EQUINE VETERINARY EDUCATION / AE / AUGUST 2020


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Fig 3: Representative image of the foreign body found in two cases. The mass was uniformly hardened with mineral deposition, giving it the appearance and the feel of an irregular enterolith. The mass was cut into two halves. The left side represents the outer surface and the right side the inner surface of the mass with the foreign body imbedded in the middle.


4 days and flunixin meglumine (1.1 mg/kg bwt, i.v., twice a day) for 24 h followed by 0.5 mg/kg for another 2 days. Additionally, 17 horses received metronidazole (15 mg/kg bwt, orally, every 8 h), 14 horses were treated with polymyxin B (6000 U/kg bwt, i.v., twice a day), 12 horses were treated with low-molecular weight heparin (0.3 mg/kg bwt, subcutaneously, once a day) and 10 horses were administered 2 L of fresh frozen plasma. Cryotherapy for the distal limbs was applied to all horses for 1–7 days and food was gradually introduced following surgery in all horses. Post-operative complications were noted in 11/27 (41%) of


animals recovered from surgery. Complications included: fever (n = 6), diarrhoea (n = 5), incisional infection (n = 4), laminitis (n = 1), abortion 1 week after the surgery (n = 1), peritonitis (n = 1) and pulmonary oedema (n = 1). Mean hospitalisation time was 9.4 days (median: 7 days, range: 5–30 days).


Twenty-three cases survived to discharge (79%). There was


no significant difference between survivors and nonsurvivors (short or long term) regarding the signalment, clinical signs, laboratory findings, surgical findings, methods to remove the FB and post-operative variables. Four horses were subjected to euthanasia during


hospitalisation. The first case was an 8-month pregnant mare in which the FB was not discovered in surgery. The mare suffered from severe post-operative colic, peritonitis and endotoxaemia and was eventually euthanised. At necropsy examination, a FB was found in the transverse colon with necrotic intestinal wall surrounding it. Three cases were subjected to euthanasia 2, 3 and 17 days after surgery due to post-operative complications – two suffered from colitis and the third from peritonitis. Twenty horses were available for long-term follow-up and


were alive and had returned to their previous level of activity (time range for follow-up after surgery: 1–13 years). Three horses were lost to follow-up.


Discussion


The current study presents the clinical management of 29 cases diagnosed with intestinal FBs, which were treated


surgically and resulted in a favourable outcome. Previous literature gives wide ranging prognoses following surgical FB removal, making comparisons with our investigation difficult. In the present study, 79% of the horses were released from the hospital and all the horses which were available for long- term follow-up were still alive and back to their intended use. The prognosis in the current study resembles the outcome of most reports on surgical resolution of small colon impactions (Dart et al. 1992; Rhoads et al. 1999; Frederico et al. 2006; Prange et al. 2010; de Bont et al. 2013). It is ill-advised to make a direct statistical comparison between the studies due to innate differences between them, thus we cannot ascertain if our results are truly inferior to previous studies. In previous studies it was evident that FB obstruction


usually occurs in horses younger than 4 years of age, presumably due to their less selective eating behaviour (Boles and Kohn 1977; Dart et al. 1992; Pierce 2009). In the current study, the mean age of the horses was 4.2 years, however older animals were seen as well and four horses were over 8 years of age. This broad age distribution suggests that horses may be affected at any age if the environmental conditions are suitable. It is reasonable to assume that horses kept in a stall with a strict feeding regimen were less likely to be affected than horses in a pasture or paddock with unlimited exposure to hay and presumably with less sanitary conditions. However, due to missing data regarding the husbandry practices, such a prior statement could not be confirmed from our data. Only two horses in the current study, which were kept at pasture, had a known access to foreign material in the diet. In most horses, the FBs were comprised of twine made from plastic fibres. The twine seen in the FBs is used to bind hay bales, meaning it could be found in all environments as long as it is not removed from the hay before feeding. It has been mentioned in a previous publication that seasonality may have an effect on FB presentation with a higher incidence in warm climates (Gay et al. 1979). Another study showed a higher rate of small colon impactions in cold weather (Rhoads et al. 1999). However, in the present study, the cases were spread during the entire year with no evidence of preferred season.


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