Internal medicine

Sand Accumulation

Sand accumulation in the ventral aspect of the large colon can be a life-threatening issue for horses.  Build ups can occur quickly or over a period of years causing sand to sediment and compact layer upon layer.  The increased weight in the large colon acts like a pendulum and can cause displacement of the remainder of the gastro-intestinal tract, resulting in colic.  Annual sand management programs such as drenching or addition of psyllium-based products to feed can aid in reducing this build up.  Recently, some success has been achieved with the use of an Equissage® pad, facilitating the vibration of impacted sand and aiding its movement out of the gastro-intestinal tract.

Sarcoids

All members of the equid family (horses, mules, donkeys, zebras) can be affected with cases reported in approximately 2-8% of the population.  Sarcoids can occur almost anywhere on the skin, although there are some regions that are more predisposed to their development.   The sarcoid has several implications, and is a form of cancer.

Sarcoids are likely to multiply on a horse and may enlarge:

  • quickly – especially when the sarcoid is traumatised or interfered with
  • slowly – some can remain static/quiescent for many months/years

Trauma can trigger the development of the most aggressive forms of sarcoid, from even the earliest and smallest lesions. The tumours may ‘spread’ across the horse, meaning that more develop over time. There may be different ‘types’ and ages of sarcoid on the one horse as they continue to spread over the life of the equine at an unpredictable rate.

Ways Sarcoids affect horses
  • Secondary ulceration and infection – can become a serious welfare issue in badly affected horses which can result in low blood protein levels and anaemia. Horses can be destroyed on human grounds in severe cases.
  • Development at highly sensitive body sites (eg. eyelids, joints, coronary bands) which can lead to functional problems. Treatment at these sites is usually restricted, and more problematic.
  • Cosmetic issues – sarcoids can be unsightly if located in prominent positions on the horse’s body and can also make wearing certain tack and rugs difficult.
  • Unsettling nature – flies are attracted to sarcoidsespecially in the summer months and this can be highly distressing for the horse.  Some horses also experience performance limitations because of their sarcoids.

Sarcoids are a common cause of loss of commercial value even in high performance horses.

How do horses get Sarcoids?

There is a strong suggestion that sarcoid is transmissible between horses, but it is not yet clear what mechanism is involved in this.  Transmission appears to take place primarily in the summer months, so vector (fly) transmission is likely and close contact with cattle has been suggested as a risk factor.  It is thought that bovine papilloma virus (BPV1) is involved in some way, however this is still being researched and a definitive cause has not yet been found.  The tendency for horses to develop a sarcoid may be inherited as studies have shown that related horses may be severely affected and some families and some breeds may be more (or less) susceptible.

Types of Sarcoids
  1. Occult
  2. Verucose
  3. Nodular
  4. Fibroblastic
  5. Mixed
  6. Malignant
Pars Pituitary Intermedia Dysfunction (PPID/Cushings)

Pituitary Pars Intermedia Dysfunction is one of the most common diseases of the endocrine system that can affect horses.  It causes the horse’s pituitary gland, which utilizes hormones to control body functions, to work overtime. This can lead to a variety of problems for horses, ranging from unexplained laminitis to abnormal fat deposits. PPID affects both male and female horses, all breeds and horses as young as 5 years of age with middle-aged to geriatric horses being the more commonly diagnosed age group.  The clinical signs of PPID vary widely and often early clinical signs can go unrecognised.

  • Decreased athletic performance and/or lethargy
  • Delayed shedding/decreased shedding
  • Weight loss
  • Cresty neck/fat pads around tail head/swollen sheath
  • Excessive thirst
  • Excessive urination
  • Abnormal (increased or decreased) sweating
  • Loss of muscle mass
  • Laminitis
  • Recurrent infections

There is no cure for PPID but the disease can be managed with the use of pergolide.  Most horses show an improvement and resolution of the above listed clinical signs within 6 months of starting treatment.  Once initiated, pergolide treatment needs to be continued for the life of the horse.

McLaren Vale Equine Veterinary Services, equine vet starting, McLaren Vale region, Adelaide
Equine Metabolic Syndrome (EMS)

Equine Metabolic Syndrome can affect all types of horses and is particularly prevalent in ponies.  Certain breeds have been recognised to be at greater risk of EMS including Welsh, Shetland ponies Morgans, Arabs and Warmblood horses.  It is a condition of obesity which can predispose to laminitis and shares similarities with Type II diabetes in humans.

The disease is characterised by a reduction in the normal response to insulin (insulin resistance). Insulin’s most important function is the control of glucose levels in the blood and when insulin resistance occurs the normal relationship between insulin and glucose levels becomes disrupted.

In addition to insulin resistance the syndrome also encompasses other potential metabolic derangements including:

  • altered energy metabolism
  • changes in fat composition
  • clotting disorders
  • inflammation and damage to blood vessels, especially those in the feet giving rise to laminitis.

Management of EMS cases involved dedicated attention to feeding and exercise for the life of the horse.  Horses with EMS should be fed a diet that is low in soluble sugars and starches, and additional medication such as Metformin can be used in short term management of cases.

McLaren Vale Equine Veterinary Services, equine vet starting, McLaren Vale region, Adelaide
McLaren Vale Equine Veterinary Services, equine vet starting, McLaren Vale region, Adelaide