# Small mares x Big Stallions = Explosive Birth?



## jcwh (31 March 2011)

what "rumors" i've heard once that if you put a small mare to a bigger stallion, the foal will grow too huge inside the mare and then result in foaling difficulties.

another side of this that i've heard is that the foal will be just right growing inside the mare, and will continue genetic growth after birth.

i mean as long as the difference isn't too huge, is it a risk?
(i mean, i'm not putting shetland x shire, but 15h cob x 17h warmblood?)
assuming the mare is ALWAYS the smaller one.

also, whose size does the foal usually take? mare's or stallion's? 
thanks!


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## Springs (31 March 2011)

The size of the foal will be governed by the mare carring it, so yes you could put a 15hh mare to a 17hh stallion. The issues I see with difficulty at birth has been more to do with the mare been too fat.


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## Dolcé (31 March 2011)

I recently found an article on some research that had been done using shetland mares and shire stallions, have a look at the link below.

http://www.bluemoongypsies.com/shire-shetland.pdf


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## varkie (1 April 2011)

I have personally come across several attempted births now with smaller mares to bigger stallions, where the foals have been lost - and in one case the mare also.  In each case, following birth, the foal was found to be significantly too large for the mare to have birthed successfully - in one particular instance foal had to be removed in pieces to get it out.  

To be fair, I have known a couple of births of small mare to large stallion where the mare has managed to give birth to a live foal, but in those cases, births were hard on the mare, and the mare needed help.

So my own experiences suggest that a small mare / large stallion cross may or may not be successful, but that there is a strong chance that it may not be.  Birthing mares is risky enough without adding risk factors - so why do it?

I don't think I go much on that paper.  For starters, it was done about seventy five years ago.  Secondly, they only used a few mares!  Not exactly a representative sample!  To be a good study, they would have needed to have bred many mares for the study.  If you breed only a couple, you run the chance of the foals taking after the mare, and therefore not giving a true representation of the outcomes of small/large breedings.


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## Arabelle (1 April 2011)

My vet advised me to go no more than a hand bigger for my maiden mare.  As previous poster said, why take unneccessary risks?


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## TBB (1 April 2011)

Seem to recall that Prof Twink Allen was doing that sort of experimentation in Newmarket (shetlands and shires) with success and as far as I can remember he did it both ways, large mare/small stallion and small mare/large stallion, he has probably published something on it.


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## magic104 (1 April 2011)

15hh QH x Welsh dam, sire 16.1hh Trak = 16.1hh offspring


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## jcwh (1 April 2011)

so no more than a hand bigger?
has anyone experienced a birth without problems?
also, i'm not breeding at all! so no risks!
it's just for when i do want to breed in the future, at least i should know.


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## SmilingMadly (1 April 2011)

Whilst the the foal should not grow bigger than the size of the uterus whilst inutero, the associated compensatory growth issues once born are potentially huge.


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## tikino (1 April 2011)

my mare has successful gave birth to a foal from bigger stallion mare is 15h2 and stallion was 17h2 both foaling have been easy.


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## madlady (1 April 2011)

In theory the mare's build should prevent the foetus from growing so big that the mare cannot deliver and in the majority of cases this works but approximately 5% of all foalings have issues - from the easily fixable to the ones that cost the lives of mares and foals.

I've seen the case studies where shetlands have been inseminated by shires and vice versa and the results come within the 'normal' parameters - 95% of births are all OK.

My vet is another one though who would say no more than a hand difference for a first foal and 2 hands maximum difference.

As others have said - why potentially increase the risks of problems.


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## zizz (1 April 2011)

I put my mare (14.1) to a 16.2 stallion. her first foal for over 10years and as you can see the filly was tiny when she was born, more than capable of walking under mum's stomach. I was present for the birth but no assistance was needed, and I would repeat the cross again.







Filly is now 9 months and approx 12.2 at withers.


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## ritajennings (1 April 2011)

Rule of thumb is up to two hands bigger.
Even if you used a stallion the same size as your mare if you do not know the breeding as she might have a much bigger horse in her linage, the same goes for a stallions linage you could end up with a much larger horse than expected.


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## varkie (1 April 2011)

Bone should also come into it.  Putting a SP mare to a traditional cob stallion is asking for trouble, even if they're not too dissimilar in height.

The rules say that you can go up to two hands difference, one hand in a maiden mare.  I think I'd personally feel a little uncomfortable going much above a hand.  

Birth is a big deal, hard on the mares, and even when everything is perfect, can so easily go wrong - I think the odds of problems must be higher than 5% - again, my own experience suggests it's higher.  And with those odds of problems in perfect on paper matings, why run the risks even higher by adding potential issues?


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## MillionDollar (1 April 2011)

I put two NF mares in-foal to a 16.1 WB, one mare was 13.1 and the other 13.2. Both had perfect textbook births, both were maidens and both foals were average sized.


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## cruiseline (1 April 2011)

I have seen foaling problems with big mares to smaller stallion!!!! We have one mare, she is 16 hands and has never been in foal to a stallion over 16.2, she ALWAYS needs help with foaling. I loaned her out one year (never again) the loaners were warned that she would need assistance (stallion was 15.2) and they missed the foaling  She struggled with foaling (as predicted) and a still born foal was the result 

I personally think the size of the mares pelvis is where the problem lies, after all the old saying 'she has good child bearing hips' might have some merit after all!!


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## jcwh (1 April 2011)

zizz said:



			I put my mare (14.1) to a 16.2 stallion. her first foal for over 10years and as you can see the filly was tiny when she was born, more than capable of walking under mum's stomach. I was present for the birth but no assistance was needed, and I would repeat the cross again.







Filly is now 9 months and approx 12.2 at withers.
		
Click to expand...

mmm who's the sire? that's one gorgeous girl you have!
another though - the NF mares to 16.2 WB stallion = 3 hands difference??

the bone was a good issue, but as i recall traditional ISH were made from ID x TB, what if it was a TB mare (assuming TB mare = light and finer boned) x RID stallion (assuming bigger boned)
would there be complications there too?


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## ritajennings (1 April 2011)

Covered loads of TB mares with RID stallion with no problems. I do know some people do prefer a TB stallion on RID mare I suppose because the mare would be roomier.
Being a draught breeder it would be alittle against the grain to put a RID mare to anything else than a RID stallion as they can only breed one foal a year and IMO we do not have enough pure bred foals being born.


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## Spring Feather (1 April 2011)

I've bred smaller mares to larger stallions lots of times and I have never had any complications or had to assist with the births.


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## dianchi (1 April 2011)

Last year i heard of a 15hh mare to a 17.2hh Luso, foal was overdue and needed a plasma transplant.
Personally wouldnt risk it myself


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## Rosehip (2 April 2011)

Being from a farming family I would never put a big boned sire on a slight boned dam, especially as a first pregnancy. This follows bovine, ovine, porcine and equine. 
Look at the problems freisian cows have when put to belgian blue or charolais bulls.

I have a SHP type in foal to a SHP stallion, the next stallion I will use is 1/4 arab coloured. A slightly bulkier stallion, but still well within her 'range'. 

Having viewed a 4 year old 11.2 sec A mare with a view to bringing on as a driving pony, I walked away rapidly when told that she had ran with, and been covered by, a 14.2 traditional stallion. 
Why would anyone think that was ok??

To the poster who covered maiden newforest mares with a 16.2 WB - what was the thinking behind that? Far too risky IMO.


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