Hydrolyzed casein reduces browsing of trees and shrubs by white-tailed deer

Abstract

Hydrolyzed casein (HC) and retail products that contain HC are evaluated as repellents to minimize deer damage to trees and shrubs. Three different experiments demonstrate that HC is an effective deer repellent. Technical-grade HC completely eliminated browse damage to evergreen shrubs (Gaultheria shallon Pursh.) and conifers (Thuja plicata Donn.) during the test periods. Retail sources of HC (concentrated baby formula powders) are not as effective as pure hydrolyzed protein, but do offer browse protection when alternative sources of browse are available. For nursery, orchard, and reforestation applications, HC is a promising deer repellent to minimize losses due to browse. For the private homeowner, a simple repellent formulated with glue and a HC-containing baby formula may offer considerable browse protection when alternative forage is available.