Effects of prophylactic antimicrobial duration for colic surgery

  

© Maria Itina Dreamstime.com

Colic surgery remains one of the most challenging procedures performed in equine practice. Even with major
advances in anaesthesia, surgical techniques and postoperative care, it continues to carry significant risks. Horses requiring surgery are often already critically ill, the procedures can be lengthy, and opening the intestine inevitably increases the risk of bacterial contamination. To minimise the chance of postoperative infection, surgeons routinely administer prophylactic antibiotics, known as surgical antimicrobial prophylaxis (SAP).

However, the widespread use of antibiotics raises another important concern: antimicrobial resistance. The more frequently antibiotics are used, and the longer they are administered, the greater the selective pressure encouraging bacteria to develop resistance. Antibiotics can also disrupt the normal community of beneficial microorganisms living within the horse's digestive tract – the gut microbiome – which plays an important role in digestion, immunity and overall health.

In human medicine, evidence has shown that extending antibiotic prophylaxis beyond 24 hours after abdominal surgery offers little additional benefit and may even be harmful. Current human guidelines therefore recommend limiting SAP to less than 24 hours whenever possible. Whether the same approach could safely be adopted in equine colic surgery has remained uncertain.

To investigate, researchers led by Louise L. Southwood at the Department of Clinical Studies, New Bolton Center, University of Pennsylvania, together with colleagues from the Children's Hospital of Philadelphia, carried out a prospective randomised clinical trial comparing 24 hours and 72 hours of antibiotic prophylaxis following colic surgery.

The study enrolled 140 horses recovering from colic surgery, with 71 receiving potassium penicillin and gentamicin for 24 hours and 69 receiving the same treatment for 72 hours. The researchers monitored the horses for postoperative complications, including surgical wound infections and gastrointestinal problems. They also examined how the different treatment durations affected the horses' gut microbiome and "resistome" - the collection of antimicrobial resistance genes carried by the bacteria living in the intestine.

To analyse these changes, faecal samples from a subset of 49 horses were collected when they entered hospital and again before discharge. Using advanced DNA sequencing techniques, the team identified both the bacterial species present and the antibiotic resistance genes they carried.

The clinical results were reassuring. There were no significant differences between the two treatment groups in any measured postoperative complication. Rates of incisional infection were almost identical, occurring in around 16–17% of horses regardless of whether antibiotics had been given for one day or three. Gastrointestinal complications were also similar.

The microbiological findings told a different story.

Simply being hospitalised and undergoing surgery significantly altered the composition of the horses' intestinal microbiome. Overall bacterial diversity declined during hospitalisation, while genes associated with resistance to the antibiotics used during treatment became more common. These changes were considerably more pronounced in horses that received antibiotics for 72 hours.

In particular, the longer treatment group showed significantly higher levels of beta-lactam resistance genes, including TEM beta-lactamases, by the time they left hospital. These genes enable bacteria to resist an important class of antibiotics, raising concerns that prolonged treatment may increase selective pressure for antimicrobial resistance without providing additional clinical benefit.

The researchers conclude that limiting surgical antimicrobial prophylaxis to 24 hours appears to be the preferable strategy for horses undergoing colic surgery. It provided postoperative outcomes comparable to a 72-hour course while causing less disruption to the gut microbiome and resulting in fewer increases in antimicrobial resistance genes.

The authors note several limitations, including the study being conducted at a single hospital, relatively small numbers for detecting rare complications, and the fact that clinicians were aware of which treatment each horse received. Nevertheless, the findings provide encouraging evidence that shorter antibiotic courses may safely reduce antimicrobial use in equine practice while helping to preserve both the gut microbiome and the long-term effectiveness of these vital medicines.

For more details, see:

Southwood, L. L., Long, A., Perez, J., Daniel, S., Bittinger, K., Aitken, M., & Redding, L.

Effect of surgical antimicrobial prophylaxis duration for colic surgery on complications and resistome. 

Equine veterinary journal, (2026) 58(2), 390–403.

https://doi.org/10.1002/evj.70137

Equine anaesthesia becomes safer, but risks remain higher than in people and dogs

   

© KellyVandellen Dreamstime.com

General anaesthesia in horses has become significantly safer over the past two decades,
according to the latest findings from the Confidential Enquiry into Perioperative Equine Fatalities (CEPEF4). The large international study shows that advances in anaesthetic techniques, monitoring and recovery management have reduced the number of horses dying after anaesthesia, although the risks remain substantially higher than those seen in both human and small animal medicine.

Approximately every 10 years, the CEPEF project brings together veterinary hospitals around the world to assess the safety of equine general anaesthesia and identify factors that influence patient outcomes. The fourth phase of the study (CEPEF4) analysed 47,396 general anaesthetic procedures performed at 93 veterinary centres across 28 countries between November 2020 and June 2023, making it the largest and most comprehensive assessment of equine anaesthesia undertaken to date.

Researchers followed every horse for seven days after anaesthesia, recording whether the animal survived, was euthanased or died, while also analysing 249 different patient, surgical and anaesthetic variables.

The overall mortality rate associated with general anaesthesia was 1.2%, representing a substantial improvement compared with the 1.9% reported in the previous major enquiry (CEPEF2) in 2002. Horses undergoing procedures unrelated to colic had an even lower mortality rate of 0.6%, compared with 0.9% previously. Among horses requiring emergency surgery for colic, where patients are already critically ill, mortality fell from 7.8% to 4.2%.

Despite this encouraging progress, horses remain one of the highest-risk domestic species to anaesthetise. In comparison, modern human anaesthesia carries an anaesthesia-related mortality estimated at around one death in 100,000 to 200,000 anaesthetics (approximately 0.001% or lower) in healthy patients. In dogs, reported anaesthetic mortality is typically around 0.05–0.2% in healthy animals, increasing in those that are seriously ill. Even with recent improvements, healthy horses therefore continue to face a considerably greater risk.

The study highlights the recovery period as the most dangerous stage of anaesthesia. Unlike people or dogs, horses are large prey animals whose instinct is to stand as quickly as possible when they regain consciousness. This natural behaviour can result in panic, falls and catastrophic injuries while they are still uncoordinated.

Among otherwise healthy horses undergoing non-colic procedures, fractures sustained during recovery accounted for more than one-third (35.7%) of all deaths. Abdominal complications were responsible for 18.1%, while central nervous system disorders accounted for 13.2%.

The researchers also identified several factors associated with increased risk. Pregnant mares, geriatric horses, animals in poor body condition, patients with more severe underlying disease, urgent procedures and anaesthetics lasting either less than one hour or more than two hours all carried greater odds of death.

Importantly, the study also identified clinical practices associated with improved survival. Horses whose anaesthesia included invasive blood pressure monitoring, end-tidal carbon dioxide measurement, arterial blood gas analysis and continuous body temperature monitoring experienced significantly lower odds of death. Adequate pain relief, including combinations of opioid drugs with non-steroidal anti-inflammatory medications before anaesthesia, together with the administration of alpha-2 agonist sedatives immediately before recovery, were also associated with improved outcomes.

The findings provide valuable evidence that continued investment in monitoring equipment, careful anaesthetic management and recovery protocols is improving safety for equine patients. They also offer practical guidance to veterinarians when planning anaesthesia for higher-risk horses and help owners make informed decisions about treatment.

Although healthy horses can still die following routine anaesthesia, the steady decline in mortality over successive CEPEF studies demonstrates how advances in veterinary medicine continue to make equine anaesthesia safer. Researchers believe the extensive CEPEF4 database will continue to generate new insights that could further reduce risks in the years ahead, particularly during the critical recovery period where the greatest opportunities for improvement remain.

 

For more details, see:

Miguel Gozalo-Marcilla, José I. Redondo, Regula Bettschart-Wolfensberger, Luis Domenech, Javier Doménech, G Mark Johnston, Polly M. Taylor.

The Confidential Enquiry into Perioperative Equine Fatalities: phase 4 (CEPEF4) – a worldwide observational, prospective, multicentre cohort study in 2025.

Veterinary Anaesthesia and Analgesia (2025) Vol 52,  (5), p 525-538.

https://doi.org/10.1016/j.vaa.2025.06.005

Progress towards understanding the cause of Equine Grass Sickness

Pony with chronic grass sickness (McGorum et al)

 An international team of researchers has identified what they believe to be the probable cause of equine grass
sickness (EGS). Their findings suggest that a neurotoxin, similar in action to snake venom toxins but produced by pasture microbes, is the likely culprit. The work is set to be published in the Equine Veterinary Journal (EVJ) and is currently freely available online. A special editorial in the January 2025 issue of EVJ, authored by Bruce McGorum and colleagues, highlights the study’s findings and their implications. 

This breakthrough has the potential to pave the way for novel treatments and improved diagnostics for this devastating disease.

 

Equine grass sickness (EGS), also known as equine dysautonomia, is a major cause of mortality in horses and ponies in Great Britain, with more than 80% of cases proving fatal. First recognised in Scotland over 100 years ago, EGS remains most prevalent in Great Britain but has been reported in several northern European countries, South America, and very infrequently in North America.

 

EGS damages the autonomic nervous system, which controls involuntary bodily functions, with particularly severe effects on the gastrointestinal tract. Clinical signs range from depression, difficulty eating and swallowing, and weight loss to gastric reflux, abdominal pain, and death. The disease causes rapid degeneration of nerves, leading to paralysis of the gastrointestinal tract and other systemic effects such as muscle weakness, drooping eyelids, excessive salivation, sweating, and muscle tremors.

 

As there is currently no effective treatment for the most severe (acute and sub-acute) forms of the disease, horses are euthanised on humane grounds, typically within 24-48 hours of showing abnormal signs. In contrast, up to 50% of horses with the mild (chronic) form of grass sickness may survive with intensive nursing and supportive care.

Researchers from the Dick Vet Equine Hospital (RDSVS University of Edinburgh), Newcastle University, Istituto Zooprofilattico Sperimentale delle Venezie, and the University of Padova have made significant strides in identifying the neurotoxin responsible for EGS. Using electron microscopy, they examined post-mortem samples from horses with EGS and compared them to control samples. Their findings revealed that 72.2% of neuromuscular junctions (NMJs) in EGS-affected horses displayed abnormal morphology, compared to just 6.9% in controls.

 

These abnormalities are believed to represent a toxin-specific signature for a neurotoxic enzyme known as phospholipase A2. This enzyme disrupts the microscopic sites of communication between nerves and muscles (NMJs), which are crucial for normal muscle function.

 

Ongoing work aims to definitively identify the source of this toxin. Researchers suspect it is produced by a microbe, such as a bacterium or fungus, that thrives on pasture during the cold and dry weather conditions that typically precede outbreaks of EGS.

 

Interestingly, neurotoxic phospholipase A2 enzymes are also found in the venom of many poisonous snakes. While venomous snakes are not implicated in EGS, researchers hope that drugs being developed to treat nerve damage in snakebite victims could help promote nerve regeneration and recovery in horses with grass sickness.

 

Professor Bruce McGorum, R(D)SVS said: “Identifying a probable cause of Equine Grass Sickness represents a significant breakthrough. We hope that this discovery will lead to novel treatments and improved diagnostics for this devastating condition. We are very grateful for the generous support we have received from horse owners, veterinary surgeons, scientists, charities and funding bodies.” 

 

“Further work is underway to determine the source of this neurotoxin; it is likely to be produced by a microbe such as a bacterium or fungus which grows on the horse’s pasture during the cold and dry weather which precedes the disease.” 

 

This discovery represents a significant step forward in understanding equine grass sickness. By pinpointing the probable cause, researchers can now focus on developing effective treatments and preventive strategies. Advances in identifying the toxin’s source and exploring therapeutic interventions for nerve regeneration offer hope for reducing the impact of this devastating disease.

 

For more details, see:

 

McGorum, B., Pirie, R.S., Bano, L., Davey, T., Harris, J. and Montecucco, C. (2025), 

Neurotoxic phospholipase A₂: A proposed cause of equine grass sickness and other animal dysautonomias (multiple system neuropathies). 

Equine Vet J, 57: 11-18.

https://doi.org/10.1111/evj.14442

 

McGorum BC, Davey T, Dosi MCM, Keen JA, Morrison LR, Pirie RS, Shaw DJ, Harris JB.  

Equine grass sickness is associated with major abnormalities in the ultrastructure of skeletal neuromuscular junctions. 

Equine Vet J.  2025; 57(1): 193–202.

https://doi.org/10.1111/evj.14063

Iron-related inflammatory markers in colic

 

Colic is a major concern for horse owners, with two main types: those treatable with medicine
and those needing surgery. Quickly identifying which cases need surgery is crucial. 

 

In the early stages of inflammation, the liver releases acute phase proteins (APPs) like haptoglobin, fibrinogen, and serum amyloid A. Recent studies propose that blood iron levels could also indicate inflammation severity in colic cases.

 

Paulo Canola and colleagues evaluated serum ferritin, transferrin and iron levels as acute phase inflammatory markers in horses admitted to the hospital with colic. 

 

Ferritin, which stores iron in a non-toxic form, helping to regulate iron levels in the body, is recognized as a positive inflammatory marker, increasing in the acute phase

 

Transferrin, a glycoprotein found in blood plasma that binds to iron and transports it throughout the body, decreases in acute inflammation.

 

The researchers analysed these markers alongside total protein, fibrinogen, ceruloplasmin, albumin, and haptoglobin levels in blood samples from 12 colic surgery cases and 10 healthy horses. They compared healthy horses with colic cases, small and large intestinal obstructions, and survival rates. The work is published in the Journal of Equine Veterinary Science.

 

They found higher transferrin and haptoglobin levels and lower serum iron in colic cases compared to healthy horses. Large intestinal obstruction cases had lower transferrin levels than small intestinal obstruction cases. Fibrinogen levels were higher in horses more likely to die from strangulating lesions.

 

The researchers suggest that the acute phase proteins examined in the study could be used to evaluate the acute inflammatory response in horses with colic requiring surgery. 

 

 

For more details, see: 

 

P.A. Canola, R.F. de Salles, E.R. Daneze, M.F.R. Sobreira, B.E. de Oliveira, M.L. Favero, M.L. Antonioli.

Iron-related markers of inflammation in horses with colic.

Journal of Equine Veterinary Science, (2024) vol 134, 105010,

https://doi.org/10.1016/j.jevs.2024.105010

Signs of anthelmintic resistance in tapeworms?

Horses frequently carry tapeworm infections, particularly Anoplocephala perfoliata. While these parasites can be linked to colic, most infected horses generally tolerate them well and show no adverse signs.. 

Tapeworms are commonly found in horses grazing on pasture because the intermediate host, an oribatid mite, resides in the pasture environment. In contrast, tapeworms are seldom observed in horses in dry and arid conditions.

 

Two drugs, praziquantel and pyrantel, are commonly employed for tapeworm control and are generally acknowledged as effective in managing these parasites.

 

While the issue of anthelmintic resistance has garnered widespread attention concerning roundworms, it has not received as much consideration in relation to tapeworms. Anthelmintic resistance in equine tapeworms, as in other parasites, poses a significant challenge in the management of horse health. 

 

In contrast to roundworms, which can be easily diagnosed and assessed through a faecal egg count, tapeworms present a greater challenge as they excrete eggs sporadically. This erratic pattern not only complicates diagnosis but also poses challenges in evaluating the response to treatment and identifying anthelmintic resistance.

 

In a report from North America, Martin K. Nielsen, affiliated with the M.H. Gluck Equine Research Center in the Department of Veterinary Science at the University of Kentucky in Lexington, USA, sheds light on an apparent treatment failure involving praziquantel and pyrantel pamoate against tapeworms. The report relates to animals on a Thoroughbred stud farm in Central Kentucky in 2023. The findings have been published in the "International Journal for Parasitology: Drugs and Drug Resistance."

 

Fifty-six young horses were initially dewormed using a combination of ivermectin and praziquantel, followed by a treatment with pyrantel pamoate. The effectiveness of the deworming was assessed by checking the number of parasite eggs in their faeces on the day of treatment and again 14 days later.

 

Two groups of female horses, consisting of 39 and 45 individuals, were also given the ivermectin/praziquantel treatment, and their faeces were examined before and after treatment.

 

In the yearlings, the overall effectiveness against tapeworms, measured by FECR levels, was 23.5% for praziquantel and 50.9% for pyrantel pamoate. 

 

Praziquantel successfully removed tapeworm eggs in three out of 17 yearlings, but five other yearlings changed from having no tapeworm eggs to having them after treatment. 

 

Unfortunately, pyrantel pamoate did not eliminate tapeworm eggs in any of the 14 yearlings that tested positive for tapeworms.

 

Among the tested mares, nine out of 84 were found to have tapeworm eggs, and after praziquantel treatment, seven of them still tested positive for tapeworm eggs.

 

The results also showed that the ivermectin and pyrantel pamoate treatment was not very effective against roundworm (strongylid)  parasites in the young horses. The average reduction in the number of parasite eggs in their faeces was 75.6% or less, and the upper limit of the 95% credible interval was below 90% in all cases.

 

Nielsen highlights that the results differ significantly from the initial field efficacy studies conducted for both active compounds, raising concerns about the potential development of anthelmintic resistance.

 

He suggests the need for continued research and advancements in parasite management strategies to develop more sustainable approaches in addressing equine tapeworm infections.

 

 

 

For more details, see:

.

Apparent treatment failure of praziquantel and pyrantel pamoate against anoplocephalid tapeworms

M K Nielsen 

Int J Parasitol Drugs Drug Resist. 2023 Aug:22:96-101.

 doi: 10.1016/j.ijpddr.2023.06.002

Discussing colic

The latest edition of the Fresh Scoop podcast from Morris Animal Foundation covers colic in
horses. Join Drs. Kelly Diehl and Sharanne Raidal as they discuss the subject, including types of colic, clinical signs, diagnostics, treatments and ongoing research. 

 

For more details, go to:

 

https://www.morrisanimalfoundation.org/article/episode-62-understanding-colic-horses

 

Or, you can download the podcast from all the usual places

Call for colic research

 Clinicians and scientists are invited to submit abstracts for the upcoming 14th International
Equine Colic Research Symposium, set to be held in Scotland next year.

This event, held every three years, and organized in rotation by the American Association of Equine Practitioners and the British Equine Veterinary Association, will take place in Edinburgh on July 10th to 12th, 2024.

 

The Colic Research Symposium presents a unique opportunity for equine veterinarians to absorb and digest the latest knowledge, clinical practice and scientific advances in the treatment and prevention of colic, from the world’s leading international equine gastroenterology experts.

 

Spanning 2.5 days, the symposium encompasses a wide array of topics delivered through concise 12-minute oral presentations. These presentations will cover diverse subjects such as surgical techniques, treatment methods, parasitology, gastric ulceration, endotoxemia, pharmacology of intestinal motility, colic complications, epidemiology, digestion physiology, the intestinal microbiome, and metabolomics. 

 

Each session will be followed by three minutes for questions and discussion. 

 

Poster sessions will be held during the first two days, providing an opportunity to explore additional research beyond the oral presentations and enabling delegates to review and discuss the work with presenters.

 

Clinicians and scientists have until 1 February 2024 to submit abstracts of recent work that they wish to present at this meeting. See:

https://form.jotform.com/230473925626359

 

For more details of the 14th International Equine Colic Research Symposium, see:

https://www.beva.org.uk/Education/CPD/Event-Details/eventDateId/1740

Risks of colic surgery

 Despite advances in anaesthesia and surgical techniques, there is still a significant risk
associated with equine colic surgery. It is a major surgical procedure that carries inherent risks such as anaesthetic complications, postoperative infections, and failure of the surgical site to heal properly.

In addition, colic surgery is usually performed under emergency conditions, when the horse’s health is already compromised.  

 

Even with successful surgery, horses with colic will likely require intensive care and monitoring in the postoperative period, which can be costly and time-consuming. It is important for horse owners to be aware of the risks associated with colic surgery and to have a frank discussion with their veterinarian about the potential outcomes and prognosis. Early intervention and prompt surgical treatment can improve the chances of a positive outcome, but it is not a guarantee of success.

 

To better assess the risk factors for colic surgery, researchers in Italy reviewed records of horses subjected to colic surgery in three referral centres between 2018 and 2021.

In a study published in the journal Animals, Alessandro Spadari and his colleagues from the Veterinary Teaching Hospitals at the Universities of Bologna, Perugia, and Turin, examined data from 451 horses that underwent colic surgery. The researchers found that the short-term survival rate for all horses who underwent surgery was 68.5%, and for those that recovered from both the surgery and anaesthesia, the survival rate was 80%.

 

The study also identified several potential risk factors that could affect the outcome of the surgery, including age, body condition score (BCS), packed cell volume (PCV), and total plasma protein (TPP) before and after surgery, amount of reflux, type of disease, type of lesion, duration of surgery, surgeon's experience, and the amount of intra- and postoperative fluids administered.

 

Through multivariate analysis, the researchers found that PCV at arrival, TPP after surgery, and BCS had the highest predictive power for short-term survival after colic surgery. 

Horses with a body condition score (BCS) of less than 4 out of 9 were found to have a higher risk of a negative outcome in the study. Additionally, horses that arrived at the referral centre with a packed cell volume (PCV) greater than 50% and total plasma protein (TPP) levels below 5.7 or above 7.4 had a poorer prognosis than horses with other values.

 

The type of lesion also played a significant role in the outcome of the surgery, with horses diagnosed with large colon volvulus, pedunculated lipoma, and small intestinal volvulus having the worst prognosis.

 

The authors of the study suggest that their findings may aid surgeons in making informed decisions and communicating the risks to referring veterinarians and horse owners. They recommend conducting additional prospective studies to validate the impact of the predictive indices examined in this research on short-term survival.

 

 

For more details, see:

 

Short-Term Survival and Postoperative Complications Rates in Horses Undergoing Colic Surgery: A Multicentre Study. 

Spadari, A.; Gialletti, R.; Gandini, M.; Valle, E.; Cerullo, A.; Cavallini, D.; Bertoletti, A.; Rinnovati, R.; Forni, G.; Scilimati, N.; Giusto, G. 

Animals 2023, 13, 1107. 

https://doi.org/10.3390/ani13061107

New colic researched planned

(c) Maria Itina Dreamstime.com

 Colic features heavily in research projects being supported by the Morris Animal
Foundation in 2022.

New equine health studies to receive funding this year include:

• Studying Intestinal Inflammation

Two research teams will take different approaches to investigate the interaction between inflammation and gut motility, to assist in developing methods of preventing ileus (reduced gut motility) after colic surgery. These approaches could dramatically assist recovery and shorten hospitalization times.

• Understanding Risk Factors for Colic Secondary to Transportation

Researchers will look for colic risk factors associated with transportation, to develop better management recommendations for horses requiring transport.

• Helping Underserved Communities Recognize Early Signs of Colic

Researchers will develop an educational program for horse owners and enthusiasts in underserved communities in Colombia to improve early recognition of colic, a key component of successful treatment.

• New Prognostic Test for Postoperative Complications

Researchers will search for biomarkers to identify horses at higher risk for postoperative surgical complications as a first step toward a new prognostic test.

“Colic consistently ranks among the top health concerns of horse owners and veterinarians,” said Dr. Janet Patterson-Kane, Chief Scientific Officer. “We decided to focus on this topic in this year’s equine call for proposals to advance our understanding of intestinal disease associated with colic and ultimately assist in improving outcomes for horses around the world.”

For more details, see:

https://www.morrisanimalfoundation.org/article/new-equine-colic-studies-2022

Alternative approach to colic ops

 

Standing flank laparotomy may be a suitable option for surgical treatment of some cases of equine colic, a recent study has concluded.

The standard surgical approach for colic is through an incision in the ventral midline, with the horse under general anaesthesia. General anaesthesia poses additional risks over and above those of the surgery itself, and the personnel and equipment required increases the cost.

 

Operating through a flank incision would avoid the need for general anaesthesia and should be less expensive.

 

Marco Lopes and co-workers conducted a retrospective analysis of clinical records of 37 equids (horses, ponies and a donkey) treated using a standing flank laparotomy at five hospitals, between 2003 and 2020. Their findings are published in the Equine Veterinary Journal.

 

They did not include cases of small colon impaction in their analysis, as previous work had already shown that such cases could be dealt with using a flank incision.

 

Financial considerations were the main reason for the choice of technique. However, in ten cases of nephrosplenic entrapment the surgeon preferred a flank incision.

 

In seven animals the decision for euthanasia was taken immediately as they were found to have an untreatable condition, or the likelihood of survival was very poor.

 

Twenty of the 30 horses found to have a treatable condition survived. These conditions included small intestine inflammation or impaction, large colon displacement (especially nephrosplenic ligament entrapment) and sand impaction, 

 

The authors identify limitations of the technique:

• the horse must stand still during the operation, so standing flank laparotomy cannot be performed in horses with severe colic that cannot be adequately controlled medically
• additional peritoneal analgesia may be needed
• access to the peritoneal cavity and the abdominal organs is not as good as with a ventral midline incision.
• a second incision on the opposite flank may be needed
• surgeons are not as familiar with standing flank laparotomy 
•  scars in the flank are more likely to be seen than those in the ventral midline.

 

They conclude that this series of cases indicates that standing flank laparotomy is a viable approach for abdominopelvic exploration in some horses with colic attributed to conditions of the small intestine, caecum, large colon and peritoneum.

 

For more details, see: 

 

Standing flank laparotomy for colic: 37 cases

Marco A. F. Lopes, Joanne Hardy, Kelly Farnsworth, Raphael Labens, W. Y. Eunice Lam, Erik Noschka, Tiago Afonso, Claudia Cruz Villagrán, Luiz C. P. Santos, Montague Saulez, Gal Kelmer

Equine Vet J (2021)

 

https://doi.org/10.1111/evj.13511

 

Strongylus vulgaris implicated in peritonitis?

Strongylus vulgaris (commonly known as the blood worm) used to be a common cause of colic before the advent of ivermectin, which proved to be very effective against the parasite. The larvae migrate up the arteries supplying the intestines, causing damage as they go. This can lead to thrombus formation and ischaemic damage, typically involving the large intestine.

Anthelmintic resistance, particularly among the cyathostomins (small red worms), has led to reduced use of anthelmintics. In some countries, including Sweden, anthelmintics have been restricted to use on prescription only.  There is concern that this may be allowing Strongylus vulgaris to make a comeback.

What is the current relationship between gastrointestinal parasites and colic? Research has been carried out at the Swedish University of Agricultural Sciences, in Uppsala, Sweden. The work, by Ylva Hedberg-Alm and colleagues, is published in the journal Animals (Basel).

Blood and faecal samples were collected from horses presented to the Horse Clinic, at the University Animal Hospital. Each horse with a gastro-intestinal condition (colic, colitis, peritonitis, weight loss) was matched with a control horse of similar age seen during the same week for a condition unrelated to the gastrointestinal tract. The owners were questioned about management and history

The findings were compared between those presenting with colic and those with problems unrelated to colic. A total of 137 cases and 137 controls were included in the study. Age and gender distribution was similar between the groups.

Faecal samples were examined for strongyle egg counts, and for Anoplocephala perfoliata (tapeworm) eggs. The presence of S. vulgaris was confirmed using a polymerase chain reaction (PCR) test. (S. vulgaris eggs look like those of other strongyles, including the more common cyathostomins.)

Blood samples were evaluated for antibodies to S. vulgaris using an ELISA test.

The researchers found that exposure of Swedish horses to S. vulgaris was common. Most horses, both cases and controls, were positive in the S. vulgaris ELISA test. In addition, horses with peritonitis had significantly higher ELISA values compared to controls and to other gastrointestinal diagnoses, suggesting S. vulgaris was involved in this case group. 

They also found that despite new legislation, 29% of owners did not use faecal analyses to monitor the parasite burden. The use of additional methods to diagnose specific parasites, such as S. vulgaris, was low. Owners rarely used pasture management methods to reduce the parasite burden on the grazing.

The authors suggest that, considering exposure to S. vulgaris appears high, there is a need for education in specific faecal diagnostics and pasture management. 

 

For more details, see:

Parasite Occurrence and Parasite Management in Swedish Horses Presenting with Gastrointestinal Disease—A Case–Control Study
Ylva Hedberg-Alm, Johanna Penell, Miia Riihimäki, Eva Osterman-Lind, Martin K. Nielsen, and Eva Tydén
Animals (Basel). 2020 Apr; 10(4): 638. 
doi: 10.3390/ani10040638

Equine Pain and Welfare App

 

How do you tell if your horse is in pain? You may “know” straight away that something is not right.

But people are not always able to interpret correctly the signs of pain displayed by horses and donkeys. After all, having evolved as prey animals, it is in their interest not to show signs of pain that might bring them to the attention of a predator looking for its next meal.

Dr Thijs van Loon and colleagues at the faculty of veterinary medicine of Utrecht University have been researching pain recognition in horses. Their work resulted in the development of composite pain scales that the researchers showed could be used to accurately measure pain in horses as well as donkeys.

Such scales generally comprise several indicators, including behavoural parameters (such as lying down, rolling and scratching), physiological variables, (heart rate and respiratory rate), and facial expressions, (positioning and movement of the ears, nostrils, eyelids, and mouth).

These signs are particularly useful for detecting pain or discomfort in patients suffering from colic, facial or orthopaedic pain.

Assessment methods developed in the studies have now been distilled into an App, the Equine Pain and Welfare App (EPWA), which provides a reliable way to recognise pain and calculate a pain score.

The App guides the user through a two-minute pain assessment based on facial expressions or a five-minute assessment of body language. Users are advised to contact a veterinarian for horses scoring above five on a scale of 0 to 18.

The scores can be stored on the App, allowing users to monitor changes to a horse's welfare over time.

Other features of the App include a diary where you can keep track of how much your horse eats, the amount of exercise he does and any medication he has.

There is also a handy check of whether your horse is showing signs compatible with PPID (Cushings disease).

The research team say that the current version of EPWA has been downloaded thousands of times already and is helping owners to recognise pain and discomfort in their horses and donkeys, thereby improving their health and welfare.

They are now working to develop a version specifically aimed at working donkeys in rural communities and developing countries. The Working Equine Pain and Welfare App ('W-EPWA') will be provided free of charge in order to encourage its widespread use and improve the health and welfare of horses and donkeys worldwide.

EPWA is a joint initiative of the Faculty of Veterinary Medicine at Utrecht University and Stichting de Paardenkamp. It is available (free) from the usual app stores.

For more details, see:

https://www.epwa.nl

Outcome of colic surgery

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Colic is a common problem in horses, and although many cases will respond quickly to medical treatment, some do not, and surgical intervention is required to correct the problem. This is not something to be undertaken lightly. There are risks associated with general anaesthesia and with the surgical procedure itself. A period of convalescence lasting months will likely be required.

A further concern is the risk that the horse will not regain its original athletic ability.

A study in the Netherlands has looked at the outcome of horses after colic surgery.

Johannes van Loon and colleagues at Utrecht University reviewed the clinical records of 283 horses treated surgically after being presented for acute colic at the department of Equine Sciences.

As well as looking at survival and complication rates, they also considered the functional outcome and behavioural problems

They found that of the horses that underwent colic surgery, 59% went home alive. Of those, 96% were still alive a year later. More than half of them suffered at least one or two episodes of colic during that time.

Encouragingly, almost two thirds of horses that returned home achieved at least their previous level of performance.

Owners reported altered behaviour and gait-related problems in up to 46.2% of horses.

The researchers suggest that Improving veterinary aftercare, in collaboration with other disciplines such as physiotherapy and saddle fitting, during rehabilitation could produce further improvement in athletic performance and welfare after recovery from colic surgery

 

For more details, see:

Colic Surgery in Horses: A Retrospective Study Into Short- And Long-Term Survival Rate, Complications and Rehabilitation Toward Sporting Activity.

Johannes P A M van Loon, Emi M S Visser , Marjolein de Mik-van Mourik, Pieternel Kerbert, Tsjester Huppes, Eveline S Menke

J Equine Vet Sci (2020) 90:103012.

DOI:10.1016/j.jevs.2020.103012