B&G 2 Quart Duster 1152-A distributes dust when you pump it. As long as the product you are using is labeled to be applied to cattle, this would be a great applicator for you.
When using a B&G 2 Quart Duster 1152-A, you can use an N95 Valved Respirator Mask along with some Safety Goggles.
The B&G 2 Quart Duster does come with the white cap that is pictured on the site.