How can I have more cowbell?

Usually in Harvest Moon games you have a cow bell that you can use to get your cow to follow you so it is easy to take them outside to graze. I don't have one, and can't figure out how to get one, and pushing my cow around to get it outside is a very slow process.

Where can I get a cowbell?

I believe you are looking for the Farm Bell. You can get the Farm Bell blueprints by raising Neil's FP (you also need at least 10 full-grown animals [chickens count]). Give him stuff he likes (such as milk and eggs) and he'll eventually give up the blueprint for the Farm Bell.

You can also get them out by using your pets after you unlock Rod after building his house.

You can get the plans for Rod's house at Rebecca's shop once you've completed Dunhill's Town Popularity Plan #2.

Rod's shop in the plaza sells pets (cats, dogs, and horses) and is open Monday through Thursday.