Increasing awareness of the association between insulin and iron in equine metabolic syndrome

The relationship between iron and insulin sensitivity has long been recognized and studied in humans and other animals, but largely ignored in the equine population. With the knowledge that elevated circulating insulin is the direct and most common cause of laminitis associated with equine metabolic disorders, the association between equine insulin and iron dysregulation needs further investigation.

Drs. Eleanor Kellon and Kathleen Gustafson of the Equine Cushing’s and Insulin Resistance Group (ECIR) performed a retrospective analysis of lab results maintained in the group’s database and data from the only controlled feeding study in horses. The latter study was specifically designed to substitute horses as a model for captive black rhinos, a cousin of the horse, because the researchers recognized the relationship between metabolic disease and iron overload in rhinos (Nielsen et al., 2012).

All animals from the ECIR database had abnormally elevated insulin. Ferritin, a measure of body iron stores, exceeded the published reference range in all animals and there was a tendency for ferritin to increase with age. Likewise, data from the previously published report showed that ferritin was significantly elevated in the group with confirmed hyperinsulinemia when compared to the group with a normal insulin response.

Kellon and Gustafson suggest that these results indicate possible similar interactions between hyperinsulinemia and body iron burden in the horse and that iron may be a modifiable risk factor for hyperinsulinemia. They emphasize that iron is unlikely to be a primary causal factor but that the interaction is worth scientific investigation in controlled studies.

“Studies investigating the bidirectional relationship between iron and hyperinsulinemia in horses are extraordinarily limited, despite considerable scientific inquiry in other species. Our goal is to increase awareness of the potential for iron overload in horses with hyperinsulinemia and stimulate further study.”

For more details. See:

Possible Dysmetabolic Hyperferritinemia in Hyperinsulinemic Horses
Eleanor M. Kellon and Kathleen M. Gustafson
Open Veterinary Journal, (2019), Vol. 9(4): 287–293

https://www.openveterinaryjournal.com/OVJ-2019-04-078%20E.M.%20Kellon%20and%20K.M.%20Gustafson.pdf

Nielsen, B.D., Vick, M.M. and Dennis, P.M. 2012. A Potential Link between Insulin Resistance and Iron Overload Disorder in Browsing Rhinoceroses Investigated through the Use of an Equine Model. J. Zoo Wildl. Med. 43, S61–S65.
  
https://doi.org/10.1638/2011-0145.1

For more about the Equine Cushing’s and Insulin Resistance Group go to https://www.ecirhorse.org/

Planning NEF 2020

Research-led presentations will feature strongly in the 2020 National Equine Forum (NEF) following the response to this year’s event.

Feedback from delegates, together with social media activity, live stream and podcast views have been used to identify what the equestrian industry particularly like.

To date Dr Rachel Murray’s 2019 presentation on what cardiovascular fitness, core stability and muscle development of the horse has received more than 6,000 views on the NEF YouTube channel. Ashleigh Wallace’s talk on rider asymmetry and its impact on the horse, and Dr Andrew Hemmings’ observations on Equine Stereotypic Behaviour also proved to be highly popular.

“Given the enthusiastic response we have had to these presentations the key focus of our 2020 programme will be on research-led aspects of equine health and welfare,” said programme convener Georgina Crossman. “High profile vets, scientists and industry experts will be sharing their knowledge and views on disease, welfare, human behaviour and global welfare issues.”

NEF, held in March each year, is an important annual event uniting diverse elements of the equestrian industry for friendly, non-partisan debate. The aim is to inform, educate and help the industry to speak with the strength of one voice on topical matters affecting the current and future management and wellbeing of the horse. It is organised by a committee of volunteers representing various sectors of the equestrian industry and has as its President HRH The Princess Royal.

Details of the NEF 2020 programme will be announced towards the end of the year and a limited number of Early Bird tickets will be available from December. 

For further information on the NEF and to view past presentations visit 

https://www.nationalequineforum.com.

Whip Use in Equestrian Sports

The use of the whip in equestrian sports has come under increased scrutiny and public criticism. Research, so far, has centred on the racing industry and has failed to identify improved performance when the whip is used.

Studies reported at the 15^th Annual International Equitation Science Conference looked at the use of the whip in other disciplines.

Jane Williams presented the results of a study that looked at how horse-riders use whips. Over 3,000 riders took part in a survey, which revealed that 72% of respondents regularly rode with a whip when doing roadwork, hacking, schooling and or lessons. 

Nearly 70% of survey participants agreed that whips should only be used by experienced riders. Additionally, the great majority wanted to see tighter restrictions on whip usage in competitions, including during warmup. 

Those surveyed were asked to share how they use whips.  Most responded that they are used to reinforce aids, for training, and should be used lightly and never continuously out of aggression or frustration.

Dr Williams said  “It is encouraging to see most riders believed the whip should be used as a training aid, however when asked how and when to use it in this way, this was not always aligned to how horse’s learn, outlining a need for increased rider education.”

Another study, by Kirstin Spencer and colleagues, evaluated recordings of British Show jumping (BS) affiliated competitions between August 2018 and January 2019.  

This study included 285 horses and riders competing at heights between 0.8m and 1.25m.   Statistical analyses were conducted to determine if and how whip usage related to performance. 

The findings revealed that approximately 76% of riders carried a whip, and 14% of those riders actually used their whip in competition.  Additionally, this study found that increased whip usage correlated with decreased performance. Riders using the whip were found to accumulate more faults than those who did not.

Ms Spencer said “Observations found whips often being used with poor timing which may reflect rider education issues such as misunderstanding a horse’s cognitive ability and how it learns.  Potential issues were also recognised within BS regulations, for example, significant use took place whilst riders held their reins and BS technically excludes this type of use.  Initial findings raised further questions as to the efficacy of using a whip to enhance horse performance in BS competition.”

Further research into how whips are used across the industry and in competition will provide insight on how to best establish and change regulations in order to promote horse welfare and preserve equestrian sports.

For more details, see:

Understanding whip use in riders in sports horse disciplines

J. Williams, L. Greening, D. Marlin, H. Randle.

Proc 15^th ISES Conference, (2019) p43

Evaluation of whip use in British Showjumping

K. Spencer, R. Verwijs, J. Williams.

Proc 15^th ISES Conference, (2019) P44

You can download the Proceedings of the 15^th International Society for Equitation Science Conference at:

https://equitationscience.com/previous-conferences/2019-15th-international-conference