Weed, insect, and disease control may also be required for pastures. A healthy, productive pasture will resist invasion from most poisonous weeds and provide good quality forage. When pastures are overgrazed, horses will eat the grass and legume species down to the soil, which allows weeds to take over.
1 Melasma can be triggered by birth control pills because it increases hormones throughout the body. # 2  This is one of the most common causes of melasma. 3  Pregnancy: During pregnancy the body will become very hormonal and skin conditions like acne vulgaris and melasma/chloasma become very common.
Melasma is hyperpigmentation of the skin associated with increased melanin deposition. It occurs on any surface of the skin that is exposed to sun but on the face in particular. While it has a predilection for the forehead and cheeks, it may also occur on the lips, particularly the upper lip.