1. Manure excretion from beef cattle in feedlots in the USA.
Sweeten (1994) gives the following estimate of total annual manure production by cattle on feed, based on estimates from ASAE (1988) and 9.4 million feedlot places (in thousands of tons):
|
Dry manure |
11,813 |
|
Nitrogen |
467 |
|
Phosphorus |
125 |
An estimate based on assumptions on FCR, meat production, and average nutrient content in the feed, results in an estimated annual excretion of 521.1 * 103 tons N (of which ca. 70 % as N mineral) and 81.3 * 103 tons P. Assumptions are: a production of 3.55 million tons LW, a FCR of 8, an average feed quality (per kg feed) of 21.6 g and 3.8 g P, a N digestibility of 75% and a retention (per kg LWG) of 26 g N and 7.5 g P.
The difference in estimation of the P excretion is particularly large, probably because the assumed average P-content in the feed is too low, which is highly dependent on type and amount of mineral mixture added, and the value of P retention for these older animals is too high. Thus, we take the estimate recalculated from Sweeten as a best approximation.
2. Manure excretion by veal calves in the EU.
This is based on following assumptions:
- FCR of ca. 1.5 kg powder for 1 kg growth;Total excretion per animal is ca. 4.9 kg N and 0.6 kg P. No distinction is made between N mineral and N organic as the liquid manure is collected jointly. WUMM (1994) gives higher annual excretion per animal (5.4 kg N and 0.96 kg P) due to a higher FCR (of 1.85) but lower nutrient content of the feed, for the Netherlands only. As the FCR in other countries in Europe is generally lower than in the Netherlands (see Section 2.2.2) the calculated value seems to be a reasonable overall estimate.
- average nutrient content in feed of 24% CP, 0.72% P;
- annual production of ca. 6 million veal calves growing 180 kg; and
- retention in 1 kg LW of 30.2 g N and 7.6 g P.
Total annual excretion of veal calves, based on the given assumptions is about 29,400 ton N and 3,600 ton P.
3. Manure excretion from intensive sheep fattening WANA.
This is based on following assumptions:
- FCR of about 5 for 1 kg growth;Intake and excretion per kg LWG (in g):- average nutrient content in feed of 14% CP (=112 g N/kg), 10.5 % DCP (=84 g N/kg) and 0.5% P;
- annual production of 212.8 * 103 tons LW (100,000 ton mutton with dressing percentage of 47%); and
- retention in 1 kg LW of 24 g N and 6 g P (fat animals).
|
|
Total N |
Dig N |
Total P |
|
Intake in 5 kg feed |
112 |
84 |
25 |
|
in 1 kg growth |
|
24 |
6 |
|
Excretion in manure |
28 |
|
19 |
|
Excretion in urine |
|
60 |
|
