4-Manure-management/4.1-Excretions/4.1.2-N-and-TAN-Excretions.md

@@ -8,37 +8,32 @@ For the calculation of NH<sub>3</sub>, N<sub>2</sub>O, NO and N<sub>2</sub> emis
 
 The Equation below describes the annual N mass balance for an average animal place as defined in Chapter [1.1](/1-General-aspects/1.1-symbols,-units,-definitions) (m<sub>l</sub> = 0 for all animals except dairy cows and laying hens; m<sub>p</sub> = 0 for animals for meat production):
 
-![grafik](uploads/e020fd738fe4c2777347993b2c8a6601/grafik.png)
+![grafik](uploads/8d4bbde741e5c02103e6f43e59f8faaa/grafik.png)
 
 The N intake with feed (m<sub>feed</sub>) is determined by the intake of feed and the average crude protein content of the feed. As a rule, the amount of feed intake is a function of the energy requirements of the animal and the energy content of the feed. The calculation is based on the assumption that the energy requirements be exactly satisfied. In the respective equation the energy requirements and the energy content of the feed are given in ME units (ME = metabolizable energy). For dairy cows the units to be used are NEL units (NEL = net energy lactation), see Chapter [2.4.4](/2-Input-data/2.4-Animal-activity-and-performance-data/2.4.4-Energy-requirements).
 
-![grafik](uploads/f2c8e9f960273dfc38ef65e4bfac8f61/grafik.png)
+![grafik](uploads/5ed6e2d39297112911b4c7657b6f8491/grafik.png)
 
 For animals kept for meat production, the amount of feed needed annually per average animal place can be calculated using the feed conversion factor, see the next equation:
 
-![grafik](uploads/0a5ae80573913a531f48b1e3bd02ad40/grafik.png)
+![grafik](uploads/39b47abca2c99403423599e6a299027d/grafik.png)
 
 According to the definition of the average animal place , the annual weight gain Δw<sub>annual </sub>of fattening animals with a lifespan shorter than one year is calculated as follows:
 
-![grafik](uploads/13db0d73b3c6a338190bba1e8af8a117/grafik.png)
+![grafik](uploads/630c7c2c9bb0dcf7be5e9dcbedf9c1ed/grafik.png) The other components of the N balance are given by: 
 
-The other components of the N balance are given by:
-
-![grafik](uploads/0308c63dde6b83eaa4cb9db291e3da4d/grafik.png)
-
-![grafik](uploads/f46085979e41d59ccd08b47b7afb89aa/grafik.png)
+![grafik](uploads/16f2e43cddef7a913f8cec62ae2c3f72/grafik.png)
 
 ## TAN excretion
 
 The amount of TAN needed for the assessment of the emissions of N species from mammals (see Chapter [1.2](/1-General-aspects/1.2-Inventory-model-py-gas-em)) is defined as the share of digestible N taken in with feeds that is not retained in the animal or excreted with milk or offspring. This definition presupposes the knowledge of the digestibility of crude protein (X<sub>DXP</sub>). As already mentioned above, for poultry the excretion of uric acid nitrogen (UAN) should be considered instead of TAN excretions. However, the inventory considers the amount of UAN to be TAN. The calculation of UAN is performed in analogy to the following equation for the TAN excretion, where the losses on the right-hand side are represented by N retention in case of pullets and by the sum of N retention and N in eggs in case of laying hens.
 
-![grafik](uploads/78ece9df8cd8bf423cf8f0e8faf58338/grafik.png)
+![grafik](uploads/529854056499191564f42253f4b03d24/grafik.png)
 
 If the value of X<sub>DXP</sub> is not known, it must be estimated. For this purpose, the quantity X<sub>DE</sub> (digestibility of energy, see Chapter [2.4.7](/2-Input-data/2.4-Animal-activity-and-performance-data/2.4.7-Digestibilites)) is used in the inventory. Since X<sub>DE</sub> is usually somewhat larger than X<sub>DXP</sub>, this results in a certain overestimation of the TAN quantity and thus also of the NH<sub>3</sub> emissions. For dairy cows the amount of TAN is calculated differently, see dairy cow chapter below.
 
 The relative TAN content x<sub>TAN</sub> of the excreta is defined as:
-
-![grafik](uploads/254290abbb62a3d2106ad9eb74172183/grafik.png)
+![grafik](uploads/31570197124382a82d6408454472e972/grafik.png)
 
 ## <span dir="">Partitioning of N excretions between different housing systems and grazing</span>
 
@@ -58,19 +53,18 @@ The relative TAN content x<sub>TAN</sub> of the excreta is defined as:
 
 <span dir="">The annual N intake m<sub>feed </sub>is directly proportional to the intake of crude protein XP<sub>int</sub>, which is calculated analogously to the GE intake (GE<sub>int</sub>) described</span> in Chapter [2.4.5](/2-Input-data/2.4-Animal-activity-and-performance-data/2.4.5-Feed-and-energy-intake#modeling-ge-intake).
 
-![grafik](uploads/d1301eca6b404a052299a2d501f2a578/grafik.png)
+![grafik](uploads/9031f212193cdb63022669c3a39a028c/grafik.png)
 
 The annual amount on N retained in weight gained is calculated as follows:
 
-![grafik](uploads/bd97b7d5b3d389bb7173b61580f0e88a/grafik.png)
+![grafik](uploads/3ea03f933ebc434d691f75c7fa613fb5/grafik.png)
 
 The amount of N used for milk production ist proportional to the milk yield and milk protein content. Data on these input variables for dairy cows are described in Chapter [2.4.8](/2-Input-data/2.4-Animal-activity-and-performance-data/2.4.8-Milk-yield-and-milk-composition).
 
-![grafik](uploads/e813f9212417f6da8622a87ce23538ac/grafik.png)
-
+![grafik](uploads/c0bb6d832bf19a4b616465123a77c660/grafik.png)
 <span dir="">The N requirement for pregnancy is calculated proportionally to the number of births per year. </span>[<span dir="">DLG (2005, 2014)</span>](/9%20Literature#dlg-deutsche-landwirtschaftsgesellschaft-ed-2005)<span dir=""> use the value 0.025 kg kg<sup>-1</sup> as the proportionality factor x<sub>N,offspring</sub>. This only represents the N requirement for the fetus. In the emission calculation model, however, with reference to </span>[<span dir="">GfE (2001)</span>](/9%20Literature#gfe-gesellschaft-f%C3%BCr-ern%C3%A4hrungsphysiologie-ausschuss-f%C3%BCr-bedarfsnormen-2001)<span dir="">, p. 47, equation (2.2.1), the N requirement for the development of the pregnant uterus is also taken into account. This results in a combined nitrogen requirement of x<sub>N, p</sub> = 0.0302 kg per kg of calf birth weight. As in </span>[<span dir="">DLG (2014)</span>](/9%20Literature#dlg-deutsche-landwirtschaftsgesellschaft-ed-2005)<span dir="">, p. 34, the birth weight is set at 45 kg. (For </span>[<span dir="">DLG, 2005</span>](/9%20Literature#dlg-deutsche-landwirtschaftsgesellschaft-ed-2005)<span dir="">, it can be derived from the N-balance calculations described there that the birth weight was assumed to be 45 kg.)</span>
 
-![grafik](uploads/253159f5ea604d066ecab4b43af29946/grafik.png)
+![grafik](uploads/7c90e58c189de306604f720f19d845f9/grafik.png)
 
 **TAN excretion**
 
@@ -78,15 +72,15 @@ The amount of N used for milk production ist proportional to the milk yield and
 
 <span dir="">Urine N cannot satisfactorily be related to the N intake with feed (e.g. </span>[<span dir="">Kebreab et al., 2001, 2002</span>](/9%20Literature#kebreab-e-france-j-beever-de-castillo-ar-2001)<span dir="">; </span>[<span dir="">Gehman et al., 2008</span>](/9%20Literature#gehman-am-kononoff-pj-mullins-cr-janicek-bn-2008)<span dir="">), because the actual XP digestibility of the feed decreases as feed intake rate increases. Hence, in order to obtain urine, the inventory model Py-GAS-EM first calculates faecal N excretion which is then subtracted from total N excretion to obtain TAN excretion.</span>
 
-![grafik](uploads/1a6b1b5402ca186f5c60a5d6755294f5/grafik.png)
+![grafik](uploads/f270deb48a4511f25e1f3a6d4862dd92/grafik.png)
 
 <span dir="">The method for calculating faecal N excretion was derived in Denmark on the basis of experimental data and is in good agreement with similar methods reported in the literature (</span>[<span dir="">Kristensen et al., 1998</span>](/9%20Literature#kristensen-vf-kristensen-t-aaes-o-hansen-ok-1998)<span dir="">, p. 117). A review of the procedure using German data showed that it can be transferred to German conditions </span>[<span dir="">(KTBL, 2021)</span>](/9%20Literature#ktbl-kuratorium-f%C3%BCr-technik-und-bauwesen-in-der-landwirtschaft-2021-1)<span dir="">. After adapting to the notation in this report, the faecal-N formula from </span>[<span dir="">Kristensen et al. (1998)</span>](/9%20Literature#kristensen-vf-kristensen-t-aaes-o-hansen-ok-1998)<span dir="">, p. 117 is:</span>
 
-![grafik](uploads/c9f500625b274c7c68245e15882a8f0f/grafik.png)
+![grafik](uploads/d2c55a019445e224a1035d3f396543cb/grafik.png)
 
 <span dir="">For the relative TAN content of the total N-excretions:</span>
 
-![grafik](uploads/5d5bb7f3d69e524339748a7124807f1f/grafik.png)
+![grafik](uploads/27d7bcb4bd840cdae24f2dae91a4e174/grafik.png)
 
 ## Calves
 
@@ -104,7 +98,7 @@ The N intake rate is assessed from the dry matter intake rate of the various die
 
 The amount of N retained is calculated assuming an N content of the animal body of 0.0272 kg kg<sup>-1</sup> ([LfL, 2006a](/9%20Literature#lfl-bayerische-landesanstalt-f%C3%BCr-landwirtschaft-2006a), Table 8).
 
-## Male cattle > 2 years
+## Male cattle \> 2 years
 
 <span dir="">In accordance with </span>[<span dir="">KTBL (2006b)</span>](/9%20Literature#ktbl-kuratorium-f%C3%BCr-technik-und-bauwesen-in-der-landwirtschaft-ed-2006b)<span dir="">, pg. 412, the nitrogen excretion is assumed to amount to 84 kg pl<sup>-1</sup> a<sup>-1</sup> N, 60 % of which is assumed to be TAN (according to (</span>[<span dir="">EMEP, 2019</span>](/9%20Literature#emep-2019)<span dir="">-3B-31, Table 3.9, other cattle).</span>