CALCIUM: Powdered vs Crushed?

[Sojourner]

I've seen both proposed over the other.

I buy oyster shell for the wild birds anyway, but I'm not necessarily enthused about putting that through my spice grinder to crunch it up smaller.

There is F.M. Brown's Cuttlebone Calcium Powder being sold on Amazon. Powdered, obviously.

Then there is a "crushed egg shell" product ("Hatched! Eggshell") being sold on Glamorous Gouldians for $5/lb, which is not a horrible price. Though shipping could add significantly to that. Is that somehow better than crushed oyster shell?

I honestly have NO IDEA what I ought to be using.

So what are you using, and why?

[dunker817]

I do both. I use an oyster shell mineral supplement with charcoal and I used powdered egg shell in my egg food. To be honest, I don't really have much confidence with them eating the oyster shell. I assume they get eat it some. I offer the mineral supplement because I don't have a way to hang a mineral block in the aviary.

[debbie276]

I run oyster shell through a coffee grinder and add to my mineral mix. I have no confidence that they will eat powder
What they love the most is egg shell from the hard boiled eggs. I leave the pieces as big as I can and they LOVE breaking off what they want. You could also grind up the egg shell if you want it smaller with very little effort.

[Sojourner]

I have little confidence in the idea of a bird eating powdered anything, either, but I see so MUCH of it - powdered vitamins, powdered cuttlebone, powdered mineral supplements, "fortified" seed that has been dusted with powdered vitamins and minerals.

It doesn't seem reasonable that a bird that needs to pick things up with their beaks could get much out of powdered whatever. But then, what do I know?

Clearly not much.

I guess the powdered stuff would work fine if you're putting it in something else, like egg food. But just putting it in a bowl? Doesn't make sense to me, so I figured I'd better ask, LOL!

[Leo519]

I provide powdered oyster shell for my finches and canary in a little hanging treat cup and they all eat it from time to time. I also have a cuttlebone in the cage that all of them nibble on as needed, and 2-3 times a month I provide some "bird charcoal" that I mix in with their oyster shell powder and all of them eat a little of the charcoal as well. I get the oyster shell powder from a local pet store and it's about $2-$3 for 10 ounces. I forget the exact price - the small bag of it I got about 6 months ago and so far it seems like it seems like it will last a few lifetimes for my dozen birds

[Lucille]

I went looking on the internet to find out exactly how finches would digest either powdered or crushed calcium. From what I saw, and by all means jump in and add if you know more, is that food is ground up into bits in the gizzard and then digested.
It is difficult to see how something like a pebble (bit of crushed shell) could actually get digested. I cannot digest pebbles, but then, I do not have a gizzard.
Informative articles I found that do not actually answer the question, but are interesting anyway:

http://www.health.harvard.edu/staying-
healthy/what_you_need_to_know_about_calciumhttp://jn.nutrition.org/content/129/1/9.fullhttp://www.newyorkbirds.net/calcium-vit-d.html

What I am looking for is a cite to a scientific article showing exactly how a bit of oyster shell gets turned into useable calcium in a finch.

[debbie276]

http://www.backyardnature.net/birdguts.htm

[Babs _Owner]

Sojourner

Just recently I had a lot of baby finch hatchlings. I initially I was using the powdered egg supplement from the petstore sprinkled on the food.
Babies crops never seems really full.

At the advice of some great members, I turned to mashed up chicken eggs w/shells.

Babies crops are now very full. So I am assuming that powder wasnt doing more than falling the to botton of the seed bowl.

[Sally]

Lucille Here is a link to a good explanation of why finches do not need grit (gravel) in their diet. A lot of confusion comes from the interchangeable use of the word grit. We often talk about oystershell grit, but when grit is referred to in the context of helping digest/grind seed, that is what we often (or used to anyway) call gravel. Finches don't grind their food, because they hull the seed. Doves, on the other hand, don't hull their seed, so they need grit (gravel) to grind up the seed for them.

Usually, on sites that are talking about finches, when they say grit, they are referring to oystershell grit, which does supply calcium.

http://www.finchinfo.com/diet/grit_is_not_necessary.php

[Lucille]

Sally,
Thanks for the info.
I realize that finches do not need grit or gravel as a mechanical means to assist digestion, but I was trying to find answers to the powder/oystershell debate and trying to find precise descriptions of how a piece of oystershell is digested by a finch.
Finches DO grind their food, but apparently do so via keratin plates in the gizzard. Whether that keratin can change a piece of oystershell into a particle that can be absobed by the finch? That's the question.grit and gizzards

[debbie276]

From the link I posted above:
http://www.finchinfo.com/diet/nutrients_and_sources.php
The gizzard:
The bird stomach's second chamber is known as the gizzard. If you've ever eaten a chicken gizzard you know how tough and rubbery it is. To accomplish what the gizzard does, it absolutely must be tough, for the gizzard's main function is to grind and digest tough food. Though the gizzard consists of very powerful muscles, it alone can't pulverize everything the typical bird eats; you know how hard uncooked rice and corn kernels are, and these aren't even considered hard types of grain.
Something other than muscle power is needed. This "something else" is acquired when grain- eating birds pick up grit and small rocks as they peck seeds from the ground.
This mineral matter accumulates in the gizzard, and ultimately the gizzard grinds the particles against the seeds, smashing them. Turkey gizzards can actually pulverize English walnuts and steel needles! Bird species that eat softer food possess less well developed gizzards. In some species, the gizzard remains small and insignificant during the summer when the diet consists of soft food such as flesh, insects, or fruit, but it grows more powerful during the winter when seeds are the main food. Since birds eat such a wide variety of foods, you can imagine that variations on the stomach theme are many. One of the most elegant is found among grebes, which are very common water-birds you're bound to see if you visit local lakes or the seashore. Grebes swallow their own feathers, which accumulate in the region between the gizzard and the intestine following it. This feather-clogged zone then serves as a filter for sharp fish bones that somehow make it past the stomach.

Once food leaves the gizzard, its voyage through the intestines is fairly similar to that taken by food in our own intestines; nutrients are absorbed into the body, and waste is eventually excreted. Intestines are short in birds which eat easily absorbed food, such as fruit, flesh, and insects, but long in species eating seeds, plants, and fish. Swifts, which are insect-eating birds you'll see skating across the suburban summer sky, possess intestines only about three times their body length. In contrast, intestines of vegetarian ostriches are roughly twenty times their body length. Easily absorbed berries pass through a thrush's intestine in less than half an hour, while rougher food may need half a day or more.

[Lucille]

"Finches don't grind their food"
VS
"This mineral matter accumulates in the gizzard, and ultimately the gizzard grinds the particles against the seeds, smashing them. "

There appears to be some disagreement as to the actual facts?

[debbie276]

The article I linked to explains how the gizzard and intestines function in a variety of birds, the gizzard "grinds" the food.
Here's another article that may help:
http://www.fernbank.edu/Birding/digestion.htm
Birds have a two part stomach, a glandular portion known as the proventriculus and a muscular portion known as the gizzard. Hydrochloric acid, mucus and a digestive enzyme, pepsin, are secreted by specialized cells in the proventriculus and starts the process of breaking down the structure of the food material. The food then passes to the second part of the stomach, the gizzard. The gizzard performs the same function as mammalian teeth, grinding and disassembling the food, making it easier for the digestive enzymes to break down the food. In most birds the gizzard contains sand grains or small rocks to aid the grinding process.

and another:
http://www.d.umn.edu/~seel0083/document ... ersion.pdf