Did you know that through our work with WALTHAM, we have been involved in laminitis research since the late 1990’s? In fact, Dr Pat Harris, Director of Science here at SPILLERS and head of the WALTHAM Equine Studies Group co-founded the WALTHAM International Laminitis Consortium, which brings together world-leading veterinary, nutrition and research experts. With laminitis high on the list of concerns for so many horse owners, we wanted to share some the recent findings with you, this time focusing on our search to find ways that can help to predict which horses and ponies may be a greater risk…

2007

  • Results of our first UK based study which looked potential ‘screening tests’ (such as feeding small amounts of fructan, the storage form of sugar in plants) that could help to identify horses and ponies at greater risk of developing laminitis were published.
  • Another paper revealed a link between breed, insulin resistance and the risk of laminitis.

 

2009

  • The ‘cresty neck scoring’ (CNS) system, which is now used globally, was published providing a more objective method of assessing fat in this area independently of body condition score.
  • Research found that being obese, having a high CNS or neck circumference: height ratio and a high level of insulin in the blood (hyperinsulinemia) may put some individual’s a greater risk of developing pasture associated laminitis.

 

2010

  • The first of many studies which looked at ways of safely managing weight loss in obese ponies was published. This and future studies aimed to help reduce the risk of laminitis and other health concerns associated with obesity.

 

 

2011

  • On average, soaking hay for 16 hours in cold water (8°C) was found to reduce water soluble carbohydrate content (WSC - sugar + fructan) by nearly a third. However even after soaking, the level of WSC 7 out of the 9 hays was still higher than currently recommended for laminitics.

2012

  • Research suggests that measuring an individual’s response to feeding a meal high in glucose might help to identify those at greater risk of laminitis.

 

2014

  • On average, soaking hay for 16 hours in tepid water (16°C) was found to reduce WSC content by 49%.
  • Hay soaked for 9 hours was found to contain significantly more bacteria compared to dry hay and as a result, we currently recommend soaking for no more than 3-6 hours in hot weather. However the potential consequences of this rise in bacteria are still not understood and something we are currently investigating – watch this space!
  • Fourteen days of low intensity exercise in previously laminitic ponies was found to significantly reduce certain inflammatory blood markers to a levels similar to those in non-laminitic ponies. As with people, the benefits of exercise may be far wider than simply burning calories!

 

2016

  • Excess weight gain as a result of feeding cereals reduced tissue insulin sensitivity whereas weight gain as result of feeding fat/ oil did not. This research suggests that the source of excess calories rather than obesity per se may have greater bearing on insulin sensitivity. Reduced insulin sensitivity is a component of insulin dysregulation which is a known risk factor for laminitis.

 

2017

  • A change in grazing, a move to ‘good quality’ grazing and being a pony of cold blooded breed were all found to be significant risk factors for laminitis in a group of Danish horses and ponies, regardless of the season.
  • Research reveals that high levels of insulin and low levels of adiponectin (a hormone secreted by fat cells that helps to regulate fat and glucose metabolism) in the blood could predict the risk of laminitis for months or even years after it first occurred. This 3 year study was the first to try identify risk factors in ponies that had not previously had laminitis. We are now working on a follow up study to see if we can improve our ability to predict those at risk by monitoring a group of ponies every 6 months.
  • Research shows that the current threshold levels used for interpreting the results of the combined glucose/ insulin tolerance test which is often recommended for diagnosing insulin dysregulation, needs to be adjusted for ponies. This supports our other research that also suggests that ponies need to have different testing protocols (compared to horses) for other important diagnostic tests such as the Oral Sugar Test.

 

Why is research important?

Development of laminitis is complex and likely to involve multiple systems within the body. Whilst several potential causes have been identified, the exact mechanisms involved and how they relate to each other is still not fully understood. We are far from having all of the answers but by continuing to invest in scientific research, we hope  to gather as many pieces of the puzzle as possible and in turn, help  nutritionists, vets and researchers throughout the world learn how best to treat and ultimately prevent laminitis in the future.

 

For advice on managing horses and ponies prone to laminitis contact the SPILLERS Care-Line.

 

References

Bamford, N. J., Potter, S. J., Baskerville, C. L., Harris, P. A., & Bailey, S. R. (2016). Effect of increased adiposity on insulin sensitivity and adipokine concentrations in different equine breeds adapted to cereal-rich or fat-rich meals. The Veterinary Journal, 214, 14-20.

 

Carter  RA    Treiber KH, Geor RJ ,  Douglass L, and HARRIS P (2009) Prediction of incipient pasture-associated laminitis from hyperinsulinemia, hyperleptinemia, and generalized and localized obesity in a cohort of ponies –  Equine Vet Journal  41 (2) 171-178

 

Longland AC, Barfoot C & Harris PA (2011) Effects of  soaking on the water-soluble carbohydrate and crude protein content of hay  Vet Rec June 11 (168) p 618

 

Longland A, Barfoot C, & HARRIS P, (2014) Effect of water temperature and agitation on loss of water –soluble carbohydrates and protein from grass hay: implications for equine feeding management. Veterinary Record 174 68.

 

Luthersson N, Mannfalk M, Parkin T. D. H. & Harris P (2017).  Laminitis: Risk factors and outcome in a group of Danish horses Journal of Equine Veterinary Science 53 June 68 -73

 

Morrison P.K., Dugdale A.H.A, Grove-white DH, Harris P.A., Barfoot C.F & Mcg Argo C (2017) Repeatability of the combined Glucose/insulin test in ponies of the same breed and gender, across time Journal of Equine Veterinary Science, 52, p57.

 

Menzies-Gow NJ, Wray H, Bailey SR, HARRIS P, Elliott J (2014). The effect of exercise on plasma concentrations of inflammatory markers in normal and previously laminitic ponies Equine Vet J. 46 317-321

 

Menzies-Gow N.J, Harris P.A., Potter K. and Elliott J. (2017) Prospective cohort study evaluating risk factors for the development of pasture-associated laminitis in the UK EVJ (49). 300 – 306

 

Moore-Colyer MJS, Lumbis K, Longland A, Harris P (2014) The Effect of Five Different Wetting Treatments on the Nutrient Content and Microbial Concentration in Hay for Horses. PLoS ONE 9(11): e114079. doi:10.1371/journal.pone.

 

Tinworth KD Edwards S, HARRIS PA, Sillence MN,  Hackett P & Noble GK (2010) Pharmacokinetics of metformin after enteral administration in insulin-resistant ponies. Am J vet Res 71 1201-1206

 

Tinworth, KD, Boston, RC, Harris PA, Sillence, MN, Raidal, SL and Noble, GK (2012) The effect of oral metformin on insulin sensitivity in insulin-resistant ponies. The Veterinary Journal, 191, 79-84.

 

Treiber KH, Hess TM Kronfeld DS Boston RC Geor RJ & HARRIS P (2007) Insulin resistance and compensation in laminitis-predisposed ponies characterised by the minimal model Pferdeheilkunde 23 237 –240