The major considerations to animal health are increased deposits of silt and microbes on the plant material. The deposits of silt will reduce the energy content of the forage since animals are eating more soil and less digestible forage – this is generally not significant as plants will grow and dilute the ash content – though animal weight gain may be diminished for a short period. However, this can be significant for horses which are more susceptible to high sand content in their diets. For horses it may be necessary to allow pastures to grow to dilute the ash content or, if tall, to mow or harvest and allow regrowth to occur.

Of major concern should be any considerations of microbial contamination. If the water flowed past manure piles or came from sewage treatment plants, it contained microbes that many be harmful to grazing animals. The general recommendation is to wait 1 to 2 weeks after the water has receded to allow microbes populations to diminish.

The next concern is physical damage to the pasture by hooves of grazing animals. Animals can leave hoof depressions (pugging) that makes the pastures surface uneven for future grazing. Pastures that are composed of sod-forming grasses can be grazed first (e.g. bluegrass, bromegrass, reed canarygrass) and pastures composed primarily of bunch grass (e.g. orchardgrass, tall fescue, timothy) must be slightly drier before animals are introduced to avoid the pugging.

Most of the pastures grasses will survive a week or two of being under water. Longer flooding periods may require that pastures be reseeded with the desirable species. Legumes, especially alfalfa, will be more susceptible to damage from periods of standing water.

Most pastures will recover without serious production losses if silt deposits are not over 2 inches and erosion is minimal.

Recovery usually depends on the type of legume. Alfalfa probably will recover from moderate silting better than white clover varieties. White clover will not survive silting that covers the ends of the growing stems or stolons. Ladino clover, however, will fill in stands from a few surviving plants if the area is not too large.

Grasses such as ryegrass, orchardgrass, fescue and meadow foxtail will probably grow through a moderate silt deposit (less than 2 inches), and can stand several days of flooding without injury. Tall fescue will tolerate longer flooding than ryegrass or orchardgrass. Meadow foxtail and reed canary grass can stand longer submersion than other perennial grasses.