Since collecting the cattle manure is easier than goats and sheep
in a dispersed area, in this study cattle manure is assumed to be the
main source for biogas production and sheep manure is the second
choice in case of shortage of cattle manure. It is important to
mention that the methane content in yielded biogas from sheep
and cattle manure is 70e72% and 56e60%, respectively [36]. The
average biogas production from cattle manure is assumed to be
0.96 m3/cow/day [37]. Regarding data in Tables 2 and 3 and
considering the limited number of cattle in the village, biogas
production can be predicted.