If they’re anything like cows, the methane they release may do more to contribute to global warming than the CO2 from lawnmowers would.
goats are actually far more efficient at turning foodstuffs into milk and energy than cows are...i do not ever recall a goat farming in the 20 years I spent at home while my parents raised them...that includes the morning and evening milkingsI had to do before and after school...