Byron bay Lectures

Fructans and starches not responsible for pasture laminitis.

Fructans and starch are not responsible for most cases of laminitis, Dr Teresa Hollands told delegates at the Laminitis Awareness 2010 seminar.

Most cases of laminitis occur when horses are eating grass. Pasture associated laminitis accounts for 66% of cases occurring in the UK. But what causes the laminitis?

Experiments have shown that giving large meals of starch or fructans can cause laminitis. Large amounts of these carbohydrates suddenly arriving in the horse’s large intestine disrupt the normal population of bacteria in the gut, leading to a cascade of inflammatory and toxic events.

However, Dr Hollands, nutritionist at Dodson and Horrell, explained that this process is unlikely to be involved in the majority of cases of pasture-associated laminitis.

Firstly, grass contains little starch. Of the pasture plants commonly found in the UK, only clover has significant amounts of starch. Grasses store glucose that they can’t use straight away as fructans.

It has been shown that laminitis can be induced by giving a large bolus of fructan  (5g-12.5g fructan/kg body weight).  That’s about 3.75kg fructan for a 500kg horse.

How much fructan would a horse eat when grazing? Grass contains higher levels of fructan during the winter. Mixed pasture might contain 150g fructan/kg dry matter of grass in the winter (compared with 6.6g/kg in the summer). If a 500kg horse eats an amount of grass equivalent to 2.5% of his body weight, (12.5kg), his total intake of fructans would be about 1.9kg.

So the full daily intake falls short of the levels that have been shown to cause laminitis. And what’s more, as horses are “trickle feeders”, that fructan intake is spread out over 24 hours. So even in the winter when the fructan levels in the grass are highest, the horse is only likely to eat something like 50g fructan/hour. In the summer the figure is likely to be about 5g fructan an hour - a thousand times less than the amount needed to cause laminitis.

What’s more, recent work has shown that fructans are fermented in the small intestine, and so are even less likely to reach the hindgut in sufficient quantities to cause food-induced laminitis.

So how does grass cause laminitis? “We need to move away from thinking about individual components of the diet "  Dr Hollands suggested. “In the end it is the calories that are the main risk factor.”

“Grass provides more than enough calories for most horses in light work.”

She explained that recent work with World Horse Welfare and Napier University used alkanes to measure grass intake.  Every day, some horses ate an amount of grass equivalent to 5% of their body weight. Some individuals increased their body weight by 4% a week.

“So you can see that grass easily provides horses with excess calories,” she said “ leading to gradual accumulation of fat. Excess calories over time equals fat. Not all fat is the same.”

She explained that research had shown that some adipose (fat) tissue is metabolically active. The fat cells (adipocytes) release numerous biologically active substances (adipocytokines), which affect glucose and fat metabolism. When present in excess they can lead to insulin resistance, which in turn can result in laminitis.

“The slow insidious eating of excess grass over years is the problem; not the grass they ate today. People get insulin resistance and diabetes because they have been on a bad diet for years, not because they ate a doughnut today!”

What can you do to prevent laminitis associated with insulin resistance?

First you need to reduce the fat. Give thirty minutes exercise daily with a heart rate of 80 beasts per minute. (“Turnout in the paddock is not enough” she says). Accept that the horse or pony will lose weight (fat) over the winter.  Indeed encourage him to do so by using lightweight rugs only - so that he burns fat to keep warm.

Do not starve the horse. Maintain the bulk intake (at 2.5% of body weight) - otherwise he will be prone to developing stereotypies or gastric ulcers. But reduce the calorie intake - soak the hay for 12hours or feed oat or barley straw.

Make sure horses do not get too much grass. Consider using a muzzle; increase the number of horses (and /or cattle and sheep) on the pasture. It’s important to feed a balanced diet.  Make sure the horses receive adequate proteins, minerals and vitamins by feeding a low calorie commercial feed balancer.

The solution is to reduce obesity, ensure nutrition is optimal, and increase exercise.

Paddock Paradise

 

Goals: To create maximum movement in the horse

           To provide different footings for the horse

1. Use as many natural resources as possible to create tracks

The difficulty people have is wanting the place to ‘look nice’. Fair enough but the paddock must be set for the horse FIRST!

So where possible use natural banks or rock outcroppings, treelines etc as ‘fences’.

2. Motivation to move is key, ie water must be as far from the paddock as possible to ensure the horse moves from water to paddock and back again.
3. Terrain is important, Rock should be placed in varying sizes. Use larger rock and roadbase around dams…mix it up! The idea is to a) create a surface that the horse can dry his feet on…ideally if they can get around 4 hours a day (the horses seem to do this too!) of not standing in paddock wet or mud it helps the feet a great deal and b) create a surface that will naturally wear the feet.
4. Create good rock entrances to dams to avoid muddying the water and making possibly dangerous mud traps. Horses will play in the mud and water if they choose by going in a little deeper if it is safe.
5. Use roadbase at your gate
6. Put down 10ml aggregate in shelters
7. Use a mix of roadbase and 10ml aggregate around trees
8. Try to create a distance of at least 100m (500 would be great!!!) into the water spot and roadbase that. Of course, all things costing a fortune, this can be added to slowly and built up over time!
9. Do not create pockets where horses can get boxed in, and ensure there is plenty of movement area around the gates.
10. If using shelters for groups a large open barn system is best or a simple wall with roof, or just a roof…avoids boxing situations.

 

Stabling options.

Our climate is extremely difficult to keep horses well in. Although stabling is not necc the best for horses in my opinion it is for this climate!for many horses, not all!)

Traditionally we have bedding of sawdust or shaving, ricehulls and some still use straw. However we can utilise our rock here…10 ml aggregate in the box really does the feet wonders. Find out what suits your horse…that means maybe bringing in an itchy horse around 4pm or leaving a horse out as late as possible...try to not let the horses stand in a box for over 12 hours. Box size should be as large as possible. Legal minimum is 3.6 x 3.6 for horses and 3x3 for ponies (minis are easy lol!) but the ‘king’ sized box is much more preferable if possible. (5x5). Stables with an attached yard are great. If you have a hot sort of horse that you are concerned goes a little silly after a night in the box then use the round pen to let of steam first…or consider, more ideally, if this horse really needs to come in. We are not in a natural situation, and we need to find the right balance for each individual for maximum mental and physical health. There are very few absolutes ie we cannot say rugging is evil never do it, or stabling is evil never do it!! We have NO HOPE of recreating the natural ‘wild’ environment for horses now, we don’t have enough space in the right places.

Feeding Rhodes mixed in with Lucerne is a great way to ensure you are not overfeeding the ‘greens’ and also making a slow feeder will reduce boredom and  slow them down. Toys can provide amusement too.

Slow feeders...google them up and see where it leads you!

 

The Circulatory system Part one.

Blood is an essential component of the mechanism whereby oxygen is transferred from the lungs to all of the body’s organs and tissues.

 

Blood is carried AWAY from the heart via the Arteries and TOWARDS by the veins.

What we hear from the heart is the movement of blood and closing of heart valves (lub dup!)

The 2 Atria (singular is Atrium) fill and contract, then the 2 ventricles fill and contract.

 

So just how much blood does a horse have anyway?

It varies some from breed to breed, but an average value is:

 

80 ml (cc) per kilogram of body weight

100 ml/kg for “hot bloods” such as the Thoroughbred 

65 ml/kg for “cold bloods” such as a Pecheron.

So, the average 545.5 kilogram horse has about 54.5 litres of blood

How much can be lost before the danger of shock becomes significant?

The general rule of thumb is that an animal will start to show signs of shock from blood loss when 10% of its blood volume has been lost.

 

A horses BP is 120/70

Blood pressure (BP) is a force exerted by circulating blood on the walls of blood vessels, and is one of the principal vital

 

BP varies between a maximum (systolic) and a minimum diastolic pressure. Systolic blood pressure occurs near the end of thecardiac cycle when the ventricles are contracting. Diastolic pressure is minimum pressure in the arteries, which occurs near the beginning of the cardiac cycle when the ventricles are filled with blood.

Blood pressure changes in response to stress, nutritional factors, drugs, disease, and exercise.

Hypertension refers to arterial pressure being abnormally high, as opposed to hyptension when it is abnormally low. The horse’s BP is taken with a cuff around the tail base.