle for broodmares from Lanes End "Ask the Experts"...This is where I mentioned that each year, the mare (Zenny) will foal later and later each time. They don't breed a mare until 27-30 days after she's foaled...gestation period usually averages more than 11 months. Let's see if the Mosses will decide to breed her for a 2015 foal or let her rest a year to get her back into an earlier foaling date in 2016. I know Zenny herself was a slow developing foal so that might weigh in on the Mosses decision whether or not to breed her in 2014. :oD
    http://www.zenyatta.com/experts/ask-the-experts-7

    if Zenny continues the pattern though she will probably always foal at 342-345 days just to be on the safe side. It would be interesting to see if she does.
  • KayJay said:

    Thanks Pepper for the explanation. I was still stuck in the "skipping a year to get an earlier due date" conversation. : /

    You're welcome. If it makes it easier, just remember that a mare can safely foal a month before her breeding date, i.e. a mare bred in June of 2014 can have a full term foal in May of 2015.
  • I just figure gestation is about 11 mo...go forward a year and back one month. It all happens when it happens. :))) Ya just have to watch carefully the closer it gets to due date.
  • edited January 24

    KayJay said:

    Thanks Pepper for the explanation. I was still stuck in the "skipping a year to get an earlier due date" conversation. : /

    You're welcome. If it makes it easier, just remember that a mare can safely foal a month before her breeding date, i.e. a mare bred in June of 2014 can have a full term foal in May of 2015.
    300 days is considered full term (this is wrong) Usually you start watching mares more carefully at day 300, but apparently foals born before day 320 are considered premature. 340 days is full term.
  • EriNC said:

    KayJay said:

    Thanks Pepper for the explanation. I was still stuck in the "skipping a year to get an earlier due date" conversation. : /

    You're welcome. If it makes it easier, just remember that a mare can safely foal a month before her breeding date, i.e. a mare bred in June of 2014 can have a full term foal in May of 2015.
    300 days is considered full term
    I always heard 11 months was full term for mares. Just shows you can learn something new everyday.


  • You're welcome. If it makes it easier, just remember that a mare can safely foal a month before her breeding date, i.e. a mare bred in June of 2014 can have a full term foal in May of 2015.

    300 days is considered full term

    I always heard 11 months was full term for mares. Just shows you can learn something new everyday.


    I was wrong on that any foals born before 320 days is premature 340 days is full term.

  • When I worked at an Arabian breeding farm 95% of our mares foaled between 345-355 days from their breeding date, however out of 110 broodmares all except 2 were artificially inseminated so it made it easier to determine when they would foal. When I bred my TB mare, we live covered her three days in a row (the vet determined through some kind of test that those would be her most fertile days), she foaled exactly a year to the day of her last meeting with the stallion. It was her first and sadly her last foal as she passed away suddenly from colic a year and a half later.
  • There's a mare on Mare Stare that was due on December 10th. She's still waiting.
  • VA_in_CA said:

    There's a mare on Mare Stare that was due on December 10th. She's still waiting.

    Wow! Can mares be induced?
  • edited February 3

    VA_in_CA said:

    There's a mare on Mare Stare that was due on December 10th. She's still waiting.

    Wow! Can mares be induced?
    I think they can...but not sure...gotta research this one. But I believe the mare that VA_in_CA is talking about is a miniature horse and they seem to take longer in foaling. We find they run past their estimated due date a lot of times.

    Update: My bad...according to MareStare's average gestation lengths...the miniature horse's average gestation is 320 days...it was the donkey that had a longer gestation (375 days) than the full-sized horse. :o(
  • Yes, she is a miniature , and it's her first foal.
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