## 3 Results
### Cow Diary Production  
The EU produces around 158 million tonnes of cow milk annually [43]. The main milk-producing countries were Germany (20.8%), France (15.8%), the Netherlands (8.9%), and Poland (7.7%). Milk production systems vary significantly, ranging between low and highland, and intensive to extensive [25]. The majority of milk production occurs in intensive systems where dairy cows are generally kept inside, feed is imported from off-farm, and during lactation, cows are generally milked two or more times a day [44]. In addition to the energy use associated with feed and housing, various processes related to milling consume a considerable amount of energy, including milk cooling, milk harvesting, water heating, and water pumping.  
The following studies were located and included in this paper: [PERSON] (2013), who conducted 12 LCAs on milk production, including energy use parameters, across three European countries [25]; [PERSON] (2012), who calculated energy use averages in milk  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline  & \multicolumn{2}{c}{**Animal Feed**} & \multicolumn{2}{c}{**Direct Energy Use**} \\
**Production System** & **Low** & **High** & **Low** & **High** \\ \hline Cow milk & 1.11 & 4.4 & 0.54 & 1.76 \\ Beef & 17.34 & 27.23 & 9.36 & 31.97 \\ Pork & 11.6 & 16.41 & 2.6 & 11.1 \\ Broiler & 6.5 & 14.82 & 0.5 & 6.6 \\ Egg & 10.3 & 13.2 & 0.6 & 10.3 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Low and high range of energy inputs according to feed and direct energy inputs per production systems MJ/kg.  
Figure 1: Range of energy inputs of studies covered in this review according to species MJ/kg.  
production for six countries through conducting 18 LCAs; [PERSON] (2013), who calculated the energy use across 22 commercial dairy farms in Ireland (1975); [PERSON] and [PERSON] (2004), who provided energy use parameters through LCAs for 23 dairy farms in Sweden (2012), and [PERSON] et al. (2007), who provided energy use parameters through an LCA of organic and conventional systems in the Netherlands (1976). These studies had significant variations, while the total energy inputs per energy-corrected milk (ECM) varied from 2.1 to 5.3 MJ (Figure 2 and Table 11). Organic systems appeared to require less energy input generally, but this was inconclusive, though due to production methods, these energy inputs are more likely to come from renewable sources (2012; 2015). The energy embedded in the feed was by far the highest energy input in all but one of the studies.  
A number of studies provided data on direct electrical energy use on dairy farms (Table 2). These studies generally illustrated that milk cooling and milk harvesting were the largest electrical energy consumers, followed by water heating and water pumping (2012). From the studies that included liquid fuel energy use, there was relatively little information available on its specific uses. However, it is generally assumed that this was allocated to tractor use associated with pasture management (2012). It is important to note that individual studies provided different sets of data depending on a range of factors, including the production system and the type of milking system (2012).  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Source** & **Country** & **Milk Cooling** & **Milk Harvesting** & **Water Heating** & **Water Pumping** \\ \hline [PERSON] et al., 2013 & Italy & 38\% & 31\% & 13\% & 18\% \\ [PERSON] et al., 2018 & Italy & 29\% & 35\% & 23\% & 14\% \\ [PERSON] et al., 2017 & Finland & 42\% & 23\% & 32\% & 3\% \\ [PERSON] et al., 2018 & Ireland & 41\% & 25\% & 28\% & 6\% \\ [PERSON] et al., 2018 & Ireland & 29\% & 53\% & 11\% & 7\% \\ [PERSON] et al., 2013 & Ireland & 39\% & 25\% & 29\% & 6\% \\ \hline \hline \end{tabular}
\end{table}
Table 2: Electrical energy breakdown dairy farms EU (based on (2012)).  
Figure 2: Energy inputs cow milk MJ/ECM (kg) (based on (2012; 2013; 2015; 2015)).