Goats are quickly becoming the livestock of choice for people who have small acreage. You can reasonably place seven or eight goats on an area that would only sustain one cow. Start small with just a few goats and buy more -- if after careful observation of the land, it reveals that vegetation is still available and you are not having to supplement with hay or grain.
The quantity and quality of vegetation on the land is a major factor in the number of goats that can be raised on the available area. If enough vegetation is not available, then you will have to provide supplemental feeding or decrease the number of goats on the area.
Goats will eat plants that other livestock leave. Therefore you can raise goats with other animals -- such as cows -- to get more use out of your small acreage. If vegetation is ample, then you can run one to three goats for each cow that you have; and since goats prefer weeds, they leave the grasses and clover for the other livestock to eat.
Overpopulation of an area will cause parasites to become a serious issue. Stomach worms suck the blood from goats causing anemia and possibly death. Observe your goats carefully for signs of parasite infestation and treat with medication -- and consider possibly downsizing your herd.
Goats reach sexual maturity at around five months of age and have a gestation period of 145 to 155 days -- with multiple births being the normal. Therefore, your herd can double in less than a year causing overpopulation of your available land. You will have to make decisions about which goats to keep and which ones to sell to sustain the land.