# The Carbon Footprint of Milk Production on a Farm
## 3 Results and Discussion
### The CF Range in Milk Production
A high CF value was noted on farms using mainly dry feed and grains, whereas a lower CF value was observed under systems using silage and grazing. A study by [PERSON] et al. [52] determined the CF to be at a level of 1.23 kg CO\({}_{2}\) eq kg\({}^{-1}\) FPCM under an intensive system in Ireland, whereas in another study by [PERSON] et al. [53], this value for farms with lower productivity was 1.49 kg CO\({}_{2}\) eq kg\({}^{-1}\) FPCM. In contrast, [PERSON] et al. [54] presented an analysis of 53 farms in Rwanda, where the average emissions amounted to 2.42 kg CO\({}_{2}\) eq litre\({}^{-1}\) FPCM, with the main impact factors including local feed availability and slurry management. The CF of milk production varied significantly depending on the country, production system, farm scale and calculation methodology. In a study conducted on 71 farms in Ireland, Spain, Portugal, the UK and France, the CF values for 1 Mg of FPCM milk ranged from 884 to 2494 kg CO\({}_{2}\) eq (i.e., from 0.88 to 2.49 kg CO\({}_{2}\) eq kg FPCM), depending on the feeding system (grazing, mixed, non-grazing) [22]. The average value for grazing systems was 1.13 kg CO\({}_{2}\) eq kg\({}^{-1}\) FPCM. For mixed systems, the value was 1.24 kg CO\({}_{2}\) eq kg\({}^{-1}\) FPCM, and for non-grazing systems, it was as high as 1.52 kg CO\({}_{2}\) eq kg\({}^{-1}\) FPCM. It is worth noting that the scatter of the results was significant, with both the lowest and highest CF values observed in the zero-grazing system. In Latin America, the CF range was between 1.54 and 3.57 kg CO\({}_{2}\) eq kg\({}^{-1}\) FPCM. The emission values were significantly influenced by, e.g., the region of production (tropical vs. temperate), feeding system (zero-grazing, semi-confinement, pasture), and farm profile (dual-purpose vs. specialised) [43]. In addition, the analysis considered the differences in the daily milk yield per cow, which ranged from 8.4 to 20.1 kg day\({}^{-1}\), significantly affecting the emission intensity. In India, for farms producing buffalo milk, the CF was estimated at 2.24 kg CO\({}_{2}\) eq kg\({}^{-1}\) FPCM [55], whereas, for cows in the Hisar region in India, the result was 2.13 kg CO\({}_{2}\) eq kg\({}^{-1}\) FPCM [49]. In Kenya, the values noted ranged from 2.19 to 3.13 kg CO\({}_{2}\) eq kg\({}^{-1}\) FPCM, with the highest CF value observed for systems based solely on grazing [39]. In Brazil, according to a study conducted in Sao Paulo, the CF values without bioeconomic allocation amounted to 2.41 kg CO\({}_{2}\) eq kg\({}^{-1}\), while after allocation, to 2.19 kg CO\({}_{2}\) eq kg\({}^{-1}\) FPCM [5]. Comparisons between farms revealed that the integration of net emissions with carbon sequestration balancing can significantly reduce the carbon footprint intensity. Analyses conducted in various countries and climate zones revealed significant differences in the CF levels of milk production. For example, in Australia, the average CF was 1.11 kg CO\({}_{2}\) eq kg\({}^{-1}\) FPCM [14], while according to a study by [PERSON] et al. [3], in Italy, this value amounted to 1.19 kg CO\({}_{2}\) eq kg\({}^{-1}\) FPCM. In tropical countries, such as Ethiopia, the CF can be as high as 3.2 kg CO\({}_{2}\) eq kg\({}^{-1}\) FPCM, mainly due to the low productivity and lack of access to modern technologies [14]. In tropical countries (e.g., Peru, Kenya), the CF was typically higher, also due to less intensive production systems, feed seasonality and a higher share of methane fermentation in total emissions [39, 42]. In contrast, in the temperate zone (e.g., Europe), higher production efficiency and lower CF values per milk unit were observed, which was associated with better herd management and higher productivity [22]. These differences must be taken into account when developing climate policies tailored to local conditions. A study by [PERSON] et al. (2019), focusing on Canada, showed that the regional diversity of environmental conditions and production practices had a significant impact on the CF value of milk production.