# What causes runts?



## MaggieJ (Feb 6, 2006)

What causes runts?

On the surface of it, it seems a pretty silly question... but really, what is happening in momma bun's womb that causes one rabbit out of a litter to be so much smaller than the rest? Is it genetic? Does it not receive its fair share of nutrients during development? Is it born the same size as the others, but just weaker and so can't compete for its fair share of milk? 

I have always found runts particularly appealing. (My best cat when I was a kid started out as a pitiful little runt... I suppose that is what started it.) In the rabbit litters, the runt always seems cuter, sweeter and more intelligent than its littermates. 

There was one in the last litter that I still regret sending to freezer camp late last fall. It started so tiny, but it was smart and managed to work around its pushier siblings. If they were mobbing the hay, he went and ate grain. If they pushed him out at the grain dish, he didn't waste his energy... he ate greens or hay until there was space for him. He grew so well that by butchering time he was no longer the smallest one. And he was just such a nice-natured little guy.

If it had been a little doe, I probably would have kept her and let her grow out to see how she shaped, but keeping a buckling over the winter would have upset my floor pen arrangement and I sent him to freezer camp with the others. 

No one ever talks about the runts... and the books don't cover it except to either advise culling at birth or advise giving them a chance. So if anyone knows anything about them, would you please share?


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## Meg Z (Jun 8, 2004)

Good question. I assume that it's not getting as much nourishment as the others in the womb, but I never considered how it happens.

I just had my second runt ever. One of a litter of 12 is half the size of the others. The first runt didn't grow well at all, and the gap between it and it's siblings just got bigger. It ended up being snake food as I couldn't see it growing enough to make people food, and it just wasn't 'right' so wouldn't have made a pet, either. It was about a third of the size of its sibs when I gave up on it. 

This one...we'll see. I wouldn't dispatch it out of hand. I figure it should have a chance, but I also have only the experience of that other one to go on. I was anticipating it being just good enough for snake food too, but if it's got a possibility to grow out and make a pet for someone, I'll give it that chance. Why not? 

But you've made me wonder what causes it...specifically. I guess it's research time.......

Meg


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## MaggieJ (Feb 6, 2006)

The runts I've been getting from time to time were from larger litters too... sometimes I have wondered how they survive even the first couple of days. And some don't, of course. The ones that do make it are very lively and healthy... just tiny. Sigh. I guess I just can't help rooting for the underbunny.


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## Beaniemom (May 25, 2007)

I dunno why, most of mine seem to make it though, its always the strongest ones that get out of the box first to freeze it seems! I really don't pay much attention to the runts anymore, either they make it or they don't, and sometimes by FCD I can't tell anymore. I do have one runt in my current litter being grown out, and it is just soooo cute! If I was going to do a Mini SF line for pets, I might save it, but I just don't have the space to do it.


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## Somerhill (Dec 13, 2005)

This is me just thinking out loud......in sheep, when one lamb is smaller than the others in a set of twins or triplets, its because their placenta is smaller than the others. In the uterus, there are coteledons (sp?) which supply nutrients from the mother's body to the developing fetus. Each placenta attachs to some these coteledons. There are a limited number, so the larger the litter, some of the fetus get pushed out and don't get as many connections. These fetus don't grow as well, and are smaller at birth. 
It makes sense to me that this could be true in rabbits, too. 

Lisa at Somerhill
www.somerhillfarm.com


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## MaggieJ (Feb 6, 2006)

Thanks, Lisa... That makes sense and I suppose that (or something like it) is what is going on in rabbits too. After all, it usually _is _the larger litters that have a runt.


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## Kittikity (Oct 21, 2004)

It also makes sense in reverse.. From what I've seen from you guys so far, the smaller litters usually have the bigger babies.. More room, more connections..


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## CookingPam777 (Oct 16, 2007)

Lack of nutrition?


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## Meg Z (Jun 8, 2004)

That does make sense...but my first runt was in a litter of three. :shrug:

I went out a while ago and checked my little blue runt. He's half the size of the other one I grabbed for comparison, but he's lively, and he's been eating. We'll see how he does. So far, so good.

Meg


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