Hyperlipaemia is a metabolic disorder which predominately affects pony breeds, although larger breeds of horses can also be susceptible. Studies have indicated that up to 5% of ponies on studs in Victoria develop the condition each year. 

Hyperlipaemia is a life threatening metabolic condition with an inherited risk in certain bloodlines of ponies. However, the main trigger for onset is rapid reduction of feed intake in heavily conditioned ponies, with heavily pregnant and lactating mares requiring a high energy demand being the most susceptible. It has also been reported in fasting or starved donkeys. 

Another condition with a similar sounding name is hyperlipidaemia, which relates to excess blood levels of lipids or fats. It is a common finding in horses and ponies following exercise or reduced energy intake due to colic, surgery and short periods without regular feed. 

Hyperlipaempia is caused by the body’s natural reaction to mobilise fat reserves for energy, thereby increasing circulating lipids (fats) in the blood. It is not life-threatening and is a transient normal reaction, except in ponies and donkeys where it can be a predisposing cause of hyperlipaemia. 

Hyperlipaemia in susceptible ponies on the other hand is a complex metabolic condition which can invariably result in death within 10 days if the symptoms are not recognized early and expert veterinary intervention and nutritional management is not carried out. 

Metabolic Changes 

In a normal healthy horse, most of the fat or lipids circulating in the blood to provide energy and omega fatty acids to the cells is in the form of a very low density lipo-protein (fat-protein complexes), produced in the liver. 

Although some fatty acids can be used to provide energy to maintain body functions, when higher levels are released and form longer chain lipo-protein complexes in the liver, they are unable to be metabolised and begin to accumulate in the liver and blood. 

It is most common in overweight middle-aged and aged ponies, especially those that have developed insulin resistance and a ‘cresty’ neck, which is the underlying trigger for insulin induced laminitis and metabolical Cushing’s Disease and associated laminitis. 

The insulin hormone, which controls blood sugar levels, is also required for the activation of a lipo-protein enzyme, lipoprotein lipase, which breaks down these fat reserves as they pass through the liver. In a pony at risk of mobilising lipoprotein complexes which are unable to be broken down due to associated insulin resistance, the complexes accumulate in the blood and metabolic function is interrupted, with increased risk of high blood lipo-protein levels, culminating in liver and kidney failure. Both these organs develop a fatty infiltration which makes them appear and feel greasy on post mortem. 

Predisposing Causes 

Obese, overweight ponies, especially heavily pregnant and lactating mares, have the highest risk of developing hyperlipaemia when there is a sudden shortage of food, requiring them to revert to use stored fat as an energy source. 

As little as 12-24 hours of negative energy balance without hard feed or ability to graze can trigger the dangerous and potentially fatal lipo-protein build-up. 

Hyperlipaemia is linked to snow falls, heavy, flooding rain and bushfires where food supply is interrupted or grazing is severely restricted, rather than a slow onset of food reduction, such as occurs in a drought or drying off of summer pasture. 

The condition is most common in cold, wintery conditions, or ponies grazing poor quality feed when the demand for energy is increased and fat reserves are mobilised to fuel metabolism, superimposed by the higher demands of pregnancy or lactation in pony mares. Long distance transport and severe sickness, such as colic, immobility and lameness (laminitis, bone fracture, hoof infections), tooth problems, heavy worm burdens and viral disease (such as Equine Herpes and Equine Influenza) can all reduce a pony’s ability to graze and maintain a regular uptake of sugars and insulin activity, which also regulates the lipo-protein enzyme. 

Typical Signs 

Early warning signs include a history of severe stress, food restriction or inability to graze due to weather, lameness or severe disease which triggers the onset of metabolically induced hyperlipaemia. 

Signs include a loss of appetite even when food is offered after the cascade of liver and blood lipo-protein accumulation occurs, depression, diarrhoea, drowsiness, weakness and reduced vitality and well being. 

As the condition progresses over 3-5 days, ponies stop drinking, become inco-ordinated, develop a fever, soft swelling in the lower limbs (oedema), muscle twitches, colicky signs, with collapse and death in 8-10 days from onset due to liver and kidney failure. Elevated blood levels of the stress hormone, cortisol, along with low insulin secretion, increases the risk of hyperlipaemia. 

The overall prognosis is poor in ponies and donkeys 4-5 days after onset, with between 45% and 85% of ponies dying despite extensive and expensive veterinary support and therapy. 

A blood sample will reveal a cloudy serum with triglyceride concentrations above 500mg/dl, or even up to 1500mg/dl in severe cases. If the serum triglyceride concentration remains below 500mg/dl as occurs with the hyperlipidaemia state, the clinical signs rarely develop into those typical of hyperlipaemia. Liver enzyme concentrations are also elevated as liver, kidney and organ failure develops. A liver biopsy will reveal fatty infiltration, which in severe cases, may rupture due to excess lipo-protein build-up, which then results in rapid collapse and death. 

 Management 

Whether hyperlipaemia is primarily due to a sudden food restriction or a disease process, once the serum triglyceride levels increase above 500mg/dl, it is difficult to manage and treat successfully in the short time of 5-7 days before liver and kidney failure develops. However, if the early warning signs are observed and nutritional support is provided with a low fat, high energy diet, then recovery is possible up to 4-5 days after onset of the condition. 

Management includes: Treat any primary disease process, such as investigating reasons for lameness, relieving colic and managing laminitis. 

1.Ensure that the pony is provided with a low-fat, highly digestible diet, split into a number of feeds per day, to help maintain a more constant blood sugar level to limit the mobilisation of fat and build-up of lipo-protein complexes in the liver and blood. A dampened feed made of 1kg millrun, 2kg crushed oats or boiled barley to encourage eating, 400g white chaff, 400g lucerne chaff, 200g Speedi-Beet (soaked in water for 10 minutes) sweetened to taste with 300g (1 cupful) of molasses and 30g of salt in 2 cupsful of warm water, provides a high energy, low fat, palatable feed to tempt ponies to eat. The addition of 100g glucose or dextrose boosts energy intake to help limit fat mobilisation and maintain insulin activity. This mix, with only half the chaff, can be mixed into a gruel in 3 times its volume of warm water and administered by stomach tube into a pony at the rate of 1 litre/100kg body weight 4 times per day until the animal starts to eat voluntarily once again. 

2. Veterinary treatment includes injections of Heparin, an anticlotting agent which helps to reduce plasma triglyceride levels, along with glucose drips and insulin injections, have been found to be helpful in minimising the build-up of harmful long chain lipo-protein complexes in the liver. Consult your own vet for advice. 

Preventative Management 

The risk of hyperlipaemia can be minimised by ensuring that susceptible, overweight ponies (and donkeys) are provided with good quality feeds, preferably fed twice per day, especially when heavily pregnant or lactating under adverse cold, very wet conditions, or during long distance transport. One report of hyperlipaemia in a donkey treated at the Werribee University Clinic linked relocation of a heavily pregnant jenny with grass hay she would not eat over a 3 week period in a paddock she shared with 2 gelding donkeys which ate the hay and did not develop hyperlipaemia. Maintaining ponies in moderate condition by carefully limiting feed intake to avoid excess body weight, particularly as they age and are prone to glucose intolerance and insulin resistance is also an important preventative means of management. Consult your vet for advice 

Links on Equine Atypical Myopathy have now been added to our website, this includes information on The Disease, The Cause, Clinical Signs, Treatment, & Prevention.

This information is provided by The British Horse Society  

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It's that time of year again, Hallowe'en sees our skies spectacularly lit up with shooting colours and loud bangs from fireworks and, while these are enjoyed by most of us, our pets do not particularly enjoy the bright lights and loud noises, which bring about a sense of fear and unknown, so it is important that we prepare and manage animal accommodation to prevent injury and to make the situation as least distressing as possible for the animals...

TOP TIPS FOR HORSES & PONIES:

- Check with your local council to see if there are any organised displays near where your animals are kept, so you can prepare to reduce anxiety and stress of the animals

-Where possible keep horses & ponies in stables to reduce risk of escape or injury. If they do have to be kept outside, ensure fields are secure, so if frightened the animals cannot escape. It's also a good idea to ensure there is nothing that the animals can injure themselves on, such as misplaced fencing or large stones, should they be spooked.

-Try to plan to bring animals in during daylight hours before fireworks are set off, especially if the animals are kept a slight distance away from the stables. This is to ensure the handler is not left in a dangerous situation if the animal is spooked by fireworks whilst leading.

-If you are aware of organised displays nearby, try to plan your riding around this to reduce the risk of riders being injured should a horse & pony be spooked by a large fireworks display whilst out riding.

REMEMBER TO TRY AND KEEP THINGS AS NORMAL AS POSSIBLE FOR YOUR HORSE OR PONY, WHILST MAINTAINING EXTRA COMFORT AND SECURITY... 

Horses need to be transported for a variety of reasons, from occasional journeys such as moving home, changing owner or visiting the vet, to more frequent travelling to attend shows or events. Whatever the reason or frequency of the journey, it is important that the horse is safe and comfortable in order to minimise stress.

The process of transporting horses involves several stages:

-Preparing: planning the route and preparing the horse, vehicle and driver.

-Loading: positioning the vehicle, handling the horse and ensuring the safety of all involved.

-Travelling: ensuring the horse is comfortable, taking breaks, providing feed & water.

-Unloading: deciding where to unload, unloading safely and securely and completing any paperwork.

PLANNING THE ROUTE

Good planning will help the journey to go smoothly. Horses use up energy keeping their balance, so choose the smoothest route where possible. Stopping for breaks will give both you and the horse a rest and allow you to check how it is doing. If a journey is under a couple of hours, you may not need a break but on longer journeys allow time for them. Check the weather forecast and try to avoid travelling on very hot days.

DISTANCE AND TIME

The distance and time of the journey will affect your plans. Extended travel times can be stressful for animals:

-Horses can lose 2-3kg of weight every hour during transport. Most of this is fluid, so it is vital to provide drinking water at regular intervals to prevent dehydration, which can increase the risk of colic or respiratory disease.

-During very long journeys (over 10 hours) there is a risk of 'shipping fever', a form of pneumonia caused by dehydration, dust and poor air quality.

The Welfare of Animals (Transport) Order 2006 states that anyone who transports horses for over 65km 'in connection with an economic activity' (eg a riding school, livery yard, horse transporter or racing trainer) needs a certificate of competence awarded by DEFRA approved awarding body. The horse should be accompanied by an attendant and both the driver and the attendant need certificate. Although the Order does not apply to someone taking their own privately owned horse in their own horsebox to an event, they must meet certain basic standards. They must make sure the horse is fit to travel, use a vehicle that is fit for the purpose and treat the horse humanely throughout the journey. Also, anyone who has passed his or her car-driving test on or after January 1, 1997 is required to pass an additional test in order to tow a trailer of over 750kg. Deciding between a lorry or towed trailer depends on personal choice, finances and requirments, but the vehicle must be appropriate for the horses you are transporting and in good working order, with appropriate:

-Space: horses need adequate space to stand in their natural position, but if there is too much space, the horse will get more tired and may even fall. The law states that an adult horse must have at least 1.75m2 of floor space.

-Ventilation: horses need clean air during the journey.

-Headroom: 1.98m is the minimum, but larger horses may need more.

-Ramps: with matting or a rubber surface. The law states that the slope should not be greater than 20o, or 36.4%.

-Partitions: you may need to use partitions if transporting more than one horse, or if the vehicle is too large for one horse - these should be strong enough to stand the horses weight, and padded to avoid injury.

-Flooring: Double wooden floors are safer than single skin floors. Aluminium plank floors are safer than wooden ones, though it is important to have an isolated membrane between the aluminium floor and the steel chassis. A good quality, non-slip rubber surface will help make the journey more comfortable for the horse. Check the floor regularly for signs of mould, damp or softness, and lift mats regularly to give them a chance to dry thoroughly

VEHICLE CHECKS

Ensure that the vehicle has the correct tax and insurance and is registered to carry the weight when loaded. Before each journey, carry out vehicle checks including tyre pressure, lights, brakes, floor and hitch (for trailer).

CLOTHING AND EQUIPMENT

Horses will need appropriate clothing for the journey. This may include:

-Head collar.

-Poll guards to protect the horse's head from injury.

-Tail guards and/or bandages to prevent damage to or rubbing of the tail.

-Leg protection boots or bandages.

-Rugs may be needed for sweating or to stop a horse getting cold. However, take care not to over-rug a horse, as this can cause sweating and overheating. Check the temperature and weather forecast to make sure you have the right equipment.

The horse may need to get used to wearing this equipment, so try it out over time before you travel. Always travel with a first-aid kit.