posted by rfvv .
1. A cow can make about 12kg of waste
in a day.
( Is a cow a female? Can a cow mean both male and female ones? What about in this sentence?)
This sentence is almost correct. It's better to use the word "produce" rather than "make" in this context.
There should be a space between 12 and kg.
Cattle is the word for all the animals of this species. Cows are females. Bulls are males. Calves are the babies. (Singular forms are cow, bull, calf.)