Farmland and pastures are under water, leaving herders with little grazing land.
Their situation is mirrored across parts of East and West Africa this year as heavy rains wreak havoc.
In recent years, intense rainfall, land degradation and poor urban planning have led to more frequent flood disasters in the region, whose countries are among the most vulnerable to climate change, according to the Notre Dame Global Adaptation Initiative index.
The nomads depend on the milk for their livelihood. Like nearly 5 million in the country of 16.4 million, they face acute hunger.
Nomadic herder Fatime Tchari fended off a hungry calf as she tried to squeeze the last drops of milk from an emaciated cow in an arid corner of southern Chad.
Then she stood up, dejected.
"As you have just seen, I tried to milk six cows but I have not managed to get one litre of milk. They are stressed, sick and malnourished because of the drought and floods," Tchari said.
"It is difficult for the cows to produce milk for us in these conditions," Tchari said.
"Last year we saw our cows starve to death before our eyes, this year we are facing another disaster. We need food and vaccines to preserve our herds or we will end up losing everything."