Effect of PPID on egg shedding after deworming

It has been suggested that horses with hormonal disorders, such as insulin dysregulation and
Pituitary Pars Intermedia Dysfunction (PPID), may be more susceptible to worm infections. 

Horses with PPID often have a weakened immune system, which can allow worms, such as cyathostomes, to thrive more easily compared to healthy horses. These horses may also not respond as effectively to standard deworming treatments due to their altered immune function.

 

A study conducted in Australia aimed to determine whether horses with PPID had increased strongyle faecal egg counts (FEC) compared with control horses.

 

The study, led by Adelaina Horner, took place over a fourteen-week period and involved adult horses and ponies over eight years old in Victoria, Australia. All horses lived on pasture and had not been dewormed for at least three months prior to the study. A total of 45 privately owned horses and ponies met the criteria for inclusion, with 14 horses diagnosed with PPID and 31 serving as controls. PPID diagnosis was confirmed by elevated plasma ACTH concentrations (above 120 pg/mL) along with at least one clinical sign of the disorder.

 

All horses were dewormed with a standard dose of a commercially available ivermectin product. Faecal egg counts were taken before treatment and then every two weeks for 14 weeks. A FEC of 200 eggs per gram (EPG) or higher was used as the cutoff for significant worm burden.

 

The results showed that the egg reappearance period (ERP) after deworming was shorter in PPID horses, and cumulative FEC after deworming was higher in these horses. However, the researchers noted that some PPID horses consistently had no detectable eggs or low EPG (≤ 200) throughout the study, and this could not be explained by observed husbandry practices.

 

Worm eggs collected during the study were cultured in the laboratory, and examination of the larvae confirmed that all worms were cyathostomin species.

 

The researchers advise monitoring egg shedding before anthelmintic treatment in PPID horses, in line with sustainable worm management guidelines, as some PPID horses consistently showed low FEC results.

 

While hormonal disorders like PPID do not directly cause an increase in parasitic infections, they can impair the horse’s immune system and overall health, making them more vulnerable to worm infections and potentially reducing the effectiveness of treatments. Effective management of both the hormonal disorder and parasitic infections is crucial for maintaining the health of affected horses.

 

 

For more details, see: 

 

Strongyle egg shedding and egg reappearance periods in horses with pituitary pars intermedia dysfunction

Adelaina Horner, Nicholas J. Bamford, Michael J. Stear, David Piedrafita, Abdul Jabbar, Kristopher J. Hughes, Charles M. El-Hage, Sarah Preston

Veterinary Parasitology (2024) Vol 328, 110176

 

https://doi.org/10.1016/j.vetpar.2024.110176

Inflammatory marker increase after routine vaccination

 Routine vaccination can lead to a temporary increase in Serum Amyloid A (SAA), according to a recent study in the USA.

Serum amyloid A (SAA) is an acute-phase protein, meaning its levels in the blood increase rapidly in response to infection, injury, or stress. Due to its rapid increase during inflammatory conditions, SAA is often used in horses as a biomarker to assess inflammation or infection 

 

Researchers at the Department of Clinical Sciences, College of Veterinary Medicine, Kansas State University, conducted a two-part study to monitor the response to vaccination. Cassandra M. Baumgarten was the lead author of the study, which was published in the Journal of the American Veterinary Medical Association.

 

The study included a total of 36 clinically normal horses. Twenty-eight horses received routine booster vaccinations recommended for horses in the southern states of the USA (rabies, tetanus, West Nile virus, Eastern and Western equine encephalomyelitis, equine herpesvirus-1/-4, and influenza). Eight horses received placebo injections of saline.

 

The research team conducted daily clinical examinations of the horses, which included measuring their temperature and collecting blood samples to monitor serum amyloid A (SAA) levels for the first ten days after vaccination.

 

They found that, compared to the control group, vaccinated horses had higher SAA concentrations for up to ten days after vaccination, generally returning to normal by the ninth day. About 85.7% of the horses had their SAA levels return to normal within ten days of vaccination.

 

Fever (temperature >38.4°C) was observed in 78.6% of the horses after vaccination, but there was no correlation between fever and SAA concentration.

 

The authors suggest that elevated SAA levels for 10 days after vaccination and fever lasting 12 to 24 hours cannot be used as indicators of illness. They recommend that clinicians, when assessing a patient’s condition after vaccination, should not rely on just one or two clinical signs but rather evaluate the patient as a whole. They also state that measuring SAA for 10 days post-vaccination cannot reliably indicate illness.

 

Based on their findings that routine vaccination increases SAA concentrations, the authors suggest that when advising horse owners about travel or competition, practitioners should recommend a recovery period following vaccination.

 

They also suggest the need for further studies to investigate the effect of travel or competition on the antibody response.

 

 

 

For more details, see: 

 

Baumgarten, C. M., Delph Miller, K. M., Davis, E. G., Beard, L. A., Blevins, C. A., Wottowa, M., Hill, M., & Larson, R. L. (2024). 

Serum amyloid A increases following routine vaccination of healthy adult horses. 

Journal of the American Veterinary Medical Association, 262(9), 1181-1187. 

https://doi.org/10.2460/javma.24.04.0244

Bacterial gut diversity in TB foals improves future racing performance

 The composition of gut bacteria in one-month-old Thoroughbred foals can predict their future
athletic performance, according to a new study from the University of Surrey. Foals with lower bacterial diversity at 28 days old were also found to have a significantly increased risk of respiratory disease later in life.

 Researchers from Surrey's School of Veterinary Medicine and School of Bioscience, led by Professor Chris Proudman, examined the gut bacterial composition of Thoroughbred foals bred for flat racing and its impact on their long-term health and performance.

The three-year cohort study explored the interactions between early-life gut bacterial communities, health outcomes in later life, and athletic performance on the racetrack. The findings were published in Scientific Reports.

 

The study involved analysing 438 faecal samples from 52 foals, tracking their respiratory, gastrointestinal, orthopaedic, and soft-tissue health from birth to three years of age. The researchers also analysed data on race performance, including finishing positions, official ratings, and prize money earnings as measures of athletic performance.

 

Professor Chris Proudman, Professor of Veterinary Clinical Science at the School of Veterinary Medicine at the University of Surrey, said:   "Minimising the risk of disease and injury is important for the welfare of racehorses, and maximising their athletic potential is important for their owners. We have found that gut health, in particular the health of gut bacterial communities very early in life, exerts a profound and enduring impact on racehorse health and performance."

 

The study found a positive association between athletic performance and higher faecal bacterial diversity at one month old. Specifically, a higher abundance of the bacteria Anaeroplasmataceae was linked to a higher official rating, and increased levels of Bacillaceae at 28 days old were associated with better race placings.

 

The researchers concluded that the gut bacterial composition in the first months of life influences the risk of specific diseases and athletic performance up to three years old. Foals with lower bacterial diversity at one month old had a significantly higher risk of developing respiratory disease, which was also associated with a higher relative abundance of the bacteria Pseudomonadaceae.

 

Interestingly, the study revealed that foals treated with antibiotics during their first month of life had significantly lower bacterial diversity at 28 days old compared to those not treated with antibiotics. These foals also earned significantly less prize money and had a higher rate of respiratory disease later in life.

 

Professor Roberto La Ragione, co-investigator from the School of Bioscience at the University of Surrey, commented, "While antibiotics are essential for treating infections and ensuring the long-term health of foals, their use must be carefully managed. Our study demonstrates that antibiotic treatment can disrupt the gut microbiome with long-term consequences for health and performance. The next phase of our research will focus on minimizing this disruption when antibiotics are necessary."

 

Additionally, the researchers found that low gut bacterial diversity in early life is associated with an increased risk of soft-tissue and orthopaedic issues later on. They believe these health impacts are likely related to immunological priming, though the underlying reasons for the observed negative effects on racehorse performance are still not fully understood.

 

Dr. Kirsten Rausing, Chairman of the International Thoroughbred Breeders Federation and study sponsor through her ALBORADA Trust, remarked, "This ground-breaking study has identified the importance of gut health in our very young foals. As breeders, if we can get this right, we will produce foals that will be healthier, and that will grow into more successful racehorses."  

 

Ongoing research aims to develop novel probiotics to enhance foal gut health in early life and to investigate how antibiotics can be used while preserving gut health.

 

The researchers conclude: “For the first time, this study demonstrates a relationship between early-life gut bacterial communities and subsequent athletic performance that has implications for athletes of all species including humans.”

 

 

For more details, see:

 

Early-life gut bacterial community structure predicts disease risk and athletic performance in horses bred for racing

J. Leng, C. Moller-Levet, R. I. Mansergh, R. O’Flaherty, R. Cooke, P. Sells, C. Pinkham,O.  Pynn, C. Smith, Z. Wise, R. Ellis, A. Couto Alves, R. La Ragione and C. Proudman 

Scientific Reports (2024) vol 14, Article number: 17124 

https://doi.org/10.1038/s41598-024-64657-6 

Lyophilized colostrum: a viable alternative for foals?

 Colostrum is essential for a foal to have a good start in life. The first milk produced by mammals
after giving birth, colostrum is rich in antibodies, growth factors, and nutrients essential for newborn development. Foals require good quality colostrum in the first hours of life to ensure an adequate transfer of passive immunity.

Stud farms often maintain a supply of high-quality colostrum by collecting and freezing some from donor mares.

However, individual mare owners have more limited options. Commercial products like dried colostrum powder, usually made from processed cow colostrum, can provide some level of IgG to foals, but are generally not considered equivalent to mare colostrum in terms of quality and effectiveness.

 

Further research and development of equine-specific colostrum products, including lyophilized (freeze-dried) mare colostrum, may offer better alternatives for ensuring foal health and immunity.

 

Research by Thatyane Carla de Lima and colleagues, in Brazil, compared the quality of equine colostrum after freezing and lyophilisation, evaluating IgG concentration (using Simple Radial Immunodiffusion, SRID, and Brix refractometry) and the physicochemical characteristics of equine colostrum post-freezing and lyophilization. A report of their work is published in the Journal of Equine Veterinary Science

 

Thirty-one pregnant Quarter Horse mares participated in the study. Colostrum collected from these mares was divided into two samples: one for freezing and one for lyophilization. 

 

The research team measured the IgG concentration of both frozen and lyophilized colostrum by SRID, (the reference standard test), and Brix refractometry (a technique widely used for estimating colostrum quality in cattle.)   

 

Additionally, they evaluated properties such as pH, total protein (TP), fat, lactose, salts, total solids (TS), and density. They also tested the effect of reconstitution on the lyophilized colostrum.

 

They found no significant differences (P > 0.05) in IgG, fat, lactose, salts, TS, density, and pH between colostrum samples before and after lyophilization. Lyophilization resulted in a minor reduction (6.55%) in IgG concentration as measured by SRID.

 

 However, they did find a significant difference in the average Brix score and total protein, indicating that lyophilization alters some colostrum characteristics.

 

The results suggest lyophilization as a viable method for mare colostrum conservation, to ensure foals receive the essential nutrients and antibodies for a healthy start. It offers practical benefits, including long-term storage without refrigeration and easy transportation.

 

The authors suggest that further research, such as in vivo studies to evaluate the product's acceptance and the absorption of immunoglobulins, is recommended. 

 

For more details, see:

de Lima TC, de Sobral GG, de França Queiroz AES, et al.

Characterization of lyophilized equine colostrum. 

J Equine Vet Sci. 2024;132:104975. 

https://doi.org/10.1016/j.jevs.2023.104975

Study: Curly Horses promote immune tolerance in allergic individuals

(c) Dawny16161 Dreamstime.com

 American Bashkir Curly Horses are claimed to be hypoallergenic, but this has not been clinically proven. 

The origin of these horses remains uncertain, with their additional name "Bashkir" stemming from the misconception that they were originally imported from Russia to America. Some theories suggest a Spanish immigrant origin in South America.

Established in 2010, Curly Farm Klappholz combines Dr. Wolfgang Mitlehner's medical practice specialising in internal medicine, allergology, pulmonary, and bronchial medicine with a holiday home and riding school featuring Curly horses. This facility provides a safe environment for allergic riders to interact with and ride Curly Horses.

 

Dr. Mitlehner has conducted studies on allergic patients who have ridden Curly horses to investigate their allergic responses to these animals.The work culminated in a report published in the journal Pneumologie

 

This collaborative study involved Susanne Mitlehner from Curly Farm Klappholz, Dr. Wolfgang Mitlehner, Alexandra Mitlehner, Hans Caspar Mitlehner, Peter Stoll, and Ines Swoboda from the University of Applied Sciences in Vienna, along with Monika Reissmann from Humboldt-University of Berlin.

 

The team examined the impact of exposure to Curly Horses on 141 patients allergic to horses by assessing their lung function and nasal patency during interactions with the animals. They discovered that repeated engagement with Curly Horses, including activities such as riding and grooming, resulted in a reduction in allergic riders' reactivity. This improvement was evidenced by enhancements in FEV1, PEF, and PNIF measurements.

 

PNIF, FEV1, and PEF are standard measures used to evaluate nasal obstruction, allergic rhinitis, and lung function, particularly in conditions like asthma.

 

Repeated interactions with Curly Horses, including riding and grooming, resulted in decreased reactivity among allergic riders, as evidenced by improvements in FEV1, PEF, and PNIF measurements.

 

Further visits, involving extended periods of riding totalling up to 40 hours or more, continued to reduce reactivity to Curly Horses. It's noteworthy that allergic reactions to horses occurred in only 72 out of 1312 riding hours, with the majority occurring within the initial ten hours of riding.

 

In a subset of 41 out of the 141 patients, additional investigation explored whether repeated exposure to Curly Horses could induce tolerance to other horses. These patients participated in a tolerance induction study and underwent annual testing for horse allergy using a nasal provocation test. The results revealed that exposure to Curly Horses led to immune tolerance to other horses in 88% of patients who completed the study.

 

Dr Mitlehner elaborates “To understand the mechanism causing hypoallergenicity, we performed IgE immunoblots to determine whether Curly Horse hairs contain IgE binding proteins.” 

 

IgE immunoblots play a significant role in allergy diagnostics. By examining the pattern of IgE antibodies adhering to various allergens on the membrane, clinicians can identify the specific allergens to which a patient is sensitized. This information is vital for diagnosing allergies and formulating suitable treatment plans, such as allergen-specific immunotherapy (allergy shots) or recommendations for allergen avoidance.

 

The study revealed no differences in IgE reactivity between Curly and non-Curly Horses. Additionally, patients participating in the immune tolerance induction study did not exhibit reduced IgE reactivity to hairs from Curly or non-Curly Horses, despite having developed tolerance.

 

“However, we did find increasing levels of anti-horse IgG antibodies in the study patients.” Dr Mitleehner added.

 

“Overall, our data strongly suggests that continuous exposure to Curly Horses can induce immune tolerance, rendering these patients non-reactive to horses. The reason for the reduced clinical allergenicity of Curly Horses remains unclear, but the data suggest that blocking IgG antibodies may be of importance for immune tolerance development.”

 

For more details, see:

 

Horse allergy: Curly Horses can mediate immune tolerance

Alexandra Mitlehner, Caspar Mitlehner, Monika Reißmann, Peter Stoll, Ines Swoboda, Wolfgang Mitlehner

Pneumologie (2024); 78(01): 47-57
https://doi.org/10.1055/a-2101-9533

 

https://www.curlyfarm.de

 

Research funding announced

The Morris Animal Foundation has announced funding for new equine studies including:

Understanding the Early Stages of Equine Herpesvirus Infections Researchers will study EHV-1 to better understand how the disease develops and spreads. New information from this study will help inform the development of better diagnostics and treatments as well as improve EHV-1 control measures.

Exploring a New Vaccine Strategy for Strangles

Researchers will investigate the safety and effectiveness of a novel vaccine to protect horses against strangles, a serious infection caused by bacteria called Streptococcus equi. A safer and more effective vaccine strategy against strangles will greatly improve the prevention of this global equine health challenge.

Learning More About How the Immune System Works

Researchers will gather baseline data on equine monocytes, a type of white blood cell important for fighting off infections and reducing inflammation. Data collected is anticipated to provide real-time insight into the processes occurring within critically ill horses.

"Each of these studies has the potential to improve the lives of horses in significant ways, and we are very proud to support these innovative researchers in their efforts," said Dr. Janet Patterson-Kane, Morris Animal Foundation Chief Scientific Officer.

The Morris Animal Foundation is one of the world's largest non-profit organizations that funds scientific studies to advance the health of animals. Since 1959, it has invested over $20 million in more than 550 equine health studies.

Blood test for small redworms

A new blood test for small redworms (cyathostomins) is due to be launched in the United Kingdom.

There is a welcome emphasis now on only deworming horses when they need it. This has become necessary because of the spread of anthelmintic-resistant parasites and the need to reduce the use of anthelmintics. 

Small redworms (cyathostomins)are the main culprits. Faecal worm egg counts can detect the presence of adult worms in the intestinal tract. But until now there has been no way of knowing whether a horse is carrying inhibited larvae in the gut wall. Consequently, routine treatment for larval stages during the winter has become the recommended tactic. However, this approach results in some horses being treated unnecessarily, risking stimulating anthelmintic resistance.

Scientists at the Moredun Research Institute in Scotland, led by Professor Jacqui Matthews, have been developing a blood test for larval cyathostomins. That work, largely funded by The Horse Trust, is now coming to fruition with a commercial version of the test due to be launched next month (September 2019) by Austin Davis Biologics (ADB).

The new test can detect all stages of small redworm infections, including, crucially, the encysted larval stage.

Dr Corrine Austin, of ADB said “We are thrilled to be making this test available to horse owners after extensive research has been conducted to achieve high accuracy.” 

Prof Matthews said: “It is great to see the commercialisation of this much-needed test to support sustainable worm control in horses.”

“The test fills an important gap in our diagnostic toolbox and will enable horse owners to work with their veterinarians in targeting anthelmintic treatments against cyathostomin infections and, hence, help protect these important medicines for the future.”

For more details, see:

https://www.austindavis.co.uk/