Prickly Pear, big pads are bad

JoesMum

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This 2011 scientific paper suggests that the calcium content of the pads increases with age and that the oxalate content is variable.
http://www.sciencedirect.com/science/article/pii/S0889157510001924

It concludes (I paraphrase) that mature pads are a still a viable source of calcium.

The bigger problem with feeding a lot of pads is their laxative effect. As ever, as part of a mixed diet they're still good to feed
 

Kapidolo Farms

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Well there are also papers that indicate that smaller pads have more oxalates per ounce than larger pads. The laxative effect can be mitigated by keeping up on long fiber and free choice of foods. I don't find that as long as other foods are readily available, tortoises over eat the pads.

http://www.tortoiseforum.org/threads/some-nutritional-aspects-of-opuntia-with-citation.129949/

The thing that makes many nutrient evaluations sorta not as valuable as we might want

1) many study authors dry and grind the pad so that further analysis can be done. The drying and grinding actually alter what is found.

2) cultivar and species of pad infuse much variability into the nutrient content

3) post harvest handling can also alter nutrients. Some packaged whole small pads are treated for longer shelf life.

The smaller 'spring growth' pads are more enjoyable for people to eat. They are not the most nutritious.

Pads in the six month to before they add a new pad are considered optimal as cattle, goat, and other livestock feed.

Millions of metric tones of opuntia are fed to cattle. Free range cattle or goats (I forget, maybe it is sheep) can have as much as 70% of their diet come as opuntia before any weight gain or noticeable health issues are apparent. The high water content helps a great deal as does the fiber. You can actually floss your teeth with the fibery connective tissue in the larger pads, that's a good thing for animals that don't have teeth for it to get stuck in.

It would seem that when pads first appear that is when they are most vulnerable to be eaten by animals and insects, as they skin is soft. That is when the plant loads those pads with oxalates. As the pad grows and the skin gets thicker and tougher, the relative abundance of oxalates is less.

That oxalates are a bad thing and should be avoided is its own debate, but I would suggest that the good qualities of opuntia so far outweighs that as a concern, that it is not worth a worry.

The values for calcium in opunti are so high that most oxalates are going to be bound with calcium, if at all, in the gut - before absorption, and not go through many more progressions of metabolism where they are alleged to form 'stones' in the kidneys or bladder. At least one globally recognized expert in reptile veterinarian medicine says there is not one single incident of stone formation in a tortoise based on oxalate accumulation in the literature (which means stuff written by intetfull investigators, not some Facebook folklore). I believe him.
 
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Tom

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The values for calcium in opunti are so high that most oxalates are going to be bound with calcium, if at all, in the gut - before absorption, and not go through many more progressions of metabolism where they are alleged to form 'stones' in the kidneys or bladder. At least one globally recognized expert in reptile veterinarian medicine says there is not one single incident of stone formation in a tortoise based on oxalate accumulation in the literature (which means stuff written by intetfull investigators, not some Facebook folklore). I believe him.

Based on the above oxalate info, would you then say its okay to feed oxalis as a small part of a varied diet? I used to feed handfuls of oxalis to my adult sulcatas once in a while a few years ago before I knew what it was. I thought it was some kind of clover. I get large patches of it every year when the rains come, and I rip it all out and throw it away. In the old days, it never seemed to do any harm to the tortoises that ate it and they are all still alive and well.
 

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Based on the above oxalate info, would you then say its okay to feed oxalis as a small part of a varied diet? I used to feed handfuls of oxalis to my adult sulcatas once in a while a few years ago before I knew what it was. I thought it was some kind of clover. I get large patches of it every year when the rains come, and I rip it all out and throw it away. In the old days, it never seemed to do any harm to the tortoises that ate it and they are all still alive and well.
My adult reds love oxalis, I do pull it if I see it but boy do they love it.
 

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Based on the above oxalate info, would you then say its okay to feed oxalis as a small part of a varied diet? I used to feed handfuls of oxalis to my adult sulcatas once in a while a few years ago before I knew what it was. I thought it was some kind of clover. I get large patches of it every year when the rains come, and I rip it all out and throw it away. In the old days, it never seemed to do any harm to the tortoises that ate it and they are all still alive and well.

A bit of the apples and oranges Tom. I don't know the calcium values for oxalis. The idea with opuntia is that it is 10 to 35 : 1 potassium. That's enough calcium to sequester the potassium and oxalates, if that's how that works. Opuntia also has all that fiber to allow the "bolus" mechanism to work.

Oxalis somehow won't grow in the tortoise pen, even though it grows profusely in the rest of my yard. Kidding, they eat it when it's the smallest stub. I've tried it, it tastes good.

When I have read the diet of our native desert tortoises, I've seen they will eat things with an oxalte content that puts opuntia to shame. That, and they usually don't have standing water to drink further supports the idea that there is a high tolerance level.

But then we have the argument from the keeper who fed spinach for ten years brought a sick tortoise to a vet, who subsequently proclaimed "oh blah blah blah oxolates, blah blah blah stone" and the dry rabbit pellet method of raising sulcatas was born. Get me.

Tom, you are the 'think outside the box guy' (seems like a blend of pun and irony there). So what are your thought?
 

Holly'sMom

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I only feed new growth pads off planted pads. They grow fairly quick so it saves $$$ lol but again my torts only 3-4inches
 

Holly'sMom

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A bit of the apples and oranges Tom. I don't know the calcium values for oxalis. The idea with opuntia is that it is 10 to 35 : 1 potassium. That's enough calcium to sequester the potassium and oxalates, if that's how that works. Opuntia also has all that fiber to allow the "bolus" mechanism to work.

Oxalis somehow won't grow in the tortoise pen, even though it grows profusely in the rest of my yard. Kidding, they eat it when it's the smallest stub. I've tried it, it tastes good.

When I have read the diet of our native desert tortoises, I've seen they will eat things with an oxalte content that puts opuntia to shame. That, and they usually don't have standing water to drink further supports the idea that there is a high tolerance level.

But then we have the argument from the keeper who fed spinach for ten years brought a sick tortoise to a vet, who subsequently proclaimed "oh blah blah blah oxolates, blah blah blah stone" and the dry rabbit pellet method of raising sulcatas was born. Get me.

Tom, you are the 'think outside the box guy' (seems like a blend of pun and irony there). So what are your thought?
Are clovers bad???!?? My Belle is obsessed with eating them! Should I be keeping them out of her diet??
 

Lemonade

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Are clovers bad???!?? My Belle is obsessed with eating them! Should I be keeping them out of her diet??
Why do you think clovers are bad? As always, a variety of foods should be offered. My torts LOVE petunias, but I regulate it. lol
 

Tom

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Are clovers bad???!?? My Belle is obsessed with eating them! Should I be keeping them out of her diet??

There is a plant that looks very similar to clover called "oxalis". It is very high in oxalates and is universally not recommended for tortoise food.

Clover is a good tortoise food as part of a varied diet. It is higher in protein than some plants, so I would recommend extra measures to ensure good hydration. Clean fresh drinking water and frequent soaks.
 

Holly'sMom

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Oh man thank you for letting me know I mean I've been getting it out of my yard! I'll have to take that out
 

Tom

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Tom, you are the 'think outside the box guy' (seems like a blend of pun and irony there). So what are your thought?

I'm not sure about this one Will. I need more info to make a decision. I know that it is not deadly toxic, but are they able to tolerate a little bit without harm, or is it actually a good thing to feed them as part of a varied diet? I don't know...
 

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