The mental process flows considerably smoother when the negative effect of dry conditions have been anticipated as a periodic fact of life. Grazing Management techniques must take into account drought effects every year. The answer to this question is long and windy. While a lack of rainfall can not be changed, the impacts of drought can definitely be moderated. Managing pasture is a long term proposition.
Positive results come slowly.
One must practice patience and commitment to a well-laid out plan. When drought hits there are some quick-fix applications available which help. Hayland can be grazed. Cereals originally intended for grain can be converted to grazing. Cattle can be culled or put on feed.