Ask the expert: Is ditch hay safe for horses?

Krishona Martinson
University of Minnesota Extension
Hay bales rest alongside the highway on Tuesday, July 20, 2021 outside Flandreau.

Question: Dry conditions have made for a limited hay supply in my area. I've found a source of round bales, but they were baled from the roadside. Are these bales safe to feed to horses? 

Response: Harvesting hay from roadsides, commonly referred to as ditch hay, is a common practice and can provide livestock with suitable forage.

However, horse owners should use caution when buying and feeding ditch hay. Because ditches are not fertilized, harvested infrequently, and weeds are not routinely controlled, ditch hay tends to be of lower quality and may contain toxic weeds (e.g. wild parsnip) compared to managed hay fields.

Additionally, garbage and animal carcasses can be accidentally harvested with the hay which poses a threat to horse health. Bales harvested from ditches should be carefully inspected.

Another concern with ditch hay is herbicide residues. Highway departments tend to use herbicides containing the active ingredients picloram, clopyralid or aminopyralid to control noxious weeds like thistles. When ditches sprayed with these herbicides are baled prior to the harvest restriction listed on the label, residues can pass through the animal and end up in the manure.

When spread, the manure can cause damage to sensitive crops like soybeans. There is no documented history of human or livestock toxicity from these active ingredients. 

Interestingly, farmers need a permit to harvest highway areas that the Minnesota Department of Transportation owns. Roadways owned by county and local governments have their own regulations.

Check with your state's Department of Transportation for rules and regulations concerning ditch hay.