Photodynamic pigments are the pigments in all varieties of rye-grass, clovers, lucerne, St John’s Wort, Buttercup, plantain, parsley which make them the very dark green colour. These pigments fluoresce, are activated by light, and are known to cause photophobia and photosensitisation. This is the true cause of ‘mud-fever’, ‘sunburn’ and I believe head-flicking/shaking syndrome. When you remove these plants from the horse’s diet these conditions go away.

Mineral imbalance. Rye-grass likes a slightly acid soil (5.8) So do all sorts of fungi. The more acid your soil, the more fungi in and around the base of the plants, such as facial ecsma spores, aspergillus, rust moulds and hundreds more. Then when the grass grows quickly, which is often in our climate especially when nitrogen or super is applied, it tends to leave behind the minerals. When you realise what a huge requirement horses have for minerals like calcium/magnesium just to run their large muscles, their brain and their nervous and circulatory systems, you will go to great lengths to ensure your horse doesn’t lack a molecule! It is a waste of money and counter-productive to feed separate minerals in isolation. Whilst you think you are fixing one problem you will be creating another imbalance. Feed mixes that supply everything in the correct balance.

Fructans. Whilst clovers and lucerne store their sugars as starch which is easily digestible, all varieties of rye-grass store their sugars as fructans which horses cannot digest. When fructans reach the hind-gut the streptococcus bacteria have a feast, immediately proliferate and devastate the good flora, cause sloppy manures, metabolic chaos and trigger laminitis.

Excess carbohydrate. Rye/clover pastures are selected for rapid weight gain and milk production in livestock. The exact opposite of what we want for our horses! Rye/clovers are very high in NSC’s (non-structural carbohydrate or sugars) and when kept at a young stage of growth by grazing they are also low in fibre.

Phyto-oestrogens. Clovers especially red clover and sub-terranian clover contain phyto-oestrogens which interfere with hormones and reproduction. These can turn mares into nymphomaniacs and geldings into stallions! They also increase the number of services to conceive. There are way safer grasses to feed your horses. If possible change to cocksfoot, brown-top, any of the Poa’s, silver tussock, Yorkshire fog, prairie, or timothy and enjoy horses that are ‘good to go’ all year round!

Kikuyu may harbour mycotoxins and is also an oxalate grass so best avoided totally.

Those little black sticky things are the Ergot of the fungus “Claviceps Paspali”. They are common on the seed heads of paspalum and cause central nervous system derangement! That is hyperexcitability, belligerence, staggering and even convulsions.

Obviously not what you would want your horses to be eating. Since it occurs mainly on the seed head, it is vital not to let Paspalum seed in the spring and summer. Paspalum loves humidity.

If you cannot eliminate it completely or at least manage it so it doesn’t go to seed, then best to make the perimeter track and keep your horse on there.

Sometimes known as Reed Canary Grass – PHALARIS can harbour toxic alkaloids which cause a serious nervous syndrome and Phalaris staggers. Seasonal and weather patterns appear to affect alkaloid concentration, as most toxicity occurs in autumn and in times of drought. Regrowth after grazing or mowing also shows a considerable increase in alkaloids.

Often found on the edges of ditches and lakes. Best eliminated and certainly not to be sown.

Buttercups taking over your pasture is indicative of poor drainage. They are potentially harmful when they first grow but are no longer toxic after a hard frost or when dried in hay. The consumption of freshly growing buttercups may cause:

• Irritation and little sores or blisters around the mouth area
• Even colic like symptoms and/or diarrhoea