Donkeys, as well as some native pony breeds, are particularly susceptible to hyperlipaemia, a disease caused by too much fat in the blood.
All donkey owners should be aware of hyperlipaemia in donkeys as it carries a high risk of death even when recognised and treated promptly.
These types of equines are designed to live in harsh environments where vegetation may be sparse and of poor quality, necessitating walking for up to 16 hours a day in search of food. As a result they tend to put on weight and gain excess fat reserves when living on relatively lush pasture and with limited exercise. Unfortunately when these animals stop eating for any reason hyperlipaemia may develop.
The disease process
When a donkey stops eating enough it goes into a state of ‘negative energy balance’ (more energy being used up than is being taken in). The essential organs still require a food supply, so the body tries to use energy that is stored as fat deposits. The result is that free fatty acids are circulated to the liver to be converted to glucose for use by the body. This system is controlled by complex hormonal events, which should shut down the amount of fat released from fat stores as the liver produces the glucose for the body.
However, donkeys and small ponies are not able to efficiently turn off this fat release and the blood soon fills up with excess fat in circulation. This circulating fat can be measured in the blood as triglycerides by a vet. Large amounts of fat cause the liver and kidneys to degenerate and fail and eventually all the organs in the body fail. The result is irreversible organ damage and death.
Causes of hyperlipaemia
A number of risk factors have been identified as contributing to this condition. It is known that a female donkey is at higher risk than a male, especially when there are high energy demands such as if she is pregnant or lactating. Overweight and obese animals are at higher risk than those in average condition but even thin donkeys are at risk. Donkeys that have lost significant weight in the preceding weeks should be monitored carefully as they are at a much higher risk of developing this disease. When managing your donkey's weight, care should be taken not to crash diet as this will put your donkey at risk.
Stress will cause a donkey to reduce its feed intake and can be brought on by many stressors such as:
- Loss of a companion
- Sudden dietary change
- Social mixing
- Bad weather
- Sudden weight loss.
Any underlying disease can set off other problems such as:
- Dental problems
- Heavy worm burden
Signs of hyperlipaemia
Subtle changes in behaviour are very important early indicators of possible disease problems. So the key to spotting this condition is to know how your donkey normally looks and behaves so you can spot any subtle changes.
As with so many diseases this stoic animal may simply appear dull with a reduced appetite. Halitosis (bad breath) may be evident and there may be reduced production of dung or mucous covered dung. Later there may be ventral oedema (excessive build-up of fluid in the body's tissues) and signs of liver and kidney failure such as head pressing, circling and ataxia (lack of voluntary coordination of muscle movements). Eventually, your donkey will collapse and may suffer seizures before death.
Because the signs are so vague initially, donkey owners must act upon even minor signs, as delays in treatment can reduce the chances of successful outcome.
Prevention is much better than cure
- Where possible avoid or minimise stressful events – make changes slowly, plan ahead, prepare or train your donkey for new situations
- Follow the advice in our Transporting donkeys guide
- Do not let your donkey get over-fat, monitor feed intake carefully, especially with pregnant and lactating mares. If they are overweight follow advice in our Monitoring your donkey's weight guide
- Underweight donkeys are also at increased risk of hyperlipaemia so try to maintain your donkey in a healthy condition and use fibre based supplementary rations where possible
- Provide shelter in bad weather
- Put rugs on old and thin donkeys. Follow advice in our Feeding elderly donkeys guide
- Watch when new members are introduced to the group. Make introductions gradually over several days and even weeks to avoid bulling and minimise stress. This is particularly important when animals, other than donkeys, are introduced as donkeys are frequently the bottom of the pecking order when living with horses, ponies or mules.
Companions, bonding and death
Donkeys form strong bonds with their companions and it is essential that surviving donkeys are allowed to remain with the body of their friend until they have lost interest. Ignoring this advice can lead to significant distress and anxiety among any surviving donkeys. They may show persistent wandering, pacing and braying, as they look for the missing donkey. They may go into a hyperlipaemic crisis as a result of the stress. Please allow at least an hour before the body of the donkey is removed. Closely monitor the bereaved companion(s) for several weeks afterwards as bereavement stress can manifest itself up to three weeks after the death of a friend and result in hyperlipaemia.
Extra attention and time spent with your donkey(s) will help, but don’t be tempted to offer a lot of extra treats, which can be habit-forming and may lead to obesity. If you do decide to obtain a new donkey companion then consideration should be given to getting one of a similar age and size, whose behavioural and physical needs will match the needs of your existing donkey(s).
A dull donkey is a veterinary emergency
If you are concerned ask your vet to visit. In the meantime encourage your donkey to eat. Try fresh grass or taking your donkey to a hedgerow where it can be allowed access to non-poisonous plants, grated apple/carrot and ginger biscuits or any other foodstuff you know your donkey enjoys – this is the one time when sweet treats maybe called for.
Offer some warm clean water to drink. Your vet may take a blood sample and examine it by eye once the red blood cells have settled out as fat can be seen in the serum.
The key to dealing with hyperlipaemia is to reverse the negative energy balance before the fat released into the bloodstream has time to cause organ failure. If your donkey will eat then encourage it to do so. If not, your vet may introduce liquid food via a tube passed up the donkey’s nose and into the stomach. In severe cases the donkey may require an intravenous fluid drip. If your donkey has to be hospitalised its companion must go as well.
Depending on the cause of the hyperlipaemia your vet may also give anti-inflammatory/antibiotic medication.
Where can I found out more?
Our Veterinary department has extensive experience of recognizing and treating hyperlipaemia and is available to discuss cases with your vet. They also offer a free laboratory service for donkey blood samples submitted by your vet.
Want to know more?
Information for donkey owners