Equine Gestation Calendar

[WhiteTailsMinis]

I'm including a photo bottom of this post .....

I'd seen this fantastic wheel presented on a couple of RFD-TV equine programs and thought it was the greatest thing. So, I ordered one for this year.

It has the breed date which you align to the date, then it automatically displays (around the wheel) the foaling date (which you can choose any # you are concerned with such as 300, 330, 340 (which is what they say is the DUE DATE, and 342 and so on). What's neat is it also automatically shows you the ESTRUS date to watch for and the PMSG range (which is my last question at the end of the post under the photo).

I also like that it starts with day 1 so if I were to foal early or even abort, the wheel (based on breed date) will show exactly the # of days which either ocurred. Cool.

Okay - here's my concern or question if you will ................... I always go through all my preggors dates with the foaling calculator that we are all acustomed to using (while there are ones on the internet, I always use the LB one from the info pages).

I notice that when doing the dates on this wheel ........... the wheel is a full week later than the dates the calculator gave.

Have any of you used this wheel? It's truly quite handy but I'm unsure of the differences in the due date calculations.

What are your thoughts on why the gestation dates would be a week different between the two devices/methods?

I looked to see if the wheel was "dated" and its not but it does have the correct number of days in each month (clearly) and I just purchased it last week.

Here's the picture of what I'm referring to (then another question below) - taken with camera phone so not sure how clear it'll be for you:

My last question is (and no, I haven't googled it yet cuz you guys are so smart ....) what exactly is :

PMSG first appears in bloodstream and PMSG leaves bloodstream? Which the wheel shows a couple months long- first thought it was about the heat cycle but it didn't make sence to run so long. What is this - anyone know? My second guess is that because it falls in the dead of winter, I'm thinking maybe it's the seasonal thing that they don't come into heat in the dead of winter (you know, not enough daylight etc). Is this PMSG representative of their dormant state regarding heat cycles? Hmmm

If I can count on this wheel being accurate, it's much handier to be conveniently in the barn as we aren't always at a computer or cell phone to go online and double-check the foaling calculator.

Your thoughts are most welcomed please - especially from someone that has used this and can confirm whether or not the dates were right for them from the wheel results.

Thanks

 

[cretahillsgal]

My bet would be that your wheel is going off of a 340 day gestation

And the one here on LB is on a 330 day or something.

 

[WhiteTailsMinis]

My bet would be that your wheel is going off of a 340 day gestation

And the one here on LB is on a 330 day or something.

it's hard to see in the photo but the wheel starts with day 1 to day 362. When you select the breed date, the 1 day at a time increments actually break it down every 10 days so you see day 290, day 300, day 310, 320, and so on up to 362 and every daily increment in between ............. I say this meaning that it is not giving you only one results on a specific day of delivery (such as 340 or 342). I can see the date they would foal at 300, 330, 342, whatever date I choose to use in the results.

That's why I'm wondering why it would be off a week from the calculator as the calculator allows you to put in your own gestational date of 300, 330, 342 or whatever you choose - same as the wheel does.

 

[cretahillsgal]

it's hard to see in the photo but the wheel starts with day 1 to day 362. When you select the breed date, the 1 day at a time increments actually break it down every 10 days so you see day 290, day 300, day 310, 320, and so on up to 362 and every daily increment in between ............. I say this meaning that it is not giving you only one results on a specific day of delivery (such as 340 or 342). I can see the date they would foal at 300, 330, 342, whatever date I choose to use in the results.

That's why I'm wondering why it would be off a week from the calculator as the calculator allows you to put in your own gestational date of 300, 330, 342 or whatever you choose - same as the wheel does.

Oops! Didn't look that closely at it.

I don't know why it would be off that much then.

 

[ohmt]

Hmmm...maybe one doesn't start counting until the egg goes into the uterus? That's approximately 6 days which would account for the almost 1 weeks difference.

"Once fertilized, the oocyte (egg) remains in the oviduct for approximately 5.5 more days, and then descends into the uterus. The initial single cell combination is already dividing and by the time of entry into the uterus, the egg might have already reached the blastocyst stage.

The gestation period lasts for about eleven months, or about 342 days (normal average range 320-370 days). During the early days of pregnancy, the embryo (up to about 35 days), or fetus (after 35-40 days), is mobile, moving about in the uterus until about day 16 when "fixation" occurs. True implantation - invasion into the endometrium of any sort - does not occur until about day 35 of pregnancy with the formation of the endometrial cups, and true placentation (formation of the placenta) is not initiated until about day 40-45 and not completed until about 140 days of pregnancy. A heartbeat can be detected on day 21, and the fetus gender can be determined by day 70 of the gestation. Halfway through gestation the fetus is the size of between a rabbit and a beagle. The most dramatic fetal development occurs in the last 3 months of pregnancy when 60% of fetal growth occurs"

http://horsehints.org/HorseBreeding.htm

And here is info about PMSG (from same source as above):

"eCG (equine chorionic gonadotropin - formerly called PMS/PMSG pregnant mare serum and pregnant mare serum gonadotropin): chorionic gonadotropins secreted if the mare conceives. First secreted by the endometrial cups around the 36th day of gestation, peaking around day 60, and decreasing after about 120 days of gestation. Also help to stimulate the growth of the fetal gonads."

 

[Kim~Crayonboxminiatures]

Maybe the differnce in days is because the on-line foaling calculater includes the year so it's more specific?? I always use the on-line one to calculate the specific dates, but for an approx date I look a year ahead from the breeding dates and go back two months...

 

[attwoode]

There appears to be something goofy with the wheel. A year is typically 365 days long but there are only 20 days between what they say is 340 days and the 1yr anniversary of the breeding. I think there are five fewer days than there should be in the inside portion of the wheel wheel. The error must have been made somewhere along the line (probably related to the smaller circumference of the inner circle) and nobody caught it until you did. I think the wheel will be ok as long as you know that the actual calculated date is roughly 5 days sooner than it shows on the wheel.

 

[WhiteTailsMinis]

I knew I"d get some great feedback and some good info - thank you. I'm going to check the wheel more thoroughly when I get home tonight while referencing all the points you make here.

as always - appreciate all the info you provide - members always come through to share their expertise on subjects some of us are not skilled in. Thank you

We do have all the foaling calculator results recorded/noted so not trading that for the wheel entirely. I wonder if I couldn't contact the manufacturer of that wheel and ask a few questions regarding the points made here, particularly Attwoods comment about the 20 days on the inner wheel. I'll check that more closely on the product just in case the photo is too small to actually tell.

Thanks all - anyone out there actually use the wheel to confirm whether or not it was close to when the mare actually foaled?

 

[Reble]

My friend that has moved away had one, used to phone her up and check her wheel,

it has been at least 25 years ago.. so has been around for a while.

I just emailed her to find out how long she has had this.

 

[WhiteTailsMinis]

My friend that has moved away had one, used to phone her up and check her wheel,

it has been at least 25 years ago.. so has been around for a while.

I just emailed her to find out how long she has had this.

*** LIKE ****

Thanks!

 

[Joanne]

We used a cardboad type wheel that we bought from Nasco for years. These new plastic ones came out and I thought Great! waterproof. Nice.

But we too have found the wheel to be off compared to our internet foaling calculator and our cardboard wheels.

The one you show is one we no longer use here.

Personally I think the internet one is by far the best.