# @Carolyn: mineral requirements "Diet for wethers"



## sanhestar (Dec 10, 2008)

Hello Carolyn,

and maybe others....

I'm just working through "Diet for Wethers" and stumble about the calcium and phosphorus requirements you mention in chart five, page 28.

Calcium, maintenance: 20 mg/kg BW
Phosphorus, maintenance: 30 mg/kg BW

if I add that up to a 90kg goat the requirements would be:

calcium 1800 mg
phosphorus 2400 mg

Is this correct, this upending the ca ratio of 2:1? 

Thanks for clarifying?


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## sanhestar (Dec 10, 2008)

???

anyone an idea?


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## ryorkies (May 4, 2010)

That sounds backwards to me.

For I thought calcium was suppose to be
the 2 parts and the Phosphorus the 1 part.


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## Rex (Nov 30, 2008)

ryorkies said:


> That sounds backwards to me.
> 
> For I thought calcium was suppose to be
> the 2 parts and the Phosphorus the 1 part.


This is correct. 2 parts Calcium to 1 part Phos.


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## sweetgoatmama (Dec 10, 2008)

This has got to be a typo since the ratio is 2:1.


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## sanhestar (Dec 10, 2008)

Hello Carolyn,

thanks for looking in here.

So the correct maintenance requirement would be 40 mg/kg BW?


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## sanhestar (Dec 10, 2008)

Hello,

I'm still coming back to this.

This morning I found a table on goatsworld.com in which the same numbers appear:

http://www.goatworld.com/articles/miner ... tion.shtml

Table 12, very much at the bottom of the article. These study seems to be from the early 1990s.

another study

http://www.aces.edu/pubs/docs/A/ANR-0812/ANR-0812.pdf

page 7

mentions a maintenance requirement for calcium of 0.009 lbs for a goat with 202 lbs body weight. That would be 4500 mg.

Compared with the original requirement from the goatworld table of 20mg/kg BW (2020 mg) this is more than double. It would be ok if I assumed that the 20 mg/kg BW are a typo and calculate with 40 mg/kg/BW (4040 mg). I keep wondering why the calcium requirements are so low in that earlier study (or if there's really a typo in it).

I also struggle with the calcium requirements (and subsequently the req. for the other minerals, too) for growing goats:

10,7 gramm per kg BW

Seriously? That would mean that a 10 or 20 kg lamb would need 107 or 214 gramm (!) = 107.000 to 214.000 mg Calcium per day. One litre goat milk only contains approx. 1380 mg calcium.

Where did this numbers come from? Is it possible that there was somewhere an error made and this error is getting passed on and on? Could it be that the unit of measurement is not kg/BW but f.e. per 50 kg BW?


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## cryptobrian (Apr 26, 2012)

I think there is bound to be variability in the recommendations based upon the samples being used to represent the populations. There is a lot of data on specific goat breeds or limited sample groups that gets generalized into a broad recommendation. Were the numbers a result of a trials done on a small group of yearling african pygmy males or lactating does? I noticed both referenced as footnotes to published data. 

I usually defer to the Nutrient Requirements for Small Ruminants books. The older edition you can find portions of online. 

In the section under calcium (and other nutrients) you'll find some of the formulas used to calculate the daily requirements as well as some background on how the requirements were determined and some commentary on some of the research behind the numbers. In the end of the book, if you don't want to wade through it all, are nutrient requirements in a tabular format.


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## sweetgoatmama (Dec 10, 2008)

Yes, it seems to be a typo as everywhere else in the goat world the ratio is 2:1.
Any time you work with other people's data things can get mess up. As long as this book as been around I'm surprised that no one has caught it before.


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## sanhestar (Dec 10, 2008)

in the meantime I've contacted the author of said article in goatsworld at U Del and he replied that he will look into the original article/data and come back to me on that.


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