Thursday, October 26, 2023

Benefit of lighting in trailers?

(c) Oleksii Yaremenko
 Loading horses into trailers can be challenging and potentially dangerous, especially with young horses. Could lighting in the trailer help make the process less stressful?

Claire Neveux and others investigated how lighting inside a trailer can affect the horse's experience, especially during loading and when the trailer is stationary. They found that having consistent and bright LED lighting inside the trailer can make a difference.

In their study, they used a specially designed trailer with adjustable LED lights. They tested this setup with twenty young trotter horses who were relatively new to travelling and loading. They had them load into the trailer multiple times, (“Loading Phase”). After loading, the horses remained in the stationary trailer for two minutes with the experimenter. (“Stationary phase”).


The research team used varying lighting conditions in the trailer, which included different levels of brightness and temperature, such as warm white light (3000K), neutral white light (4500K), and cold white light (6300K) generated by LED lighting. To evaluate how these distinct lighting conditions influenced the horses' reactions, the research team closely monitored the horses' behaviour and documented their heart rates.


Among their findings were that horses expressed fewer stress-related behaviours and loaded faster when there was a high light level inside the trailer.


In addition, heart rate recovered more quickly when horses were loaded and kept under artificial white light LED lighting in a stationary trailer.


However, they stress that many factors, including the horse’s environment, its personality and past experience affect the horses’ response to loading in a trailer. 


A full report of the work is published in Applied Animal Behaviour Science.



For more details, see: 


Effects of different LED lighting conditions on young horses during trailer loading and stationary confinement

Claire Neveux, Marion Ferard, Emmanuel Melac, Nicolas Pousset

Applied Animal Behaviour Science (2023) Vol 261, 105885

Sunday, October 22, 2023

Careful use of anthelminitcs can help limit resistance

 Recent research suggests that employing selective treatment regimens can significantly reduce the
development of anthelmintic resistance. This is particularly relevant in the context of parasites such as the cyathostomins (small redworms), which are among the most common internal parasites of horses. These parasites have developed resistance to various deworming drugs over the years due to their widespread and indiscriminate use.

In Sweden, a country known for its controlled approach to anthelmintic use, a study was conducted to investigate the presence of resistance to ivermectin, a commonly used deworming medication. The research found no evidence of resistance to ivermectin in cyathostomes in Sweden.


ML resistance has been observed in cyathostomins worldwide. However, the current situation in Sweden is unclear. Routine anthelmintic treatment of horses without prior diagnostic tests is rare in Sweden, since anthelmintic drugs were restricted to being available on prescription only in 2007. What effect would this have had on the development of ML resistance in the country?


To assess the effectiveness of deworming treatments, two common tests are used: the faecal egg count reduction test (FECRT) and the egg reappearance period (ERP) after treatment. FECRT evaluates whether a dewormer successfully reduces the number of internal parasite eggs in the horse's faeces. Samples are taken before treatment and around 10 to 14 days after deworming, and the two egg counts are compared. A high reduction percentage indicates that the dewormer is effective, while a low reduction percentage suggests potential resistance.


As internal parasites develop resistance to dewormers, the egg reappearance period (ERP) shortens, meaning that eggs reappear in the faeces more quickly after treatment.


A study led by Ylva Hedberg Alm and her colleagues aimed to assess FECRTs and ERPs following ivermectin (IVM) treatment in Swedish horses. Sixteen equestrian establishments, each with at least six horses excreting a minimum of 150 eggs per gram of faeces (EPG) during screening, were included in the study. FECRTs and ERPs were evaluated in faecal samples before and after IVM treatment (200 µg/kg) and for eight weeks afterward.


The questionnaire responses revealed that 69% of establishments administered anthelmintic treatments based on faecal diagnostics. All establishments achieved a high FECRT, exceeding 99.0%, and ERPs ranged from six to over eight weeks. Notably, younger horses were found to excrete cyathostomin eggs earlier after treatment than older horses.


The researchers also observed that riding schools, stud farms, and those not segregating summer and winter paddocks had shorter egg reappearance periods.


In conclusion, this study in Swedish equestrian facilities employing selective anthelmintic treatment revealed that the establishments maintained longer ERPs and showed no confirmed resistance to ivermectin. These findings support the use of selective deworming strategies as a means of reducing the risk of anthelmintic resistance in horses. The full report is available in Veterinary Parasitology.


For more details, see:


Retained efficacy of ivermectin against cyathostomins in Swedish horse establishments practicing selective anthelmintic treatment

Ylva Hedberg Alm, Eva Osterman Lind, Frida Martin, Rebecca Lindfors, Nina Roepstorff, Ulf Hedenström, Isabelle Fredriksson, Peter Halvarsson, Eva Tydén

Veterinary Parasitology (2023) Vol 322, 110007

Friday, October 20, 2023

Survey on Behavioural Challenges in Horses

(c) Kseniya Abramova
 Is your horse facing behavioural issues? How do you handle these challenges? Whether you're
a horse owner, rider, or work closely with horses, Dr. Orla Doherty would welcome your valuable input.

Dr. Doherty is conducting a research survey to gather insights on how problem behaviours in horses impact riders, handlers, and individuals involved in equine care, as well as the strategies employed to address these issues. Any additional perspectives or knowledge you can provide on this subject will be greatly appreciated. 

A veterinary surgeon, Dr. Doherty graduated from University College Dublin in 1992 and earned a Master's Degree in Animal Behaviour and Welfare from Edinburgh University in 1993. Her commitment to animal welfare led to the establishment of the Animal Behaviour Clinic in Ireland in 1994, where she has been actively addressing behaviour-related concerns in animals across the nation.


The survey results will be made publicly available. 


To take part, go to:

Thursday, October 19, 2023

Grants available for behavioural research

 Morris Animal Foundation has announced a fresh call for research proposals with the goal of enhancing the well-being of horses by advancing our understanding of behavioural health and welfare. The Foundation is particularly keen on projects related to cognition, learning, stereotypies, separation anxiety, horses' affiliative behaviour towards humans, the impact of equine temperament on their welfare, and equine psychopharmacology. Please note that proposals solely focused on behavioural measurements for non-behavioural conditions will not be considered. 

This initiative has been made possible thanks to a generous donation from Dr. Wendy Koch, a veterinarian who has been a steadfast supporter of the Foundation for over three decades. Dr. Koch embarked on her career in animal welfare with the federal government back in 1990 and achieved board certification in animal welfare in 2016. Her deep interest in equine behaviour and welfare research prompted her to champion funding in these important areas.


Researchers interested in this opportunity should submit their proposals by 4:59 p.m. ET on December 13, 2023. 


For details on how to apply, see the Foundation's Grants page at:

Monday, October 16, 2023

Breed differences in ACTH concentrations

 Plasma adrenocorticotropic hormone (ACTH) concentration is commonly measured to diagnose pituitary pars intermedia dysfunction (PPID), also known as equine Cushing’s disease. Several intrinsic and extrinsic factors affect ACTH concentrations, including breed. 

Researchers at the University of Melbourne and the University of Queensland, in Australia, conducted a study to prospectively compare plasma ACTH concentrations among different breeds of mature horses and ponies. 

Dr Nicholas Bamford and colleagues aimed to shed light on how plasma adrenocorticotropic hormone concentrations, a crucial indicator for diagnosing pituitary pars intermedia dysfunction in horses, varied across different horse breeds. 


The breed groups under scrutiny were Thoroughbred horses, Shetland ponies, and ponies of non-Shetland breeds. 


The health of the animals involved was carefully monitored to ensure they showed no signs of illness, lameness, or clinical signs associated with PPID.


Blood samples were collected twice a year, around the autumn and spring equinoxes, to capture any seasonal variations. The ACTH levels were measured using a chemiluminescent immunoassay, a common diagnostic tool. 


The results revealed that pony breeds, particularly Shetland ponies, exhibited notably higher ACTH concentrations compared to Thoroughbred horses during the autumn season. 

In spring, no differences were identified among the three breed groups.


This observation is significant, especially when diagnosing PPID and interpreting ACTH levels accurately.


The findings emphasise the importance of considering the specific breed of a horse when interpreting ACTH levels, especially during the autumn months. 


Understanding breed-related differences in ACTH concentrations is essential for a more precise assessment of a horse's health and can guide appropriate healthcare and management decisions.


For more details, see:


Investigation of breed differences in plasma adrenocorticotropic hormone concentrations among healthy horses and ponies

N.J. Bamford, A.J. Stewart, C.M. El-Hage, F.R. Bertin, S.R. Bailey 

The Veterinary Journal (2023) Vol 296–297, 105995

Saturday, October 14, 2023

Discounted Rate for Horses Inside Out Conference 2024

We are excited to announce a special discounted rate for Equine Science Update readers for next year’s Horses Inside Out conference, made possible through a generous offer from Gillian Higgins and the Horses Inside Out team.

You can get 10% off (25% if you purchase before 31st October) with the code: ESU10%


The 2024 Horses Inside Out conference, to be held in Loughborough on 17th & 18th February, will revolve around the theme of "Growth and Development", giving insights into horses' life stages, from birth to old age.


The conference promises an enriching experience suitable for all. Over the course of two days, attendees will have access to a packed programme of inspiring and educational lectures sharing the latest advancements in equine science.


In depth details, reviews and further information can be found here:

When booking, remember to input the code (ESU10%) to take advantage of the discounted rate.