Allocation within the farm module for sheep and goat

A biophysical approach shall be used for the allocation of upstream burdens to the different co-products for sheep and goat. The 2006 IPCC guidelines for national greenhouse gas inventories (IPCC, 2006) contain a model to calculate energy requirements that shall be used for sheep and, as a proxy, for goats. This model is applied in the present document. Dead animals and all the products coming from dead animals shall be regarded as waste and the Circular Footprint Formula (CFF, Section 4.4.8.1) shall be applied. In this case, however, the traceability of the products coming from dead animals shall be granted in order for this aspect to be taken into consideration in OEF studies.

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The use of the default allocation factors included in this document is mandatory whenever secondary datasets are used for the life cycle stage of farming for sheep and goat. If company-specific data are used for this life cycle stage, the calculation of the allocation factors with the company-specific data shall be performed using the equations provided. The allocation factors shall be calculated as follows60_:

% 𝒘𝒐𝒐𝒍 = [𝑬𝒏𝒆𝒓𝒈𝒚 𝒇𝒐𝒓 𝒘𝒐𝒐𝒍 (𝑵𝑬𝒘𝒐𝒐𝒍)] [(𝑬𝒏𝒆𝒓𝒈𝒚 𝒇𝒐𝒓 𝒘𝒐𝒐𝒍 (𝑵𝑬_{𝒘𝒐𝒐𝒍})+ 𝑬𝒏𝒆𝒓𝒈𝒚 𝒇𝒐𝒓 𝒎𝒊𝒍𝒌 (𝑵𝑬_𝒍) + 𝑬𝒏𝒆𝒓𝒈𝒚 𝒇𝒐𝒓 𝒎𝒆𝒂𝒕 (𝑵𝑬_𝒈)] [Equation 10] % 𝒎𝒊𝒍𝒌 = [𝑬𝒏𝒆𝒓𝒈𝒚 𝒇𝒐𝒓 𝒎𝒊𝒍𝒌 (𝑵𝑬𝒍)] [(𝑬𝒏𝒆𝒓𝒈𝒚 𝒇𝒐𝒓 𝒘𝒐𝒐𝒍 (𝑵𝑬𝒘𝒐𝒐𝒍)+ 𝑬𝒏𝒆𝒓𝒈𝒚 𝒇𝒐𝒓 𝒎𝒊𝒍𝒌 (𝑵𝑬𝒍) + 𝑬𝒏𝒆𝒓𝒈𝒚 𝒇𝒐𝒓 𝒎𝒆𝒂𝒕 (𝑵𝑬𝒈)] [Equation 11] % 𝒎𝒆𝒂𝒕 = [𝑬𝒏𝒆𝒓𝒈𝒚 𝒇𝒐𝒓 𝒎𝒆𝒂𝒕 (𝑵𝑬𝒈)] [(𝑬𝒏𝒆𝒓𝒈𝒚 𝒇𝒐𝒓 𝒘𝒐𝒐𝒍 (𝑵𝑬𝒘𝒐𝒐𝒍)+ 𝑬𝒏𝒆𝒓𝒈𝒚 𝒇𝒐𝒓 𝒎𝒊𝒍𝒌 (𝑵𝑬𝒍) + 𝑬𝒏𝒆𝒓𝒈𝒚 𝒇𝒐𝒓 𝒎𝒆𝒂𝒕 (𝑵𝑬𝒈)] [Equation 12]

For the calculation of energy for wool (NEwool), energy for milk (NEl) and energy for meat (NEg) with company specific data, the equations included in IPPC (2006) and reported below shall be used. In case secondary data are used instead, the default values for the allocation factors provided in this document shall be used.

Energy for wool, NEwool 𝑵𝑬𝒘𝒐𝒐𝒍 =

(𝑬𝑽_{𝒘𝒐𝒐𝒍}∙𝑷𝒓𝒐𝒅𝒖𝒄𝒕𝒊𝒐𝒏_{𝒘𝒐𝒐𝒍})

𝟑𝟔𝟓 [Equation 13]

NEwool = net energy required to produce wool, MJ day-1

EVwool = the energy value of each kg of wool produced (weighed after drying but before scouring), MJ

kg-1_{. A default value of 157 MJ kg}-1 _{(NRC, 2007) shall be used for this estimate}61_. Productionwool = annual wool production per sheep, kg yr-1

Default values to be used for the calculation of NEwool and the resulting net energy required are reported in Table 11.

Table 11 Default values to be used for the calculation of NEwool for sheep and goat

Parameter Value Source

𝑬𝑽𝒘𝒐𝒐𝒍 - sheep 157 MJ kg-1 NRC, 2007

𝑷𝒓𝒐𝒅𝒖𝒄𝒕𝒊𝒐𝒏𝒘𝒐𝒐𝒍 - sheep 7.121 kg Average of the four values provided in Table 1 of “Application of LCA to sheep production systems: investigating co-production of wool and meat using case studies from major global producers”, Wiedemann et al, Int J. of LCA 2015.

60 _{The same naming as used in IPCC (2006) is used.}

61 _{The default value of 24 MJ kg}-1 _{originally included in the IPPC document was modified into 157 MJ kg}-1

following the indication of FAO - Greenhouse gas emissions and fossil energy demand from small ruminant supply chains Guidelines for assessment (2016).

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Parameter Value Source

𝑵𝑬𝒘𝒐𝒐𝒍 - sheep 3.063 MJ/d Calculated using Eq. 14 𝑵𝑬𝒘𝒐𝒐𝒍 - goat 2.784 MJ/d Calculated from NEwool –

sheep using Eq. 17

Energy for milk, NEl

𝑵𝑬𝒍= 𝑴𝒊𝒍𝒌 ∙ 𝑬𝑽𝒎𝒊𝒍𝒌 [Equation 14] NEl = net energy for lactation, MJ day-1

Milk = amount of milk produced, kg of milk day-1

EVmilk = the net energy required to produce 1 kg of milk. A default value of 4.6 MJ/kg (AFRC, 1993) shall be used which corresponds to a milk fat content of 7% by weight. Default values to be used for the calculation of NEl and the resulting net energy required are provided in Table 12.

Table 12 Default values to be used for the calculation of NEl for sheep and goat

Parameter Value Source

𝑬𝑽𝒎𝒊𝒍𝒌 - sheep 4.6 MJ kg-1 AFRC, 1993

𝑴𝒊𝒍𝒌 - sheep 2.08 kg/d Estimated milk production 550 lbs of sheep milk per year (average value), milk production estimated for 120 days in one year.

𝑵𝑬𝒍 - sheep 9.568 MJ/d Calculated using Eq. 15

𝑵𝑬𝒍 - goat 8.697 MJ/d Calculated from NEl – sheep using Eq. 17

Energy for meat, NEg

𝑁𝐸𝑔= 𝑊𝐺𝑙𝑎𝑚𝑏∙

𝑎+0.5𝑏(𝐵𝑊_𝑖+𝐵𝑊_𝑓)

365 [Equation 15] NEg = net energy needed for growth, MJ day-1

WGlamb = the weight gain (BWf – BWi), kg yr-1 BWi = the live bodyweight at weaning, kg

BWf = the live bodyweight at 1-year old or at slaughter (live-weight) if slaughtered prior to 1 year of age, kg

a, b = constants as described in Table 13.

Note that lambs will be weaned over a period of weeks as they supplement a milk diet with pasture feed or supplied feed. The time of weaning should be taken as the time at which

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they are dependent on milk for half their energy supply. The NEg equation used for sheep includes two empirical constants (a and b) that vary by animal species/category (Table 13).

Table 13 Constants for use in calculating NEg for sheep62

Animal species/category a (MJ kg -1_{) b (MJ kg}-2₎ Intact males 2.5 0.35 Castrates 4.4 0.32 Females 2.1 0.45

In case company-specific data are used for the farming stage, the allocation factors shall be recalculated. In this case, the parameter “a” and “b” shall be calculated as weighted average if more than one animal category is present.

Default values to be used for the calculation of NEg are reported in Table 14.

Table 14 Default values to be used for the calculation of NEg for sheep and goat

Parameter Value Source

WGlamb - sheep 26.2-15=11.2

kg Calculated

BWi - sheep 15 kg It is assumed that the weaning happens at six weeks. Weight at six weeks read from Figure 1 in "A generic model of growth, energy metabolism and body composition for cattle and sheep", Johnson et al, 2015 – Journal of Animal Science. BWf - sheep 26.2 kg Average of the values for weight at

slaughter, sheep as provided in Appendix 5, Greenhouse gas emissions and fossil energy demand from small ruminant supply chains, FAO 2016.

a - sheep 3 Average of the three values provided in Table 13.

b - sheep 0.37 Average of the three values provided in Table 13

NEg - sheep 0.326 MJ/d Calculated using Eq. 16

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Parameter Value Source

NEg - goat 0.296 MJ/d Calculated from NEg – sheep using Eq. 17

The default allocation factors to be used OEF studies for sheep and goat are provided in Table 14 together with the calculations. The same equations63 _{and default values used for} the calculation of the energy requirements for sheep are used for the calculation of the energy requirements for goats after application of a correction factor.

𝑁𝑒𝑡 𝑒𝑛𝑒𝑟𝑔𝑦 𝑟𝑒𝑞𝑢𝑖𝑟𝑒𝑚𝑒𝑛𝑡, 𝑔𝑜𝑎𝑡 = [𝑔𝑜𝑎𝑡 𝑤𝑒𝑖𝑔ℎ𝑡 𝑠ℎ𝑒𝑒𝑝 𝑤𝑒𝑖𝑔ℎ𝑡]

0.75

× 𝑁𝑒𝑡 𝑒𝑛𝑒𝑟𝑔𝑦 𝑟𝑒𝑞𝑢𝑖𝑟𝑒𝑚𝑒𝑛𝑡 𝑠ℎ𝑒𝑒𝑝

[Equation 16]

Sheep weight: 64.8 kg, average of male and female sheep for different regions in the

world, data from Appendix 5, Greenhouse gas emissions and fossil energy demand from small ruminant supply chains, FAO 2016.

Goat weight: 57.05 kg, average of male and female goats for different regions in the

world, data from Appendix 5, Greenhouse gas emissions and fossil energy demand from small ruminant supply chains, FAO 2016.

Net energy requirement, goat = [(57.05) / (64.8)]0.75 _{• Net energy requirement, sheep}

[Equation 17]

Table 15 Default allocation factors to be used OEF studies for sheep at farming stage

Sheep Goat64 Allocation factor, meat % 𝒎𝒆𝒂𝒕 = [(𝑵𝑬_𝒈)] [(𝑵𝑬𝒘𝒐𝒐𝒍)+ (𝑵𝑬𝒍) + (𝑵𝑬𝒈)] = 2.52% 2.51 % Allocation factor, milk % 𝒎𝒊𝒍𝒌 = [(𝑵𝑬_𝒍)] [(𝑵𝑬𝒘𝒐𝒐𝒍)+ (𝑵𝑬𝒍) + (𝑵𝑬𝒈)] = 73.84% 73.85% Allocation factor, wool % 𝒘𝒐𝒐𝒍 = [ (𝑵𝑬𝒘𝒐𝒐𝒍)] [(𝑵𝑬_{𝒘𝒐𝒐𝒍})+ (𝑵𝑬_𝒍) + (𝑵𝑬𝒈)] = 23.64% 23.64%