Not all grass growing in your horse’s paddock is actually good for them. Although these grasses are generally considered safe for horses (many are even included in horse pasture blends), they can have side effects that can affect the health and behaviour of your horse. Symptoms may range from mild to severe in some instances.

GRASSES BEST AVOIDED:

Botanical name		Common name
Lolium perenne		Perennial Rye Grass
Lolium multiflorum		Annual Rye Grass
		Clover
Paspalum		Paspalum (there are hundreds of varieties)
Cynodon dactylon		Couch grass, Bermuda grass
Phalaris arundinacea		Canary grass
		Cats ear (often confused with dandelion)
Pennisetum clandestinum		Kikuyu
Setaria sphacelata		Setaria
Cenchrus ciliaris		Buffel grass
Panicum maximum		Green panic, Guinea grass
Digitaria decumbens		Pangola
Urochloa mutica		Para grass
Brachiaria decumbens		Signal grass
Setaria incrassata		Purple pigeon grass
Festuca arundinacea		Tall fescue

 Grasses that can harbour fungi which produce myco-toxins:

•  Rye Grass (Perennial) 
•  Tall Fescue
•  Paspalum
•  Phalaris (Reed Canary Grass)
•  Bermuda Grass (couch)
•  Clover  
•  Kikuyu 

There are also hundreds of different fungi living in and around the general soil environment, more so in moist, humid climates. Some are beneficial but many produce harmful mycotoxins. The more acidic the soil environment the more pathogenic fungi abound. Sometimes you see rust mould on crops or grasses, sometimes you see a black mould on grass seed-heads. Topping the grass and leaving it to decay in the paddock creates an ideal environment for fungi too.
 

Oxalate grasses :

•  Seteria
•  Kikuyu
•  Buffel
•  Green panic
•  Pangola
•  Para grass
•  Guinea grass
•  Signal grass
•  Purple pigeon grass 

High potassium:
All short rapidly growing grass in spring and early autumn has the potential to be high in potassium at the same time low in sodium. 

• Kikuyu also gets exceptionally high in potassium and nitrates, and very low in sodium  which can cause kikuyu ‘poisoning’ particularly in autumn or after a drought breaking rain
• rye (is also a nitrate accumulator)
• clover
• Lucerne * stores sodium in the roots so the leafy part contains no sodium
• kelp / seaweed *
• molasses *
• cider vinegar *
• Soya bean Meal*
  
• Ginseng, dandelion, nettle, sage, yarrow, rosehips, slippery elm, garlic, plantain, echinacea, chamomile, comfrey, chicory *

*Whilst many of these herbs and feeds can have great health benefits, they need to be taken into account when arriving at the sum-total potassium content of your horse's diet.

Photosensitivity:

• Clover  

Toxic to horses:

• Cat's ear flat weed (looks like dandelion)
• Phalaris (Blue Canary Grass)

SAFE HORSE GRASSES INCLUDE:

Prairie grass

Rhodes grass

Brown top

Cocksfoot

Yourkshire fog

Timothy

Crested Dog's tail