Can I ask ... are you *needing* to wean now for some reason?
Drinking cow's milk is not a necessity ... we personally don't plan on introducing it to our little one in the future. This resource has some great information on the subject:
Cow's Milk - Is It Necessary?
Calcium and toddlers
And this source says:
"Many societies throughout the world remain very healthy without ever drinking milk once weaned from the breast. Remember that milk is species specific. Cow's milk is intended for baby cows, who grow much faster than human babies and have very different nutritional needs."
Hope this helps!