How cam we estimate the amount of nitrogen taken up by livestock (all animals) as their feed in an year for a country by utilizing the data of livestock population by FAO?
Sajjad,
To obtain this estimate you need to know: (1) Average per head daily feed Dry Matter Intake (kg DMI/head/day) for each livestock category, and (2) Average crude protein (CP) concentration in the diet (% of feed dry matter) of each animal category.
First you need to estimate the amount of CP an animal consumes per year as:
CP intake (kg/head/year) = DMI (kg/head/day) x (CP%/100) x 365
In the next step CP intake can be converted to N intake as:
N intake (kg N/head/year) = CP intake/6.25
(6.25 is the factor used to convert Crude Protein to N)
Once you estimated the ‘per head annual N intake’ for an animal category, then if you know the total animal population in that category in a country, you can estimate the total N intake for that population. Follow these steps for all livestock categories in the country.
This procedure is very well explained in the IPCC Guidelines for National Greenhouse Gas Inventories (2006) Chapter 10, which can be downloaded from the link below:
http://www.ipcc-nggip.iges.or.jp/public/2006gl/pdf/4_Volume4/V4_10_Ch10_Livestock.pdf
Sajjad,
To obtain this estimate you need to know: (1) Average per head daily feed Dry Matter Intake (kg DMI/head/day) for each livestock category, and (2) Average crude protein (CP) concentration in the diet (% of feed dry matter) of each animal category.
First you need to estimate the amount of CP an animal consumes per year as:
CP intake (kg/head/year) = DMI (kg/head/day) x (CP%/100) x 365
In the next step CP intake can be converted to N intake as:
N intake (kg N/head/year) = CP intake/6.25
(6.25 is the factor used to convert Crude Protein to N)
Once you estimated the ‘per head annual N intake’ for an animal category, then if you know the total animal population in that category in a country, you can estimate the total N intake for that population. Follow these steps for all livestock categories in the country.
This procedure is very well explained in the IPCC Guidelines for National Greenhouse Gas Inventories (2006) Chapter 10, which can be downloaded from the link below:
http://www.ipcc-nggip.iges.or.jp/public/2006gl/pdf/4_Volume4/V4_10_Ch10_Livestock.pdf
Respected Sir,
Susantha Jayasundara
Thank you so much for writing a very detailed answer. It's pretty clear to me now. I'll now work to find out dry matter intake and crude protein contents. Wish you best of health and success.
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