Until recently, I had no idea of the impact that various aspects of pasture can have on the health and temperament of our horses. Go through the list of symptoms carefully. As you read, light bulbs will go on for you regarding horses you currently own or know of, or have owned or known in the past. You too, will realise how countless, perfectly good horses have suffered, been punished, become 'problem horses', caused accidents, labelled 'bad', 'crazy', 'unmanageable', deemed unrideable, diagnosed with brain tumors, wobbler syndrome, fractured pelvis, tendon injuries and sent to the knackery, all because of the grass!!!!!

This information provides an explanation for many things going on with our horses where extensive investigations have previously failed. It comes from years of my own personal observations and experiences and those of the hundreds of horses and riders I have met and assisted over the last 10 years throughout Australia & NZ. Additionally, in the spring of 2004 I conducted the "Equine Health & Behaviour Survey" in NZ, the results of which have been very revealing.

Horse owners frequently experience unexplained changes in their horse's temperament and personality. If you are like me and believe that horses do not 'plot against us' and are definitely NOT 'dirty' 'nutty' or 'mongrels' (the list goes on!), then there must be other reasons for this kind of behaviour. There is a strong correlation between the soils and pasture and the raft of health and behavioural problems our horses are plagued with, some mildly, some chronically and sometimes acutely. Aggressiveness, herd-bound behaviour, pasture heaves, obesity and laminitis are just a few that spring to mind.

For example - things have been going great with your horse, and then he starts spooking at things in the arena, or rushing out of the float, or you are paying for a lesson and he's not 'himself', so it's a complete waste of money, all of these sorts of things.

·      He doesn't like to being touched or brushed...  
·      I've had the saddle fit checked but it's still like he's got a sore back... 
·      Why do some horses bleed from the nose when they're out at 
        pasture?
·      What is the cause of head-shaking / flicking?
·      Why can't I get rid of that mud-fever?
·      How come my horse has got sore feet? Goes to bite me when I'm
        doing up the girth?
·       I'm feeding my horse heaps but he won't put on any condition...
·       My horse is on 'nothing' but I can't keep the weight off...
·       What is the cause of many respiratory troubles? Skin troubles?

I believe the answers to these questions and many, many more, lie within the following information.

(The following information is not intended to replace veterinary advice, merely to give you an overview. If symptoms persist or are acute, call your veterinarian).

An Overview
In Australia and New Zealand horses are either kept on pasture primarily meant for other stock like sheep or cattle, or on paddocks grazed by horses alone. Both situations can lead to problems. The former consists of high production grasses (eg the rye/clover mixes) which, because of our climate and the fertilizer regimes applied to them, reach even higher production. This is counter-productive to the health of the horse, whose digestive system is highly specialised and different to other species. A horses’ natural diet consists of grass, herbs, shrubs and leaves which is RICH in fibre and LOW in carbohydrates.

High production grasses are LOW in fibre and HIGH in sugars and carbohydrates and are very prone to serious mineral imbalances. They can be VERY high in potassium and nitrates and low in sodium. This in turn causes the horses system to be 'stripped' of calcium and magnesium. Add to this that some common pasture grasses (setaria, kikuyu, etc) have oxalates which bind up calcium predominately but will also bind magnesium. Some departments of primary industries in Australia recommend to not graze horses on 100% oxalate pastures for longer than 4-6 weeks at any one period of time.

In Australia a large majority of pastures are under half the recommended calcium levels and a large part of Australia also has low zinc levels. Combined with oxalated grasses this is a bad combination for horses, and they must be properly supplemented to help avoid major mineral imbalances such as 'Big Head' (Hyperparathyroidism) and magnesium deficiencies.

Nutrient uptake by grasses is influenced by many things; soil ph, type of soil, water content, air and soil temperature, fertilizers, organic matter and stress such as livestock grazing. As these elements vary, so will the nutritional uptake. Also some pastures and plants accumulate specific elements, for example lucerne accumulates calcium; annual rye grass accumulates nitrates; salt bush accumulates selenium.

Fertilising with super-phosphate, urea, or nitrates accelerates growth and causes plants to be shallow rooted and therefore less able to uptake minerals from deeper in the soil, urea will also create more NSC (Non Structural Carbohydrates) in grasses. These also lower the pH (acidifies) the soil and pasture, which then reduces the availability of all major minerals. In healthy soil there needs to be the right balance of fungi to bacteria. The lower the pH, the more fungi and the less bacteria. Fungi really thrive in these acid conditions. Rye-grass also loves a lower pH. This IS the root cause of why MYCO-TOXINS and MINERAL IMBALANCES are such a big problem.

Add to this the fact that the paddock of green, growing grass your horse is grazing is the equivalent of a bowl of sugar! Then we go to the feed store and buy more sugar in the form of molassed grains. No animal stays healthy for long when their diet is predominantly sugar. This high sugar/carbohydrate, low fibre intake leads to amongst other things, an impaired insulin response, also known as a metabolic imbalance, contributing to insulin resistant and 'diabetic' horses and ponies which are prone to laminitis and eventually the Cushings-like syndrome. It also leads to restricted peripheral circulation (eg in the hooves) and hind-gut acidosis, which has much more serious consequences than the horse just having runny manure for a few days!!!

Many horses graze pasture that is termed 'horse-sick' because it is never fertilized or attended to. It will likely have a low pH (docks, thistles, blackberries and other undesirables love this environment) which, as already mentioned, also suits the endophyte rye-grass and fungal populations in general and also tells you loud and clear that the soils lacks, amongst other things, calcium and possibly magnesium, a soil test will confirm this.

Add all this to the fact that perennial rye-grass, paspalum, and couch, containing endophyte fungi that produce mycotoxins and Kikuyu under certain conditions contain toxins that are all known to affect the health of stock, can quite often be the dominant grass species. Something else to keep in mind is horses grazing on couch grass or white clover under curtain conditions can produce cyanide other wise known as prussic acid poisoning. Affected horses have been know to become very dangerous and can have 'bucking fits' and become uncontrollable, placing the rider or handler in very real danger.

by Jenny Paterson B.Sc (New Zealand) (Revised by Lucy Prior - Australia)  © Copyright 2009

Click on the links below to find out more -

What are Myco-toxins

Grass Tetany & Hyperkalemia

Mineral deficiencies

High Sugar diet = Lack of fibre Insulin resistance / Acidosis / Laminitis

Photo-sensitivity.. Sunburn & Mud fever

Respiratory Problems

Head-Flicking / Shaking

Pasture Grass (How safe is your horse’s pasture?) - Find out which grasses are safe for horses and which are best avoided

Provide-It plan for calm, healthy horses

Contact us for further advice