May. It is one of the first spring plants to emerge, and ewes may eat it soon after lambing. The udder and teats become so painful that the ewe will not allow the lamb to nurse. Newborn lambs die of starvation and dehydration. Surviving lambs usually are stunted from lack of milk. Cattle are affected if they are exposed to direct sunlight after eating about one pound of the green plant.
Cows refuse to let calves nurse.
In severe poisoning, all the white areas of the body may blister, and animals may lose weight rapidly. Sheep and cattle recover gradually after they stop eating spring parsley. Scabs form after blistering Ewes and cows may refuse to allow young to nurse How to Reduce Losses To reduce losses from spring parsley, keep sheep and cattle off infested ranges in early spring until other plants appear. There is no known treatment for light-skinned animals that are affected by eating spring parsley, but they recover spontaneously if kept in the shade. Spring parsley can be controlled by spraying plants in the bud to early bloom stages of growth with an amine salt of 2,4-D applied at the rate of 1.0 kg per acre of acid equivalent.