Clinical findings and management of 153 horses with large colon sand accumulations

Diagnostic approaches, aetiological agents and their associations with short-term survival and laminitis in horses with acute diarrhoea admitted to referral institutions

BACKGROUND

An international description of the diagnostic approaches used in different institutions to diagnose acute equine diarrhoea and the pathogens detected is lacking.

OBJECTIVES

To describe the diagnostic approach, aetiological agents, outcome, and development of laminitis for diarrhoeic horses worldwide.

STUDY DESIGN

Multicentre retrospective case series.

METHODS

Information from horses with acute diarrhoea presenting to participating institutions between 2016 and 2020, including diagnostic approaches, pathogens detected and their associations with outcomes, were compared between institutions or geographic regions.

RESULTS

One thousand four hundred and thirty-eight horses from 26 participating institutions from 4 continents were included. Overall, aetiological testing was limited (44% for Salmonella spp., 42% for Neorickettsia risticii [only North America], 40% for Clostridiodes difficile, and 29% for ECoV); however, 13% (81/633) of horses tested positive for Salmonella, 13% (35/262) for N. risticii, 9% (37/422) for ECoV, and 5% (27/578) for C. difficile. C. difficile positive cases had greater odds of non-survival than horses negative for C. difficile (OR: 2.69, 95%CI: 1.23-5.91). In addition, horses that were positive for N. risticii had greater odds of developing laminitis than negative horses (OR: 2.76, 95%CI: 1.12-6.81; p = 0.029).

MAIN LIMITATIONS

Due to the study's retrospective nature, there are missing data.

CONCLUSIONS

This study highlighted limited diagnostic investigations in cases of acute equine diarrhoea. Detection rates of pathogens are similar to previous reports. Non-survival and development of laminitis are related to certain detected pathogens.

Ingestion of Soil by Grazing Sport Horses

Data on soil ingestion in horses are lacking in contrast to other free-range animals. The importance of soil as a vector for environmental pollutants to food is less relevant in horses but several disorders secondary to soil ingestion, such as sand colic or enteritis have been reported. Therefore, soil ingestion has been studied on Irish sport horses grazing at three offered levels of daily herbage: 2, 3 and 4% of their body weight. Soil ingestion was estimated by the faecal recovery of a soil natural marker. Horses had 4.5, 4.1 and 3.7% of soil in their total intake respectively for the 2, 3 and 4% herbage offers. The 4% offer presented significantly less intake (543 g/d) compared to the more restricted offers (624 and 648 g respectively for 3 and 2%). The post-grazing sward height was significantly lower on the 2% offer (3.1 cm) compared to the higher offers (4.1 and 4.4 cm respectively for 3 and 4%). Thus, restricted herbage allowance made grazing closer to the ground and increased soil ingestion. The sward height appeared to be a reliable indicator to manage animal withdrawal from a pasture to limit soil ingestion and the risk of gastrointestinal pathologies caused by it.

Psyllium supplementation is associated with changes in the fecal microbiota of horses

OBJECTIVE

Prophylactic supplementation of psyllium husk is recommended to enhance passage of ingested sand from the gastrointestinal tracts of horses. We hypothesized that psyllium supplementation would increase fecal sand passage and favorably alter bacterial populations in the hindgut. Six yearlings and six mature mares were fed a psyllium supplement in the diet daily for seven days. Voluntarily-voided feces were collected over the course of 29 days, prior, during, and after treatment. Feces were analyzed for acid detergent fiber (ADF) and acid detergent insoluble ash analyses. Microbial DNA was also isolated, and the V4 region of the 16S ribosomal RNA gene was PCR-amplified and sequenced using MiSeq technology.

RESULTS

Fecal ADF concentration was greater in adults while silica concentration was greater in yearlings. Mature mare fecal ADF decreased during and just after supplementation but thereafter increased. No changes in silica levels were noted in either group over time. Fecal microbial population phylogenetic diversity was greatest mid-supplementation and lowest at 11 days post-supplementation. Functional profiles of the microbial communities presented some benefits for psyllium supplementation. These findings provide compelling evidence for further detailed studies of prophylactic psyllium supplementation.

Differential Defecation of Solid and Liquid Phases in Horses-A Descriptive Survey

Simple Summary

Free faecal liquid is a condition in horses where faeces are voided in one solid and one liquid phase. The presence of free faecal liquid may cause management problems in equine husbandry and is potentially contributing to impaired equine welfare. Causes of free faecal liquid are not known, but nutritional factors such as the feeding of specific forages have been suggested to be of importance. Characterization of horses showing free faecal liquid and their feeding and management was, therefore, performed via an internet-based survey in order to map the condition further. Results showed that horses with free faecal liquid included a large variety of different breeds, ages, disciplines, coat colours, housing systems and feeding strategies, meaning that almost any type of horse could be affected. Horses that were reported to show free faecal liquid did so with all types of feeding strategies, but changes from wrapped forage to hay, to pasture, or to another batch of wrapped forage often resulted in diminished signs of free faecal liquid. Horses were also reported to have a comparably high incidence of colic in relation to published data for other horse populations. The results indicated that more detailed studies are required for a further understanding of the underlying cause of free faecal liquid.

Abstract

Free faecal liquid (FFL) is a condition in horses where faeces are voided in one solid and one liquid phase. The liquid phase contaminates the tail, hindlegs and area around the anus of the horse, resulting in management problems and potentially contributing to impaired equine welfare. The underlying causes are not known, but anecdotal suggestions include feeding wrapped forages or other feed- or management-related factors. Individual horse factors may also be associated with the presence of FFL. This study, therefore, aimed to characterize horses showing FFL particularly when fed wrapped forages, and to map the management and feeding strategies of these horses. Data were retrieved by a web-based survey, including 339 horses with FFL. A large variety of different breeds, ages, disciplines, coat colours, housing systems and feeding strategies were represented among the horses in the study, meaning that any type of horse could be affected. Respondents were asked to indicate if their horse had diminished signs of FFL with different changes in forage feeding. Fifty-eight percent (n = 197) of the horse owners reported diminished signs of FFL in their horses when changing from wrapped forages to hay; 46 (n = 156) of the horse owners reported diminished signs of FFL in their horses when changing from wrapped forages to pasture; 17% (n = 58) reported diminished signs of FFL when changing from any type of forage batch to any other forage. This indicated that feeding strategy may be of importance, but cannot solely explain the presence of FFL. The results also showed that the horses in this study had a comparably high incidence of previous colic (23%, n = 78) compared to published data from other horse populations. In conclusion, the results showed that FFL may affect a large variety of horse types and that further studies should include detailed data on individual horse factors including gastrointestinal diseases as well as feeding strategies, in order to increase the chance of finding causes of FFL.

Owner-Reported Clinical Signs and Management-Related Factors in Horses Radiographed for Intestinal Sand Accumulation

Clinical problems related to intestinal sand accumulation in horses are common in certain geographic areas, but the clinical signs appear nonspecific and the course of the accumulation remains somewhat obscure. This study examined the association between the presence and size of intestinal sand accumulations and owner-reported clinical signs, management, and feeding practices, as well as behavioral patterns in horses with radiographic diagnosis of sand accumulation. Owners of the horses filled in an online questionnaire. A total of 447 responses met the inclusion criteria. The size of the sand accumulation detected in the radiographs was not significantly associated with the age, body condition score, sex, or use of the horses. Horses reported to have expressed colic had significantly larger sand accumulations than those without this sign, and a similar association was detected in horses with poor performance. The highest odds ratio for sand accumulation was for the combination of colic and poor performance, followed by colic combined with diarrhea/loose feces or hyperesthesia to touch of the abdominal wall. Larger sand accumulations were detected in greedy horses that eat all their roughage, whereas dominant position in group hierarchy was associated with less sand. The possibility of abdominal sand accumulation should be considered as one of the differentials in horses with multiple owner-reported clinical signs such as colic, poor performance, diarrhea, and hyperesthesia to touch of the abdomen.

Colic Prevention to Avoid Colic Surgery: A Surgeon's Perspective

Management factors associated with colic, particularly related to stall confinement and nutrition, have been linked to alterations in gastrointestinal mucosal transport, motility, and microbiome, which in turn creates conditions that induce colic. In particular, meal feeding creates large changes in water movement in and out of the colon and alters the microbiome. These conditions may in turn result in colic conditions such as large colon impaction or large colon volvulus. In addition, a range of management and nutritional factors have been found to place horses at risk of select colic conditions such as ileal impaction. Other specific colic conditions, such as strangulating lipomas, may be related to fat metabolism in geldings and ponies, although the association with nutrition and the endocrine system are less well defined. It has long been understood that parasites are associated with colic, and with the advent of highly effective anthelmintics, parasite-induced colic has been markedly reduced. Nonetheless, equine mangers and veterinarians have to be aware of changes in parasite resistance or patterns of activity, such as the resurgence of large strongyles with surveillance-based management of parasites. Overall, understanding management risk factors can lead to recommendations that prevent colic in horses. Additional study of these factors may ultimately lead to reductions in the prevalence of colic by suggesting optimal management practices.