What are the most common causes of ill thrift in horses?

In most cases where horses are showing ill thrift, they are not necessarily sick or off their feed.

The main causes of ill thrift are:

  • 1. Malnutrition
  • 2. Parasites/worms
  • 3. Teeth
  • 4. Sore feet
  • 5. Lice
  • 6. Chronic infection
  • 7. Ulcers
  • 8. Vices
  • 9. Horse being ‘bullied’ at feed trough
  • 10. Overtraining
  • 11. Old age

    • 1. Malnutrition:

  • This can be one of the most common causes of ill thrift, weight loss and debility in horses. If a horse is not getting enough feed to satisfy its needs, it will lose weight.
  • Lack of the proper minerals: If a horse is short of fodder, it will also be short of minerals.
  • Lack of a properly balanced diet can be a cause of malnutrition.
  • Some land may be deficient in some minerals, for example copper, and in itself this could cause ill thrift. But this is not very common in horses.
  • Horses are natural grazers who eat little and often. Their natural diet is mainly grasses, which have a high roughage content. Horses should be fed an appropriate diet that reflects their needs and consideration should be given to the age, type, weight, condition, health and level of work of the individual horse.

    • 2. Parasites/Worms:

  • Horses with a heavy worm infestation do not thrive irrespective of the amount of feed they get or how good the feed quality may be.
  • Horses in intensive grazing systems, i.e. paddocks where large numbers of horses are grazed over the years, are more likely to develop a high worm burden.
  • Good pasture management is important to avoid over-grazing and to aid worm control. This includes, for example, picking up droppings, rotating grazing areas, mixed grazing and where possible, by reducing the stocking density.

    • Could a horse that is dosed regularly with pastes still have worms?

  • Yes, many of the common parasites in horses are showing resistance to worm doses, especially the worm larvae or developing stages (cyasthosomes), which are embedded in the gut wall/lining. Most of the regularly used worm doses fail to get to them.

    • What is the better dosing option to overcome the problem of worm resistance?

  • Many owners are now requesting the veterinary surgeon to stomach tube their horse with a selected wormer for better more effective anti-worm treatment.

    • 3. Teeth problems:

  • Teeth problems are a common cause of ill thrift particularly in older horses.
  • Basically horses with sharp teeth cannot chew their feed adequately for proper digestion.
  • In many of these cases, sharp teeth may also tend to cut the horse’s gums and inner cheek area making it sore and irritated. Where this occurs, the horse becomes reluctant to eat, in order to avoid the pain associated with chewing the feed.
  • Also some horses with sharp teeth will not chew the hay or grass adequately, so it is left in a ‘ball’ at the back of the horse’s mouth. Others may tend to drop the partially chewed hay out on the ground.
  • Treatment and prevention of this problem is basic routine teeth care - rasping etc.

    • 4. Sore Feet:

    How could sore feet affect a horse’s body condition?

  • Basically any continuous pain can prevent a horse from thriving.
  • When the feet are sore, the horse is not inclined to move about the paddock, which is part of the horse’s normal behaviour to find new grazing areas and to keep itself warm.
  • The loss of weight occurs even more rapidly in severe sleety weather conditions which we are currently experiencing as the horse is not moving about to keep itself warm.
  • A typical example is Laminitis which is very painful causing reluctance to move around the paddock. In these cases, it is very difficult to keep condition on the affected horse as part of the treatment of Laminitis is to cut back on its feed intake.
  • If a horse has severe lameness with a lot of pain, it loses weight very rapidly.
  • These cases require veterinary diagnosis and treatment.
  • Close monitoring of the paddock underfoot conditions and routine farrier treatments are also an important part of prevention.
  • Where the ground is very wet and becomes ‘poached’ in the muddy areas, for example in the feeding areas, this can cause foot problems, ill thrift and health problems. In these circumstances, it is important to ensure that a horse has a ‘dry lie’ in an adequately sized, well-drained sheltered area where it can be comfortable and fed.