Feeding management of the colic patient

Feeding management of the colic patient

 Dr C.E. Foote

Equine Consulting Services

Colic is responsible for more deaths in horses than any disease group except for old age. Prevalence at university hospitals and some practices rank simple colic and impaction colic as the most common diseases. Diseases which cause strangulation obstruction have the highest case fatality rate. Information about incidence, mortality and risk factors is helpful in making decisions about individual cases as well as herd problems. 

Incidence

In one study conducted in the US, the following incident rates were reported:

• Out of 100 horses in the general population, 4-10 cases of colic is expected in one year
• About 10-15% of the colic cases are repeat cases with some horses having 2-4 colic episodes in a year
• Most colic signs represent simple colic or ileus with no specific diagnosis identified in 80-85% of cases
• In one study, approximately 30% of horses with colic were identified by owners but never seen by veterinarians because the colic was transient or resolved by owner treatment
• Studies of colic cases diagnosed in veterinary practices have also reported a predominance of simple obstruction or spasmodic colic
• Impactions make up about 10% of cases
• Obstructing or strangulating diseases requiring surgery make up from 2-4% of colic cases though some risk factors in certain populations can increase this rate
• In the normal farm population, horse mortality from all types of colic was 0.7 deaths per 100 horse-years, with a colic case fatality rate of 6.7%. In one study case fatalities were due to stomach rupture, strangulating lesions or enteritis.

Risk Factors

The following factors have been significantly associated with increased risk of colic:

• Feed type and volume
  • Grain overload increases the risk of colic and laminitis. Daily feeding of concentrate from 2.5 to 5kg/day and >5kg/day to adult horses increased the risk of colic compared to horses fed no grain.
  • Pelleted feeds and sweet feeds were associated with an increased risk of colic compared to no grain fed or single grain diets
• Recent change in diet
  • a change in diet during the 2 week period before examination was associated with colic
• Recent change in type of hay
  • A change in the type of hay may result in colic for many reasons. Hay of poorer quality is often less digestible, thereby predisposing to colonic impaction
  • Feeding from round bales were also associated with an increased risk
• Poor dentition has been linked to colic due to poor mastication of food, though this has not been scientifically evaluated.
• History of previous colic
  • Horses having a history of colic were at higher risk for more colic episodes
• History of previous abdominal surgery for colic
  • Horses which had previous abdominal surgery were also at higher risk of repeat colic.
  • Horses have a higher rate of repeat colic (1-2 episodes) within the first 2-3 months after surgery after which the rate decreases to near normal
• Recent change in weather conditions
  • Change in weather conditions during the 3-day period before examination was significantly associated with increased risk of colic
  • Cold weather which affects water intake has been linked to increased impaction colic, however most likely the focal increase in colic episodes was not directly related to the weather, but rather due to management changes caused by the weather.
• Recent change in stabling
  • In a study conducted in the UK, recent change in housing management was the most commonly reported putative risk factor for spasmodic or undiagnosed colic
  • Anecdotal information from large breeding farms suggest that the routine of feeding horses grain after being brought in from pasture and then keeping them in stalls increases the risk of colic and specifically colon tympany and displacement. Altering the routine by keeping horses turned out after feeding grain decreases the rate of colic albeit based on farm records and veterinarian impression. Similarly, when hay is available to horses on lush pasture, the hay will be consumed as part of the diet and colic rate is decreased with horses turned 24 hour per day
• Arabian breed
  • Explanations for association of Arabian breed with colic include differing management practices for Arabians, increased awareness and concern about colic among Arabian horse owners or genetic predisposition to gastrointestinal disorders among Arabians. 
• Administration of an anthelmintic during the 7-day period before examination
• Failure to receive regular deworming
  • Receiving anthelmintics on a regular basis was associated with decreased risk of colic. Administration of anthelmintics however is not without risk. Colic was associated with recent deworming, irrespective of the product used. In foals, recent deworming may cause colic associated with intestinal obstruction resulting from rapid death of intraluminal ascarids, and recent (within 2 weeks) administration of an anthelminthic can increase the risk of intestinal disease associated with larval cyathostomiasis.
• Age > 10 years
  • Young and older horses appear to be at less risk of simple colic, however middle aged horses have been reported to be at higher risk. Older horses may have more opportunity for development of disease or exposure to causal factors. The incidence of certain forms of colic is more common among older horses (e.g. strangulating lipomas)
  • Weanling and yearlings are more likely to have ileocecal intussusceptions
• Sex is an apparent risk for some disease such as inguinal hernia in stallions and large colon displacement/volvulus in peripartutient mares however for the most part male and female horses appear to be equally affected by simple colic
• Regular exercise (vs pastured at all times)
  • Horses that received no exercise other than that obtained in their pasture were significantly less likely to develop colic than were horses exercised at least once per week. It was observed that horses at pasture, which are generally from larger farms with lower density of horses are at decreased risk of colic or being observed to have colic
  • Racehorses, event horse and horses used on endurance rides all have an increased risk of gastric ulceration which can be linked to some colic episodes.
• Horse transport increased the risk of colic risk in several studies

Post-operative feeding management of the colic patient

Small intestinal disorders

A concern with feeding of high bulk feeds, such as long-stem hay in the early postoperative period is distension at the site of enterotomy and/or anastomosis. In horses with sutured esophageal wounds, a traditional hay-grain diet can result in development of fatal complications presumably because this high bulk diet promotes distension at the incision site, increasing the probability for wound dehiscence. On the other hand, horses with esophageal injuries that are sutured closed can make a full recovery if fed a soft diet (e.g. slurry made from pelleted feeds) for 8-10 weeks following the injury. Fresh grass (hand grazing) and mashes or slurries made from alfalfa pellets or pelleted complete feeds are suitable feedstuffs. Molasses may be added to the mash to enhance palatability. Small meals should be fed every 3-4 hours in an effort to minimize physical stress at the anastomosis site. In uncomplicated cases of resection there should be a gradual introduction to long-stem hay after 3-4 days of soft diet feeding. Bran mashes are not recommended for horses recovering from small intestinal surgery. Diets based on Lucerne are recommended, as is beet pulp shreds and stabilized rice bran (a source of digestible fat) also are suitable feedstuffs and vegetable oil 100-500ml per day. Grains should be avoided as the capacity for starch digestion is probably greatly diminished.

Large intestinal disorders

Horses should be fed small amounts of grass or soft grass hay at frequent intervals (every 2-3 hours) as early as 12 hours post-surgery providing there is no evidence of gastric reflux or poor intestinal motility. First cut hay is preferred because of higher dry matter digestibility compared to more mature forages. No grain or concentrate should be introduced until 10-14 days post surgery. However the feeding of a low bulk pellet feed such as Equine Senior feeds may be beneficial. In the early postoperative period, horses that have undergone extensive resection should be fed small amounts of a low-bulk feed such as Lucerne pellets or a pelleted commercial feed. Subsequently legume forage should be the predominant component of the ration. Following experimental colon resection, a ration of Lucerne hay or a Lucerne/grass hay mix provided better results when compared to straight grass hay perhaps due to higher digestibility and protein content. Supplemental phosphorus can be provided in supplement form or by feeding 500g wheat or stabilized rice bran daily. If additional calories are required, a fat and fibre concentrate rather than grain or sweet feed is recommended.

Horses with impaction of the large intestine (caecum or colon) should be fed soon after resolution of the impaction. Fresh grass, Lucerne pellets, shopped alfalfa hay and other sources of highly digestible fibre are preferred. It has been suggested that pelleted feeds may allow for increased rate of passage due to smaller particle size when compared to long-stem roughage. Thorough oral examination should be undertaken to establish whether inadequate mastication of feed is an underlying cause of the impaction.

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References

Cohen, N., Gibbs, P., Woods, A. (1999). Dietary and other management factors associated with equine colic. Proceedings of the American Association of Equine Practitioners, Vol 45.

Geor, R.J., (2005). Nutritional considerations for the colic patient. American Association of Equine Practitioners – Focus meeting 2005 – Quebec, QC, Canada.

White, N.A. (2005). Prevalence, demographics and risk factors for colic. American Association of Equine Practitioners – Focus meeting 2005 – Quebec, QC, Canada.