How to calculate the percentage crude protein of soyabean and sorghum mix given 4.5kg per day of hay and supplemnt of 2kg per day of the mixwhere protein required is 0.752kg per day.?

Answer 1

Here's the best i can come up with, (I'm an undergraduate studying nutrition...seriously check the math).

You entire ration amount consumed per day is 4.5 kg hay + 2 kg of sorghum and soybean mix = 6.5 kg total daily consumption on an "as fed" basis.

The amount of protein that you desire to be consumed daily is 0.752 kg (little bit odd...i feed poultry and i usually go by feed bag CP and TP %'s...but i can roll with this)

So, as a percentage of your daily diet you desire to have 0.752 kg protein/6.5 kg total ration = 11.7 % protein on an "as fed" basis.

So...what are average values of protein for soybeans, sorghum, and hay...

Hay, sun-cured appears to be around 16.4% CP (though, this could vary...depending on harvest, moisture, etc.).

Soybean = 5.9% CP (probably on an "as-fed" basis) (source: http://books.Google.com/books?id=5P57esibXEYC&pg=PA37&lpg=PA37&dq=percent+protein+in+soybean&source=web&ots=Qv9oWR6EXq&sig=hwPWwZ3sUwRxL8rQCy9jdg7gRdk&hl=en&sa=X&oi=book_result&resnum=4&ct=result)

Sorghum = 7.9% CP (source:http://jn.nutrition.org/cgi/reprint/88/4/370.pdf)

(obviously these are the best estimates of this i could find...i don't know anything about the quality, growth, etc. of the materials you're using)

Hay's probably cheaper than your soybean/sorghum mix...so you could take out the hay protein from your total protein first: 4.5 kg of hay w/ 16.4% of that being protein gives .738 kg of protein provided in your daily hay ration, (assuming all protein can be utilized by the animal). So...0.752 kg - .738 kg =0.014 kg of protein left to be accounted for. Now comes the fun part.

We need 0.014 kg of protein out of 2 kg of supplement containing a mix of sorghum and soybean. 0.014 kg of protein/ 2 kg of total = 0.7% CP required out of our sorghum and soybean mix to meet the rest of the daily requirement.

On an off note: Assuming 100% soybean diet 2 lb of feed would contain 2 * 5.9% = .118 lb of protein, considerably more than needed to finish off the necessary protein requirement. The same would be true of sorghum. So if my thought process is correct, either of these materials could by itself provide what you need.

I think that covers everything in the question.

Crystad@clemson.edu