Conversely, DST can adversely affect farmers, parents of young children, and others whose hours are set by the sun and they have traditionally opposed the practice, although some farmers are neutral. One reason why farmers oppose DST is that grain is best harvested after dew evaporates, so when field hands arrive and leave earlier in summer their labor is less valuable. Dairy farmers are another group who complain of the change. Their cows are sensitive to the timing of milking, so delivering milk earlier disrupts their systems. Today some farmers' groups are in favor of DST.