Racehorses, Swimming, and Colic

Performance horses are kept in top physical condition by a variety of methods, and where facilities exist, swimming can be a beneficial means of exercise. However, some veterinarians have observed an association between swimming and the onset of colic. A team of Australian researchers recently took a closer look at the link and determined that while swimming-induced colic does occur, it doesn't happen as frequently as some might have thought, affirming swimming as a good source of exercise for athletic equine athletes.

A team of researchers led by Liz Walmsley BVSc, MACVSc, MRCVS, a clinical tutor and resident in equine surgery at the University of Melbourne Faculty of Veterinary Medicine, set out to determine how often swimming-induced colic (SC) occurred in racehorses as opposed to other forms of colic. The researchers classified the ailment as swimming-induced if it occurred within 30 minutes after the horse swam.

The team's retrospective study examined records of racehorses that were seen for colic at a large equine racetrack hospital between January 2002 and December 2004. Key findings included:

  • During the study period there were 361 colic cases documented with 136 of those being considered SC cases;
  • Approximately 1 out of every 1,200 swims during the three-year study period resulted in an SC case.
  • Some horses had SC on more than one occasion;
  • Five of 136 SC cases required surgical intervention; and
  • The prognosis after SC was good, with all 136 cases surviving.

The team collected additional information on 21 surgical SC cases from three additional Australian equine hospitals. Data was collected from January 2002 to June 2009 and showed:

  • In all cases horses had a poor response to pain-killing drugs;
  • Abnormal distension of the large or small intestine was reported 14 of 21 cases;
  • Twenty horses survived (the nonsurvivor was diagnosed with severe large colon torsion [twist] and was euthanized 24 hours after surgery due to complications); and
  • Eighteen of 21 survivors went on to race post-operatively.

The cause of SC remains unknown, but Walmsley indicated that some horses seem more prone to colic (of any kind) than others. Additionally, it's important to discuss any new treatment or exercise options—swimming included—with a veterinarian prior to beginning the activity with an animal.

Her team concluded, "swimming exercise infrequently results in colic, yet with high numbers of horses swimming, it is a relatively common reason for racetrack veterinarians to examine a horse for colic."

The study, "Colic after swimming exercise in racehorses: an investigation of incidence, management, surgical finding and outcome," was published in May in the Australian Veterinary Journal. The abstract can be viewed online.

Disclaimer: Seek the advice of a qualified veterinarian before proceeding with any diagnosis, treatment, or therapy.