and with it, laminitis…
Although we have come down to earth with a bump and, after the extraordinary February of this year, March has turned out to be a (fairly) normal March, spring is in the air. The trees are beginning to show signs of green, the daffodils are flowering and, here at least, the violets are in full swing. And the grass is starting to grow… Grass has a very bad press these days – and in some ways quite rightly – but should we be panicking?
We have long realised that there is a correlation between grass and founder or laminitis; for many years it was believed to lie in high concentrations of proteins but in recent years we have come to realise that it is a carbohydrate overload in the form of certain sugars that is the primary trigger. Spring grasses have always been to blame but in fact, late summer and autumn grasses can be high in damaging sugars too. So why do we particularly think of spring and is grass really all that bad?
In traditional circles, horses rarely see the light of day in the winter months and will be kept alive on a mixture of hay, possibly haylage, and commercial feed, almost always grain or cereal based with molasses to give it a “temptation factor” and to act is a binding agent. Hay alone is not a big problem, albeit that it is dead grass, it is often of a reasonable quality and has restricted sugar and starch content. Haylage is not simply hay bundled in plastic! Haylage is hay that has been cut “wet” and wrapped immediately. One of the principle reasons for producing haylage is the lack of need to dry the hay for several days, risking it being rained upon. It can also be stored longer, provided it is well sealed and the packing remains undamaged. The disadvantage is that the sugars in the hay are fermented creating a sweet, albeit to some, slightly acrid, smelling soft hay. The alcohol formed by this fermentation is reconverted into sugars by the body. These sugars are then in turn broken down by the body but rather than a slow bacterial breakdown, as with grass and hay, it is a much more rapid conversion similar to grain and cereal. As a result, horses on a diet including haylage and/or commercial feeds are maintaining their blood sugar levels throughout the winter.
Turning out for the first time on a beautiful spring morning, sun shining, birds singing and a crispness in the air that follows an early morning ground frost, would seem to be a great pleasure – and particularly for our horses. But the combination of low temperatures and sunshine will greatly increase the levels of damaging sugars in the grass. Already well stocked up on blood sugars from a winter of restricted movement and bad food, our horse is now confronted with field of delicious grass that will tip the balance completely. The overload results in rapid sugar intoxication and the equally rapid onset of laminitis.
Horses that are kept outdoors 24/7 all year round and not fed any form of grain or cereal based feed are much less likely to suffer from laminitis, even when confronted by the same carbohydrate rich grass. The reason is quite simple; during the winter period, the blood sugar levels drop considerably and a healthy horse will lose weight at this time. This does not mean it loses musculature, but any fat reserves that may have built up during the previous season will certainly have diminished. Because the blood sugar level is now low, the “hit” of spring sugars is not going to have the same effect on the feet. What we are doing, in effect, is breaking the cycle of insulin resistance (IR). If we keep building on the blood sugar levels, year in, year out, then the bomb is bound to go off at some time; if we break the cycle every winter, we effectively “defuse” the bomb. And like many things, if we carry on with a bad habit, the consequences often become irreversible. Insulin resistance is prevalent and is in most cases at the irreversible stage. Metabolic diseases such as PPID and EMS will often have their origins in insulin resistance.
Does the sort of grass make a difference? Yes, and no. Rye grass, very prevalent in Northern Europe because of its ease of growth and high yield, particular for the dairy and meat industry, probably has the worst press – and quite rightly too. Its sugar content is sufficiently high to form a rapid trigger for laminitis problems; nevertheless, many horses that are exposed to rye grass all year round, seem to develop something of a resistance to insulin resistance – a sort of immunity? And horses that are allowed to break their IR cycle every year are highly unlikely to succumb on rye grass.
That said, keeping horses – or any grazer for that matter – on a single type of grass is fundamentally wrong. Different grasses, weeds, plants and shrubs all bring with them their own very important characteristics and properties that horse must be allowed to tap into.
Extract from the Sabots Libres Newsletter, Spring 2016