1. Conversion factors for the calculation of Livestock Units per pig, laying hen and broiler
2. Accuracy of the calculation method to estimate the share of LLM systems in total pork production
3. Key indicators and their parameters
4. Feed rations, N and P content, digestibilities and excretion for pigs, broilers and laying hens in the Netherlands, Canada and the tropics
5. Some consequences of internalization of externalities
To make comparisons among animal species within various agro-ecological zones possible, Sere & Steinfeld (1995) use livestock units (LUs), based on cattle carcass weights (being the highest in the OECD countries) with one head of cattle in OECD countries equal to one LU. Their next step was to calculate the equivalent LU for one head of cattle in other agro-ecological zones, with lower carcass weights. These calculations resulted in one head of cattle in e.g. Sub-Saharan Africa being equal to 0.457 LU and one head of cattle in Central and South America to 0.75 LU. This calculation method does not make it clear how monogastrics should be converted to LUs. However, one of the criteria to delineate LLM-systems is an annual average stocking rate above 10 LUs per hectare of agricultural land. Therefore, it is necessary to estimate the LUs per pig, broiler and laying hen.
The metabolic weight1 of an animal is an appropriate indicator for making comparisons among different animal species. For this reason we will calculate the LUs per pig, broiler and laying hen on the basis of metabolic weights.
1 metabolic weight is equal to (Live weight)0.75.
Assuming an average head of cattle in an OECD country weighs 600 kg, results in a metabolic weight of 6000.75 = 121.23 kg. We set this equal to one LU.
Assuming an “average” pig on a farm weighs 70 kg, its metabolic weight equals (70)0.75 = 24.20 kg. One “average” pig thus equals (1/121.23) * 24.20 = 0.20 LU. Thus, an average annual stocking rate of at least 10 LU’s per hectare of agricultural land roughly equals an annual average stocking rate of 50 pigs per hectare of agricultural land.
Assuming an “average” broiler on a farm weighs 1.2 kg, its metabolic weight equals (1.2)0.75 = 1.15 kg. One “average” broiler thus equals (1/121.23) * 1.15 = 0.0095 LU. An average annual stocking rate of at least 10 L’s per hectare of agricultural land thus roughly equals an annual average stocking rate of 1100 broilers per hectare of agricultural land.
Assuming an “average” laying hen on a farm weighs 1.8 kg, its metabolic weight equals (1.8)0.75 = 1.55 kg. Therefore, one “average” broiler equals (1/121.23) * 1.55 = 0.013 LU. An average annual stocking rate of at least 10 LUs per hectare of agricultural land thus roughly equals an annual average stocking rate of 780 laying hens per hectare of agricultural land.
To estimate the share of LLM systems in total pork production, Sere & Steinfeld (1995) used the following calculation method per country:
share of LLM systems in total pork production = 0.5 * urbanization degree * total pork output
Because the share of LLM systems in total pork production in the developed countries can be expected to be at a higher level than (0.5 * urbanization degree), for countries with a per capita income above US$ 6000 pa the factor was raised to (0.7 * urbanization degree).
In Box A1 the real situation in several countries is compared with the results obtained applying the calculation method of Sere & Steinfeld (1995). It can be concluded that the calculation method applied results in good approximations of the share of LLM systems in total pork production.
|
Philippines Share of LLM systems in total pork production according to Seré. Total pork production in 1991 amounted to 704.200 metric tons. Urbanization degree was 43%. Per capita income was lower than US$ 6000 pa. LLM share = (0.5 * 0.43) * 704200 = 151403 metric tons (21.5%). Real situation. No data were found for the share of LLM systems in total pork production. It is known that 82% of the total pig population is raised by smallholders and backyard pig farmers (Sayoc, 1993). This would suggest the share of LLM systems to be 18%. However, the same source mentions the fact that these smallholders and backyard pig farmers with their 82% share in pig population account for a much lower (but unknown) proportion of total pork output. So the share of LLM systems is at least somewhat higher than 18%. Vietnam Share of LLM-systems in total pork production according to Seré. Total pork production in 1991 amounted to 731.847 metric tons. Urbanization degree was 22%. Per capita income was lower than US$ 6000 pa. share of LLM systems = (0.5 * 0.22) * 731.847 = 80.503 metric tons (11%). Real situation. No data were found for the share of LLM systems in total pork production. It is known that 97% of the total pig population is kept in the farmer’s backyard (the private sector) and only 3% on large-scale state farms (The Tong & Van Kinh, 1993). This would suggest the share of LLM systems to be 7%. But, as in the Philippine situation, it can be expected that these large-scale state farms account for a relatively higher proportion of total pork output. So the share of LLM systems is at least somewhat higher than 3%. Netherlands Share of LLM systems in total pork production according to
Seré. Total pork production in 1991 amounted to 1.630.000 metric
tons. Urbanization degree was 89%. Per capita income was higher than US$ 6000
pa. share of LLM systems = (0.7 * 0.89) * 1.630.000 = 1.015.490 metric tons
(62.3%). Real situation. For 1991 it is known that 57% of the total pig
stock at one moment was kept on specialized pig farms and 43% on more or less
mixed farms (Anonymous, 1992). Assuming that the pigs on the specialized farms
account for an equivalent proportion of the total pork output, this results in a
share of LLM systems of 57%. |
|
DIRECT INDICATORS |
Parameters |
Relevant impact domains |
|
Physical indicators |
||
|
Soils |
- Soil fertility (organic matter, macro nutrients such as
nitrogen, phosphorus, etc., sodium, CEC, pH, micro-nutrients |
- concentrates/feed, crop - livestock interactions,
waste/manure |
|
Water quality |
- N and P in water (drainage effluents, water bodies and drinking water) - Pesticide/herbicide residues in water (drainage effluents, water bodies and drinking water) - Water purity, biological activity (from manure runoff and
discharge) |
- waste/manure, waste processing - range utilization, concentrates/feed - waste/manure, waste processing |
|
Pesticide use and other toxic compounds |
- Pesticide use and residues in the environment (insects, fish, birds, mammals, feed chains) and food - Heavy metals in feed/food chains |
- concentrates/feed, range utilization - concentrates/feed, waste/manure |
|
Atmosphere quality |
- Methane emissions (measurement in atmosphere and tentative balance between natural and animal production of methane (rumen fermentation, manure)) - Discharged pollutants from animal processing
industries |
- methane, waste/manure - waste processing |
|
Biological indicators |
||
|
Habitat and biodiversity |
- Agricultural habitats (hedgerows, woodland, drainage) and
environmental biodiversity change (wildlife and plant species abundance and
occurrence, sensitivity indicators or rare species, agriculturally used plant
and/or animal species |
- Animal genetic resources, wildlife/biodiversity,
waste/manure |
|
Agricultural indicators |
||
|
Domestic animals |
- Animal density (numbers/unit area by species) - Manure availability (use for fuel or fertilizer, manure management practices) - Industrial processed animal products |
- range utilization, forest utilization, crop - livestock interactions, concentrates/feed, waste/manure - crop - livestock interactions, waste/manure, methane - waste processing |
|
Feeds and feeding |
- Types of feed resources used - Feeding practices and feed conversion efficiency - Productive uses of wastes from processing |
- range utilization, forest utilization, crop - livestock interactions, concentrates/feed, methane - range utilization, crop - livestock interactions, concentrates/feed - waste/manure, waste processing, crop - livestock
interactions |
|
Socio-economic indicators |
||
|
Land use |
- Land use changes (cultivated areas, grasslands, forests,
wetlands, cropping on marginal areas, etc.) |
- concentrates/feed, range utilization, forest utilization,
crop - livestock interactions |
|
Micro-economic indicators |
- Income of farmers from agricultural/livestock production - Role of livestock in the wealth accumulation/food safety/risk management processes - Productivity levels of animal production (offtake rates,
herd growth, feed conversion efficiency, energy conversion rates) |
- concentrates/feed, range utilization, crop - livestock interactions - concentrates/feed, range utilization, crop - livestock interactions - concentrates/feed, crop - livestock interactions,
methane |
|
Macro-economic indicators |
- Demand for feed commodities - Competition between food and feed crops - Demand for livestock products and services (draught, manure) - Livestock subsector productivity at country or regional level - Prices of inputs, products and services (animal
product/grain price ratio, costs of transport, etc.) |
- concentrates/feed, range utilization, forest utilization, crop-livestock interactions - concentrates/feed, crop - livestock interactions - concentrates/feed, crop - livestock interactions - concentrates/feed, range utilization, forest utilization - concentrates/feed, range utilization, crop - livestock
interactions, waste/manure, waste processing |
|
Policy indicators |
- Subsidies or taxes for meat, milk and feeds, and for inputs (fuel/equipment, producer (or consumer) subsidy equivalent for meat or crop production, exchange rates) - Government interventions and regulatory measures - Animal health campaigns |
- concentrates/feed, range utilization, forest utilization, crop - livestock interactions - concentrates/feed, range utilization, forest utilization, waste processing, waste/manure - range utilization, forest utilization,
concentrates/feed |
PIGS
For pigs, a further distinction is made between growing pigs and sows and their piglets, and also which part of the excreted N and P ends up in urine, and which part in faeces. This distinction is made, because the utilization of nutrients in urine may be very different from that in faeces (see section 3.2.4).
Growing pigs (25-110 kg)
Netherlands
The following data were adapted from Annex 1 of Brandjes et al. (1995):
feed conversion ratio: 2.86
annual feed intake 748 kg of which 132 kg starter feed and 616 kg fattening feed
average nutrient content starter feed: 28.5 g N*kg-1 and 5.8 g P*kg-1
average nutrient content fattening feed: 27.0 g N*kg-1 and 5.0 g P*kg-1.
Average nutrient content of feed for growing pigs can be calculated as follows:
average N content = ((132*28.5) + (616*27))/748 = 27.3 g*kg-1
average P content = ((132*5.8) + (616*5.0))/748 = 5.1 g*kg-1.
Total N and P intake then equals:
total N intake = 27.3*2.86 = 78.1 g*kg-1 LWG
total P intake = 5.1*2.86 = 14.6 g*kg-1 LWG.
Nitrogen digestibility is calculated from the following data from Tables IV and V given in Brandjes et al. (1995):
total N intake of a high-productive growing pig = 20 kg*pig-1*yr-1
total N excretion of a high-productive growing pig = 14 kg*pig-1*yr-1
N excretion in faeces of a high-productive growing pig = 22% of total excretion = (0.22*14) = 3.08 kg*pig-1*yr-1.
N digestibility can then be calculated as follows:
N digestibility = (20-3.08)/20 = 84.6%
P digestibility is calculated on the basis of an average feed ration for growing pigs in the Netherlands, as given by Brand & Melman (1993) and on the basis of data given in Anonymous (1994c): P digestibility = 39.1%
Total digestible N and P intake and N and P-excretion in faeces can now be calculated:
total digestible N intake = 0.846*78.1 = 66.1 g*kg-1 LWG
total digestible P intake = 0.391*14.6 = 5.7 g*kg-1 LWG
N excretion in faeces = (1-0.846)*78.1 = 12.0 g*kg-1 LWG
P excretion in faeces = (1-0.391)*14.6 = 8.9 g*kg-1 LWG.
Data on retention were adapted from Brandjes et al. (1995): 22.5 and 5.0 g*kg-1 LWG for N and P respectively.
Nitrogen and P excretion in urine then equals:
N excretion in urine = 66.1 - 22.5 = 43.6 g*kg-1 LWG
P excretion in urine = 5.7 - 5.0 = 0.7 g*kg-1 LWG.
Total N and P excretion by porkers:
total N excretion = 78.1 - 22.5 = 55.6 g*kg-1 LWG
total P excretion = 14.6 - 5.0 = 9.6 g*kg-1 LWG.
Canada
An average feed conversion ratio of 3.60 is adopted from Anonymous (undated): 3.73 and Simpson et al. (1994): 3.5-3.7 for US. Von Hahn (pers. comm., 1995) provided feed rations in use in Canada. Important components are wheat, barley, wheat bran and soymeal. Nitrogen and P contents could directly be adopted from the provided feed rations. However, N and P-digestibilities had to be calculated, based on data from Anonymous (1994c). Assumptions and calculations resulted in the following data:
feed conversion ratio: 3.60
average nutrient content: 30.0 g N*kg-1 and 6.5 g P*kg-1.
Total N and P intake then equals:
total N intake = 30.0*3.60 = 108.0 g*kg-1 LWG
total P intake = 6.5*3.60 = 23.4 g*kg-1 LWG.N digestibility = 84.0%
P digestibility = 47.0%
Total digestible N and P intake and N and P excretion in faeces can now be calculated:
total digestible N intake = 0.84*108.0 = 90.7 g*kg-1 LWG
total digestible P intake = 0.47*23.4 = 11.0 g*kg-1 LWG
N excretion in faeces = (1-0.840)*108.0 = 17.3 g*kg-1 LWG
P excretion in faeces = (1-0.47)*23.4 = 12.4 g*kg-1 LWG.
Data on retention were adapted from Brandjes et al. (1995): 22.5 and 5.0 g*kg-1 LWG for N and P respectively.
N and P excretion in urine then equals:
N excretion in urine = 90.7 - 22.5 = 68.2 g*kg-1 LWG
P excretion in urine = 11.0 - 5.0 = 6.0 g*kg-1 LWG.
Total N and P excretion by porkers:
total N excretion = 108.0 - 22.5 = 85.5 g*kg-1 LWG
total P excretion = 23.4 - 5.0 = 18.4 g*kg-1 LWG.
Tropics
An average feed composition for growing pigs was derived from Eusebio, (1984). Important components are ground maize, soybean oil meal, rice bran and sorghum. From data given in Anonymous (1994c), average N and P contents and digestibilities were calculated. Feed conversion ratio of 4.0 was derived from different sources: Daying (1994): 3.47, World Bank (1987; 4.6), Simpson (1988): 3.43-4.05 and Eusebio (1984): 4.1. Calculations and assumptions resulted in the following data:
feed conversion ratio: 4.0;
average nutrient content feed: 23.4 g N*kg-1 and 6.7 g P*kg-1
average nutrient digestibilities: 77% for N and 19% for P.
Total N and P intake then equals:
total N intake = 23.4*4.0 = 93.6 g*kg-1 LWG
total P intake = 6.7*4.0 = 26.8 g*kg-1 LWG.
Total digestible N and P intake and excretion in faeces can be calculated as follows:
total digestible N intake = 93.6*0.77 = 72.1 g*kg-1 LWG
total digestible P intake = 26.8*0.19 = 5.1 g*kg-1 LWGN excretion in faeces = 93.6 - 72.1 = 21.5 g*kg-1 LWG
P excretion in faeces = 26.8 - 5.1 = 21.7 g*kg-1 LWG.
Data on retention were adapted from Brandjes et al. (1995): 22.5 and 5.0 g*kg-1 LWG for N and P respectively.
N and P excretion in urine:
N excretion in urine = 72.1 - 22.5 = 49.6 g*kg-1 LWG
P excretion in urine = 5.1 - 5.0 = 0.1 g*kg-1 LWG.
Total N and P excretion by porkers:
total N excretion = 21.5 + 49.6 = 71.1 g*kg-1 LWG
total P excretion = 21.7 + 0.1 = 21.8 g*kg-1 LWG.
Results from all performed calculations for growing pigs are summarized in Table A1.
Table A1: Nutrient excretion for growing pigsA1 Nutrient excretion for growing pigs
|
country |
FCR |
feed content (g*kg-1) |
total intake (g*kg-1 LWG) |
digestible intake (g*kg-1 LWG) |
in faeces (g*kg-1 LWG) |
retention (g*kg-1 LWG) |
in urine (g*kg-1 LWG) |
total excretion (g*kg-1 LWG) |
|||||||
|
N |
P |
N |
P |
N |
P |
N |
P |
N |
P |
N |
P |
N |
P |
||
|
Neth. |
2.86 |
27.3 |
5.1 |
78.1 |
14.6 |
66.1 |
5.7 |
12.0 |
8.9 |
22.5 |
5.0 |
43.6 |
0.7 |
55.6 |
9.6 |
|
Can. |
3.60 |
30.0 |
6.5 |
108.0 |
23.4 |
90.7 |
11.0 |
17.3 |
12.4 |
22.5 |
5.0 |
68.2 |
6.0 |
85.5 |
18.4 |
|
tropics |
4.0 |
23.4 |
6.7 |
93.6 |
26.8 |
72.1 |
5.1 |
21.5 |
21.7 |
22.5 |
5.0 |
49.6 |
0.1 |
71.1 |
21.8 |
- world average feed conversion = (0.52 * (0.5*(2.86+3.60)) + (0.48 * 4.0) = 3.60- world average N excretion in faeces = (0.52 * (0.5*(12.0+17.3)) + (0.48 * 21.5) = 17.9 g*kg-1 LWG
- world average P excretion in faeces = (0.52 * (0.5*(8.9+12.4)) + (0.48 * 21.7) = 16.0 g*kg-1 LWG
- world average N excretion in urine = (0.52 * (0.5(43.6+68.2)) + (0.48 * 49.6) = 52.9 g*kg-1 LWG
- world average P excretion in urine = (0.52 * (0.5*(0.7+6.0)) + (0.48 * 0.1) = 1.8 g*kg-1 LWG
- world average total N excretion = (0.52 * (0.5*(55.6+85.5)) + (0.48 * 71.1) = 70.8 g*kg-1 LWG
- world average total P-excretion = (0.52 * (0.5*(9.6+18.4)) + (0.48 * 21.8) = 17.7 g*kg-1 LWG.
Sere & Steinfeld (1995) provided data on world pork production in LLM-systems. Assuming a dressing percentage of 70, total Live weight gain, and thus total N and P excretion can be calculated. Results are given in Table 3.3.
Sows and piglets
Netherlands
The following data were adapted from Annex 1 in Brandjes et al. (1995):
annual feed intake: 1712 kg feed of which 615 kg piglet feed and 1097 kg sow feed
average nutrient content piglet feed: 29.0 g N*kg-1 and 6.3 g P*kg-1
average nutrient content sow feed: 25.4 g N*kg-1 and 6.5 g P*kg-1.
Average nutrient content and total N and P intake can be calculated as follows:
average N content = (615*29.0) + (1097*25.4) = 26.7 g*kg-1
average P content = (615*6.3) + (1097*6.5) = 6.4 g*kg-1.total N intake of a sow including piglets = (615*29.0) + (1097*25.4) = 45.7 kg*sow-1*yr-1
total P intake of a sow including piglets = (615*6.3) + (1097*6.5) = 11.0 kg*sow-1*yr-1.
Nitrogen digestibility is calculated with data from Tables IV and V given in Brandjes et al. (1995):
total N excretion of a high-productive sow including piglets = 32 kg*sow-1*yr-1
N excretion in faeces of a high-productive sow including piglets = 27% of total excretion = (0.27*32) = 8.64 kg*sow-1*yr-1.
N digestibility can then be calculated as follows: N digestibility = (45.7-8.64)/45.7 = 81.1%.
Phosphorus digestibility is calculated on the basis of an average feed ration for sows, as given by Brand & Melman (1993) and on the basis of data given in Anonymous (1994c):
P digestibility = 38.9%
Total digestible N and P intake and excretion in faeces can now be calculated:
total digestible N intake = 0.811*45.7 = 37.1 kg*sow-1*yr-1
total digestible P intake = 0.389*11.0 = 4.3 kg*sow-1*yr-1N excretion in faeces = (1-0.811)*45.7 = 8.6 kg*sow-1*yr-1
P excretion in faeces = (1-0.389)*11.0 = 6.7 kg*sow-1*yr-1.
Data on retention were adopted from Brandjes et al. (1995): 14.0 and 3.0 kg*sow-1*yr-1 for N and P respectively.
Nitrogen and P excretion in urine then equals:
N excretion in urine = 37.1 - 14.0 = 23.1 kg*sow-1*yr-1
P excretion in urine = 4.3 - 3.0 = 1.3 kg*sow-1*yr-1.
Total N and P excretion by sows including piglets:
total N excretion = 8.6 + 23.1 = 31.7 kg*sow-1*yr-1
total P excretion = 6.7 + 1.3 = 8.0 kg*sow-1*yr-1.
Canada
No data on feed consumption and feed rations for sows and their piglets have been found for Canada. The results from the calculations for the Netherlands have also been assumed to be valid for Canada.
Tropics
An average feed composition for piglets and sows was derived from Eusebio (1984). Important components of piglet feed are ground maize, rolled oats and dried skim milk. Important components of sow feed are ground maize, rice bran, rice middlings and lucerne meal. From data given in Anonymous (1994c), average N and P contents and digestibilities were calculated. Further assumptions made for the tropics are:
- one sow consumes 3 kg of feed daily, resulting in an annual food consumption of 1097 kg- assuming that 19 weaned piglets sow-1*yr-1 account for a piglet feed consumption of 615 kg in the Netherlands, then 14.5 weaned piglets sow-1*yr-1 in the tropics will account for (615/19) * 14.5 = 469 kg
- assuming that retention for a sow with 19 weaned piglets sow-1*yr-1 amounts to 14.0 and 3.0 kg*sow-1*yr-1 for N and P respectively (Brandjes et al., 1995), then the retention for a sow with 14.5 weaned piglets sow-1*yr-1 will be (14.0/19) * 14.5 = 10.7 kg N sow-1*yr-1 and (3.0/19) * 14.5 = 2.3 kg P sow-1*yr-1.
Calculations and assumptions resulted in the following data:
annual feed intake: 1566 kg feed of which 469 kg piglet feed and 1097 kg sow feed
average nutrient content piglet feed: 34.9 g N*kg-1 and 6.2 g P*kg-1
average nutrient content sow feed: 22.1 g N*kg-1 and 9.1 g P*kg-1.
Average nutrient content and total N and P intake can now be calculated:
average N content = ((469*34.9) + (1097*22.1))/(469+1097) = 25.9 g*kg-1
average P content = ((469*6.2) + (1097*9.1))/(469+1097) = 8.2 g*kg-1total N intake of a high-productive sow including piglets = (469*34.9) + (1097*22.1) = 40.6 kg*sow-1*yr-1
total P intake of a high-productive sow including piglets = (469*6.2) + (1097*9.1) = 12.9 kg*sow-1*yr-1.
For both feeds, N and P digestibilities are:
N digestibility sow feed = 74%
N digestibility piglet feed = 88.4%
P digestibility sow feed = 41%
P digestibility piglet feed = 58.4%average N digestibility = ((469*88.4) + (1097*74))/(469+1097) = 78.3%
average P digestibility = ((469*58.4) + (1097*41))/(469+1097) = 46.2%.
Total digestible N and P intake and excretion in faeces then equals:
total digestible N intake = 0.783*40.6 = 31.8 kg*sow-1*yr-1
total digestible P intake = 0.462*12.9 = 6.0 kg*sow-1*yr-1N excretion in faeces = (1-0.783)*40.6 = 8.8 kg*sow-1*yr-1
P excretion in faeces = (1-0.462)*12.9 = 6.9 kg*sow-1*yr.
Assuming a retention of 10.7 kg N sow-1*yr-1 and 2.3 kg P sow-1*yr-1 (see above), N and P excretion in urine can be calculated:
N excretion in urine = 31.8 - 10.7 = 21.1 kg*sow-1*yr-1
P excretion in urine = 6.0 - 2.3 = 3.7 kg*sow-1*yr-1.
Total N and P excretion by sows including piglets:
total N excretion = 8.8 + 21.1 = 29.9 kg*sow-1*yr-1
total P excretion = 6.9 + 3.7 = 10.6 kg*sow-1*yr-1.
Results from all performed calculations for sows (including piglets) are summarized in Table A2.
Table A2: Nutrient excretion for sows Nutrient excretion for sows
|
country |
feed content (g*kg-1) |
total intake (kg*sow-1 *yr-1) |
digestible intake (kg*sow-1 *yr-1) |
in faeces (kg*sow-1 *yr-1) |
retention (kg*sow-1 *yr-1) |
in urine (kg*sow-1 *yr-1) |
total excretion (kg*sow-1 *yr-1) |
|||||||
|
N |
P |
N |
P |
N |
P |
N |
P |
N |
P |
N |
P |
N |
P |
|
|
Neth.+Can. |
26.7 |
6.4 |
45.7 |
11.0 |
37.1 |
4.3 |
8.6 |
6.7 |
14 |
3.0 |
23.1 |
1.3 |
31.7 |
8.0 |
|
tropics |
25.9 |
8.2 |
40.6 |
12.9 |
31.8 |
6.0 |
8.8 |
6.9 |
10.7 |
2.3 |
21.1 |
3.7 |
29.9 |
10.6 |
- world average N excretion in faeces = (0.52 * 8.6) + (0.48 * 8.8) = 8.7 kg*sow-1*yr-1
- world average P excretion in faeces = (0.52 * 6.7) + (0.48 * 6.9) = 6.8 kg*sow-1*yr-1
- world average N excretion in urine = (0.52 * 23.1) + (0.48 * 21.1) = 22.1 kg*sow-1*yr-1
- world average P excretion in urine = (0.52 * 1.3) + (0.48 * 3.7) = 2.5 kg*sow-1*yr-1
- world average total N excretion = (0.52 * 31.7) + (0.48 * 29.9) = 30.8 kg*sow-1*yr-1
- world average total P excretion = (0.52 * 8.0) + (0.48 * 10.6) = 9.2 kg*sow-1*yr-1.
In order to calculate total excretion by sows in LLM systems, the number of sows has to be determined. The procedure adopted to do so is as follows. Anonymous (1995a) provided data on carcass weights for the major pork producing countries in the world. Sere & Steinfeld (1995) provided data on pork production in LLM systems. Combining the data on carcass weights and pork production, results in the number of porkers annually produced in LLM systems. The number of sows can then be calculated by using data on the number of weaned piglets per sow per year. For OECD countries it is assumed that one sow produces 17.4 weaned piglets per year (Brandjes et al., 1995; 19 for the Netherlands and Simpson et al., 1994; 17.8 for Japan and 15.3 for the US). For other countries, the number is assumed to be 14.2 (Simpson et al., 1994; 11.6 for China, Payne, 1990; 14.5, Taiganides, 1992; 16.6 for Singapore).
BROILERS
In the calculations for feed requirements for broiler production the feed requirements for broiler parent stock has been ignored. In India this accounted for only 3.5% of total feed demand for poultry (Anonymous, 1990).
Netherlands
The following data were adapted from Annex 1 in Brandjes et al. (1995):
feed conversion ratio: 1.91
average nutrient content feed: 35.7 g N*kg-1 and 5.7 g P*kg-1.
Total N and P intake then equals:
total N intake = 35.7*1.91 = 68.2 g*kg-1 LWG
total P intake = 5.7*1.91 = 10.9 g*kg-1 LWG.
Data on retention were adapted from Brandjes et al. (1995): 28.0 and 4.0 g*kg-1 LWG for N and P respectively.
Total N and P excretion by broilers:
total N excretion = 68.2 - 28.0 = 40.2 g*kg-1 LWG
total P excretion = 10.9 - 4.0 = 6.9 g*kg-1 LWG.
Canada
An average feed conversion ratio of 1.85 is adapted from Von Hahn (pers. comm., 1995). Von Hahn also provided feed rations in use in Canada. Important components are corn, soymeal and wheat. Nitrogen and P content could directly be adapted from the provided feed rations. Calculations resulted in the following data:
feed conversion ratio: 1.85
average nutrient content feed: 33.5 g N*kg-1 and 7.5 g P*kg-1.
Total N and P intake:
total N intake = 33.5*1.85 = 62.0 g*kg-1 LWG
total P intake = 7.5*1.85 = 13.9 g*kg-1 LWG.
Data on retention were adapted from Brandjes et al. (1995): 28.0 and 4.0 g*kg-1 LWG for N and P respectively.
Total N and P excretion by broilers:
total N excretion = 62.0 - 28.0 = 34.0 g*kg-1 LWG
total P excretion = 13.9 - 4.0 = 9.9 g*kg-1 LWG.
Tropics
An average feed conversion of 2.18 was derived from Anonymous (1990): 2.25, Zanders (1994): 2.4 and Jianlin & Yunlong (1994): 1.9. Average feed composition was derived from Anonymous (1990). Important feed components are yellow maize, rice polish and groundnut cake. Average N and P contents were calculated from data given in Anonymous (1994c). Calculations and assumptions resulted in the following data:
feed conversion ratio: 2.18
average nutrient content feed: 33.6 g N*kg-1 and 8.86 g P*kg-1.
Total N and P intake:
total N intake = 33.6*2.18 = 73.2 g*kg-1 LWG
total P intake = 8.86*2.18 = 19.3 g*kg-1 LWG.
Data on retention were adapted from Brandjes et al. (1995): 28.0 and 4.0 g*kg-1 LWG for N and P respectively.
Total N and P excretion:
N excretion = 73.2 - 28.0 = 45.2 g*kg-1 LWG
P excretion = 19.3 - 4.0 = 15.3 g*kg-1 LWG.
Results from all the calculations for broilers are summarized in Table A3.
Table A3: Nutrient excretion for broilersA3 Nutrient excretion for broilers
|
country |
feed conversion |
feed content (g*kg-1) |
intake (g*kg-1 LWG) |
retention (g*kg-1 LWG) |
excretion (g*kg-1 LWG) |
||||
|
N |
P |
N |
P |
N |
P |
N |
P |
||
|
Neth. |
1.91 |
35.7 |
5.7 |
68.2 |
10.9 |
28 |
4 |
40.2 |
6.9 |
|
Can. |
1.85 |
33.5 |
7.5 |
62.0 |
13.9 |
28 |
4 |
34.0 |
9.9 |
|
tropics |
2.18 |
33.6 |
8.86 |
73.2 |
19.3 |
28 |
4 |
45.2 |
15.3 |
- world average feed conversion = (0.58 * (0.5*(1.91+1.85)) + (0.42 * 2.18) = 2.01
- world average N excretion = (0.58 * (0.5*(40.2+34.0)) + (0.42 * 45.2) = 40.5 g*kg-1 LWG
- world average P excretion = (0.58 * (0.5*(6.9+9.9)) + (0.42 * 15.3) = 11.3 g*kg-1 LWG.
Sere & Steinfeld (1995) provided data on world poultry meat production in LLM systems. Assuming a dressing percentage of 75, total Live weight gain, and thus total N and P excretion can be calculated. Results are given in Table 3.3.
LAYING HENS
For laying hens, a further distinction has been made between productive laying hens and growing laying hens.
Productive laying hens
Netherlands
The following data were adapted from Annex 1 in Brandjes et al. (1995):
feed conversion ratio: 2.38
average nutrient content feed: 29.1 g N*kg-1 and 6.2 g P*kg-1.
Total N and P intake:
total N intake = 2.38*29.1 = 69.3 g*kg-1 eggs
total P intake = 2.38*6.2 = 14.8 g*kg-1 eggs.
Data on retention were adapted from Brandjes et al. (1995): 19.2 and 2.1 g*kg-1 eggs for N and P respectively.
Total N and P excretion by laying hens:
total N excretion = 69.3 - 19.2 = 50.1 g*kg-1 egg
total P excretion = 14.8 - 2.1 = 12.7 g*kg-1 eggs.
Canada
An average feed conversion ratio of 2.6 is adapted from Von Hahn (pers. comm., 1995). Von Hahn also provided feed rations in use in Canada. Important components are wheat, corn and soymeal. N and P content could directly be adapted from the provided feed rations. Calculations resulted in the following data:
feed conversion ratio: 2.6
average nutrient content feed: 28.8 g N*kg-1 and 6.6 g P*kg-1.
Total N and P intake:
total N intake = 2.6*28.8 = 74.9 g*kg-1 eggs
total P intake = 2.6*6.6 = 17.1 g*kg-1 eggs.
Data on retention were adapted from Brandjes et al. (1995): 19.2 and 2.1 g*kg-1 eggs for N and P respectively.
Total N and P excretion by laying hens:
total N excretion = 74.9 - 19.2 = 55.7 g*kg-1 eggs
total P excretion = 17.1 - 2.1 = 15.0 g*kg-1 eggs.
Tropics
Average feed composition was derived from Anonymous (1990). Important components are yellow maize, rice polish, fish meal and groundnut extraction. Average feed conversion of 2.7 was derived from Zanders (1994): 2.7 and Jianlin & Yunlong (1994): 2.8-3.0 to 1. Using data given in Anonymous (1994c), average N and P contents were calculated. Calculations and assumptions resulted in the following data:
feed conversion ratio: 2.7
average nutrient content feed: 29.1 g N*kg-1 and 8.7 g P*kg-1.
Total N and P intake:
total N intake = 2.7*29.1 = 78.6 g*kg-1 eggs
total P intake = 2.7*8.7 = 23.5 g*kg-1 eggs.
Data on retention were adapted from Brandjes et al. (1995): 19.2 and 2.1 g*kg-1 eggs for N and P respectively.
Total N and P excretion by laying hens:
total N excretion = 78.6 - 19.2 = 59.4 g*kg-1 eggs
total P excretion = 23.5 - 2.1 = 21.4 g*kg-1 eggs.
Results from all performed calculations for laying hens are summarized in Table A4.
Table A4: Nutrient excretion for laying hens Nutrient excretion for laying hens
|
country |
feed conversion |
feed content (g*kg-1) |
intake (g*kg-1 eggs) |
retention (g*kg-1 eggs) |
excretion (g*kg-1 eggs) |
||||
|
N |
P |
N |
P |
N |
P |
N |
P |
||
|
Neth. |
2.38 |
29.1 |
6.2 |
69.3 |
14.8 |
19.2 |
2.1 |
50.1 |
12.7 |
|
Can. |
2.6 |
28.8 |
6.6 |
74.9 |
17.1 |
19.2 |
2.1 |
55.7 |
15.0 |
|
tropics |
2.7 |
29.1 |
8.7 |
78.6 |
23.5 |
19.2 |
2.1 |
59.4 |
21.4 |
- world average feed conversion = (0.42 * (0.5*(2.38+2.6)) + (0.58 * 2.7) = 2.61
- world average N excretion = (0.42 * (0.5*(50.1+55.7)) + (0.58 * 59.4) = 56.7 g*kg-1 eggs
- world average P excretion = (0.42 * (0.5*(12.7+15)) + (0.58 * 21.4) = 18.2 g*kg-1 eggs.
Sere & Steinfeld (1995) provided data on world poultry egg production in LLM systems. Thus, total N and P excretion by productive laying hens can be calculated. Results are given in Table 3.3.
Growing laying hens
Netherlands
The following data were derived from van WUMM (1994):
length of production cycle: 140 days of which 21 non-productive
weight gain during production cycle: 1316 gram
feed intake: 6.2 kg
average nutrient content feed: 33.3 g N*kg-1 and 6.5 g P*kg-1total N intake = 6.2*33.3 = 206.5 g per growing laying hen
total P intake = 6.2*6.5 = 34.5 g per growing laying hen.
Retention per kg LWG equals 28 g N*kg-1 LWG and 6.3 g P*kg-1 LWG (WUMM, 1994). Retention per growing laying hen can be calculated:
N retention = 1316*28 = 36.8 g N per growing laying hen
P retention = 1316*6.3 = 8.3 g P per growing laying hentotal N excretion = 206.5 - 36.8 = 169.7 g per growing laying hen
total P excretion = 34.5 - 8.3 = 26.2 g per growing laying hen.
Canada
Von Hahn (pers. comm., 1995) provided feed rations in use in Canada. Important components are wheat and soymeal. N and P content could directly be adapted from the provided feed rations. Feed intake, weight gain per growing laying hen and length of production cycle are assumed to be equal to values valid for the Netherlands.
Calculations and assumptions resulted in the following data:
average nutrient content feed: 28.8 g N*kg-1 and 6.9 g P*kg-1
total N intake = 6.2*28.8 = 178.6 g per growing laying hen
total P intake = 6.2*6.9 = 42.8 g per growing laying hen.
As for the Netherlands, retention per growing laying hen equals 36.8 g N and 8.3 g P per Kg LWG.
Total N and P excretion by growing laying hens:
total N excretion = 178.6 - 36.8 = 141.8 g per growing laying hen
total P excretion = 42.8 - 8.3 = 34.5 g per growing laying hen.
Tropics
Feed intake, weight gain per growing laying hen and length of production cycle were derived from Anonymous (1987). Average feed composition was derived from Anonymous (1990). Important components are yellow maize, rice polish and groundnut extraction. With data given in Anonymous (1994c), average N and P contents were calculated:
feed intake: 7.7 kg
weight gain during production cycle: 1630 gram
average nutrient content feed: 33.0 g N*kg-1 and 8.35 g P*kg-1;
total N intake = 7.7*33.0 = 254.1 g per growing laying hen
total P intake = 7.7*8.4 = 64.7 g per growing laying hen.
Retention per kg LWG equals 28 g N*kg-1 LWG and 6.3 g P*kg-1 LWG (WUMM, 1994). Retention per growing laying hen can then be calculated as follows:
N retention = 1630*28 = 45.6 g N per growing laying hen
P retention = 1630*6.3 = 10.3 g P per growing laying hentotal N excretion = 254.1 - 45.6 = 208.5 g per growing laying hen
total P excretion = 64.3 - 10.3 = 54.4 g per growing laying hen.
Results from all performed calculations for growing laying hens are summarized in Table A5.
Table A5: Nutrient excretion for growing laying hens; Nutrient excretion for growing laying hens
|
country |
feed intake (kg) |
feed content (g*kg-1) |
intake (g per growing laying hen) |
retention (g per growing laying hen) |
excretion (g per growing laying hen) |
||||
|
N |
P |
N |
P |
N |
P |
N |
P |
||
|
Neth. |
6.2 |
33.3 |
6.5 |
206.5 |
34.5 |
36.8 |
8.3 |
169.7 |
26.2 |
|
Can. |
6.2 |
28.8 |
6.9 |
178.6 |
42.8 |
36.8 |
8.3 |
141.8 |
34.5 |
|
tropics |
7.7 |
33.0 |
8.4 |
254.1 |
64.7 |
45.6 |
10.3 |
208.5 |
54.4 |
- world average N excretion = (0.42 * (0.5*(169.7+141.8)) + (0.58 * 208.5) = 186.3 g per growing laying hen- world average P excretion = (0.42 * (0.5*(26.2+34.5)) + (0.58 * 54.4) = 44.3 g per growing laying hen.
In order to calculate total excretion by growing layers in LLM systems, the number of growing layers has to be determined. The procedure adopted to do so, is as follows. An average world egg production per laying hen is calculated as follows:
- egg production in the Netherlands = 17.7 kg*laying hen-1*yr-1 (Brandjes et al., 1995)- egg production in Canada = 15.0 kg*laying hen-1*yr-1 (pers. comm. von Hahn)
- egg production in tropical regions = 14.0 kg*laying hen-1*yr-1 (Jianlin & Yunlong, 1994; Zanders, 1994 and Simpson et al., 1994)
- world average egg production = (0.42 * (0.5*(17.7+15.0)) + (0.58 * 14.0) = 15.0 kg*laying hen-1*yr-1.
Sere & Steinfeld (1995) provided data on egg production in LLM systems. Combining the data on egg production per laying hen and total egg production, results in the number of laying hens annually housed in LLM systems. The number of growing laying hens can then be calculated by using data on the production cycle of both growing laying hens and productive laying hens. Assuming the length of the production cycle of a grower laying hen amounts to 140 days, and the length of the production cycle of a productive laying hen is 419 days, the number of growing laying hens present per productive layer equals 140/419 = 0.334.
Country Comparisons
To determine the consequences of environmental policies in different regions for the competitiveness of pig production, the important considerations are current structure of the pig farming sector (concerning e.g. animal densities, and related to this, the amount of land available for manure spreading, financial position of the farms, integration with overall agriculture, etc.) and current and future environmental policies.
Environmental policies in the regions considered here (Denmark, Niedersachsen, Bretagne, Flanders and the Netherlands) include standards on the application of minerals from organic manure, rules on the application of manure and the period of the year when spreading of manure is not allowed. Standards for applying manure are rather strict in Denmark and to a smaller extent also in the Netherlands and Niedersachsen. Current standards are relatively mild in Flanders, while Bretagne is in between. The mildness of the standards in Flanders is related to the low phosphate excretion level of pigs, as assumed in the Flanders manure law. It is considered to be some 25% lower than in the Netherlands. This implies that in the Netherlands manure from less pigs is allowed to be applied per ha. Policy responses to reduce ammonia emission have only been implemented in the Netherlands and Flanders.
Manure surpluses at farm level (the amount of manure that cannot be applied at the farm) exist in all regions. However, differences among the regions to get rid of these surpluses are great, and structural characteristics of the agricultural sector are critical. Currently manure surpluses can be applied within relatively short distances in Denmark, Bretagne and Niedersachsen, which is related to lower animal densities. In Flanders and the Netherlands, manure often has to be transported over larger distances. The need for environmental investments is highest in the Netherlands and Flanders, mainly aimed at reducing ammonia emission. The need for investments is smallest in Denmark; investments are mainly required to enlarge the manure storage capacity of the farm up to a total of nine months. Bretagne and Niedersachsen are somewhere in between.
The financial situation of pig farms (with respect to trends in family farm income and cash flow) is important to assess the ability to meet any substantial cost increase. The financial position of pig farms in Niedersachsen is on average insufficient to meet any substantial cost increase. The financial position of pig farms in Bretagne is strongest, but also in Denmark and Flanders farms are doing well. In the Netherlands it is identified as being slightly worse.
Competitive relations among the regions are likely to change with adjustments in environmental policy, given the present structure of pig farming and the financial situation. Related to the considerations discussed above, the perspectives of pig farming are identified as being good in Denmark and Bretagne. Flanders and the Netherlands take a middle position. Perspectives are not good in Niedersachsen. Within a given region, perspectives differ among several pig farming types. For instance in Flanders, the perspectives of farms that combine pig breeding with pig fattening are better than the more specialized or the opposite types i.e. the mixed pig farming (Source: Brouwer & Godeschalk, 1993).
Strictness of standards of manure application: effects on monogastric livestock sectors in the Netherlands
Recently, a study has been conducted into the socio-economic consequences of possible standards for (inorganic and organic) manure application on soils, to be implemented in the future. These standards are given in table A6.
Manure application standards are stricter with increasing variant number. Variant 4 approaches P equilibrium fertilization. The autonomous variant takes into account socio-economic consequences resulting from GATT regulations, European agricultural policy and technical and economical developments; current manure standards are assumed not to be changed.
Compared with income levels in 1992/1993, income levels for specialized pig breeding farms in the autonomous variant will decrease by 40% in the year 2000. For farms that combine pig breeding and fattening this percentage amounts to 20% and for farms with laying hens to only 1%. After the year 2000 part (ca. 20%) of the pig and poultry farms will stop their activities; the forthcoming production capacity may be taken over by the existing farms, that thus can enlarge their production and partly compensate their loss of farm income. At national level this would mean that the total decrease of production in pig and poultry husbandry in the autonomous variant is expected to be moderate.
Table A6: Combinations of maximum N and P emission levels1 for grassland and arable land; Combinations of maximum N and P emission levels1 for grassland and arable land (kg*ha-1*yr-1)
|
variant |
grassland |
arableland |
||
|
N |
P |
N |
P |
|
|
autonomous |
- |
65.5 |
- |
48.0 |
|
1 |
350 |
17.5 |
175 |
17.5 |
|
2 |
250 |
13.1 |
125 |
13.1 |
|
3 |
150 |
8.7 |
75 |
8.7 |
|
4 |
100 |
4.4 |
25 |
4.4 |
1 Emission level is defined as the difference between the supply of N and P (excluding mineralization, deposition, and N binding by leguminoses) and crop uptake.
In table A7 consequences of the other emission level variants on income levels and number of farms are given for farms that combine pig breeding and fattening and for farms with laying hens. Also effects on the total size of the Dutch pig and poultry stock and employment opportunities in the agro-industry are given. Stricter manure standards result in decreasing opportunities to apply manure on grasslands and arable lands, consequently, costs of manure removal from the farm will increase. This is the main cause of decreasing income levels in the pig sector. Extra expense will also have to be incurred for investments in manure storage and application systems and feeding systems. From table A7 it is obvious that consequences for farms with laying hens are much less severe. Reason is that it is assumed that dried manure from laying hens will mainly be exported to surrounding countries (70% of total manure from laying hens for variant 1 up to 90% for variant 4). However, a large part of the farms with laying hens will still have to invest in manure drying installations
The influence of stricter manure application standards on the size of the Dutch pig and poultry stock is modest. For variant 4, extra reductions in animal numbers amount to 7.6 and 8.0% for respectively porkers and sows. There is no influence on the number of laying hens. Impact on employment in primary agricultural sectors and agro-industry is modest as well. For variant 4 employment decreases by 9%, compared to the autonomous variant. In general, two thirds of the employment losses occur at the primary production level and one third in the agro-industry. (Source: Anonymous, 1995b.)
Table A7: Consequences of combinations of maximum N and P emission levels on income level and number of farms with pigs and laying hens, size of the pig and poultry stock and employment in the agro-industry; data are valid for the year 2000; Consequences of combinations of maximum N and P emission levels on income level and number of farms with pigs and laying hens, size of the pig and poultry stock and employment in the agro-industry; data are valid for the year 2000
|
variant |
autonomous |
1 |
2 |
3 |
4 |
|
pig breeding and fattening farms |
|
|
|
|
|
|
change of income level, relative to autonomous var. |
43,0001 |
-5,000 |
-10,000 |
-15,000 |
-30,000 |
|
idem, as percentage |
100 |
-12 |
-23 |
-35 |
-70 |
|
perc. of the number of farms that stop, relative to autonomous
var. |
242 |
+2 |
+4 |
+7 |
+17 |
|
farms with laying hens |
|
|
|
|
|
|
change of income level, relative to autonomous var. |
78,0001 |
0 |
0 |
-5,000 |
-6,000 |
|
idem, as percentage |
100 |
0 |
0 |
-6 |
-8 |
|
perc. of the number of farms that stop, relative to autonomous
var. |
142 |
0 |
0 |
+1 |
+2 |
|
change in animal numbers relative to numbers in
‘92/93 |
|
|
|
|
|
|
porkers |
-8.2 |
-9.2 |
-9.9 |
-11.7 |
-15.8 |
|
sows |
-4.3 |
-5.4 |
-6.0 |
-7.6 |
-12.4 |
|
laying hens |
-5 |
-5 |
-5 |
-5 |
-5 |
|
percentage of employment in agriculture (incl.
agro-industry), relative to 1990 |
89 |
89 |
88 |
86 |
80 |
1 absolute number in Dutch guilders2 percentage of farms in ‘92/93 that stop their activities due to autonomous variant
1 Heavy metal content of mineral fertilizers is determined by
the production process and by the purity of the mineral resources
used.
