A poster requested screenshot of my feed calculator...

[saysfaa]

I only have one question: why? Especially if you really recommend that people don't...

Because understanding why it doesn't make sense to mix one's own feed allows people to make a realistic choice.

Instead of something like some unknown people saying it is is easy because of chicken keeping for thousands of years without knowing all this. Or cheaper. Or better. Or whatever.

And other unknown people saying it isn't.

And/or if someone were going to do it anyway, they have at least a chance of heading in the right direction to do it as well as possible.

At least, that is why I might have shared such a calculator if I had gotten as far as making one.

 

[K0k0shka]

Because understanding why it doesn't make sense to mix one's own feed allows people to make a realistic choice.

Instead of something like some unknown people saying it is is easy because of chicken keeping for thousands of years without knowing all this. Or cheaper. Or better. Or whatever.

And other unknown people saying it isn't.

And/or if someone were going to do it anyway, they have at least a chance of heading in the right direction to do it as well as possible.

At least, that is why I might have shared such a calculator if I had gotten as far as making one.

The “why” isn’t “why did you share the calculator”. It’s “why are you going through all this instead of using commercial feed that already has everything in it”.

 

[saysfaa]

Oh. Lol.

I'm not sure if you are asking everyone. If so...

I'm working my way into it because it is interesting in itself if not taken too seriously or with a time crunch. Some of it applies a little even when using commercial feed.

And because eventually I'd like to be able to meet their needs to a reasonably degree because of this... https://www.backyardchickens.com/th...ens-after-all-due-to-genetic-editing.1526230/

In the meantime, I feed commercial feed.

 

[U_Stormcrow]

I only have one question: why? Especially if you really recommend that people don't...

Because there is value in learning how to do a thing, or seeing how others have approached a problem, independant of simply using a solution of their crafting.

and because some people who might see a solution and assume its easy - in spite of others assuring them otherwise - might reconsider when faced with an overwhelming amount of admittedly incomplete data that wnet into the crafting of that "easy" solution.

Putting a rocket into orbit is easy. You need only provide sufficient thrust to exceed the pull of gravity (approx 9.8 m/s^2) for long enough to reach an orbital plane appropriate to your velocity. Simple. The doing of it proves a bit more complicated.

 

[U_Stormcrow]

The “why” isn’t “why did you share the calculator”. It’s “why are you going through all this instead of using commercial feed that already has everything in it”.

Oh, I do use commercial feeds. and strongly recommend that others do, too - unless they are in a country with no superior commercial alternative, or have very unique circumstances and considerations.

But also, I enjoyed the process of learning about feed components, their effects, and limitations - which has helped me in choosing what to attempt (largely unsuccessfully) to introduce to my pasture to make it better forage for my birds.

 

[saysfaa]

... I enjoyed the process of learning about feed components, their effects, and limitations ..

I've been studying the "nutritional aspects" pages on feedopedia for many of the feedstuffs they have. I noticed many of the feeds have the antinutrients you talk about quite often.

Have you looked into anything to do with how cumulative the effects are?

Logically, it should depend on what the effect is - tannins from one source being cumulative with the same type of tannins from another source. Maybe all types of tannins being cumulative. But tannins not being cumulative with, say, phytates.

Things aren't always logical, though, at least not without knowing more than I do.

 

[Faeshka]

@U_Stormcrow Thanks for making this feed calculator available. How did you arrive at the reference values for the methionine, lysine, threonine and tryptophan levels in the various components? I've looked at both feedipedia and feedtables and am not entirely certain what units you're using. The numbers seem very different from both the % protein and g/16gN numbers. Most of my feed formulation experience is with horses, so I'm used to just working with methionine and lysine as %. Or is there something about chickens that's different?

 

[U_Stormcrow]

@U_Stormcrow Thanks for making this feed calculator available. How did you arrive at the reference values for the methionine, lysine, threonine and tryptophan levels in the various components? I've looked at both feedipedia and feedtables and am not entirely certain what units you're using. The numbers seem very different from both the % protein and g/16gN numbers. Most of my feed formulation experience is with horses, so I'm used to just working with methionine and lysine as %. Or is there something about chickens that's different?

My target numbers (that is, the levels I desire) are based on my readings into studies of various (production) chicken breeds/lines, but the NRCS numbers make a good (if old) jumping off point.

Almost all of my numbers come from Feedipedia, but they require math to arrive at.

I'll demonstrate (or you could look at the formulas). Let's take "Standard Oats" since for some reason they've suddenly become popular with folks that know next to nothing about chicken nutrition, but want to make their own feed anyways...

Screenshot:

If you look at Methionine, it says 1.8 Average, expressed as a % of protein. And looking up at protein, you see its expressed as 11% of DM. 1.8 multiplied by .11 = .198 (which is actually 0.198% of dry matter). The minimum target (from NCRS and others) is at least 0.3% in your final feed.

This actually reveals a problem with my spreadsheet - it doesn't correct for "as fed", accounting for the moisture content of the feed. In the case of standard oats, Feedipedia found them to be (on average) 87.1% dry matter, so I'd need to multiply the .198 by 87.1% for a final ("as fed") Met level in the average standard oat of 0.1725%

It would take adding one more column and altering a formula or five, I've just not gotten around to it. Since most dry ingredients seek a level around 90% dry matter, mentally adjusting the outputs by 0.9 when it matters (rarely) to get a rough estimate is adequate.

Now in other cases, see for instance, Soybean meal, the amino acids are listed as g/16gN. That is pretty close to the same thing as % protein, written differently, for reasons that have to do with chemistry (and more averages).

 

[U_Stormcrow]

Hope that helps! I need to go make dinner. NOT chicken (tonight).