Objective—To characterize the texture, mineralogic
features, and chemical features of enteroliths
obtained from horses.
Sample Population—Enteroliths from 13 horses
Procedure—Enteroliths were harvested from 13
horses that underwent ventral midline celiotomy for
treatment of colic or necropsy because of colonic
obstruction and rupture caused by enteroliths. Dietary
and environmental history were determined via questionnaires
or evaluation of medical records. In 7 horses
that underwent surgical treatment for enterolithiasis,
samples of colonic contents were obtained via an
enterotomy in the pelvic flexure. Colonic concentrations
of magnesium (Mg), phosphorus (P), sulfur (S),
sodium (Na), calcium (Ca), and potassium (K) were
determined. Enteroliths were analyzed via electron
microprobe analysis and X-ray diffraction.
Results—Enteroliths varied widely regarding degree
of porosity, presence and distribution of radiating texture,
and composition and size of the central nidus. A
distinct concentric banding was identifiable in all
enteroliths. Struvite was the predominant component
of all enteroliths, although Mg vivianite was identified
in 5 enteroliths, and there were variable quantities of
Na, S, K, and Ca in the struvite within enteroliths.
Despite an abundance of Ca in colonic fluids, Mgphosphate
minerals were preferentially formed, compared
with Ca-phosphates (apatite), in equine
Conclusions and Clinical Relevance—Enteroliths
comprise 2 major Mg phosphates: struvite and Mg
vivianite. There is wide variability in macrotexture and
ionic concentrations between and within enteroliths.
(Am J Vet Res 2001;62:350–358)
Objective—To determine the adsorptive capability of di-tri-octahedral smectite (DTOS) on Clostridium perfringens alpha, beta, and beta-2 exotoxins and equine colostral antibodies.
Sample Population—3 C perfringens exotoxins and 9 colostral samples.
Procedures—Alpha, beta, and beta-2 exotoxins were individually co-incubated with serial dilutions of DTOS or bismuth subsalicylate, and the amount of toxin remaining after incubation was determined via toxin-specific ELISAs. Colostral samples from healthy mares were individually co-incubated with serial dilutions of DTOS, and colostral IgG concentrations were determined via single radial immunodiffusion assay.
Results—Di-tri-octahedral smectite decreased the amount of each C perfringens exotoxin in co-incubated samples in a dose-dependent manner and was more effective than bismuth subsalicylate at reducing exotoxins in vitro. Decreases in the concentration of IgG were detected in samples of colostrum that were combined with DTOS at 1:4 through 1:16 dilutions, whereas no significant decrease was evident with DTOS at the 1:32 dilution.
Conclusions and Clinical Relevance—Di-tri-octahedral smectite effectively adsorbed C perfringens exotoxins in vitro and had a dose-dependent effect on the availability of equine colostral antibodies. Results suggested that DTOS may be an appropriate adjunctive treatment in the management of neonatal clostridiosis in horses. In vivo studies are necessary to fully assess the clinical efficacy of DTOS treatment.